221 ACUS11 KWNS 240014 SWOMCD SPC MCD 240013 KYZ000-INZ000-ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-240145- MESOSCALE DISCUSSION 1490 NWS STORM PREDICTION CENTER NORMAN OK 0713 PM CDT TUE JUL 23 2013 AREAS AFFECTED...PORTIONS OF SRN MO...FAR SERN KS...A LARGE PART OF AR...SRN IL...SWRN INDIANA...WRN KY CONCERNING...SEVERE THUNDERSTORM WATCH 437... VALID 240013Z - 240145Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 437 CONTINUES. SUMMARY...THE SVR POTENTIAL CONTINUES ACROSS WW 437...AND ISOLATED SVR STORMS MAY OCCUR FARTHER E ACROSS THE OHIO RIVER VALLEY. DISCUSSION...CLUSTERS OF VIGOROUS CONVECTION CONTINUE NEAR AND S OF A FRONTAL ZONE EXTENDING FROM SRN KS INTO SRN MO AND SRN IL/INDIANA. WWD-MOVING OUTFLOW BOUNDARIES ARE EVIDENT ACROSS N-CNTRL AR AND S-CNTRL MO...WITH NEW CONVECTIVE DEVELOPMENT ON THE COOL SIDE OF THE BOUNDARIES. THESE BOUNDARIES MAY ALSO BOOST STORM INTENSITY AS THEY INTERACT WITH SFC-BASED CONVECTION SHIFTING SEWD/SWD OVER NWRN AR. THE MOST UNSTABLE AIR MASS IS CONFINED TO NWRN AR...SWRN MO...AND ADJACENT FAR SERN KS...WHERE CONVECTIVE OVERTURNING HAS BEEN THE LEAST WIDESPREAD THUS FAR AND THE HIGHEST CONDITIONAL SVR POTENTIAL WILL EXIST. OTHERWISE...AT LEAST SOME SVR POTENTIAL WILL REMAIN INTO THE EVENING WITH SVR HAIL/DMGG WIND POSSIBLE WITH MODEST MID-LEVEL FLOW LIKELY FOSTERING MULTICELLULAR CONVECTION. ADDITIONAL CONVECTION DEVELOPING E OF WW 437 NEAR A SYNOPTIC BOUNDARY FROM SERN MO INTO FAR SWRN INDIANA MAY POSE AN ISOLATED SVR THREAT INTO THE EVENING. HOWEVER...THE SPATIOTEMPORAL EXTENT OF ANY SVR POTENTIAL SHOULD BE TOO LIMITED FOR WW ISSUANCE E OF WW 437 AS NOCTURNAL STABILIZATION OCCURS AMIDST FORCING FOR ASCENT. ..COHEN.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PAH...MEG...LSX...LZK...SGF...SHV...TSA... LAT...LON 36649436 37199496 37799480 37829358 37819216 37859001 38268819 37768729 36948819 36569050 36239117 35229140 33809205 33429283 34589420 36649436  793 ACUS11 KWNS 240045 SWOMCD SPC MCD 240044 OKZ000-KSZ000-240145- MESOSCALE DISCUSSION 1491 NWS STORM PREDICTION CENTER NORMAN OK 0744 PM CDT TUE JUL 23 2013 AREAS AFFECTED...SRN KS/NRN OK CONCERNING...SEVERE THUNDERSTORM WATCH 438... VALID 240044Z - 240145Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 438 CONTINUES. SUMMARY...VERY LARGE HAIL AND DAMAGING WINDS ARE EXPECTED WITH CONVECTION AS IT SPREADS FROM NORTH TO SOUTH ACROSS KS INTO OK. DISCUSSION...TWO MAIN CLUSTERS OF SEVERE THUNDERSTORMS HAVE EVOLVED ACROSS KS THIS EVENING. THE NRN MOST CLUSTER INITIATED NORTH OF A WELL DEFINED SFC BOUNDARY WITHIN WEAK WARM ADVECTION BUT HAS NOW EXPANDED IN AREAL COVERAGE AND LEADING EDGE IS ACCELERATING SWD AT ROUGHLY 30KT NEAR HUT. CONSIDERABLE AMOUNT OF CONVECTION HAS BECOME ORIENTED N-S FROM NW OF SLN...SWD TO NEAR HUT WHICH MAY ULTIMATELY ENHANCE SWD MOVEMENT AS PRECIP SHIELD BEGINS TO EXPAND AND POSSIBLY FORM A COLD POOL. A MUCH SLOWER AND MORE ISOLATED STORM HAS DEVELOPED JUST SE OF DDC WHERE INTENSE SFC HEATING COINCIDED WITH ENHANCED LOW LEVEL CONVERGENCE NEAR SFC LOW. THIS STORM IS GRADUALLY EXPANDING AND IS EXPECTED TO PROPAGATE SWD INTO NWRN OK IN THE NEXT FEW HOURS. VERY LARGE HAIL AND DAMAGING OUTFLOW MAY ACCOMPANY EACH OF THESE CLUSTERS. ..DARROW.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SGF...TSA...ICT...OUN...GID...DDC... LAT...LON 39429953 37419474 34669474 36679954 39429953  789 ACUS11 KWNS 240051 SWOMCD SPC MCD 240050 NMZ000-AZZ000-240215- MESOSCALE DISCUSSION 1492 NWS STORM PREDICTION CENTER NORMAN OK 0750 PM CDT TUE JUL 23 2013 AREAS AFFECTED...CNTRL/SERN AZ...FAR SWRN NM CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 240050Z - 240215Z PROBABILITY OF WATCH ISSUANCE...5 PERCENT SUMMARY...A FEW STORMS COULD PRODUCE LOCALIZED SVR WIND GUSTS INTO THIS EVENING...THOUGH THE ISSUANCE OF A WW IS NOT ANTICIPATED. DISCUSSION...ISOLATED TO SCATTERED CONVECTION THAT DEVELOPED OVER THE HIGHER TERRAIN AND AIDED BY OROGRAPHIC ASCENT SHOULD PERSIST DURING THE NEXT FEW HOURS. WEAK MID-LEVEL FLOW PER THE 00Z TUS RAOB AND AREA VWP DATA SUGGEST THAT CONVECTION WILL LARGELY LACK ANY APPRECIABLE ORGANIZATION AND MAY STRUGGLE TO MOVE OFF THE HIGHER TERRAIN TOWARD THE LOWER ELEVATIONS/DESERT FLOOR. ONE EXCEPTION MAY BE ACROSS PARTS OF SERN AZ...WHERE SOMEWHAT GREATER CONVECTIVE COVERAGE WITHIN A PLUME OF ENHANCED MID-LEVEL MOISTURE/UPDRAFT-SHELTERING HAS ENCOURAGED MORE ROBUST COLD POOL GROWTH AND ENSUING LEADING-EDGE CONVECTIVE REGENERATION. DCAPE VALUES IN EXCESS OF 800 J/KG ASSOCIATED WITH STEEP LOW-LEVEL LAPSE RATES WILL SUPPORT INTENSE DOWNDRAFTS...WITH A FEW SVR WIND GUSTS POSSIBLE ON A LOCALIZED BASIS. NOCTURNAL COOLING/STABILIZATION WILL YIELD A DOWNWARD TREND IN CONVECTIVE INTENSITY AFTER SUNSET. ..COHEN/HART.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...EPZ...TWC...FGZ...PSR... LAT...LON 31231043 32011067 33481142 34101214 34531208 34431111 33370981 32530886 31850814 31310827 31231043  586 ACUS01 KWNS 240101 SWODY1 SPC AC 240059 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0759 PM CDT TUE JUL 23 2013 VALID 240100Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF CENTRAL/SRN KS...MUCH OF OK...SRN MO...WRN AND NWRN AR AND FAR SWRN IL... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A PORTION OF THE CENTRAL HIGH PLAINS... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SWRN GA...NWRN FL AND THE ERN FL PANHANDLE... ...KS/OK/SWRN MO/NWRN-WRN AR... LATE AFTERNOON/EARLY EVENING SURFACE ANALYSES SHOWED A BOUNDARY EXTENDING FROM SRN MO WWD INTO FAR NERN OK AND THEN WNWWD THROUGH SOUTH CENTRAL KS /BETWEEN KICT AND KP28/ TO AN AREA OF LOW PRESSURE IN SWRN KS. OBJECTIVE ANALYSES AND 00Z SOUNDINGS OVER THIS SLIGHT RISK AREA INDICATED THE ENVIRONMENT REMAINS VERY STRONGLY TO EXTREMELY UNSTABLE WITH MLCAPE RANGING FROM 3000-4000 J/KG. VERTICALLY VEERING WIND PROFILES ALONG AND SOUTH OF THE SURFACE BOUNDARY AS SAMPLED BY THE 00Z OUN SOUNDING AND OBJECTIVE ANALYSES INDICATED EFFECTIVE BULK SHEAR OF 35-50 KT OVER KS/OK. A STRENGTHENING SLY LLJ FROM WRN TX INTO OK IS EXPECTED TO VEER OVERNIGHT. THESE FAVORABLE THERMODYNAMICS...PW NEAR 2 INCH AT 00Z OUN SOUNDING...AND SUFFICIENT BULK SHEAR SUGGEST THE ONGOING STORMS OVER CENTRAL/SRN KS HAVE THE POTENTIAL TO SPREAD SWD INTO THE REST OF SRN KS AND OK. DAMAGING WINDS...SOME SIGNIFICANT...AND LARGE HAIL...SOME VERY LARGE...REMAIN A LIKELY THROUGH TONIGHT /WELL AFTER DARK/. ...PART OF SRN GA INTO NWRN FL AND THE ERN FL PANHANDLE... PRIOR TO THE BOUNDARY LAYER STABILIZING...ADDITIONAL DAMAGING WINDS WILL BE POSSIBLE AS THE LEADING EDGE OF AN MCS SPREADS E/SEWD THROUGH THIS REGION. ...PART OF WRN NEB INCLUDING THE PANHANDLE TO DAKOTAS... RESIDUAL MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR OF 40-50 KT SUGGEST AT LEAST THE LONE STORM OVER WEST CENTRAL NEB WILL PERSIST SSEWD THROUGH SWRN NEB AND MAY REACH NWRN KS. ...SRN NEW ENGLAND TO LONG ISLAND... OVERALL ISOLATED SVR WEATHER THREAT HAS DIMINISHED ACROSS THIS REGION AS STORMS HAVE EITHER MOVED OFFSHORE...AND/OR THE BOUNDARY LAYER IN ADVANCE OF ANY REMAINING STORMS WILL FURTHER STABILIZE LIMITING TSTM DEVELOPMENT/INTENSITY. ..PETERS.. 07/24/2013  095 ACUS11 KWNS 240111 SWOMCD SPC MCD 240111 NEZ000-SDZ000-COZ000-240215- MESOSCALE DISCUSSION 1493 NWS STORM PREDICTION CENTER NORMAN OK 0811 PM CDT TUE JUL 23 2013 AREAS AFFECTED...WRN NEB CONCERNING...SEVERE THUNDERSTORM WATCH 439... VALID 240111Z - 240215Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 439 CONTINUES. SUMMARY...PERKINS AND CHASE COUNTIES MAY NEED TO BE ADDED TO THE SEVERE THUNDERSTORM WATCH IF SUPERCELL MAINTAINS INTENSITY OVER THE NEXT HOUR. DISCUSSION...ONE PRIMARY SUPERCELL IS DIGGING SEWD ACROSS CNTRL PORTIONS OF WW439. THIS STORM IS MOVING AT ROUGHLY 35KT AND COULD EXIT KEITH COUNTY BY 0230Z. LARGE HAIL IS THE PRIMARY SEVERE THREAT AND PORTIONS OF SWRN NEB MAY NEED TO BE ADDED TO THE WATCH IF THIS STORM DOES NOT WEAKEN. ..DARROW.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LBF...UNR...BOU...CYS... LAT...LON 43040302 43050144 40910139 40890293 43040302  236 ACUS11 KWNS 240116 SWOMCD SPC MCD 240116 LAZ000-ARZ000-240245- MESOSCALE DISCUSSION 1494 NWS STORM PREDICTION CENTER NORMAN OK 0816 PM CDT TUE JUL 23 2013 AREAS AFFECTED...SRN AR...NRN LA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 240116Z - 240245Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...AN ISOLATED SVR THREAT WILL EXIST INTO THE EVENING HOURS...THOUGH THE ISSUANCE OF A WW IS UNLIKELY. DISCUSSION...A LARGE MASS OF CONVECTION HAS MATERIALIZED ACROSS SRN AR WITHIN AN ENVIRONMENT CHARACTERIZED BY RICH DEEP-LAYER MOISTURE AND LIMITED MLCINH...AS SAMPLED BY THE 00Z SHV RAOB. WITH A PW VALUE AROUND 1.9 INCHES AND AROUND 2000-2500 J/KG OF MLCAPE BASED ON THIS SOUNDING...ENHANCED CONVERGENCE OVER THE SRN FLANK OF THE COLD POOL CORRESPONDING TO THE CONVECTIVE MASS WILL FAVOR ITS FORWARD PROPAGATION INTO/ACROSS NRN LA FROM SRN AR DURING THE NEXT FEW HOURS. WATER LOADING WILL ENHANCE THE POTENTIAL FOR STRONG DOWNBURSTS WITH THE POSSIBILITY FOR DMGG WIND GUSTS. HOWEVER...WITH LOW-LEVEL LAPSE RATES BECOMING LESS STEEP IN ASSOCIATION WITH NOCTURNAL COOLING...THIS THREAT IS EXPECTED TO GRADUALLY DECREASE. ..COHEN/HART.