758 ACUS11 KWNS 310037 SWOMCD SPC MCD 310037 OKZ000-310130- MESOSCALE DISCUSSION 0346 NWS STORM PREDICTION CENTER NORMAN OK 0737 PM CDT SAT MAR 30 2013 AREAS AFFECTED...EAST-CENTRAL AND NORTHEAST OK CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 310037Z - 310130Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...A CONDITIONAL SEVERE HAIL THREAT EXISTS ACROSS THE AREA. TRENDS WILL BE MONITORED AND WW ISSUANCE IS POSSIBLE IF COVERAGE INCREASES. DISCUSSION...STRONG TSTM DEVELOPMENT HAS RECENTLY BEEN NOTED NORTH OF TUL...IN AN ENVIRONMENT CHARACTERIZED BY MODERATE MLCAPE OF 1000-1500 J/KG AND DEEP-LAYER SHEAR OF 40 KTS. COVERAGE HAS BEEN SPARSE IN NERN OK THUS FAR AS FORCING FOR DEEP ASCENT IS NEGLIGIBLE...BUT SOME ADDITIONAL DEVELOPMENT IS POSSIBLE IN THE VICINITY OF A WEAK SFC LOW NEAR TUL AND A REMNANT BOUNDARY ORIENTED N/S ALONG A OKM-TUL-BVO LINE...AS WELL AS ALONG A WNW/ENE ORIENTED OUTFLOW BOUNDARY MOVING SOUTH OUT OF SERN KS. WHILE LOW-LEVEL FLOW IS RELATIVELY WEAK...BACKED FLOW TO THE SOUTH AND EAST OF THE AFOREMENTIONED BOUNDARIES IS LENGTHENING HODOGRAPHS TO SOME EXTENT AND WILL FAVOR SUPERCELLS WITH ANY DEEP SUSTAINED CONVECTION. GIVEN STEEP LOW-LEVEL LAPSE RATES AND POTENTIALLY FAVORABLE STORM MODE...LARGE HAIL WILL BE POSSIBLE. IF COVERAGE OF STORMS INCREASES ACROSS THE AREA...WW ISSUANCE WILL BE CONSIDERED. ..DEAN/MEAD.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TSA... LAT...LON 35349628 35879643 36579629 36919593 36889537 36899493 36379462 35399463 35349628  727 ACUS01 KWNS 310059 SWODY1 SPC AC 310057 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0757 PM CDT SAT MAR 30 2013 VALID 310100Z - 311200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PART OF THE SRN PLAINS INTO SWRN MO TO THE ARKLATEX... ...SRN PLAINS INTO SWRN MO/WRN AR AND THE ARKLATEX... DESPITE THE LACK OF LARGE SCALE ASCENT THIS EVENING ACROSS THE SRN PLAINS...A SHORTWAVE TROUGH /CURRENTLY EXTENDING FROM ERN WY INTO THE DAKOTAS/ WILL AMPLIFY SEWD RESULTING IN AN INCREASE IN DEEP LAYER ASCENT INTO THE SRN PLAINS LATER TONIGHT. A COLD FRONT CURRENTLY EXTENDING FROM CENTRAL IA SWWD THROUGH NERN-SOUTH CENTRAL KS TO THE TX PANHANDLE WILL CONCURRENTLY INCREASE IN FORWARD SPEED LATE TONIGHT...REACHING ERN IL SSWWD INTO AR AND THEN WSWWD ALONG THE RED RIVER VALLEY TO THE TX SOUTH PLAINS BY 12Z SUN. SWLY LOW LEVEL WINDS EXTENDING FROM TX INTO SRN/ERN OK TO THE LOWER MS VALLEY WILL SUPPORT ONGOING WAA THIS FORECAST PERIOD AND THE POTENTIAL FOR ADDITIONAL TSTMS WITHIN A MODERATELY UNSTABLE-STEEP MIDLEVEL LAPSE RATE ENVIRONMENT. WNWLY MEAN WINDS SUGGEST STORMS SHOULD TEND TO MOVE ESEWD. REGIONAL RADAR IMAGERY SHOWED ONGOING STRONG TO SEVERE STORMS ACROSS PORTIONS OF CENTRAL AND SWRN OK...AND CENTRAL TX /GENERALLY IN VICINITY AND NE OF KBWD/. THE STORMS IN SWRN OK AND THE TX BIG COUNTRY...THOUGH LACKING LARGE SCALE SUPPORT/ASCENT THIS EVENING...ARE LIKELY BEING SUPPORTED BY APPARENTLY ENHANCED LOW LEVEL CONVERGENCE PER A HEAT LOW THAT DEVELOPED THIS AFTERNOON OVER NWRN TX /SW OF KSPS/. STEEP LOW-MID LEVEL LAPSE RATES...MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR OF 40 KT REMAIN FAVORABLE FOR ORGANIZED STORMS PRODUCING HAIL...SOME VERY LARGE /EXCEEDING 2 INCH DIAMETER/ ACROSS SRN OK AND NRN TX...AND DAMAGING WINDS. GENERALLY STRAIGHT HODOGRAPHS WITH SOME LOW LEVEL CURVATURE SUGGEST SPLITTING SUPERCELLS REMAIN POSSIBLE INTO THE EVENING. FARTHER NE INTO NERN OK/SWRN MO TO NWRN AR...ONGOING STORMS ARE LOCATED WITHIN THE NERN EXTENT OF A STEEPER MIDLEVEL LAPSE RATE PLUME AND MARGINAL-MODERATE INSTABILITY. EFFECTIVE BULK SHEAR OF 40-50 KT IS SUPPORTIVE OF ORGANIZED STORMS. FOR SHORT TERM DETAILS...REFER TO SPC MESOSCALE DISCUSSION 346. A FAVORABLE DOWNSTREAM CAPE/SHEAR ENVIRONMENT INTO ERN OK/WRN AR SUGGESTS A CONDITIONAL POTENTIAL FOR STRONG TO SEVERE STORMS TO PERSIST SSEWD THROUGH THE OVERNIGHT. AN INCREASE IN LARGE SCALE ASCENT INTO THE SRN PLAINS LATER TONIGHT SHOULD SUPPORT AN INCREASE IN TSTM COVERAGE WITH THE GREATEST POTENTIAL FOR SEVERE STORMS BEING ACROSS THE SERN TX PANHANDLE INTO SRN OK AND NRN TX WHERE THE AIR MASS WILL REMAIN MODERATELY UNSTABLE AND SUFFICIENTLY SHEARED. ..PETERS.. 