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAN...LZK...SHV... LAT...LON 32129253 32169348 32459394 33069399 33499387 33709374 33749344 33609316 33389307 33299238 32989189 32249199 32129253  336 ACUS11 KWNS 240247 SWOMCD SPC MCD 240246 MOZ000-ARZ000-OKZ000-KSZ000-240345- MESOSCALE DISCUSSION 1495 NWS STORM PREDICTION CENTER NORMAN OK 0946 PM CDT TUE JUL 23 2013 AREAS AFFECTED...A LARGE PART OF AR...SRN MO...FAR SERN KS CONCERNING...SEVERE THUNDERSTORM WATCH 437... VALID 240246Z - 240345Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 437 CONTINUES. SUMMARY...A LARGE PART OF SVR TSTM WATCH 437 WILL BE ALLOWED TO EXPIRE ON SCHEDULE AT 03Z...THOUGH THE SVR THREAT COULD PERSIST ACROSS PARTS OF SWRN MO AND FAR SERN KS AFTER 03Z PERHAPS WARRANTING A LOCAL EXTENSION IN TIME. DISCUSSION...ACROSS MOST PORTIONS OF WW 437...WIDESPREAD CONVECTIVE OVERTURNING HAS LARGELY DIMINISHED THE SVR THREAT IN THE NEAR TERM AND THE WW MAY BE ALLOWED TO EXPIRE ON SCHEDULE AT 03Z. HOWEVER...A WWD-MOVING OUTFLOW BOUNDARY ACROSS SWRN MO AND FAR NWRN AR MAY CONTINUE TO BE THE FOCUS FOR NEW CONVECTIVE DEVELOPMENT DURING THE NEXT FEW HOURS. THE 00Z SGF RAOB SAMPLES AN ENVIRONMENT WITH STRONG BUOYANCY AND MODERATE MID-LEVEL FLOW WHICH COULD YIELD SOME SVR THREAT PERSISTING BEYOND 03Z IN SWRN MO...FAR SERN KS...AND FAR NWRN AR. ALSO...INTENSE CONVECTION UPSTREAM ACROSS KS MAY MOVE ACROSS PARTS OF THE REGION LATER TONIGHT...AND THIS ACTIVITY WILL BE MONITORED FOR ADDITIONAL WW ISSUANCE LATER TONIGHT. ..COHEN.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LZK...SGF...SHV...TSA... LAT...LON 37949470 37729255 36999159 34329178 33679262 33929394 34939436 36759453 37259503 37949470  193 ACUS11 KWNS 240247 SWOMCD SPC MCD 240247 OKZ000-KSZ000-240345- MESOSCALE DISCUSSION 1496 NWS STORM PREDICTION CENTER NORMAN OK 0947 PM CDT TUE JUL 23 2013 AREAS AFFECTED...SRN KS/NRN OK CONCERNING...SEVERE THUNDERSTORM WATCH 438... VALID 240247Z - 240345Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 438 CONTINUES. SUMMARY...MCS IS EXPECTED TO EXPAND AND SPREAD SEWD OVER THE NEXT FEW HOURS. DISCUSSION...CONSIDERABLE AMOUNT OF CONVECTION HAS EVOLVED ACROSS SRN KS THIS EVENING WITHIN ZONE OF WEAK WARM ADVECTION. EARLIER ACTIVITY THAT INITIATED NEAR THE SFC LOW WITHIN DEEPLY MIXED ENVIRONMENT OVER SWRN KS HAS WEAKENED WITH LOSS OF DAYTIME HEATING. AS A RESULT...IT APPEARS THE GREATEST CONCENTRATION OF STORMS WILL BE FOCUSED ALONG A NW-SE CORRIDOR FROM ROUGHLY ICT-TUL. AN UPWARD EVOLVING MCS WILL CONTINUE TO EXPAND IN AREAL COVERAGE ACROSS SCNTRL/SERN KS OVER THE NEXT FEW HOURS AND SPREAD INTO NRN/NERN OK. 00Z SOUNDING AT OUN EXHIBITED A VERY UNSTABLE PROFILE WITH MUCAPE IN EXCESS OF 5000 J/KG AND PW VALUES APPROACHING 2 INCHES. VERY DAMAGING WINDS MAY OCCUR WITH LEADING EDGE OF MATURING MCS...IN ADDITION TO LARGE HAIL. ..DARROW.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SGF...TSA...ICT...OUN...GID...DDC... LAT...LON 39439954 37409473 34659472 36699955 39439954  048 ACUS11 KWNS 240527 SWOMCD SPC MCD 240526 ARZ000-TXZ000-OKZ000-240630- MESOSCALE DISCUSSION 1497 NWS STORM PREDICTION CENTER NORMAN OK 1226 AM CDT WED JUL 24 2013 AREAS AFFECTED...ERN/CNTRL OK...NERN TX CONCERNING...SEVERE THUNDERSTORM WATCH 438... VALID 240526Z - 240630Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 438 CONTINUES. SUMMARY...NEW SEVERE TSTM WATCH WILL LIKELY BE ISSUED TO SUPERSEDE WW 438 WHICH IS SCHEDULED TO EXPIRE AT 06Z. DISCUSSION...BOWING MCS WHICH RECENTLY PASSED THROUGH THE TULSA METRO AREA HAS HAD A HISTORY OF MEASURED SEVERE WIND GUSTS ALONG THE APEX OF THE BOW /66 KT AT KTUL AND 60-70 MPH GUSTS MEASURED AT A FEW OK-MESONET SITES/. OUTFLOW FROM THE N/S-ORIENTED CLUSTER ALONG THE OK/AR BORDER APPEARS TO HAVE STALLED AND/OR DISSIPATED AROUND 1-2 COUNTIES W OF THE BORDER. CURRENT MOVEMENT OF THE BOW SUGGEST THE THRUST OF THE LINE MAY LARGELY REMAIN ON THE COOL SIDE OF THE BOUNDARY. NEVERTHELESS...WITH SURFACE TEMPERATURES HOLDING IN THE 80S TO THE W OF THE BOUNDARY...A 25 KT SWLY LLJ SAMPLED IN TLX VWP DATA...IT APPEARS PLAUSIBLE THAT ADDITIONAL ROBUST UPDRAFTS WILL FORM ALONG THE WRN FLANK OF THE LINE AND POTENTIALLY YIELD FURTHER COLD POOL DEVELOPMENT TO THE W. PRIMARY THREAT WILL REMAIN DAMAGING WINDS...BUT SEVERE HAIL AND A BRIEF QLCS TORNADO ARE POSSIBLE GIVEN THE MATURE NATURE OF THE MCS INTERACTING WITH THE OUTFLOW BOUNDARY. ..GRAMS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LZK...SHV...TSA...FWD...OUN... LAT...LON 36829678 36609728 35729716 34689682 33739612 33169543 33209464 33659435 34389442 35449497 36059515 36139577 36829678  657 ACUS02 KWNS 240550 SWODY2 SPC AC 240548 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1248 AM CDT WED JUL 24 2013 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER SRN MN...NRN IA...WRN WI AND SERN SD... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF WRN KS AND NWRN OK...FAR SWRN NEB AND ERN CO... ...SYNOPSIS... AN UPPER TROUGH WILL GRADUALLY DROP SWD ACROSS THE NRN PLAINS AND UPPER MS VALLEY...WITH AN EXTREME POSITIVE TILT AND NWLY FLOW ALOFT. DURING THE DAY...A COLD FRONT WILL STRETCH FROM SRN SD INTO SRN MN AND WRN WI AND WILL PROVIDE A FOCUS FOR A FEW SEVERE THUNDERSTORMS. TO THE S...A WEAK SHORTWAVE TROUGH IS FORECAST TO TRAVEL SEWD ACROSS KS...WITH LOW PRESSURE CENTERED OVER SERN CO OR SWRN KS. THIS LOW WILL ALSO PROVIDE A FOCUS FOR POTENTIALLY SEVERE THUNDERSTORMS...WHICH ARE LIKELY TO GROW UPSCALE INTO AN MCS DURING THE EVENING AND OVERNIGHT HOURS...SUPPORTED BY A BROAD SLY LOW LEVEL JET. ELSEWHERE...A WEAK SFC LOW ACROSS THE SERN STATES BENEATH AN UPPER LEVEL TROUGH WILL LIKELY RESULT IN A FEW CLUSTERS OF STORMS ACROSS SC AND SERN GA. ...WRN KS...NWRN OK...ERN CO AND SWRN NEB... EARLY CONVECTION MAY BE ONGOING ACROSS SWRN NEB...NWRN KS AND NERN CO IN PART DUE TO A STRONG SLY LOW LEVEL JET...AND SOME OF THIS ACTIVITY COULD CONTAIN HAIL. THE GREATER SEVERE THREAT WILL BE LATER IN THE DAY WHEN INSTABILITY IS MAXIMIZED ACROSS MUCH OF ERN CO AND WRN KS. BACKED SURFACE WINDS N AND E OF THE LOW WILL BE FAVORABLE FOR SUPERCELLS...AND PERHAPS A FEW TORNADOES IN ADDITION TO LARGE HAIL. A DAMAGING WIND THREAT IS EXPECTED TO INCREASE DURING THE EVENING AND OVERNIGHT AS THE LOW LEVEL JET INCREASES AND FEEDS WHAT IS LIKELY TO BE AN MCS. MODELS DIFFER ON THE MCS TRACK BUT THE MOST LIKELY AREA IS SWRN KS INTO NWRN OK. ...SRN MN...NRN IA...WRN WI...SERN SD... STRONG HEATING WILL COMBINE WITH FORCING ALONG A DEVELOPING COLD FRONT TO PRODUCE SCATTERED THUNDERSTORMS. DEEP LAYER SHEAR WILL INCREASE AS THE TROUGH DROPS SWD. THIS COMBINED WITH COLD TEMPERATURES ALOFT WILL FAVOR SEVERAL SUPERCELLS CAPABLE OF LARGE HAIL. A TORNADO OR TWO WILL ALSO BE POSSIBLE ESPECIALLY WITH CELLS THAT TRACK EWD ALONG THE SYNOPTIC BOUNDARY INTO SRN MN. ...SC INTO SERN GA... A WEAK SURFACE TROUGH IS FORECAST TO DEEPEN WITH THE HELP OF HEATING...FROM SERN GA INTO SC. NLY WINDS ACROSS SC WILL VEER TO WLY ACROSS SERN GA...MAXIMIZING CONVERGENCE ACROSS COASTAL SC AND GA. A FEW CLUSTERS OF STORMS ARE EXPECTED BY AFTERNOON...WHICH SHOULD PROPAGATE SEWD IN A MULTICELLULAR FASHION WITH A FEW SEVERE WIND GUSTS AND MARGINALLY SEVERE HAIL POSSIBLE. ..JEWELL.. 07/24/2013  198 ACUS01 KWNS 240601 SWODY1 SPC AC 240559 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT WED JUL 24 2013 VALID 241200Z - 251200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... AMPLIFIED LARGE SCALE PATTERN OF A LONGWAVE TROUGH IN THE ERN U.S. AND A RIDGE IN THE WEST WILL BE MAINTAINED THIS FORECAST PERIOD. A NWLY FLOW REGIME WILL PERSIST FROM THE NRN ROCKIES THROUGH THE NRN/CENTRAL PLAINS EXTENDING INTO THE MID SOUTH AND SERN STATES. A COUPLE OF MIDLEVEL SHORTWAVE TROUGHS ARE EXPECTED TO MERGE/CONSOLIDATE ACROSS THE CANADIAN PRAIRIE PROVINCES...WITH THIS FEATURE APPROACHING THE INTERNATIONAL BORDER /NRN ND AND NRN MN/ BY 12Z THURSDAY. THE ONLY OTHER SHORTWAVE TROUGH OF NOTE IS A FEATURE THAT WILL TRACK ANTICYCLONICALLY FROM THE GREAT BASIN REACHING SERN WY/NRN CO TO ADJACENT NEB/KS BY LATE IN THE PERIOD. AT THE SURFACE...HIGH PRESSURE WILL SHIFT E AND SEWD FROM THE UPPER MS VALLEY INTO THE GREAT LAKES AND OH VALLEY REGION. AT 12Z TODAY...A COLD FRONT SHOULD EXTEND FROM NRN VA SWWD TO WRN TN...AND THEN WWD THROUGH NRN AR TO FAR NRN OK. THE ERN PORTION OF THIS BOUNDARY WILL WEAKEN AS IT MOVES SEWD AND SWD...REACHING THE CAROLINAS WWD THROUGH THE CENTRAL OR SRN PORTIONS OF THE CENTRAL GULF COAST STATES BY 12Z THURSDAY. THE WRN EXTENSION OF THIS FRONT WILL SETTLE SWD THROUGH AR/OK THIS FORECAST PERIOD. MEANWHILE...A WEAK FRONTAL ZONE WILL SHIFT EWD THROUGH THE DAKOTAS AND SHOULD EXTEND FROM SERN MANITOBA/NWRN MN TO NERN SD AND WRN NEB AT 25/00Z. LATE IN THE PERIOD...THIS BOUNDARY WILL BE OVERTAKEN FROM THE NW BY A COLD FRONT PRECEDING CANADIAN SHORTWAVE TROUGH. ...SRN DELMARVA TO THE CAROLINAS AND CENTRAL GULF COAST STATES... SURFACE HEATING EXPECTED TODAY WITHIN A VERY MOIST AIR MASS /DEWPOINTS IN THE LOWER 70S/ WILL RESULT IN A MODERATELY UNSTABLE ENVIRONMENT...DESPITE GENERALLY WEAK MIDLEVEL LAPSE RATES. TSTMS ARE EXPECTED TO DEVELOP BY LATE MORNING/EARLY AFTERNOON AS INHIBITION WEAKENS. ACTIVITY SHOULD FORM ALONG AND AHEAD OF THE WEAK COLD FRONT ADVANCING INTO THIS REGION AND ALSO ALONG A LEE TROUGH AND SEA BREEZE BOUNDARIES. WEAK DEEP LAYER SHEAR SHOULD SUPPORT MAINLY MULTICELLS WITH HAIL AND STRONG WIND GUSTS BEING THE PRIMARY THREATS. GIVEN UNCERTAINTY IN WHERE THE GREATEST STORM COVERAGE WILL OCCUR...HIGH SEVERE PROBABILITIES WILL NOT BE INTRODUCED AT THIS TIME. THE ESEWD PROGRESSION OF A WELL FORMED MCV...PER CURRENT RADAR IMAGERY OVER NRN LA...MAY PROVIDE ADDITIONAL FORCING FOR ASCENT TO SUPPORT TSTM DEVELOPMENT INTO PART OF THE LOWER MS VALLEY TODAY. ...AR/LA WWD THROUGH OK/N TX... UNCERTAINTY IN THE PLACEMENT OF AN ONGOING LARGE MCS OVER THE ERN EXTENT OF THE SRN PLAINS INTO AR AT THE START OF D1 SUGGESTS THE THREAT FOR SVR STORMS...ESPECIALLY ACROSS AR MAY BE LIMITED. OTHERWISE...MLCAPE OF 2000-3000 J/KG IS EXPECTED ALONG AND SOUTH OF THE COLD FRONT AND CONVECTIVE OUTFLOW BOUNDARIES ACROSS OK AND N TX INTO THE TX/OK PANHANDLES. THE COVERAGE OF NEW TSTM DEVELOPMENT ACROSS THESE AREAS IS NOT EXPECTED TO BE SUFFICIENT TO SUPPORT A CATEGORICAL RISK AREA...GIVEN THE LACK OF STRONGER FORCING FOR ASCENT. HOWEVER...THE DEGREE OF INSTABILITY AND EFFECTIVE BULK SHEAR OF 25-30 KT WILL SUPPORT MULTICELL STORMS CAPABLE OF PRODUCING DAMAGING WINDS AND HAIL. ...PARTS OF THE SRN AND CENTRAL HIGH PLAINS... MODERATE INSTABILITY IS EXPECTED TO DEVELOP ACROSS THIS REGION WITH AN UPSLOPE LOW LEVEL FLOW REGIME SUPPORTING TSTM DEVELOPMENT INITIALLY OVER THE HIGHER TERRAIN. DESPITE RELATIVELY WEAK LOWER TROPOSPHERIC WINDS...VERTICALLY VEERING WIND PROFILES WILL RESULT IN BULK SHEAR SUFFICIENT FOR MULTICELLS AND A FEW SUPERCELLS. A FEW OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING HAIL AND STRONG WIND GUSTS. A STRENGTHENING SLY LLJ ALONG THE HIGH PLAINS SUGGESTS ACTIVITY COULD PROPAGATE EWD ONTO THE HIGH PLAINS...WITH FORCING FOR ASCENT BEING AUGMENTED ON THE NRN END OVER ERN WY/NERN CO AND SWRN SD/WRN NEB WITH THE APPROACH OF THE GREAT BASINS TROUGH. ...CENTRAL/NRN MN TO NWRN WI...AND WWD TO ERN DAKOTAS... HEIGHT RISES AND SOME MIDLEVEL WARMING SHOULD LIMIT TSTM DEVELOPMENT ALONG THE EWD MOVING FRONTAL ZONE IN THE DAKOTAS TODAY...WITH A GREATER POTENTIAL FOR TSTM DEVELOPMENT THIS EVENING AND TONIGHT ACROSS CENTRAL AND NRN MN. THIS ACTIVITY WILL BE SUPPORTED BY AN INCREASE IN LOW LEVEL WAA AND FORCING FOR ASCENT AHEAD OF THE CANADIAN THROUGH. GENERALLY WEAK INSTABILITY SHOULD LIMIT THE OVERALL SEVERE WEATHER THREAT. ..PETERS/COHEN.. 07/24/2013  594 ACUS03 KWNS 240715 SWODY3 SPC AC 240713 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0213 AM CDT WED JUL 24 2013 VALID 261200Z - 271200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... AN UPPER LOW WITH EMBEDDED SHORTWAVE TROUGH WILL MOVE SLOWLY EWD ACROSS THE UPPER MS VALLEY AND UPPER GREAT LAKES REGION ON FRIDAY...WITH COLD FRONT MOVING ACROSS ERN WI AND MI DURING THE DAY. TO THE SW...AN MCS IS EXPECTED TO BE ONGOING ACROSS ERN KS AND OK...ALTHOUGH MODELS DIFFER IN THE PRECISE LOCATION WITH THE NAM MUCH FARTHER N THAN THE GFS OR ECMWF. THE SRN SOLUTION IS PREFERRED...WITH A SEVERE THREAT POSSIBLE ACROSS ERN OK...WRN AR AND PERHAPS NRN TX LATE. ...OK...WRN AR...NRN TX... WIND PROFILES WILL NOT BE VERY STRONG BUT HEATING ALONG THE WRN AND SRN FRINGES OF AN EXISTING MCS OVER KS AND/OR OK SHOULD ALLOW THIS SYSTEM TO PERSIST AND POSSIBLY GAIN SOME STRENGTH DURING THE DAY. THE TRACK OF THIS SYSTEM IS HIGHLY UNCERTAIN...THUS WILL MAINTAIN ONLY 5% SEVERE PROBABILITIES UNTIL LATER OUTLOOKS CAN ASCERTAIN PATH AND POTENTIAL WIND THREAT. GIVEN SLOW SYSTEM MOTION...VERY HEAVY RAINFALL IS LIKELY. ...ERN WY INTO ERN CO... RELATIVELY COOL TEMPERATURES ALOFT WILL REMAIN OVER THE CNTRL AND NRN HIGH PLAINS AND FRONT RANGE WITH MODEST NWLY FLOW ALOFT. DAYTIME HEATING ALONG WITH SELY UPSLOPE FLOW MAY RESULT IN ISOLATED STORMS CAPABLE OF MARGINALLY SEVERE HAIL IN A NARROW ZONE WITH SWD MOVING CELLS. ...SERN WI...NRN IL...WRN LOWER MI... PRECIPITATION IS LIKELY TO BE ONGOING ALONG A COLD FRONT...WITH ONLY MINIMAL DESTABILIZATION EXPECTED DURING THE DAY. WITH POOR OVERALL LAPSE RATE PROFILES...AND WEAK FLOW IN THE LOW LEVELS...MOST STORMS ARE EXPECTED TO BE SUB-SEVERE. ..JEWELL.. 07/24/2013  913 ACUS11 KWNS 240732 SWOMCD SPC MCD 240732 LAZ000-ARZ000-TXZ000-OKZ000-240900- MESOSCALE DISCUSSION 1498 NWS STORM PREDICTION CENTER NORMAN OK 0232 AM CDT WED JUL 24 2013 AREAS AFFECTED...SERN OK...NERN TX CONCERNING...SEVERE THUNDERSTORM WATCH 440... VALID 240732Z - 240900Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 440 CONTINUES. SUMMARY...ISOLATED DAMAGING WIND THREAT CONTINUES WITH A SWD-MOVING QLCS IN SERN/E-CNTRL OK. PROBABILITY OF SEVERE TSTM WATCH ISSUANCE DOWNSTREAM INTO NERN TX IS 40 PERCENT BY 09Z. DISCUSSION...MEASURED WIND GUSTS HAVE SUBSIDED INTO THE 40-50 MPH RANGE PER OK-MESONET AND KMLC ASOS WITH QLCS THAT EXTENDED FROM LE FLORE TO POTTAWATOMIE COUNTIES IN OK. SWD-MOVEMENT OF THE ERN PORTION CONTINUES AT AROUND 40-50 KT AND WILL LIKELY SURGE ACROSS THE RED RIVER BETWEEN 08-09Z. MUCH OF THIS SURGE IS OCCURRING ON THE COOL SIDE OF A REMNANT OUTFLOW BOUNDARY FROM AN EARLIER MCS OVER TEXARKANA ON TUE EVENING. GIVEN PROBABLE LOW-LEVEL STABILIZATION IN THE WAKE OF THE EARLIER MCS...DAMAGING WIND THREAT WILL PROBABLY BE LIMITED E OF A PRX TO SHV LINE. POTENTIAL ALSO EXISTS FOR INCREASING FORWARD-PROPAGATION OF THE WRN PORTION OF THE QLCS GIVEN A 30 KT SWLY LLJ SAMPLED IN TLX/FWS VWP DATA. INTENSE REFLECTIVITY CORES HAVE THUS FAR REMAINED WELL N/NE OF THE SURFACE OUTFLOW...BUT COULD EVENTUALLY ACCELERATE SWD IF THE COLD POOL DEEPENS. ..GRAMS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LZK...SHV...TSA...FWD...OUN... LAT...LON 35439622 35289580 34849528 34659466 34099439 32949390 32349404 32379557 33569716 34719722 35729711 35439622  974 ACUS48 KWNS 240850 SWOD48 SPC AC 240849 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0349 AM CDT WED JUL 24 2013 VALID 271200Z - 011200Z ...DISCUSSION... MODELS ARE GENERAL AGREEMENT WITH THE LARGE SCALE PATTERN EVOLUTION THROUGH THE D8 PERIOD. A LARGE UPPER LOW WILL BE SITUATED OVER THE UPPER GREAT LAKES ON SAT/D4...AND WILL SLOWLY ROTATE EWD ON D5 AND EVENTUALLY EJECT ACROSS EITHER NEW ENGLAND OR INTO QUEBEC ON D6. WHILE MOISTURE WILL FAVOR STORMS DAILY WITH THE ASSOCIATED WEAK COLD FRONT...WIDESPREAD SEVERE WEATHER IS UNLIKELY. TO THE W...A NW FLOW PATTERN WILL REMAIN OVER THE PLAINS FROM D4 INTO D5. THIS WILL RESULT IN A LEE TROUGH WHICH WILL PROVIDE A FOCUS FOR ISOLATED DIURNAL STORMS ACROSS ERN MT...WY...AND CO. COOL TEMPERATURES ALOFT AND FAVORABLE DEEP LAYER SHEAR PROFILES WILL LIKELY RESULT IN MARGINALLY SEVERE HAIL. FOR THE D6-D8 PERIOD...MODELS AGREE THAT A TROUGH WILL MOVE ACROSS THE PACIFIC NW AND NRN ROCKIES...BUT DISAGREE ON TIMING. SEVERE WIND AND HAIL WILL BE LIKELY WITH THIS TROUGH AND COLD FRONT WHEN IT MOVES ACROSS MT AND INTO THE DAKOTAS...BUT PREDICTABILITY IS TOO LOW. ..JEWELL.. 