03/31/2013  642 ACUS11 KWNS 310115 SWOMCD SPC MCD 310114 OKZ000-TXZ000-310245- MESOSCALE DISCUSSION 0347 NWS STORM PREDICTION CENTER NORMAN OK 0814 PM CDT SAT MAR 30 2013 AREAS AFFECTED...SRN OK...FAR N TX CONCERNING...SEVERE THUNDERSTORM WATCH 68... VALID 310114Z - 310245Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 68 CONTINUES. SUMMARY...THE THREAT FOR ISOLATED LARGE HAIL AND LOCALIZED STRONG WIND GUSTS CONTINUES NEAR-TERM BUT SHOULD GRADUALLY DIMINISH THIS EVENING AS NOCTURNAL COOLING OCCURS WITHIN A VERY WEAKLY-FORCED ENVIRONMENT. DISCUSSION...A CONVOLUTED SURFACE PATTERN PERSISTS WITH SEVERAL SMALL-SCALE CONVECTIVE OUTFLOWS AND PRE-FRONTAL TROUGHS AHEAD OF A STRONGER COLD FRONTAL SURGE EXPECTED LATER TONIGHT. MODIFIED 00Z FWD RAOB AND PURCELL OK PROFILER SUGGESTS PRESENCE OF 1500 J/KG MLCAPE AMIDST 35-40 KT DEEP-LAYER SHEAR WILL CONTINUE TO SUPPORT ISOLATED SUPERCELLS FROM ALONG THE RED RIVER NEWD INTO ERN OK. HOWEVER...ANEMIC LOW-LEVEL FLOW...EVEN DIFFLUENT IN PARTS OF S-CNTRL OK/N-CNTRL TX...SHOULD REMAIN THE PRIMARY LIMITING FACTOR TO RE-INTENSIFICATION/SUSTENANCE OF LARGE HAIL POTENTIAL BEYOND THE NEXT COUPLE OF HOURS AS THE BOUNDARY LAYER COOLS AND MLCIN SLOWLY INCREASES. THIS SCENARIO IS SUPPORTED BY 21-22Z HRRR RUNS WHICH DEPICT CONVECTION DIMINISHING SUBSTANTIALLY BY 03-04Z. ..GRAMS.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TSA...FWD...OUN... LAT...LON 34099980 35259786 35349621 35089522 34339532 34079609 33639731 33649949 34099980  512 ACUS11 KWNS 310345 SWOMCD SPC MCD 310344 ARZ000-OKZ000-310515- MESOSCALE DISCUSSION 0348 NWS STORM PREDICTION CENTER NORMAN OK 1044 PM CDT SAT MAR 30 2013 AREAS AFFECTED...ERN OK...WRN AR CONCERNING...SEVERE THUNDERSTORM WATCH 69... VALID 310344Z - 310515Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 69 CONTINUES. SUMMARY...PRIMARY THREAT OF SEVERE HAIL SHOULD PERSIST NEXT FEW HOURS AS CORRIDOR OF GREATEST RISK MAKES SLOW E/SEWD PROGRESS. A DOWNSTREAM WW IS NOT ANTICIPATED ATTM. DISCUSSION...GREATEST SUPERCELL RISK SHOULD REMAIN CONFINED ACROSS THE SW TO CNTRL PORTIONS OF WW 69 INTO EARLY MORNING GIVEN THE PREDOMINANT FEED OF MODEST LOW-LEVEL W/SWLYS SUPPORTING WAA ATOP REMNANT OUTFLOW IN THE WAKE OF SAT MORNING CONVECTION. SURFACE TEMPERATURES HAVE COOLED INTO THE 50S TO LOWER 60S ACROSS MUCH OF AR...SUGGESTING HAIL POTENTIAL WILL BE INCREASINGLY MARGINAL WITH ERN EXTENT INTO AR ESPECIALLY GIVEN THE DEARTH OF INSTABILITY NOTED IN THE 00Z LZK RAOB. FARTHER WEST...FETCH OF STEEP MID-LEVEL LAPSE RATES /AS SAMPLED BY 00Z LMN RAOB/ AMIDST 30-40 KT EFFECTIVE SHEAR WILL CONTINUE TO SUSTAIN SUPERCELLS PRODUCING SEVERE HAIL FOR AT LEAST A FEW MORE HOURS. BUT WITH CONTINUED NOCTURNAL SURFACE COOLING AND A RELATIVELY WEAK LLJ...OVERALL INTENSITY HAS LIKELY PEAKED AND SHOULD GRADUALLY DIMINISH WITH TIME. ..GRAMS.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LZK...SHV...TSA...OUN... LAT...LON 33999533 34519634 34949625 36039500 36209354 35929284 35259301 34499405 33999533  448 ACUS02 KWNS 310512 SWODY2 SPC AC 310510 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1210 AM CDT SUN MAR 31 2013 VALID 011200Z - 021200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... A BROAD UPPER TROUGH WILL EXTEND FROM THE NRN PLAINS EWD INTO NEW ENGLAND WITH STRONG WINDS ALOFT ROTATING AROUND AN ERN CANADA UPPER LOW. AT THE SURFACE...A COLD FRONT WILL DRIFT SWD AND WILL EXTEND ROUGHLY FROM NWRN TX EWD INTO THE CNTRL GULF COAST STATES DURING THE DAY. S OF THIS FRONT...BOUNDARY LAYER DEWPOINTS IN THE 50S TO LOWER 60S F WILL RESULT IN MARGINAL INSTABILITY AND THUNDERSTORMS. AN APPROACHING SHORTWAVE TROUGH WILL ALSO BE MOVING EWD ACROSS THE FOUR CORNERS STATES OVERNIGHT AND WILL HELP INDUCE SLY RETURN FLOW ACROSS TX WHICH WILL ENHANCE NOCTURNAL THUNDERSTORM POTENTIAL WITH SOME SEVERE STORMS POSSIBLE. ...NWRN TX... SHORTWAVE RIDGING WILL OCCUR DURING THE DAY WITH STRONG HEATING S OF THE COLD FRONT. THIS FRONT SHOULD ADVANCE SWWD ACROSS THE TX PANHANDLE AS WEAK LOW PRESSURE DEVELOPS OVER SERN NM/W TX. BACKED SURFACE WINDS WILL HELP MAINTAIN DEWPOINTS IN THE 40S...WHICH WILL RESULT IN SUFFICIENT INSTABILITY FOR A FEW STRONG TO SEVERE THUNDERSTORMS GIVEN THE STEEP LAPSE RATE ENVIRONMENT AND MODERATE DEEP LAYER SHEAR. THE FRONT WILL BE A FOCUS FOR STORMS...WITH HAIL AND WIND DEVELOPING. NAM SUGGESTS A LOCALIZED ZONE OF SEVERE POTENTIAL ALONG WRN PORTION OF FRONT AND NEAR MOIST AXIS. CELLS WITH HAIL MAY EVENTUALLY MERGE AND PERSIST INTO THE EVENING AS A SELY LOW LEVEL JET DEVELOPS. A FEW SEVERE WIND GUSTS MAY THUS OCCUR. WITH SUCH LOW DEWPOINTS...MAXIMUM HAIL SIZE IS EXPECTED TO BE BETWEEN 1.00 AND 1.75 INCHES. ..JEWELL.. 