07/24/2013  966 ACUS11 KWNS 240947 SWOMCD SPC MCD 240947 OKZ000-TXZ000-241045- MESOSCALE DISCUSSION 1499 NWS STORM PREDICTION CENTER NORMAN OK 0447 AM CDT WED JUL 24 2013 AREAS AFFECTED...CNTRL OK...N-CNTRL TX CONCERNING...SEVERE THUNDERSTORM WATCH 440... VALID 240947Z - 241045Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 440 CONTINUES. SUMMARY...OVERALL SEVERE THREAT APPEARS INCREASINGLY MARGINAL AND SHOULD CONTINUE TO WANE. AN ADDITIONAL WW IS NOT ANTICIPATED BEYOND 11Z. DISCUSSION...EARLIER QLCS WEAKENED SUBSTANTIALLY IN THE PAST HALF HOUR AS IT MOVED ACROSS RED RIVER IN BOTH RADAR REFLECTIVITY AND CG LIGHTNING DETECTIONS. ASSOCIATED GUST FRONT HAS SURGED WELL W OF THIS ACTIVITY INTO WRN OK. WLY LOW-LEVEL FLOW ATOP THE SURFACE COLD DOME IS SUPPORTING WAA AND SUSTENANCE OF RENEWED ELEVATED UPDRAFTS ACROSS N-CNTRL OK. SOME OF THIS ACTIVITY COULD PRODUCE SEVERE HAIL GIVEN LARGE BUOYANCY SAMPLED IN THE 05Z LAMONT RAOB...BUT SHOULD BE MARGINALIZED BY THE DOMINANT CLUSTER MODE. A STRONG WIND GUST OR TWO CANNOT BE RULED OUT...BUT ATTEMPTS AT AN ORGANIZED SWD-MOVING COLD POOL PRODUCING SEVERE WIND GUSTS WILL PROBABLY BE MITIGATED BY SURFACE STABILIZATION IN THE WAKE OF THE INITIAL MCS. ..GRAMS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TSA...FWD...OUN... LAT...LON 36289729 35559664 34599638 33529619 32949682 33079787 34439856 36489842 36289729  017 ACUS01 KWNS 241241 SWODY1 SPC AC 241238 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0738 AM CDT WED JUL 24 2013 VALID 241300Z - 251200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... LITTLE CHANGE TO THE LARGE-SCALE PATTERN IS FORECAST THROUGH THE D1 PERIOD WITH A LONG-WAVE TROUGH ACROSS ERN NORTH AMERICA AND A RIDGE OVER THE INTERMOUNTAIN WEST INTO THE CANADIAN ROCKIES. THE MOST PROMINENT FEATURE EMBEDDED WITHIN THIS BROADER REGIME IS A STRONG SHORT-WAVE TROUGH AND ASSOCIATED MID AND UPPER-LEVEL JET STREAKS WHICH WILL PROGRESS SEWD THROUGH CNTRL CANADA. DOWNSTREAM FROM THIS IMPULSE...A NUMBER OF LOW-AMPLITUDE PERTURBATIONS WILL TRANSLATE SEWD WITHIN A BELT OF ENHANCED MIDLEVEL FLOW PRESENT FROM THE S-CNTRL CANADIAN PRAIRIE PROVINCES INTO THE NRN/CNTRL PLAINS AND OZARK PLATEAU. IN THE LOW LEVELS...A COLD FRONT INITIALLY FROM NEW ENGLAND SWWD THROUGH THE TN VALLEY TO SRN HIGH PLAINS WILL MOVE EWD TO OFF THE NEW ENGLAND AND THE MID ATLANTIC COASTS. THE WRN EXTENSION OF THIS FRONT WILL ADVANCE MORE SLOWLY SWD ACROSS THE GULF COAST STATES AND SRN PLAINS. ELSEWHERE...A WEAK FRONT WILL MOVE EWD ACROSS THE DAKOTAS AND UPPER MS VALLEY. THIS BOUNDARY WILL TRAIL WWD TO A LEE LOW OVER THE NRN HIGH PLAINS. ...SRN PLAINS ACROSS THE GULF COAST STATES THIS AFTERNOON AND EVENING... CONSIDERABLE AIR MASS OVERTURNING HAS OCCURRED OVERNIGHT ACROSS OK AND AR INTO NERN TX AND NRN LA OWING TO WIDESPREAD STORM DEVELOPMENT. 12Z REGIONAL SOUNDINGS INDICATE THAT THE SURROUNDING ENVIRONMENT REMAINS CHARACTERIZED BY STEEP MIDLEVEL LAPSE RATES AND A MOIST BOUNDARY LAYER WHICH WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS BY AFTERNOON WITH MLCAPE APPROACHING 1500-2500 J/KG. THE SEWD PROGRESSION OF A SHORT-WAVE TROUGH INTO THE LOWER MS VALLEY WILL AUGMENT LOW-LEVEL CONVERGENCE ALONG THE SYNOPTIC COLD FRONT AND RESIDUAL OUTFLOW BOUNDARIES TO FOSTER SCATTERED SURFACE-BASED TSTMS BY AFTERNOON. UPSCALE GROWTH OF STORMS INTO SWD-MOVING CLUSTERS OR LINES APPEARS PROBABLE WITH AN ASSOCIATED RISK FOR ISOLATED DAMAGING WINDS AND HAIL. UNCERTAINTIES IN SPECIFIC STORM-SCALE-RELATED DETAILS AND THE TENDENCY FOR STRONGER VERTICAL SHEAR TO REMAIN DISPLACED TO THE NORTH OF THE GREATEST AIR MASS DESTABILIZATION PRECLUDE THE INTRODUCTION OF HIGHER SEVERE PROBABILITIES AND A CATEGORICAL SLIGHT RISK ATTM. ...HIGH PLAINS THIS AFTERNOON AND INTO TONIGHT... HEATING ALONG THE HIGH TERRAIN AND LOW-LEVEL UPSLOPE FLOW WILL PROMOTE ISOLATED TO WIDELY SCATTERED TSTM DEVELOPMENT THIS AFTERNOON AMIDST A STEEP LAPSE RATE AND MODESTLY MOIST THERMODYNAMIC ENVIRONMENT. THE STRONGEST VERTICAL SHEAR WILL RESIDE ACROSS THE NRN HIGH PLAINS WHERE MARGINAL SUPERCELL STRUCTURES CAPABLE OF HAIL AND LOCALLY DAMAGING WINDS WILL BE POSSIBLE INTO TONIGHT. THE WIND/HAIL THREAT WILL EXTEND SWD ACROSS THE CNTRL/SRN HIGH PLAINS IN ASSOCIATION WITH MULTICELL CLUSTERS WHICH SHOULD WEAKEN BY LATE EVENING. SUB-SLIGHT RISK PROBABILITIES WILL BE MAINTAINED OWING TO UNCERTAINTIES IN STORM COVERAGE. ...MID ATLANTIC INTO CAROLINAS... WEAK HEIGHT FALLS/FORCING FOR ASCENT ASSOCIATED WITH A SHORT-WAVE TROUGH MOVING THROUGH THE OH/TN VALLEYS WILL COMBINE WITH HEATING ALONG THE BLUE RIDGE AND CONVERGENCE ALONG A LEE TROUGH TO FOSTER SCATTERED STORMS THIS AFTERNOON. VERTICAL SHEAR WILL BE RATHER WEAK...BUT THE PRESENCE OF A MOIST AND MODERATELY UNSTABLE AIR MASS WILL BE SUPPORTIVE OF PULSE STORMS AND POSSIBLE MULTICELL CLUSTERS CAPABLE OF LOCALLY STRONG WIND GUSTS. ...UPPER MS VALLEY THIS AFTERNOON AND EVENING... LOW-LEVEL UPLIFT ALONG THE COLD FRONT MAY BE SUFFICIENT FOR ISOLATED TO WIDELY SCATTERED STORM DEVELOPMENT LATER THIS AFTERNOON INTO EVENING. POOR MIDLEVEL LAPSE RATES AND MARGINAL BOUNDARY LAYER MOISTURE CONTENT WILL LIMIT PARCEL BUOYANCY...THOUGH THE PRESENCE OF A MODESTLY STRONG DEEP WNWLY WIND FIELD MAY SUPPORT A FEW STRONG STORMS CAPABLE OF HAIL AND/OR GUSTY WINDS. ..MEAD/MOSIER.. 07/24/2013  032 ACUS01 KWNS 241626 SWODY1 SPC AC 241623 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1123 AM CDT WED JUL 24 2013 VALID 241630Z - 251200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... IN MID-UPPER LEVELS...SYNOPTIC PATTERN WILL REMAIN CHARACTERIZED BY ERN CONUS TROUGHING AND WRN RIDGE...WITH ENHANCED BELT OF NW FLOW ALOFT FROM CANADIAN PRAIRIE PROVINCES ACROSS MID-UPPER MS AND TN RIVER VALLEYS. AMPLIFICATION AND EWD MOVEMENT OF SYNOPTIC TROUGH IS EXPECTED...WITH ITS POSITION REACHING SERN ONT...WV...GA AND NERN GULF BY END OF PERIOD. HEIGHT FALLS ACCORDINGLY ARE FCST ACROSS PORTIONS SERN CONUS FROM MS/AL EWD ACROSS SC AND SRN NC...WHILE ERN BRANCH OF UPPER-LEVEL JET EXTENDS FROM INLAND CAROLINAS NEWD OVER NEW ENGLAND. IN SHORTWAVE TRAIN...TROUGH NOW OVER LOWER OH VALLEY AND AR IS EXPECTED TO PIVOT SEWD AND EWD THROUGH PERIOD...REACHING PORTIONS WV AND MIDDLE-ERN TN BY 00Z...THEN OVER VA AND CAROLINAS BY 12Z. CONVECTIVELY ENHANCED PERTURBATION -- NOW EVIDENT FROM SRN AR WWD ACROSS RED RIVER REGION -- SHOULD MOVE SEWD OVER MS DELTA REGION THROUGH 06Z BEFORE WEAKENING OVER NRN GULF. PAIR OF VORTICITY MAXIMA -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER NERN AB AND SRN NUNAVUT...ARE EXPECTED TO PHASE INTO STG SHORTWAVE TROUGH AND DIG SEWD ACROSS SK/MB...REACHING TO JUST N OF CANADIAN BORDER WITH ND/MN BY 12Z. AT SFC...COLD FRONT WAS ANALYZED FROM NEW ENGLAND SWWD OVER NRN/WRN VA...NRN TN...AND NRN AR...BECOMING ILL-DEFINED OVER OK IN WAKE OF EARLIER MCS...THEN BETTER EVIDENT AGAIN OVER SRN PANHANDLE OF TX AND ERN NM. FRONT IS EXPECTED TO PROCEED SWD ACROSS ERN PLAINS AND EWD ACROSS NEW ENGLAND AND MID-ATLC REGION. BY 00Z...FRONT SHOULD REACH CAPE COD...SWWD THROUGH WEAK FRONTAL-WAVE LOW OVER ERN NC...TO CENTRAL GA...NRN LA AND NW TX. WRN SEGMENT OF FRONT SHOULD STALL OVER SERN NM AND WRN/CENTRAL TX OVERNIGHT...PERHAPS HAVING CAUGHT UP TO OUTFLOW BOUNDARY FROM WEAKENING MCS NOW OVER N TX. FARTHER E...FRONT SHOULD ADVANCE OFFSHORE CAROLINAS IN WAKE OF EWD-MOVING FRONTAL-WAVE LOW. WEAK COLD FRONT NOW OVER SRN MB...E-CENTRAL ND AND WRN SD SHOULD MOVE SLOWLY SEWD TO NWRN MN BY 00Z...BUT STALL FARTHER SW WITH LEE-SIDE/FRONTAL-WAVE LOW FORMATION FCST OVER CENTRAL/SERN MT TODAY. LOW WILL MOVE SEWD ALONG FRONT TOWARD NERN WY AND PERHAPS SWRN SD OVERNIGHT. ...SRN MID-ATLC TO CAROLINAS... SCATTERED TSTMS IN CLUSTERS ARE EXPECTED TO DEVELOP THROUGHOUT AFTN...PRIMARILY INVOF SFC TROUGH AND SECONDARILY OVER HIGHER TERRAIN FARTHER W. SOME OF THIS ACTIVITY MAY PRODUCE DAMAGING GUSTS APCHG SVR LIMITS. SFC DEW POINTS UPPER 60S TO 70S F ARE COMMON AREA-WIDE...BUT LOW-LEVEL MOISTURE CONTENT INCREASES SEWD...WITH GPS PW AROUND 1.5 INCHES OVER RDU AREA AND OVER 2 INCHES IN MYR-SAV CORRIDOR. VIS IMAGERY SUGGESTS SFC HEATING SHOULD BE STRONGEST FROM NRN SC NWD ACROSS NC INTO VA. MODIFIED RAOBS AND FCST SOUNDINGS SUGGEST MLCAPE 1000-1500 J/KG OVER HIGHER PIEDMONT...GIVEN WEAKER MOISTURE CONTENT AND POOR LAPSE RATES ALOFT...BUT VALUES NEAR 2000 J/KG OVER ERN SC AND NEAR AND E OF I-95 IN NC. HEIGHT FALLS ALOFT ARE EXPECTED AHEAD OF SHORTWAVE TROUGH AND ASSOCIATED SYNOPTIC AMPLIFICATION...CONTERMINOUS WITH AGEOSTROPHIC FORCING ACCOMPANYING LEFT-EXIT REGION OF 250-MB JET...DIURNAL SFC DESTABILIZATION...GRADUAL DEEPENING OF PREFRONTAL SFC TROUGHING PRIOR TO LOW FORMATION...AND RELATED SUBTLE INCREASE IN LOW-LEVEL LIFT. HOWEVER...WEAK LAPSE RATES AND LACK OF SUBSTANTIAL VERTICAL SHEAR WILL LIMIT OVERALL CONVECTIVE ORGANIZATION. THOUGH LOCALIZED CONCENTRATIONS OF SVR MAY OCCUR NEAR BOUNDARY INTERSECTIONS AND MESOSCALE COLD-POOLS...OVERALL THREAT APPEARS TOO DISPERSED AND UNORGANIZED TO WARRANT CATEGORICAL OUTLOOK ATTM. ...SERN CONUS TO