03/31/2013  985 ACUS01 KWNS 310552 SWODY1 SPC AC 310550 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1250 AM CDT SUN MAR 31 2013 VALID 311200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF CENTRAL... SOUTH...AND EAST TX TO THE LOWER MS VALLEY... ...SYNOPSIS... A POLAR VORTEX WILL ROTATE ESEWD ACROSS ONTARIO TODAY/TONIGHT AND MAINTAIN A CYCLONIC FLOW REGIME EAST OF THE ROCKIES TO THE ERN U.S. COAST. WHILE STRONGEST MID AND UPPER LEVEL WINDS WILL EXTEND FROM THE LEE OF THE CANADIAN ROCKIES THROUGH THE NRN PLAINS TO THE OH VALLEY AND NERN STATES...MODEST WNWLY FLOW IS EXPECTED FROM THE SRN PLAINS TO THE GULF COAST REGION. MEANWHILE...THE CLOSED LOW ASSOCIATED WITH THE ERN PACIFIC REX BLOCK IS EXPECTED TO UNDERGO SUBSTANTIAL WEAKENING THIS FORECAST PERIOD AS IT SHIFTS EWD ACROSS CA REACHING NV BY 12Z MON. AT THE SURFACE...A FRONT EXTENDING FROM AR WSWWD ALONG THE RED RIVER VALLEY TO THE TX SOUTH PLAINS AT 12Z TODAY WILL MOVE SWD...TENDING TO WEAKEN AS IT ADVANCES TOWARD S TX...THE LOWER MS VALLEY AND THE CENTRAL GULF COAST STATES. ONE OR MORE OUTFLOW BOUNDARIES ATTENDANT TO POTENTIALLY ONGOING CONVECTION/EMBEDDED TSTM COMPLEXES ALONG THE RED RIVER VALLEY INTO AR AT THE START OF DAY 1 MAY LOCALLY ENHANCE THE SWD MOVEMENT OF THE AFOREMENTIONED FRONT TODAY. ...CENTRAL/SOUTH/EAST TX TO THE LOWER MS VALLEY... CONVECTION/EMBEDDED TSTMS ARE EXPECTED TO BE ONGOING AT 12Z TODAY FROM THE SERN TX PANHANDLE EWD THROUGH SRN OK AND N TX...POTENTIALLY EXTENDING INTO AR. THE PRESENCE OF STEEP MIDLEVEL LAPSE RATES...MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR AROUND 40 KT /ESPECIALLY INVOF THE RED RIVER/ SUGGEST THE POTENTIAL FOR SOME OF THIS ACTIVITY TO BE SEVERE EARLY SUN MORNING. A SHORTWAVE TROUGH TRACKING INTO THE BASE OF THE CENTRAL/ERN U.S. LONGWAVE TROUGH WILL GLANCE THE ARKLATEX REGION...WHILE A SECOND SHORTWAVE TROUGH...CURRENTLY LOCATED OVER THE SWRN STATES...IS EXPECTED TO REACH THE TX PORTION OF THE SLIGHT RISK AREA BY LATE THIS AFTERNOON. SURFACE HEATING ALONG AND S OF THE ONGOING CONVECTION AND SWD MOVING FRONT WITHIN A MOIST AIR MASS WILL RESULT IN MODERATE INSTABILITY...GIVEN THE PRESENCE OF STEEP MIDLEVEL LAPSE RATES /7-8 C PER KM/. DESPITE THE LACK OF STRONGER DEEP LAYER FORCING FOR ASCENT...NEW TSTM DEVELOPMENT SHOULD OCCUR WITHIN THE DESTABILIZING ENVIRONMENT AS THE SURFACE FRONT ADVANCES SWD. EFFECTIVE BULK SHEAR OF 40-50 KT AND STRAIGHT HODOGRAPHS WILL PROVE FAVORABLE FOR SPLITTING STORMS WITH HAIL AND DAMAGING WINDS THE PRIMARY THREATS. THE STRONGEST INSTABILITY SHOULD BE LOCATED WITH WSWWD EXTENT ACROSS SOUTH CENTRAL TX...WHERE THE POTENTIAL EXISTS FOR STORM DEVELOPMENT THIS AFTERNOON AND EVENING...BUT OVERALL STORM COVERAGE MAY BE LESS. STORMS THAT DO DEVELOP IN THIS AREA COULD PRODUCE VERY LARGE HAIL /EXCEEDING 2 INCH DIAMETER/...BUT CONFIDENCE IN THE OVERALL COVERAGE OF THIS THREAT PRECLUDES THE INCLUSION OF A SIGNIFICANT HAIL AREA. ...SRN AL AND WRN FL PANHANDLE... TSTMS WILL BE POSSIBLE FROM THE LOWER MS VALLEY EWD TO THE SERN STATES. WEAKER MIDLEVEL LAPSE RATES WITH EWD EXTENT INTO THE CENTRAL GULF COAST REGION WILL TEND TO LIMIT THE DEVELOPMENT OF STRONGER INSTABILITY. THESE FACTORS COMBINED WITH WEAK EFFECTIVE BULK SHEAR SHOULD RESULT IN A MINIMAL SEVERE WEATHER THREAT INTO SRN AL AND THE WRN FL PANHANDLE. ...SACRAMENTO/SAN JOAQUIN VALLEYS... TSTM DEVELOPMENT IS EXPECTED IN THE CENTRAL VALLEY OF CA...ESPECIALLY THIS AFTERNOON INTO THE EARLY EVENING. ALTHOUGH EFFECTIVE BULK SHEAR WILL BE QUITE WEAK LIMITING THE POTENTIAL FOR STORM ORGANIZATION...500 MB TEMPERATURES /-22 TO -24 C/ AND LOW-MID LEVEL LAPSE RATES AROUND 7 C/KM SUGGEST SUB-SEVERE HAIL WILL BE POSSIBLE WITH THE STRONGER ACTIVITY. ..PETERS/DEAN.. 03/31/2013  296 ACUS02 KWNS 310604 SWODY2 SPC AC 310602 DAY 2 CONVECTIVE OUTLOOK RESENT 1 NWS STORM PREDICTION CENTER NORMAN OK 0102 AM CDT SUN MAR 31 2013 VALID 011200Z - 021200Z ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... A BROAD UPPER TROUGH WILL EXTEND FROM THE NRN PLAINS EWD INTO NEW ENGLAND WITH STRONG WINDS ALOFT ROTATING AROUND AN ERN CANADA UPPER LOW. AT THE SURFACE...A COLD FRONT WILL DRIFT SWD AND WILL EXTEND ROUGHLY FROM NWRN TX EWD INTO THE CNTRL GULF COAST STATES DURING THE DAY. S OF THIS FRONT...BOUNDARY LAYER DEWPOINTS IN THE 50S TO LOWER 60S F WILL RESULT IN MARGINAL INSTABILITY AND THUNDERSTORMS. AN APPROACHING SHORTWAVE TROUGH WILL ALSO BE MOVING EWD ACROSS THE FOUR CORNERS STATES OVERNIGHT AND WILL HELP INDUCE SLY RETURN FLOW ACROSS TX WHICH WILL ENHANCE NOCTURNAL THUNDERSTORM POTENTIAL WITH SOME SEVERE STORMS POSSIBLE. ...NWRN TX... SHORTWAVE RIDGING WILL OCCUR DURING THE DAY WITH STRONG HEATING S OF THE COLD FRONT. THIS FRONT SHOULD ADVANCE SWWD ACROSS THE TX PANHANDLE AS WEAK LOW PRESSURE DEVELOPS OVER SERN NM/W TX. BACKED SURFACE WINDS WILL HELP MAINTAIN DEWPOINTS IN THE 40S...WHICH WILL RESULT IN SUFFICIENT INSTABILITY FOR A FEW STRONG TO SEVERE THUNDERSTORMS GIVEN THE STEEP LAPSE RATE ENVIRONMENT AND MODERATE DEEP LAYER SHEAR. THE FRONT WILL BE A FOCUS FOR STORMS...WITH HAIL AND WIND DEVELOPING. NAM SUGGESTS A LOCALIZED ZONE OF SEVERE POTENTIAL ALONG WRN PORTION OF FRONT AND NEAR MOIST AXIS. CELLS WITH HAIL MAY EVENTUALLY MERGE AND PERSIST INTO THE EVENING AS A SELY LOW LEVEL JET DEVELOPS. A FEW SEVERE WIND GUSTS MAY THUS OCCUR. WITH SUCH LOW DEWPOINTS...MAXIMUM HAIL SIZE IS EXPECTED TO BE BETWEEN 1.00 AND 1.75 INCHES. ..JEWELL.. 03/31/2013  466 ACUS11 KWNS 310614 SWOMCD SPC MCD 310613 OKZ000-TXZ000-310715- MESOSCALE DISCUSSION 0349 NWS STORM PREDICTION CENTER NORMAN OK 0113 AM CDT SUN MAR 31 2013 AREAS AFFECTED...PORTIONS EXTREME ERN TX PANHANDLE...WRN/SRN OK. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 69... VALID 310613Z - 310715Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...ISOLATED TSTM STRENGTHENING OVER HEMPHILL COUNTY TX AS OF 06Z LIKELY IS FIRST MANIFESTATION OF CONVECTIVE EVENT THAT SHOULD DEVELOP AND GROW UPSCALE ACROSS WRN OK THROUGH 10Z...AND MOVE ESEWD ACROSS PORTIONS CENTRAL/SRN OK. MAIN THREAT IS LARGE HAIL. TSTMS WITH ACCESS TO PREFRONTAL/WARM-SECTOR AIR NEAR SFC ALSO MAY PRODUCE STG/ISOLATED DAMAGING GUSTS. DISCUSSION...SFC MESOANALYSIS SHOWS FRONT FROM SRN PORTIONS TUL AREA SWWD INVOF OUN THEN WWD PAST CSM TO NEAR AMA. BOUNDARY SHOULD ACCELERATE SEWD AS STRENGTHENING COLD FRONT THROUGH REMAINDER MORNING WITH WEAK FRONTAL-WAVE LOW POSSIBLE OVER NW TX. STRENGTHENING FRONTOGENETIC FORCING IS FCST TO IMPINGE ON PROGRESSIVELY GREATER WARM-SECTOR MOISTURE WITH SEWD EXTENT. ALONG/AHEAD OF FRONT...SFC DEW POINTS MID-UPPER 50S F WILL CONTRIBUTE TO 1000-1500 J/KG MLCAPE...REDUCED VERY SLOWLY AMIDST PREFRONTAL WAA/MOIST ADVECTION. THESE FACTORS SHOULD OFFSET DELETERIOUS EFFECTS OF SFC DIABATIC COOLING AND WEAK PREFRONTAL WINDS ENOUGH TO CONTRIBUTE TO ADDITIONAL DEVELOPMENT AND UPSCALE GROWTH OF CONVECTION. ASSORTED STORM-MOTION ALGORITHMS APPLIED TO FCST SOUNDINGS SUGGEST ACTIVITY FORMING ALONG FRONT MAY BE UNDERCUT...BUT ONLY GRADUALLY...GIVEN ITS SEWD MOTION INFLUENCED BY DEEP-LAYER WIND PROFILES ABOVE FRONTAL CURRENT. ADDITIONALLY...STEEP LAPSE RATES AND MOISTURE ARE EXPECTED ABOVE FRONTAL SFC AND WITHIN AT LEAST 75 NM BEHIND FRONT...WHERE ELEVATED MUCAPE 500-1000 J/KG IS POSSIBLE AMIDST 35-45 KT EFFECTIVE SHEAR MAGNITUDES. ..EDWARDS/KERR.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TSA...FWD...OUN...LUB...AMA... LAT...LON 35920024 35869908 35939777 35529651 35259642 34059640 33799728 34399951 34620008 35180036 35920024  455 ACUS03 KWNS 310721 SWODY3 SPC AC 310719 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0219 AM CDT SUN MAR 31 2013 VALID 021200Z - 031200Z ...NO SVR TSTM AREAS FORECAST... ...TX... A COLD FRONT IS EXPECTED TO BE LOCATED SOMEWHERE OVER TX DURING THE DAY...EXTENDING EWD ACROSS THE GULF COAST STATES. MODELS ARE IN DISAGREEMENT WITH FRONTAL POSITION...WITH THE NAM SOLUTION SIGNIFICANTLY FARTHER S INTO CNTRL TX WHILE THE GFS AND ECMWF HAVE IT OVER NRN TX. REGARDLESS...THUNDERSTORMS WILL BE LIKELY ALONG THE COLD FRONT AND ELEVATED TO THE N AS SLY FLOW MAINTAINS MOISTURE FLUX. A SHORTWAVE TROUGH MOVING ACROSS CO/NM WILL ALSO INCREASE LIFT AS IT EMERGES OVER THE SRN PLAINS LATE. WHILE MOISTURE AND INSTABILITY WILL EXIST ACROSS THE WARM SECTOR...SHEAR PROFILES IN THE LOW TO MID LEVELS ARE FORECAST TO BE ONLY MARGINALLY FAVORABLE FOR ORGANIZED SEVERE. AS A RESULT...OVERALL SEVERE POTENTIAL APPEARS LOW. WHILE A FEW SEVERE STORMS WITH HAIL AND WIND COULD OCCUR...PREDICTABILITY IS TOO LOW FOR ANY AREAS. ..JEWELL.. 