SRN PLAINS... WIDELY SCATTERED TO SCATTERED TSTMS IN CLUSTERS SHOULD DEVELOP THIS AFTN AMIDST POCKETS OF RELATIVELY SUSTAINED CLOUD BREAKS...RELATED DIFFERENTIAL HEATING ZONES...AND OUTFLOW BOUNDARIES FROM EARLIER CONVECTION. PRECONVECTIVE AIR MASS WILL BE CHARACTERIZED BY FAVORABLE LOW-LEVEL MOISTURE...WITH SFC DEW POINTS COMMONLY UPPER 60S TO MID 70S F...BUT WEAK VERTICAL SHEAR. CONVECTIVE POTENTIAL APPEARS QUITE FRAGMENTED BY THOSE BOUNDARIES AND CLOUD COVER...WITH ANY ACCOMPANYING SVR THREAT LIMITED TO ISOLATED/SPORADIC DAMAGING GUSTS AND MRGL HAIL. ...SRN/CENTRAL HIGH PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED THIS AFTN...SUPPORTED BY STG SFC HEATING OF HIGHER TERRAIN...STEEP LOW-MIDDLE LEVEL LAPSE RATES...AND MOIST ADVECTION ON SELY FLOW. SOME OF THIS ACTIVITY MAY AGGREGATE UPSCALE INTO MULTICELLULAR CLUSTERS. ALTHOUGH MID-LEVEL FLOW WILL REMAIN WEAK...DEEP SHEAR MAY BECOME MRGLLY FAVORABLE GIVEN SELY SFC WINDS...STG VEERING OF FLOW WITH HEIGHT...AND FAVORABLE ANVIL-LEVEL WINDS FOR VENTING PURPOSES. WELL-MIXED SUBCLOUD LAYERS SHOULD SUPPORT MAINTENANCE TO SFC OF HAIL/GUSTS GENERATED ALOFT...WITH ISOLATED SVR POSSIBLE. ...NRN PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP THIS AFTN OVER HIGHER TERRAIN AND INVOF SFC LOW/FRONT...WHERE BOUNDARY-LAYER LIFT WILL BE MAXIMIZED. ADDITIONAL CONVECTION MAY DEVELOP OVER CANADA AND MOVE SEWD INTO THIS REGION THIS EVENING...FOLLOWED BY WAA-SUPPORTED CONVECTION OVERNIGHT. STG SFC HEATING AND BOUNDARY-LAYER MIXING SHOULD REDUCE SFC DEW POINTS INTO 40S AND LOW 50S MOST AREAS...AND LIMIT DIURNAL INCREASE IN BUOYANCY...BUT ALSO...YIELD WELL-MIXED SUBCLOUD LAYERS SUITABLE FOR STG/ISOLATED SVR GUSTS IN ANY DAYTIME TSTMS THAT DO DEVELOP. LOW-LEVEL SHEAR WILL BE STRONGEST N OF SFC FRONT WHERE NELY/ELY FLOW UNDERLIES NWLYS ALOFT. THIS MAY LEAD TO AT LEAST MRGL SUPERCELL CHARACTER WITH ASSOCIATED RISK OF HAIL/GUSTS NEAR SVR LEVELS. PRIMARY UNCERTAINTY FOR SFC-BASED TSTMS THIS AFTN/EVENING REMAINS CONVECTIVE COVERAGE. TSTM COVERAGE SHOULD INCREASE OVERNIGHT AS SUPPORTIVE REGIME SPREADS SEWD ACROSS WRN SD...BUT INFLOW PARCELS BECOME MORE ELEVATED. ...ERN ND TO NWRN WI/WRN LS REGION... WEAK CONVERGENCE INVOF FRONT...AND DIMINISHED MLCINH DUE TO SFC HEATING...MAY LEAD TO WIDELY SCATTERED TSTMS THIS AFTN. COVERAGE MAY INCREASE OVERNIGHT...BUT WITH CONVECTION BEING MORE ELEVATED...AMIDST LARGE-SCALE LIFT AND HEIGHT FALLS PRECEDING STRENGTHENING CANADIAN PERTURBATION. THOUGH DEEP SHEAR WILL BE FAVORABLE...PREFRONTAL/PRECONVECTIVE AIR MASS THIS AFTN SHOULD BE CHARACTERIZED BY SFC DEW POINTS MOSTLY 50S F AND SMALL MIDLEVEL LAPSE RATES...KEEPING BUOYANCY WEAK. OVERALL THREAT APPEARS MRGL...WITH ISOLATED GUSTS/HAIL NEAR SVR LIMITS PSBL. ..EDWARDS/BUNTING.. 07/24/2013  822 ACUS02 KWNS 241732 SWODY2 SPC AC 241730 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1230 PM CDT WED JUL 24 2013 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS THURSDAY INTO THURSDAY EVENING ACROSS PARTS OF SOUTHERN MINNESOTA/NORTHERN IOWA AND ADJACENT SOUTHEASTERN SOUTH DAKOTA/NORTHEASTERN NEBRASKA AND SOUTHWESTERN WISCONSIN... ...THERE IS A SLGT RISK OF SVR TSTMS THURSDAY AFTERNOON AND EVENING ACROSS WESTERN KANSAS...ADJACENT EASTERN COLORADO/SOUTHWESTERN NEBRASKA...INTO NORTHWESTERN OKLAHOMA AND ADJACENT AREAS OF THE TEXAS PANHANDLE... ...SYNOPSIS... MODELS INDICATE THAT A MID/UPPER LOW WILL CONTINUE TO DEVELOP INLAND OFF THE NORTHEASTERN PACIFIC INTO BRITISH COLUMBIA THROUGH EARLY FRIDAY. THIS MAY LEAD TO SOME SUPPRESSION OF UPPER RIDGING NEAR THE WESTERN CANADIAN/U.S. BORDER AREA...BUT THE LARGE-SCALE PATTERN OTHERWISE APPEARS LIKELY TO REMAIN GENERALLY UNCHANGED. WHILE A SUBTROPICAL HIGH CENTER LINGERS IN THE VICINITY OF THE FOUR CORNERS STATES...ANOTHER SIGNIFICANT SHORT WAVE IMPULSE IS FORECAST TO DIG INTO THE NORTHERN PLAINS AND UPPER MIDWEST...WITHIN A BROADLY CYCLONIC BELT OF WESTERLIES EXTENDING EASTWARD THROUGH NEW ENGLAND AND THE CANADIAN MARITIMES. GENERAL UPPER TROUGHINESS IS ALSO EXPECTED TO LINGER WITHIN ANOTHER BELT OF FLOW CURVING ACROSS THE CENTRAL PLAINS THROUGH THE SOUTHEAST. CONSIDERABLE MODIFICATION OF PREVIOUSLY STEEP MID-LEVEL LAPSE RATES HAS OCCURRED EAST OF THE HIGH PLAINS DURING THE PAST 12 HOURS OR SO...AND THE REMNANTS OF A LINGERING POCKET OF ELEVATED MIXED LAYER AIR...NOW CENTERED OVER THE OHIO VALLEY...ARE EXPECTED TO SUBSTANTIALLY STABILIZE FURTHER THROUGH 12Z THURSDAY. THE EVOLVING PATTERN...THOUGH...COULD SUPPORT MODEST STEEPENING OF MID-LEVEL LAPSE RATES...WITHIN A CORRIDOR ACROSS SOUTH DAKOTA AND NEBRASKA INTO THE MID MISSOURI VALLEY BY EARLY THURSDAY...AND ACROSS THE SOUTH CENTRAL PLAINS INTO THE OZARK PLATEAU REGION BY LATE THURSDAY NIGHT. AT THE SAME TIME...SUBSTANTIAL COOLING AND DRYING ASSOCIATED WITH THE PASSAGE OF A COLD FRONT...AND CONSIDERABLE OUTFLOW FROM THUNDERSTORM ACTIVITY...HAS STABILIZED LOWER LEVELS ACROSS MUCH OF THE CENTRAL PLAINS EASTWARD AND NORTHWARD THROUGH THE OHIO VALLEY/GREAT LAKES/NORTHEAST AND MID ATLANTIC STATES. THIS MAY ADVECT INTO THE GULF STATES BY THURSDAY. MODIFICATION PROBABLY WILL BE SLOW ACROSS MUCH OF THE LOWER CENTRAL PLAINS...BUT SUBSTANTIVE MOISTENING MAY OCCUR TO THE NORTH...IN A CORRIDOR AHEAD OF ANOTHER COLD FRONT...ACCOMPANYING THE AFOREMENTIONED DIGGING SHORT WAVE TROUGH. ...MID MO INTO UPPER MS VALLEY... EVEN WITH PRE-FRONTAL LOW-LEVEL MOISTENING AND SOME STEEPENING OF MID-LEVEL LAPSE RATES...MODELS SUGGEST DESTABILIZATION...IN TERMS OF CAPE...WILL BE FAIRLY MODEST THURSDAY...WITH MAXIMUM VALUES ON THE ORDER OF 1500 J/KG ACROSS SOUTHERN MINNESOTA/NORTHERN IOWA AND ADJACENT AREAS OF THE NORTHERN PLAINS/UPPER MIDWEST. STILL...THIS COULD BE SUFFICIENT...GIVEN THE DEVELOPMENT OF STRONG SHEAR AND INCREASING FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED WITH THE APPROACH OF THE UPPER IMPULSE...TO SUPPORT THE RISK FOR STRONG/SEVERE STORM DEVELOPMENT. THIS MAY INCLUDE ISOLATED SUPERCELLS...AND THE EVOLUTION OF ONE OR TWO ORGANIZED STORM CLUSTERS WITH HAIL AND STRONG WIND GUSTS...MAINLY DURING THE AFTERNOON AND EVENING HOURS. ...CENTRAL/SOUTHERN HIGH PLAINS... MODELS DO SUGGEST THAT A LOW AMPLITUDE WAVE WITH EMBEDDED SMALLER SCALE IMPULSES WILL GRADUALLY DEVELOP EAST SOUTHEAST OF THE ROCKIES...ON THE PERIPHERY OF THE SUBTROPICAL RIDGE...BY EARLY THURSDAY. THIS COULD CONTRIBUTE TO SEVERAL PERIODS OF CONVECTIVE DEVELOPMENT ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND THE IMPACTS OF EARLY PERIOD CONVECTION ON ANY POTENTIAL BOUNDARY LAYER RECOVERY ACROSS THE LOWER PLAINS REMAIN UNCLEAR. IT CURRENTLY SEEMS MOST PROBABLE THAT CONDITIONS SUPPORTIVE OF SEVERE STORM DEVELOPMENT DURING THE AFTERNOON AND EVENING HOURS WILL REMAIN CONFINED TO THE HIGH PLAINS...WHERE ISOLATED SUPERCELLS ARE POSSIBLE ALONG WITH THE UPSCALE GROWTH OF ONE OR TWO ORGANIZED STORM CLUSTERS. ..KERR.. 07/24/2013  107 ACUS11 KWNS 241734 SWOMCD SPC MCD 241733 NCZ000-VAZ000-SCZ000-GAZ000-241900- MESOSCALE DISCUSSION 1500 NWS STORM PREDICTION CENTER NORMAN OK 1233 PM CDT WED JUL 24 2013 AREAS AFFECTED...SRN VA...NC...SC...NERN GA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 241733Z - 241900Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...SCATTERED THUNDERSTORM CLUSTERS ARE FORECAST TO EVOLVE OFF OF THE HIGHER TERRAIN OF WRN NC AND NERN GA THIS AFTERNOON...WITH ADDITIONAL DEVELOPMENT LIKELY OVER THE PIEDMONT AND COASTAL PLAINS OF SC/NC AND SRN VA. ISOLATED DAMAGING WIND GUSTS WILL BE THE PRIMARY SEVERE WEATHER THREAT. WW IS UNLIKELY. DISCUSSION...AT 17Z...A COLD FRONT WAS ANALYZED FROM THE SRN DELMARVA REGION SWWD INTO WRN VA AND MIDDLE TN...WHILE A SURFACE PRESSURE TROUGH EXTENDED S INTO THE CAROLINAS AND ERN GA. MORNING RAOBS AND RAP ANALYSIS GUIDANCE ALSO SHOWED A 70 KT 250 MB JET POSITIONED FROM THE NRN/CNTRL PLAINS SEWD INTO THE TN VALLEY...WITH THE EXIT REGION OF THIS FEATURE AND ASSOCIATED UPPER DIVERGENCE APPROACHING VA AND THE CAROLINAS. VISIBLE SATELLITE IMAGERY REVEALS MOSTLY CLEAR SKIES ACROSS THE REGION...WHICH IS AIDING IN STRONG SURFACE HEATING /TEMPERATURES NEAR 90F/ AND STEEPENING LOW-LEVEL LAPSE RATES. DESPITE THIS DESTABILIZATION AND PRESENCE OF MID 60S TO MIDDLE 70S DEWPOINTS...WEAK MIDLEVEL LAPSE RATES WILL GREATLY LIMIT THE MAGNITUDE OF BUOYANCY...WITH MLCAPE VALUES GENERALLY RANGING FROM 1000-1500 J/KG. VISIBLE SATELLITE IMAGERY SHOWS DEEPENING CUMULUS DEVELOPING OVER THE HIGHER TERRAIN OF WRN NC/NERN GA...WITH ANOTHER CUMULUS FIELD /AND ISOLATED THUNDERSTORM DEVELOPMENT/ EVOLVING OVER THE CNTRL/ERN CAROLINAS AND SRN VA. DEEP-LAYER SHEAR IS WEAK ACROSS THE AREA...WHICH WILL FAVOR