03/31/2013  691 ACUS48 KWNS 310833 SWOD48 SPC AC 310832 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0332 AM CDT SUN MAR 31 2013 VALID 031200Z - 081200Z ...DISCUSSION... FROM WED/D4 TO THU/D5...A LOW-LATITUDE SHORTWAVE TROUGH WILL MOVE ACROSS SRN PLAINS AND ACROSS THE GULF COAST STATES...THEN WILL PHASE WITH THE LARGER SCALE NERN TROUGH AS IT APPROACHES THE E COAST ON FRI/D6. INSTABILITY OVER THE LAND IS EXPECTED TO REMAIN WEAK DUE TO HIGH PRESSURE RIDGE IN PLACE. HOWEVER...MOISTURE WILL INCREASE ACROSS FL DUE TO SWLY FLOW OFF THE GULF...AND SHEAR PROFILES WILL INCREASE AS WELL. THE MOST LIKELY SCENARIO IS FOR A LINE OF STORMS TO FORM OVER THE ERN GULF AND THEN MOVE ACROSS THE PENINSULA WITH PERHAPS A DAMAGING WIND/MARGINAL TORNADO THREAT. THIS COULD HAPPEN THU OR FRI...DEPENDENT ON HOW FAST THE TROUGH MOVES. IF MODELS COME INTO BETTER AGREEMENT IN LATER OUTLOOKS...A SEVERE RISK AREA COULD BE ADDED FOR FL. FOR D7-D8...THE PATTERN BECOMES MORE ZONAL BUT MODELS DO SHOW A POSSIBLE WRN TROUGH DEVELOPING...WHICH COULD LEAD TO EPISODES OF SEVERE WEATHER ACROSS THE PLAINS IN THE D9-D10 TIME FRAME. ..JEWELL.. 03/31/2013  831 ACUS11 KWNS 310954 SWOMCD SPC MCD 310954 OKZ000-TXZ000-311130- MESOSCALE DISCUSSION 0350 NWS STORM PREDICTION CENTER NORMAN OK 0454 AM CDT SUN MAR 31 2013 AREAS AFFECTED...PORTIONS SRN OK...N-CENTRAL/NE TX CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 310954Z - 311130Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...WW ISSUANCE IS BECOMING MORE LIKELY ACROSS ESPECIALLY CENTRAL-ERN PARTS OF DISCUSSION AREA -- S-CENTRAL/SERN OK AND PORTIONS N-CENTRAL/NE TX. MAIN THREAT WILL REMAIN LARGE HAIL...WITH ISOLATED DAMAGING WIND POSSIBLE. DISCUSSION...TSTMS CONTINUE TO INCREASE IN COVERAGE PRIMARILY ALONG AND BEHIND STRENGTHENING COLD FRONT THAT WAS ANALYZED AT 0930Z FROM WEAK LOW OVER NERN OK...SWWD ACROSS PVJ-DUC-LBB. CONVECTION OVER CENTRAL OK HAS PRODUCED MOSTLY MRGL SVR HAIL OF 1-1.5 INCHES WITH ISOLATED HIGHER REPORTS PER NSSL-PING DATA. COLD FRONT SHOULD CONTINUE MOVING SEWD ACROSS REGION...ITS BAROCLINICITY REINFORCED BY OUTFLOW FROM SCATTERED TO LOCALLY NUMEROUS TSTMS NOW FOUND ALONG AND BEHIND BOUNDARY. FRONTOGENETIC FORCING WILL IMPINGE ON BOUNDARY LAYER CHARACTERIZED BY SFC DEW POINTS RANGING FROM MID-50S TO LOW-60S F...SUPPORTING MLCAPE 500-1000 J/KG AND MUCAPE 1000-1500 J/KG...AMIDST 35-45 KT EFFECTIVE SHEAR MAGNITUDES FAVORABLE FOR MAINTAINING TSTM ORGANIZATION. CONTINUED UPSCALE GROWTH IS POSSIBLE WITH RESULTING MCS CROSSING RED RIVER INTO N-CENTRAL/NE TX NEAR AND W OF OUTFLOW BOUNDARY LEFT BEHIND BY EARLIER/SERN OK CONVECTION. ..EDWARDS/KERR.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SHV...TSA...FWD...OUN... LAT...LON 34939945 34779888 34799789 34989693 35289617 34679559 34049487 33329479 32929560 33019692 33739898 34939945  523 ACUS01 KWNS 311217 SWODY1 SPC AC 311215 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0715 AM CDT SUN MAR 31 2013 VALID 311300Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS PARTS OF CENTRAL...SOUTHERN AND EASTERN TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SYNOPSIS... MODELS SUGGEST THAT BLOCKING OVER THE EASTERN PACIFIC WILL WEAKEN DURING THIS FORECAST PERIOD...AS A COUPLE OF SIGNIFICANT UPSTREAM IMPULSES WITHIN THE SPLIT MID-LATITUDE WESTERLIES PROGRESS EASTWARD. THE REMNANTS OF THE SOUTHERN STREAM CLOSED LOW ARE FORECAST TO SHIFT INLAND ACROSS CALIFORNIA INTO THE GREAT BASIN BY 12Z MONDAY. HOWEVER...THE DOWNSTREAM CONFLUENCE OF THE NORTHERN AND SOUTHERN STREAMS IS EXPECTED TO LINGER ACROSS THE HIGH PLAINS...AS AN UPPER TROUGH WITHIN THE MORE PROMINENT NORTHERN STREAM CONTINUES TO AMPLIFY EAST OF THE MISSISSIPPI VALLEY...IN RESPONSE TO A STRONG SHORT WAVE IMPULSE DIGGING SOUTHEAST OF THE UPPER MIDWEST. A NUMBER OF OTHER IMPULSES ARE PROGRESSING THROUGH THE CYCLONIC NORTHERN STREAM EAST OF THE ROCKIES. THE MOST SIGNIFICANT OF THESE IS NOW DIGGING THROUGH THE LOWER MISSOURI VALLEY...AND FORECAST TO TURN EASTWARD THROUGH THE OHIO VALLEY...THEN NORTHEASTWARD TOWARD NEW ENGLAND LATER TODAY AND TONIGHT. THIS IS ACCOMPANIED BY AN INITIAL COLD FRONTAL SURGE INTO THE SOUTHERN PLAINS...WHILE A STRONGER INTRUSION OF COLD AIR BEGINS TO NOSE SOUTHWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST. MODEST LINGERING LOW-LEVEL MOISTURE ACROSS THE SOUTHERN PLAINS...NEAR AND SOUTH OF THE INITIAL FRONT...COUPLED WITH RESIDUAL VERY STEEP MID-LEVEL LAPSE RATES...ARE EXPECTED TO CONTRIBUTE TO CONSIDERABLE VIGOROUS CONVECTIVE DEVELOPMENT TODAY. SOME OF THIS ACTIVITY PROBABLY WILL DEVELOP EAST SOUTHEASTWARD INTO THE LOWER MISSISSIPPI VALLEY...AND WILL INCLUDE A FEW SEVERE STORMS. ...SOUTHERN PLAINS INTO LOWER MISSISSIPPI VALLEY... AN INITIAL STRONG/SEVERE STORM CLUSTER HAS EVOLVED NEAR THE RED RIVER VALLEY...SUPPORTED BY FORCING ASSOCIATED WITH THE SOUTHWARD SURGING FRONT...AND AT LEAST THE GLANCING INFLUENCE OF THE MISSOURI VALLEY SHORT WAVE IMPULSE. STRONGEST CONVECTION CURRENTLY APPEARS TO BE WHERE THE FRONT IS INTERSECTING A REMNANT CONVECTIVE BOUNDARY ON THE EASTERN FRINGE OF STRONGER MID-LEVEL CAPPING EXTENDING EAST SOUTHEAST OF THE RED RIVER VALLEY THROUGH THE ARKLATEX REGION. ACTIVITY PROBABLY WILL CONTINUE TO TRACK ALONG THIS BOUNDARY ACROSS THE ARKLATEX AND NORTHERN LOUISIANA BY EARLY AFTERNOON...ACCOMPANIED BY THE RISK FOR DAMAGING WIND GUSTS AND LARGE HAIL. A TORNADO MAY NOT BE COMPLETELY OUT OF THE QUESTION WITHIN A NARROW CORRIDOR ALONG THE BOUNDARY...BUT THIS THREAT APPEARS LIMITED IN GENERAL BY THE WEAK TO MODEST NATURE OF THE LOW-LEVEL FLOW FIELDS AND SHEAR. MEANWHILE...LOWER/MID TROPOSPHERIC WARM ADVECTION...MID-LEVEL COOLING...AND AN INCREASINGLY DIVERGENT UPPER FLOW FIELD BETWEEN THE DISTINCT NORTHERN AND SOUTHERN STREAMS...PROBABLY WILL SUPPORT ADDITIONAL CONVECTIVE DEVELOPMENT TO THE SOUTHWEST OF THE INITIAL CLUSTER...ROUGHLY BETWEEN WACO AND TYLER BY MIDDAY. AIDED BY MODERATELY LARGE CAPE AND FAVORABLE DEEP LAYER SHEAR BENEATH 30-40+ KNOT WEST NORTHWESTERLY 500 MB FLOW...AN ORGANIZED SEVERE THREAT IS EXPECTED TO EVOLVE...WITH THE RISK FOR DAMAGING WIND GUSTS AND LARGE HAIL. MORE UNCERTAINTY LINGERS SOUTHWARD INTO THE TEXAS HILL COUNTRY AND AREAS SOUTHEASTWARD TOWARD THE MIDDLE AND LOWER TEXAS COAST. BUT FORCING ASSOCIATED WITH A SOUTHERN STREAM IMPULSE COULD CONTRIBUTE TO ADDITIONAL STRONG/SEVERE STORM DEVELOPMENT DURING THE AFTERNOON HOURS. ...CENTRAL CALIFORNIA COASTAL AREAS AND INTERIOR VALLEY... AS THE MID-LEVEL COLD CORE /-22 TO -24C AT 500 MB/ ASSOCIATED WITH THE CLOSED LOW SPREADS INLAND TODAY...THERMODYNAMIC PROFILES MAY BECOME SUPPORTIVE OF HAIL WITH THUNDERSTORM ACTIVITY. IT MAY NOT BE OUT OF THE QUESTION THAT STRONGER CELLS COULD AT LEAST BRIEFLY APPROACH SEVERE CRITERIA...BUT THE SEVERE THREAT IN GENERAL IS EXPECTED TO BE LIMITED BY WEAK VERTICAL SHEAR. ..KERR/LEITMAN.. 03/31/2013  550 ACUS11 KWNS 311237 SWOMCD SPC MCD 311236 LAZ000-ARZ000-TXZ000-OKZ000-311430- MESOSCALE DISCUSSION 0351 NWS STORM PREDICTION CENTER NORMAN OK 0736 AM CDT SUN MAR 31 2013 AREAS AFFECTED...PORTIONS SERN OK...N-CENTRAL/NE TX...SWRN AR...NWRN LA. CONCERNING...SEVERE THUNDERSTORM WATCH 70... VALID 311236Z - 311430Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 70 CONTINUES. SUMMARY...QUASI-LINEAR MCS WILL CONTINUE TO OFFER THREAT FOR LARGE HAIL AND OCNL DAMAGING GUSTS AS IT CONTINUES TO FORWARD-PROPAGATE SEWD FROM RED RIVER REGION ACROSS NE TX...SMALL PART OF SERN OK...AND PERHAPS SWRN AR. ADDITIONAL WW MAY BE NEEDED WITHIN NEXT FEW HOURS FOR ADJOINING PORTIONS SRN AR AND LA AS CONVECTIVE AND DESTABILIZATION TRENDS WARRANT. DISCUSSION...QLCS AT 12Z WAS MOVING SEWD ABOUT 35 KT AND NEARLY COLLOCATED WITH...OR SLIGHTLY BEHIND...SFC COLD FRONT FROM PUSHMATAHA COUNTY OK SWWD TO NRN DENTON COUNTY TX. FRONT EXTENDED SWWD ACROSS ABI AREA AND MAY BE FOCUS FOR BACKBUILDING AS IT IMPINGES UPON FAVORABLY MOIST AIR MASS OVER N-CENTRAL TX...WITH SFC DEW POINTS COMMONLY 60S F. HOWEVER...EXTENT OF FRONTAL CONVECTIVE DEVELOPMENT SWWD WILL BE LIMITED BY COMBINATION OF 1. DRIER AIR MASS SW OF WW... 2. PROGRESSIVELY STRONGER EML AND RELATED CINH PER AVAILABLE RAOBS AND FCST SOUNDINGS. ACTIVITY FARTHER NE OVER WRN AR APPEARS TO BE ELEVATED BASED ON MODIFICATIONS TO LZK RAOB AND MODEL SOUNDINGS. REFLECTIVITY ANIMATIONS INDICATE WEAKENING CONVECTION OVER ERN PORTIONS AR/LA BORDER THAT TRACES BACK TO TSTMS ORIGINATING OVER E-CENTRAL OK BEFORE SUNSET YESTERDAY. THIS ACTIVITY -- WHILE SMALL RELATIVE TO CURRENT RED RIVER MCS -- STILL LEFT SUBTLE/RESIDUAL OUTFLOW BOUNDARY EXTENDING WNWWD BETWEEN TXK-SHV...TO NE TX NEAR PRX. SPUR OF CONVECTION THAT OVER CHOCTAW