PULSE AND MULTICELL CLUSTER STORM MODES. OVERALL SEVERE WEATHER THREAT SHOULD BE LIMITED BY THE WEAK SHEAR AND CAPE. NEVERTHELESS...AN ISOLATED THREAT FOR DAMAGING WINDS EXISTS GIVEN THE HOT...STRONGLY MIXED BOUNDARY LAYER AIRMASS. ..GARNER/EDWARDS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CAE...GSP...MRX... FFC... LAT...LON 34497726 33967876 33978325 34718392 35698285 37247916 37537689 36447595 35397608 34497726  101 ACUS11 KWNS 241748 SWOMCD SPC MCD 241748 FLZ000-GAZ000-ALZ000-241915- MESOSCALE DISCUSSION 1501 NWS STORM PREDICTION CENTER NORMAN OK 1248 PM CDT WED JUL 24 2013 AREAS AFFECTED...SRN AL...FL PANHANDLE...SW GA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 241748Z - 241915Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...THUNDERSTORMS WILL CONTINUE TO INCREASE THROUGH THE AFTERNOON. STORMS SHOULD REMAIN RELATIVELY UNORGANIZED...BUT A FEW STRONG WIND GUSTS ARE POSSIBLE AS STORMS TRACK E/SE ACROSS SRN AL INTO SW GA AND ACROSS THE FL PANHANDLE. DISCUSSION...THUNDERSTORMS WERE INCREASING EARLY THIS AFTERNOON IN WARM/MOIST AND MODERATELY UNSTABLE AIRMASS. THE MAIN CLUSTER OF DEVELOPING STORMS WAS AHEAD OF AN E/SEWD ADVANCING MCV. THIS FEATURE MAY HELP TO PROVIDE SOME ORGANIZATION TO STORMS AS THEY TRACK E/SE TOWARD SW GA AND ACROSS THE FL PANHANDLE THIS AFTERNOON. HOWEVER...LACK OF STRONGER UPPER FORCING FOR ASCENT AND WEAK EFFECTIVE SHEAR /LESS THAN 20-25 KT/ WILL LIMIT OVERALL ORGANIZATION. WHILE SUB-PAR MIDLEVEL LAPSE RATES WILL BE ANOTHER LIMITING FACTOR...LOW LEVEL LAPSE RATES WERE INCREASING TO AROUND 7 DEG C PER KM AND MAY STEEPEN FURTHER WITH CONTINUED DAYTIME HEATING. THESE STEEPENING LOW LEVEL LAPSE RATES COMBINED WITH PW VALUES NEAR 2 INCHES AIDING IN WATER LOADING...A FEW STRONG WIND GUSTS COULD BE POSSIBLE THROUGH THE AFTERNOON. SHOULD ANY SMALL SCALE COLD POOLS DEVELOP TO AID IN BETTER ORGANIZATION...WIND THREAT WOULD INCREASE. MARGINAL CONDITIONS AND EXPECTED LOOSE ORGANIZATION SHOULD LIMIT OVERALL SEVERE POTENTIAL AND A WW IS NOT EXPECTED AT THIS TIME. ..LEITMAN/EDWARDS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FFC...TAE...BMX...MOB... LAT...LON 31938813 32418747 32338589 32078494 31458426 30688382 30028396 29588436 29398503 29558594 30098726 30748805 31938813  070 ACUS11 KWNS 241818 SWOMCD SPC MCD 241818 SDZ000-NEZ000-COZ000-WYZ000-241945- MESOSCALE DISCUSSION 1502 NWS STORM PREDICTION CENTER NORMAN OK 0118 PM CDT WED JUL 24 2013 AREAS AFFECTED...ERN WY...SRN SD...N-CNTRL AND WRN NEB CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 241818Z - 241945Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...ISOLATED THUNDERSTORMS...POSSIBLY SUPERCELLS...MAY DEVELOP DURING THE EARLY TO MID AFTERNOON FROM PORTIONS OF ERN WY INTO SRN SD/N-CNTRL NEB. LARGE HAIL AND DAMAGING WIND GUSTS WILL BE POSSIBLE. SEVERE WEATHER PROBABILITIES WILL LIKELY BE ADJUSTED DURING THE UPCOMING 20Z DAY 1 OUTLOOK TO REFLECT CURRENT TRENDS. DISCUSSION...MESOANALYSIS SHOWS A WEAK SURFACE PATTERN IS IN PLACE OVER THE CNTRL/NRN PLAINS EARLY THIS AFTERNOON. ONE AREA OF HIGH PRESSURE WAS LOCATED OVER THE NRN HIGH PLAINS...WITH ANOTHER HIGH OVER THE UPPER MIDWEST AND GREAT LAKES REGION. IN BETWEEN THESE TWO FEATURES...A COL AND ASSOCIATED WEAK SURFACE CONVERGENCE WAS ANALYZED FROM CNTRL SD INTO WRN NEB. AIRMASS ACROSS THE REGION IS QUICKLY HEATING...WITH TEMPERATURES CLIMBING INTO THE 80S. THE DESTABILIZING BOUNDARY LAYER COMBINED WITH LOW TO MID 60S DEWPOINTS AND STEEP MIDLEVEL LAPSE RATES IS YIELDING MLCAPE VALUES UPWARDS OF 2500 J/KG. AREAS OF ENHANCED CUMULUS WERE OBSERVED IN VIS SATELLITE IMAGERY INVOF ONL-VTN...AIA...TOR...AND OVER THE BLACK HILLS. GIVEN THE THERMODYNAMIC ENVIRONMENT IN PLACE...THUNDERSTORM DEVELOPMENT CANNOT BE RULED OUT DURING THE NEXT COUPLE OF HOURS...WHICH IS SUPPORTED BY LATEST HI-RES MODEL GUIDANCE. MID/UPPER-LEVEL HEIGHT GRADIENT IS FAIRLY TIGHT OVER THE CNTRL/NRN PLAINS...AND IS FAVORING A BELT OF 40 KT NWLY FLOW AT 6 KM AGL. AS A RESULT...DEEP-LAYER SHEAR IS MORE THAN SUFFICIENT FOR SUPERCELLS...WITH EFFECTIVE BULK SHEAR VALUES RANGING FROM 40-50 KT. THESE ENVIRONMENTAL TRENDS SUGGEST THAT A LARGE HAIL/DAMAGING WIND THREAT WILL BE POSSIBLE OVER THE AREA THIS AFTERNOON. ..GARNER/EDWARDS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FSD...ABR...GID...LBF...UNR...BOU...CYS... LAT...LON 43760395 44090024 43329860 41659918 40760200 40940417 41750515 42900520 43760395  156 ACUS11 KWNS 241921 SWOMCD SPC MCD 241921 NDZ000-MTZ000-242045- MESOSCALE DISCUSSION 1503 NWS STORM PREDICTION CENTER NORMAN OK 0221 PM CDT WED JUL 24 2013 AREAS AFFECTED...N-CNTRL/NERN MT...FAR WRN ND CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 241921Z - 242045Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...CLUSTERS OF THUNDERSTORMS...INCLUDING A FEW SUPERCELLS...ARE FORECAST TO EVOLVE OFF OF A COLD FRONT LOCATED ALONG THE MT/SK BORDER...AND THEN MOVE SEWD ACROSS PORTIONS OF N-CNTRL/NERN MT INTO FAR WRN ND. LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITH THIS ACTIVITY...BUT WW DOES NOT APPEAR NECESSARY ATTM. DISCUSSION...MESOANALYSIS AT 19Z PLACES A SURFACE COLD FRONT FROM SRN ALBERTA SEWD INTO NERN MT AND NWRN ND. TEMPERATURES S OF THE FRONT HAVE WARMED INTO THE 80S...WHILE A TONGUE OF MID/UPPER 50S DEWPOINTS RESIDES ALONG AND N OF THE BOUNDARY. LOW-LEVEL THETA-E IS RELATIVELY MAXIMIZED WITHIN THE TRANSITION ZONE BETWEEN THESE TWO AIRMASSES...AND IS AIDING IN MLCAPE VALUES NEAR 1000 J/KG. MID/UPPER LEVEL WNWLY FLOW FROM 30-50 KT RESIDES ATOP THE SURFACE BOUNDARY...WITH SEVERAL WEAK UPPER IMPULSES APPROACHING THE AREA FROM THE W /PER WV IMAGERY/. VISIBLE SATELLITE IMAGERY SHOWS CUMULUS IS DEEPENING ALONG THE FRONT...AND LIGHTNING DATA INDICATES AN ISOLATED STRIKE HAS RECENTLY OCCURRED IMMEDIATELY N OF VALLEY COUNTY. ADDITIONAL ISOLATED/SCATTERED THUNDERSTORM DEVELOPMENT APPEARS LIKELY DURING THE NEXT COUPLE OF HOURS NEAR THE COLD FRONT...AFTER WHICH...ACTIVITY SHOULD SPREAD SEWD ACROSS NERN MT...POSSIBLY REACHING FAR WRN ND LATE THIS AFTERNOON OR EVENING. WEAK/MODERATE CAPE COMBINED WITH 700-500 MB LAPSE RATES NEAR 7 C/KM AND EFFECTIVE BULK SHEAR EXCEEDING 40 KT WILL FAVOR SUPERCELL STRUCTURES POSING A THREAT FOR LARGE HAIL/DAMAGING WIND GUSTS. ..GARNER/EDWARDS.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BIS...BYZ...GGW...TFX... LAT...LON 49260519 48380308 47510281 46910406 46850686 47210881 47831013 48711036 49220907 49260519  158 ACUS01 KWNS 241955 SWODY1 SPC AC 241953 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0253 PM CDT WED JUL 24 2013 VALID 242000Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL HIGH PLAINS... ...CENTRAL HIGH PLAINS... PRIMARY 20Z ADJUSTMENT IS THE ADDITION OF A CATEGORICAL SLIGHT RISK FOR A HAIL/WIND THREAT ACROSS PORTIONS OF THE REGION. STRONG/SEVERE TSTMS INCLUDING SPLITTING/SLOW-MOVING SUPERCELLS ARE ALREADY NOTED AT MID-AFTERNOON ACROSS FAR SOUTHEAST/EAST-CENTRAL WY INTO THE NEB PANHANDLE. COINCIDENT WITH WEAK CONVERGENCE/CONFLUENCE...THE BOUNDARY LAYER IS MODERATELY UNSTABLE /2000+ J PER KG MLCAPE/ WITH 50+ KT OF EFFECTIVE SHEAR. SUSTAINED MULTICELLS/SOME SUPERCELLS CAN BE EXPECTED AS STORMS DRIFT GENERALLY SOUTHEASTWARD...WHILE STORM MERGERS/COLD POOL AGGREGATION AND A MODEST LOW LEVEL JET INCREASE MAY LEAD TO THE EVOLUTION OF ONE OR MORE CLUSTERS THROUGH EARLY/MID EVENING. ...ELSEWHERE... LITTLE IF ANY CHANGES TO EXISTING OUTLOOK/ASSOCIATED REASONING...SEE PRIOR DISCUSSION BELOW AND ANY MESOSCALE DISCUSSIONS. FOR ONE...SEE MESOSCALE DISCUSSION 1503 REGARDING NORTH-CENTRAL MT/FAR WESTERN ND. ..GUYER.. 