COUNTY OK -- AHEAD OF BUT BEING OVERTAKEN BY MAIN MCS -- APPEARS TO BE ON THAT BOUNDARY. LOW-LEVEL CONFLUENCE AND LIFT SHOULD REMAIN RELATIVELY MAXIMIZED WHERE MAIN MCS ENCOUNTERS OUTFLOW BOUNDARY. WITH SOMEWHAT MORE STABLE AIR MASS E OF BOUNDARY AS LOOSE ERN BOUND AND HIGH-CINH EML WITH DRIER AIR FARTHER W...CHANNEL OF MOST FAVORABLE MCS MOTION SHOULD EXTEND SEWD OVER NE TX AND PORTIONS NWRN LA. FOREGOING AIR MASS MAY BE DESTABILIZED FAVORABLY AFTER ONSET OF DIABATIC SFC HEATING....BOOSTING MLCAPE BEYOND CURRENT 500-1500 J/KG VALUES AND WEAKENING CINH. EFFECTIVE SHEAR MAGNITUDES SHOULD REMAIN AROUND 40-45 KT IN SUPPORT OF TSTM ORGANIZATION. ..EDWARDS.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAN...LZK...SHV...TSA...HGX...FWD...OUN... LAT...LON 33109740 33839587 34429497 34479429 33819376 32959200 31679351 31469479 31529626 32109821 33109740  228 ACUS11 KWNS 311534 SWOMCD SPC MCD 311533 LAZ000-ARZ000-TXZ000-311630- MESOSCALE DISCUSSION 0352 NWS STORM PREDICTION CENTER NORMAN OK 1033 AM CDT SUN MAR 31 2013 AREAS AFFECTED...ARKLATEX CONCERNING...SEVERE THUNDERSTORM WATCH 70...71... VALID 311533Z - 311630Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 70...71...CONTINUES. SUMMARY...GUSTY WINDS AND HAIL WILL BE NOTED ALONG SQUALL LINE AS IT SPREADS SEWD ACROSS THE ARKLATEX. DISCUSSION...ONGOING SQUALL LINE THAT STRETCHES FROM SRN AR...SWWD INTO NERN TX IS PROPAGATING SEWD AT ROUGHLY 30-35KT. GIVEN THE SLOW AIRMASS RECOVERY ACROSS NRN LA IT APPEARS THIS CONVECTION SHOULD BE MAINTAINED AS IT SPREADS ACROSS INSTABILITY AXIS CHARACTERIZED BY MUCAPE OF 1000-1500 J/KG. LATEST WDSS MESH DATA SUGGESTS EMBEDDED HAIL CORES ARE MOSTLY LESS THAN ONE INCH ALTHOUGH OCCASIONALLY SPIKING TO SEVERE LEVELS AT TIMES. OTHERWISE...ISOLATED SEVERE WIND GUSTS CAN BE EXPECTED WITH THIS LINEAR MCS AS IT MOVES SEWD. ..DARROW.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LZK...SHV...HGX...FWD... LAT...LON 32029647 32689417 33719243 32389206 31209473 32029647  106 ACUS01 KWNS 311631 SWODY1 SPC AC 311629 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1129 AM CDT SUN MAR 31 2013 VALID 311630Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF TEXAS AND THE LWR MS VLY... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF CNTRL CA... ...SYNOPSIS... PROGRESSIVE SPLIT PATTERN WILL PREVAIL THIS PERIOD AS E PACIFIC UPR LOW SLOWLY WEAKENS AND MOVES EWD INTO NV EARLY MON. DOWNSTREAM FROM THE SPLIT...THE NRN STREAM WILL BECOME MORE DOMINANT AS A SERIES OF DISTURBANCES CONTINUE TO AMPLIFY SEWD ACROSS THE UPR GRT LKS....AND THE SRN STREAM IS SUPPRESSED FARTHER S ACROSS S TX AND THE NRN GULF OF MEXICO. AN IMPULSE IN THE SRN STREAM...NOW ENTERING SW TX...SHOULD REACH THE S TX CSTL PLN BY EVE AND MAY ENHANCE TSTM POTENTIAL OVER CNTRL...SRN...AND ERN TX LATER TODAY. AT THE SFC...STRONG COLD FRONT ASSOCIATED WITH AMPLIFYING NRN STREAM TROUGH WILL CONTINUE S AND SE ACROSS CNTRL PLNS...MID MS VLY...AND GRT LKS...BUT OF THE MAIN BOUNDARY OF NOTE FOR SVR WEATHER POTENTIAL WILL REMAIN LEAD FRONT/WIND SHIFT NOW ARCING FROM WRN AR S AND SW INTO CNTRL TX. ...CNTRL/E TX INTO LWR MS VLY TODAY/TNGT... NE TX/NW LA SQLN APPEARS WELL-ORGANIZED AND IS SUPPORTED BY AN APPRECIABLE COLD POOL. THE MCS SHOULD CONTINUE ESE INTO E CNTRL TX...CNTRL LA...AND WRN/SRN MS THROUGH THIS AFTN. SOME INTENSIFICATION SEEMS LIKELY DUE TO DIURNAL DESTABILIZATION...PERSISTENT MOISTURE INFLOW /30+ KT WSWLY LLJ WITH PW AOA 1 INCH/...AND MODEST UPR LVL DIVERGENCE. WHILE THE MAIN SVR THREATS SHOULD BE HAIL AND LOCALLY DMGG WIND...A TORNADO CANNOT BE RULED OUT...ESPECIALLY IN THE WRN PART OF THE CONVECTIVE SYSTEM. A SEPARATE AREA OF TSTMS MAY FORM LATER TODAY OVER CNTRL TX...ALONG WRN EXTENSION OF THE SAME FRONT ALONG WHICH THE NE TX SQLN FORMED DURING THE OVERNIGHT. WITH SFC HEATING...THERMODYNAMIC PROFILES SHOULD BECOME FAVORABLE FOR STRONG UPDRAFTS ALONG AND S OF BOUNDARY GIVEN SFC DEWPOINTS IN THE LWR 60S AND CONTINUING PRESENCE OF DEEP EML. DEVELOPMENT MAY BE FOSTERED BY APPROACH OF SW TX UPR IMPULSE. PROXIMITY OF SRN STREAM JET /WITH 500 MB WNW FLOW AROUND 40 KTS/ WILL PROMOTE STORM ORGANIZATION/SUSTENANCE...WITH DEVELOPMENT OF A FORWARD-PROPAGATING SQLN POSSIBLE BY LATE IN THE DAY. SUCH A SYSTEM...IF IT WERE TO DEVELOP...COULD EXTEND A RISK FOR SVR HAIL AND WIND E TO THE MIDDLE AND UPR TX GULF CSTL PLN BY EVE. ...CNTRL CA CST AND INTERIOR VLY THIS AFTN/EARLY EVE... MID-LVL COLD CORE /-22 TO -24C AT 500 MB/ ASSOCIATED WITH E PAC UPR LOW WILL MOVE INLAND THIS AFTN. IN CONJUNCTION WITH SFC HEATING AND SFC DEWPOINTS AROUND 50 F...THERMODYNAMIC PROFILES MAY BECOME FAVORABLE FOR HAIL AS CONVECTION/TSTMS FORM OVER REGION. SOME STRONGER CELLS COULD BRIEFLY BECOME SVR...AND A TORNADO IS NOT TOTALLY OUT OF THE QUESTION. THE OVERALL SVR THREAT SHOULD...HOWEVER REMAIN LIMITED BY RELATIVELY MODEST VERTICAL SHEAR. ..CORFIDI/ROGERS.. 