07/24/2013 .PREV DISCUSSION... /ISSUED 1123 AM CDT WED JUL 24 2013/ ...SYNOPSIS... IN MID-UPPER LEVELS...SYNOPTIC PATTERN WILL REMAIN CHARACTERIZED BY ERN CONUS TROUGHING AND WRN RIDGE...WITH ENHANCED BELT OF NW FLOW ALOFT FROM CANADIAN PRAIRIE PROVINCES ACROSS MID-UPPER MS AND TN RIVER VALLEYS. AMPLIFICATION AND EWD MOVEMENT OF SYNOPTIC TROUGH IS EXPECTED...WITH ITS POSITION REACHING SERN ONT...WV...GA AND NERN GULF BY END OF PERIOD. HEIGHT FALLS ACCORDINGLY ARE FCST ACROSS PORTIONS SERN CONUS FROM MS/AL EWD ACROSS SC AND SRN NC...WHILE ERN BRANCH OF UPPER-LEVEL JET EXTENDS FROM INLAND CAROLINAS NEWD OVER NEW ENGLAND. IN SHORTWAVE TRAIN...TROUGH NOW OVER LOWER OH VALLEY AND AR IS EXPECTED TO PIVOT SEWD AND EWD THROUGH PERIOD...REACHING PORTIONS WV AND MIDDLE-ERN TN BY 00Z...THEN OVER VA AND CAROLINAS BY 12Z. CONVECTIVELY ENHANCED PERTURBATION -- NOW EVIDENT FROM SRN AR WWD ACROSS RED RIVER REGION -- SHOULD MOVE SEWD OVER MS DELTA REGION THROUGH 06Z BEFORE WEAKENING OVER NRN GULF. PAIR OF VORTICITY MAXIMA -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER NERN AB AND SRN NUNAVUT...ARE EXPECTED TO PHASE INTO STG SHORTWAVE TROUGH AND DIG SEWD ACROSS SK/MB...REACHING TO JUST N OF CANADIAN BORDER WITH ND/MN BY 12Z. AT SFC...COLD FRONT WAS ANALYZED FROM NEW ENGLAND SWWD OVER NRN/WRN VA...NRN TN...AND NRN AR...BECOMING ILL-DEFINED OVER OK IN WAKE OF EARLIER MCS...THEN BETTER EVIDENT AGAIN OVER SRN PANHANDLE OF TX AND ERN NM. FRONT IS EXPECTED TO PROCEED SWD ACROSS ERN PLAINS AND EWD ACROSS NEW ENGLAND AND MID-ATLC REGION. BY 00Z...FRONT SHOULD REACH CAPE COD...SWWD THROUGH WEAK FRONTAL-WAVE LOW OVER ERN NC...TO CENTRAL GA...NRN LA AND NW TX. WRN SEGMENT OF FRONT SHOULD STALL OVER SERN NM AND WRN/CENTRAL TX OVERNIGHT...PERHAPS HAVING CAUGHT UP TO OUTFLOW BOUNDARY FROM WEAKENING MCS NOW OVER N TX. FARTHER E...FRONT SHOULD ADVANCE OFFSHORE CAROLINAS IN WAKE OF EWD-MOVING FRONTAL-WAVE LOW. WEAK COLD FRONT NOW OVER SRN MB...E-CENTRAL ND AND WRN SD SHOULD MOVE SLOWLY SEWD TO NWRN MN BY 00Z...BUT STALL FARTHER SW WITH LEE-SIDE/FRONTAL-WAVE LOW FORMATION FCST OVER CENTRAL/SERN MT TODAY. LOW WILL MOVE SEWD ALONG FRONT TOWARD NERN WY AND PERHAPS SWRN SD OVERNIGHT. ...SRN MID-ATLC TO CAROLINAS... SCATTERED TSTMS IN CLUSTERS ARE EXPECTED TO DEVELOP THROUGHOUT AFTN...PRIMARILY INVOF SFC TROUGH AND SECONDARILY OVER HIGHER TERRAIN FARTHER W. SOME OF THIS ACTIVITY MAY PRODUCE DAMAGING GUSTS APCHG SVR LIMITS. SFC DEW POINTS UPPER 60S TO 70S F ARE COMMON AREA-WIDE...BUT LOW-LEVEL MOISTURE CONTENT INCREASES SEWD...WITH GPS PW AROUND 1.5 INCHES OVER RDU AREA AND OVER 2 INCHES IN MYR-SAV CORRIDOR. VIS IMAGERY SUGGESTS SFC HEATING SHOULD BE STRONGEST FROM NRN SC NWD ACROSS NC INTO VA. MODIFIED RAOBS AND FCST SOUNDINGS SUGGEST MLCAPE 1000-1500 J/KG OVER HIGHER PIEDMONT...GIVEN WEAKER MOISTURE CONTENT AND POOR LAPSE RATES ALOFT...BUT VALUES NEAR 2000 J/KG OVER ERN SC AND NEAR AND E OF I-95 IN NC. HEIGHT FALLS ALOFT ARE EXPECTED AHEAD OF SHORTWAVE TROUGH AND ASSOCIATED SYNOPTIC AMPLIFICATION...CONTERMINOUS WITH AGEOSTROPHIC FORCING ACCOMPANYING LEFT-EXIT REGION OF 250-MB JET...DIURNAL SFC DESTABILIZATION...GRADUAL DEEPENING OF PREFRONTAL SFC TROUGHING PRIOR TO LOW FORMATION...AND RELATED SUBTLE INCREASE IN LOW-LEVEL LIFT. HOWEVER...WEAK LAPSE RATES AND LACK OF SUBSTANTIAL VERTICAL SHEAR WILL LIMIT OVERALL CONVECTIVE ORGANIZATION. THOUGH LOCALIZED CONCENTRATIONS OF SVR MAY OCCUR NEAR BOUNDARY INTERSECTIONS AND MESOSCALE COLD-POOLS...OVERALL THREAT APPEARS TOO DISPERSED AND UNORGANIZED TO WARRANT CATEGORICAL OUTLOOK ATTM. ...SERN CONUS TO SRN PLAINS... WIDELY SCATTERED TO SCATTERED TSTMS IN CLUSTERS SHOULD DEVELOP THIS AFTN AMIDST POCKETS OF RELATIVELY SUSTAINED CLOUD BREAKS...RELATED DIFFERENTIAL HEATING ZONES...AND OUTFLOW BOUNDARIES FROM EARLIER CONVECTION. PRECONVECTIVE AIR MASS WILL BE CHARACTERIZED BY FAVORABLE LOW-LEVEL MOISTURE...WITH SFC DEW POINTS COMMONLY UPPER 60S TO MID 70S F...BUT WEAK VERTICAL SHEAR. CONVECTIVE POTENTIAL APPEARS QUITE FRAGMENTED BY THOSE BOUNDARIES AND CLOUD COVER...WITH ANY ACCOMPANYING SVR THREAT LIMITED TO ISOLATED/SPORADIC DAMAGING GUSTS AND MRGL HAIL. ...SRN/CENTRAL HIGH PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED THIS AFTN...SUPPORTED BY STG SFC HEATING OF HIGHER TERRAIN...STEEP LOW-MIDDLE LEVEL LAPSE RATES...AND MOIST ADVECTION ON SELY FLOW. SOME OF THIS ACTIVITY MAY AGGREGATE UPSCALE INTO MULTICELLULAR CLUSTERS. ALTHOUGH MID-LEVEL FLOW WILL REMAIN WEAK...DEEP SHEAR MAY BECOME MRGLLY FAVORABLE GIVEN SELY SFC WINDS...STG VEERING OF FLOW WITH HEIGHT...AND FAVORABLE ANVIL-LEVEL WINDS FOR VENTING PURPOSES. WELL-MIXED SUBCLOUD LAYERS SHOULD SUPPORT MAINTENANCE TO SFC OF HAIL/GUSTS GENERATED ALOFT...WITH ISOLATED SVR POSSIBLE. ...NRN PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP THIS AFTN OVER HIGHER TERRAIN AND INVOF SFC LOW/FRONT...WHERE BOUNDARY-LAYER LIFT WILL BE MAXIMIZED. ADDITIONAL CONVECTION MAY DEVELOP OVER CANADA AND MOVE SEWD INTO THIS REGION THIS EVENING...FOLLOWED BY WAA-SUPPORTED CONVECTION OVERNIGHT. STG SFC HEATING AND BOUNDARY-LAYER MIXING SHOULD REDUCE SFC DEW POINTS INTO 40S AND LOW 50S MOST AREAS...AND LIMIT DIURNAL INCREASE IN BUOYANCY...BUT ALSO...YIELD WELL-MIXED SUBCLOUD LAYERS SUITABLE FOR STG/ISOLATED SVR GUSTS IN ANY DAYTIME TSTMS THAT DO DEVELOP. LOW-LEVEL SHEAR WILL BE STRONGEST N OF SFC FRONT WHERE NELY/ELY FLOW UNDERLIES NWLYS ALOFT. THIS MAY LEAD TO AT LEAST MRGL SUPERCELL CHARACTER WITH ASSOCIATED RISK OF HAIL/GUSTS NEAR SVR LEVELS. PRIMARY UNCERTAINTY FOR SFC-BASED TSTMS THIS AFTN/EVENING REMAINS CONVECTIVE COVERAGE. TSTM COVERAGE SHOULD INCREASE OVERNIGHT AS SUPPORTIVE REGIME SPREADS SEWD ACROSS WRN SD...BUT INFLOW PARCELS BECOME MORE ELEVATED. ...ERN ND TO NWRN WI/WRN LS REGION... WEAK CONVERGENCE INVOF FRONT...AND DIMINISHED MLCINH DUE TO SFC HEATING...MAY LEAD TO WIDELY SCATTERED TSTMS THIS AFTN. COVERAGE MAY INCREASE OVERNIGHT...BUT WITH CONVECTION BEING MORE ELEVATED...AMIDST LARGE-SCALE LIFT AND HEIGHT FALLS PRECEDING STRENGTHENING CANADIAN PERTURBATION. THOUGH DEEP SHEAR WILL BE FAVORABLE...PREFRONTAL/PRECONVECTIVE AIR MASS THIS AFTN SHOULD BE CHARACTERIZED BY SFC DEW POINTS MOSTLY 50S F AND SMALL MIDLEVEL LAPSE RATES...KEEPING BUOYANCY WEAK. OVERALL THREAT APPEARS MRGL...WITH ISOLATED GUSTS/HAIL NEAR SVR LIMITS PSBL.  887 ACUS11 KWNS 242136 SWOMCD SPC MCD 242136 MNZ000-NDZ000-242330- MESOSCALE DISCUSSION 1504 NWS STORM PREDICTION CENTER NORMAN OK 0436 PM CDT WED JUL 24 2013 AREAS AFFECTED...NWRN MN...ERN ND...FAR NERN SD CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 242136Z - 242330Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...THE POTENTIAL FOR ISOLATED MARGINALLY SVR THUNDERSTORMS WILL EXIST INTO THE EVENING HOURS...THOUGH THE ISSUANCE OF A WW IS UNLIKELY. DISCUSSION...THUNDERSTORMS CONTINUE MOVING SEWD INTO/ACROSS NWRN MN INVOF A PRE-FRONTAL TROUGH THAT EXTENDS FARTHER SW INTO SERN ND AND N-CNTRL SD. THE GREATEST CHANCE FOR SUSTAINED CONVECTION WILL EXIST ACROSS NWRN MN IN CLOSEST PROXIMITY TO A ZONE OF MID-LEVEL ASCENT ACCOMPANYING A LOW-AMPLITUDE SHORTWAVE TROUGH MOVING SEWD FROM SRN MANITOBA INTO ADJACENT ONTARIO PER WATER VAPOR IMAGERY. FARTHER SW ALONG THE PRE-FRONTAL TROUGH AND INVOF A COLD FRONT THAT WILL ENTER NW PARTS OF THE DISCUSSION AREA DURING THE NEXT COUPLE OF HOURS...CONVECTIVE DEVELOPMENT WILL BE POSSIBLE. HOWEVER...VIS SATELLITE DATA SUGGEST THAT THE CUMULUS FIELD IN THESE AREAS IS RELATIVELY FLAT WHERE DEEP FORCING FOR ASCENT IS RELATIVELY WEAKER...AND ADDITIONAL SUBSTANTIAL CONVECTION MAY STRUGGLE TO MATERIALIZE. MODERATE MID-LEVEL FLOW -- E.G. 30-40-KT WNWLY/S BETWEEN 3.5 AND 5 KM AGL PER MVX VWP DATA -- WILL SUPPORT ENOUGH DEEP SHEAR FOR A FEW ORGANIZED STORM STRUCTURES WITH MARGINALLY SVR HAIL/WINDS POSSIBLE. HOWEVER...WITH SFC TEMPERATURES ONLY IN THE MID 70S TO AROUND 80 DEGREES AMIDST MIDDLE 50S DEWPOINTS...SFC-BASED BUOYANCY IS RELATIVELY LIMITED WHICH SHOULD MITIGATE THE OVERALL SVR THREAT...WHICH WILL LOWER EVEN MORE AFTER SUNSET. ..COHEN/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DLH...FGF...BIS... LAT...LON 48949730 48999544 49349517 49359476 48819454 48509340 47319374 46339523 46099653 46249775 46879843 47969817 48949730  505 ACUS11 KWNS 242155 SWOMCD SPC MCD 242154 NEZ000-KSZ000-242330- MESOSCALE DISCUSSION 1505 NWS STORM PREDICTION CENTER NORMAN OK 0454 PM CDT WED JUL 24 2013 AREAS AFFECTED...CNTRL AND SERN NEB...NRN KS CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 242154Z - 242330Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...AN ISOLATED SEVERE THREAT MAY DEVELOP ACROSS SCNTRL AND SERN NEB OVER THE NEXT FEW HOURS. THE PRIMARY THREAT WOULD BE DAMAGING WIND GUSTS AND HAIL. WW ISSUANCE MAY BECOME NECESSARY ACROSS THE REGION. DISCUSSION...THE LATEST OBJECTIVE ANALYSIS SHOWS AN AXIS OF MODERATE INSTABILITY EXTENDING ESEWD ACROSS CNTRL AND SERN NEB WHERE MLCAPE IS ESTIMATED IN THE 1000 TO 2000 J/KG RANGE. SEVERAL STRONG TO SEVERE THUNDERSTORMS ARE DEVELOPING ON THE NRN EDGE OF INSTABILITY. THIS ACTIVITY IS LIKELY BEING SUPPORTED BY LARGE-SCALE ASCENT ASSOCIATED WITH A VORTICITY MAX MOVING SEWD OUT OF SRN SD EVIDENT ON WATER VAPOR IMAGERY. THE WRF-HRRR SUGGESTS THE STORMS WILL CONTINUE TO MOVE SWD TO THE VICINITY OF GRAND ISLAND AND POSSIBLY INTO NRN KS LATER THIS EVENING BUT SHOULD REMAIN ISOLATED. IN ADDITION TO THE INSTABILITY...0-6 KM SHEAR VALUES IN SCNTRL NEB ARE ESTIMATED AROUND 50 KT WHICH SHOULD SUPPORT A SEVERE THREAT. ALTHOUGH ISOLATED WIND DAMAGE AND HAIL WILL BE POSSIBLE DUE TO THE DEEP LAYER SHEAR AND INSTABILITY...THE STEEPER LAPSE RATES ARE ANALYZED ACROSS WRN NEB. THIS ALONG WITH ISOLATED CELL COVERAGE SHOULD KEEP THE SEVERE THREAT RELATIVELY CONFINED. ..BROYLES/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...OAX...TOP...ICT...GID...LBF...GLD... LAT...LON 40699640 41819740 42179844 42209942 42000052 41550079 40980084 39990043 39469968 38939813 39039685 39559614 40049608 40699640  597 ACUS11 KWNS 242203 SWOMCD SPC MCD 242202 COZ000-250000- MESOSCALE DISCUSSION 1506 NWS STORM PREDICTION CENTER NORMAN OK 0502 PM CDT WED JUL 24 2013 AREAS AFFECTED...E-CNTRL/SERN CO CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 242202Z - 250000Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...AN ISOLATED SVR THREAT WILL EXIST ACROSS E-CNTRL/SERN CO THROUGH THE EVENING HOURS. WHILE TRENDS WILL CONTINUE TO BE MONITORED...THE ISSUANCE OF A WW IS CURRENTLY UNLIKELY. DISCUSSION...CONVECTION THAT DEVELOPED IN RESPONSE TO OROGRAPHIC ASCENT INVOF THE CO ROCKIES FRONT RANGE MAY HAVE A TENDENCY TO CONGEAL INTO SMALL...FORWARD-PROPAGATING CONVECTIVE CLUSTERS OVER THE ADJACENT HIGH PLAINS THROUGH THIS EVENING. THE AIR MASS IN THIS REGION IS MODERATELY UNSTABLE...PARTLY OWING TO RELATIVELY RICH LOW-LEVEL MOISTURE FOR THESE ELEVATIONS -- E.G. SFC DEWPOINTS IN THE MIDDLE 50S -- BENEATH STEEP MID-LEVEL LAPSE RATES ACCOMPANYING AN EML PLUME. HOWEVER...ABUNDANT ANVIL SHADING DOWNSTREAM OF ONGOING CONVECTION WILL ACT TO LIMIT INSOLATION/LOW-LEVEL LAPSE RATES TO SOME EXTENT. PUX VWP DATA SUGGEST THAT DEEP SHEAR MAY BE SUFFICIENT FOR A FEW MULTICELL CONVECTIVE STRUCTURES WITH DMGG WINDS AND PERHAPS SVR HAIL ADVANCING OVER THE E-CNTRL/SERN CO HIGH PLAINS DURING THE NEXT SEVERAL HOURS. HOWEVER...THE LACK OF STRONGER DEEP FORCING FOR ASCENT...AND THE VEER-BACK-VEER SIGNATURE EVIDENT IN THE VWP DATA...REDUCE CONFIDENCE IN A MORE ROBUST SVR THREAT EVOLVING. ..COHEN/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...GLD...PUB...BOU... LAT...LON 37070409 37180466 37890493 39150457 39520371 39380256 38510220 37510246 37110320 37070409  329 ACUS11 KWNS 242227 SWOMCD SPC MCD 242227 TXZ000-NMZ000-250030- MESOSCALE DISCUSSION 1507 NWS STORM PREDICTION CENTER NORMAN OK 0527 PM CDT WED JUL 24 2013 AREAS AFFECTED...NERN/E-CNTRL NM...PORTIONS OF THE TX PANHANDLE AND TX SOUTH PLAINS CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 242227Z - 250030Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...AN ISOLATED SVR POTENTIAL WILL EXIST INTO THE EVENING HOURS...THOUGH THE ISSUANCE OF A WW IS CURRENTLY UNLIKELY. DISCUSSION...MOISTURE TRANSPORT ON DEEP ELY/S PER FDX VWP DATA WILL CONTINUE TO FEED THE ONGOING MASS OF CONVECTION OVER E-CNTRL NM. THIS ACTIVITY MAY HAVE A TENDENCY TO SPREAD NWD ACROSS PARTS OF NERN NM WHERE CLOUD-FREE AREAS HAVE CONTRIBUTED TO MODERATE BUOYANCY. STEEP LOW-LEVEL LAPSE RATES/LARGE DCAPE IN THIS ENVIRONMENT MAY SUPPORT A FEW DMGG WIND GUSTS. FARTHER TO THE E ACROSS PARTS OF THE TX S PLAINS AND TX PANHANDLE...MUCH MORE ISOLATED CONVECTION WILL CONTINUE TO EVOLVE ALONG A PAIR OF OUTFLOW BOUNDARIES IN A RELATIVELY MORE UNSTABLE ENVIRONMENT. WHILE HIGH-LEVEL WLY FLOW WILL SUPPORT CONVECTIVE VENTILATION...DEEP SHEAR THROUGH THE CLOUD LAYER IS RELATIVELY LIMITED PER LBB VWP DATA...WHICH SHOULD LIMIT THE OVERALL SUSTENANCE OF ORGANIZED SVR CONVECTION. REGARDLESS...MULTICELL CLUSTERS MAY STILL EVOLVE THROUGH THE EVENING WITH DMGG WINDS AND SVR HAIL POSSIBLE. HOWEVER...ONLY WEAK CONVERGENCE ALONG THE BOUNDARIES PER SFC OBS...AND LIMITED DEEP ASCENT...SHOULD LIMIT CONVECTIVE COVERAGE. ..COHEN/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LUB...AMA...MAF...ABQ... LAT...LON 34280457 34930575 35920574 36980490 36650332 35390175 34290031 33640005 33180048 33290254 34280457  961 ACUS11 KWNS 242257 SWOMCD SPC MCD 242257 ALZ000-FLZ000-MSZ000-LAZ000-TXZ000-250130- MESOSCALE DISCUSSION 1508 NWS STORM PREDICTION CENTER NORMAN OK 0557 PM CDT WED JUL 24 2013 AREAS AFFECTED...PORTIONS OF FAR ERN TX...CNTRL/SRN LA...SRN MS...SWRN AL...FAR WRN PARTS OF THE FL PANHANDLE CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 242257Z - 250130Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...SOME POTENTIAL FOR A FEW DAMAGING WIND GUSTS AND POSSIBLY A TORNADO MAY EXIST THROUGH THE EVENING. WHILE TRENDS WILL CONTINUE TO BE MONITORED...THE ISSUANCE OF A WW IS CURRENTLY UNLIKELY. DISCUSSION...BANDS OF CONVECTION CONTINUE TO TRACK ESEWD/SEWD INVOF CONVECTION-AUGMENTED OUTFLOW BOUNDARIES ATTENDANT TO PREVIOUSLY DECAYED MCS/S. A LONGER-TRACK MCV APPEARS TO BE AIDING THE ACTIVITY OVER CNTRL MS AND WILL CONTINUE BEING STEERED ESEWD TOWARD/ACROSS SWRN AL DURING THE NEXT SEVERAL HOURS. DIURNAL HEATING OF THE AIR S OF THE ONGOING CONVECTION HAS CONTRIBUTED TO MODERATE TO STRONG INSTABILITY. MODEST MID-LEVEL WNWLY/NWLY FLOW WILL ALLOW FORWARD PROPAGATION OF THIS PREDOMINANTLY MULTICELLULAR CONVECTION TOWARD THE GULF COAST THROUGH THIS EVENING. THE POTENTIAL FOR A FEW DMGG WIND GUSTS WILL EXIST...AS PARTLY AIDED BY WATER LOADING PROCESSES ACCOMPANYING PW VALUES AROUND 1.5-2.2 INCHES PER GPS DATA. HOWEVER...OCCASIONAL WEAK LOW-LEVEL CIRCULATIONS HAVE BEEN NOTED WITH MORE SEMI-DISCRETE CONVECTION IN JEFFERSON COUNTY MS. THIS IS LIKELY A MANIFESTATION OF SUBTLE VEERING WITH HEIGHT OF THE LOWER TROPOSPHERIC FLOW PER AREA VWP DATA. AND...WITH SEASONABLY RICH DEEP MOISTURE...AND LOWERING LCL/S FOLLOWING DUSK...THE POTENTIAL FOR A TORNADO CANNOT BE RULED OUT. HOWEVER...THE LACK OF STRONGER DEEP FORCING FOR ASCENT AND GENERALLY WEAK LOW-LEVEL FLOW MAGNITUDE SHOULD LIMIT THE SVR POTENTIAL SUCH THAT THE ISSUANCE OF A WW IS CURRENTLY UNLIKELY. HOWEVER...TRENDS WILL CONTINUE TO BE MONITORED THROUGH THE EVENING. ..COHEN/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX...LCH...SHV...HGX... LAT...LON 29869399 30389497 31599524 31519354 31839173 31628978 31688831 30978720 30388769 30008994 29859229 29869399  676 ACUS11 KWNS 242308 SWOMCD SPC MCD 242308 NDZ000-MTZ000-250045- MESOSCALE DISCUSSION 1509 NWS STORM PREDICTION CENTER NORMAN OK 0608 PM CDT WED JUL 24 2013 AREAS AFFECTED...PORTIONS OF NRN MT AND WRN ND CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 242308Z - 250045Z PROBABILITY OF WATCH ISSUANCE...60 PERCENT SUMMARY...THE AREA IS BEING MONITORED FOR THE POSSIBLE ISSUANCE OF A SVR TSTM WATCH. DISCUSSION...WITH MULTIPLE SUPERCELL STRUCTURES WITH LIKELY LARGE HAIL EVOLVING AND EXPECTED TO CONTINUE IN NERN MT...AND ADDITIONAL UPSLOPE-RELATED CONVECTION DEVELOPING ALONG THE ROCKY MOUNTAIN FRONT...CONVECTION WILL PERSIST DURING THE NEXT SEVERAL HOURS. MODERATE/STRONG INSTABILITY AND STRONG DEEP SHEAR MAY SUPPORT LARGE HAIL/DMGG WINDS...POTENTIALLY NECESSITATING A WW. ..COHEN/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BIS...BYZ...GGW...TFX... LAT...LON 46390437 47200753 47931198 48451312 49011290 49051026 48940795 48350497 47900406 46860328 46390437  652 ACUS11 KWNS 242337 SWOMCD SPC MCD 242337 SDZ000-NEZ000-KSZ000-COZ000-WYZ000-250100- MESOSCALE DISCUSSION 1510 NWS STORM PREDICTION CENTER NORMAN OK 0637 PM CDT WED JUL 24 2013 AREAS AFFECTED...SE WY...WRN-CNTRL NEB...NE CO CONCERNING...SEVERE THUNDERSTORM WATCH 441... VALID 242337Z - 250100Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 441 CONTINUES. SUMMARY...A SEVERE THREAT WILL LIKELY CONTINUE ACROSS WW 441 OVER THE NEXT FEW HOURS. WIND DAMAGE AND HAIL WILL BE THE PRIMARY THREATS. THE POTENTIAL FOR SEVERE STORMS SHOULD GRADUALLY SHIFT SWD WITH TIME. DISCUSSION...THE LATEST SFC ANALYSIS SHOWS AN 1009 MB LOW OVER SRN WY WITH DEWPOINTS IN THE MID TO UPPER 50S EXTENDING EWD FROM THE LOW ACROSS WRN NEB. NUMEROUS THUNDERSTORMS HAVE DEVELOPED ALONG THE CORRIDOR OF LOW-LEVEL MOISTURE WHERE MESOANALYSIS SHOWS MODERATE INSTABILITY WITH MLCAPE ESTIMATED IN THE 1500 TO 2500 J/KG RANGE. IN ADDITION...THE PROFILERS AT PLATTEVILLE CO AND MERRIMAN NEB SHOW 0-6 KM SHEAR IN THE 35 TO 40 KT RANGE. THIS ENVIRONMENT SHOULD CONTINUE TO SUPPORT SEVERE THUNDERSTORM DEVELOPMENT FOR SEVERAL MORE HOURS THIS EVENING. STEEP MID-LEVEL LAPSE RATES IN PLACE ACROSS THE WRN PART OF THE WATCH SHOULD ENCOURAGE HAIL FORMATION WITH THE STRONGER CELLS. IF A COLD POOL CAN ORGANIZE AND MOVE SEWD ACROSS NERN CO OR SW NEB...THEN THE WIND DAMAGE THREAT COULD INCREASE AS WELL. ..BROYLES/CORFIDI.. 07/24/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FSD...GID...LBF...UNR...GLD...BOU...CYS... LAT...LON 39570204 39560370 40000372 39970502 40360504 40370490 40990489 40960521 42580518 42570489 43450483 43470404 43010405 42950107 42999845 42899834 41759833 41690028 40710023 40699998 40419997 40310014 39990017 39960203 39570204