03/31/2013  129 ACUS11 KWNS 311655 SWOMCD SPC MCD 311654 MSZ000-LAZ000-ARZ000-TXZ000-311730- MESOSCALE DISCUSSION 0353 NWS STORM PREDICTION CENTER NORMAN OK 1154 AM CDT SUN MAR 31 2013 AREAS AFFECTED...SERN TX...LA...WCNTRL MS CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON 70...71... VALID 311654Z - 311730Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...SEVERE THUNDERSTORM WATCH WILL BE ISSUED SOON TO BETTER REFLECT ONGOING SEVERE THREAT FROM SERN TX INTO WCNTRL MS. DISCUSSION...WELL ORGANIZED SQUALL LINE CONTINUES ITS SEWD MOVEMENT ACROSS THE ARKLATEX AT ROUGHLY 35KT...THOUGH A SLIGHTLY FASTER SURGE IS NOTED WITH ARCING LINE SEGMENT NEAR THE SABINE RIVER. PROPAGATION COMPONENT WILL CONTRIBUTE CONSIDERABLY TO THE SWD MOVEMENT OF THIS MIDDLE LINE SEGMENT AS IT MOVES ACROSS LA. ADDITIONALLY...SWWD DEVELOPMENT IS EXPECTED ACROSS SERN TX ACCOUNTING FOR THE NEED TO INCLUDE PORTIONS OF HGX CWA. ..DARROW/CORFIDI.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAN...LIX...LCH...SHV...HGX... LAT...LON 31149571 33069114 31999040 30259185 31149571  230 ACUS02 KWNS 311728 SWODY2 SPC AC 311726 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1226 PM CDT SUN MAR 31 2013 VALID 011200Z - 021200Z ...NO SVR TSTM AREAS FORECAST... ...SRN PLAINS... AN UPPER-LEVEL LOW WILL MOVE EWD ACROSS THE INTERMOUNTAIN WEST ON MONDAY AS A SHORTWAVE UPPER-LEVEL RIDGE REMAINS IN PLACE ACROSS THE SRN PLAINS. AT THE SFC...A LOW IS FORECAST TO DEEPEN ACROSS ERN NM AS A COLD FRONT ADVANCES SWD INTO NE NM AND THE TX PANHANDLE. SOUTH OF THE FRONT ON THE CAPROCK OF WEST TX...SFC DEWPOINTS ARE FORECAST TO BE IN THE 40S F WITH LOWER TO MID 50S F PRESENT EWD ACROSS THE LOW ROLLING PLAINS. THIS SHOULD ALLOW FOR MODERATE DESTABILIZATION BY MONDAY AFTERNOON FROM LUBBOCK AND MIDLAND EWD. IN THE PRESENCE OF WEAK LARGE-SCALE FORCING...ISOLATED THUNDERSTORM INITIATION MAY TAKE PLACE LATE MONDAY AFTERNOON ALONG THE FRONT IN THE SRN TX PANHANDLE OR SWD ALONG A SFC TROUGH IN THE LUBBOCK AND MIDLAND AREAS. FORECAST SOUNDINGS AT LUBBOCK AND MIDLAND AT 00Z/TUE SHOW LARGE TEMP-DEWPOINT SPREADS WITH LCL HEIGHTS AROUND 2500 METERS WHICH SHOULD MAKE THE CONVECTION HIGH-BASED. IN SPITE OF THIS FACTOR...0-6 KM SHEAR IN THE 40 TO 50 KT RANGE AND STEEP LAPSE RATES COULD BE ENOUGH FOR AN ISOLATED SEVERE THREAT WITH HAIL POSSIBLE IN THE STRONGER CORES. THE SEVERE THREAT COULD INCREASE IF CONVECTION CAN PERSIST INTO THE EARLY EVENING AND REACH THE LOW-ROLLING PLAINS WHERE LOW-LEVEL MOISTURE IS FORECAST TO BE GREATER. ...NRN FL/SRN GA/FAR SRN SC... AN UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE ERN GULF COAST STATES MONDAY AS A COLD FRONT ADVANCES SEWD ACROSS THE REGION. THUNDERSTORMS COULD BE ONGOING ALONG OR AHEAD OF THE FRONT DURING THE MORNING WITH THIS ACTIVITY MOVING SEWD INTO NRN FL AROUND MIDDAY. MODEL FORECASTS SHOW A CORRIDOR OF LOW-LEVEL MOISTURE EXTENDING NEWD FROM NRN FL INTO SE GA WHERE SFC DEWPOINTS COULD BE AROUND 60 F. THIS ALONG WITH SFC HEATING SHOULD ALLOW FOR WEAK DESTABILIZATION. AS CELLS INTENSIFY EARLY MONDAY AFTERNOON...THE UNIDIRECTIONAL WIND PROFILES AND STEEP LOW-LEVEL LAPSE RATES COULD BE ENOUGH FOR A MARGINAL WIND DAMAGE THREAT. ..BROYLES.. 03/31/2013  600 ACUS11 KWNS 311801 SWOMCD SPC MCD 311800 TXZ000-311900- MESOSCALE DISCUSSION 0354 NWS STORM PREDICTION CENTER NORMAN OK 0100 PM CDT SUN MAR 31 2013 AREAS AFFECTED...PORTIONS OF CNTRL TX AND MIDDLE TX COASTAL PLAIN CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 311800Z - 311900Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...A THREAT FOR LARGE HAIL AND DMGG WINDS MAY ACCOMPANY TSTMS THIS AFTERNOON. PORTIONS OF CNTRL AND E TX ARE BEING MONITORED FOR A LIKELY WW. DISCUSSION...TSTMS HAVE BEEN SLOWLY INCREASING IN INTENSITY/COVERAGE OVER THE PAST FEW HRS IN RESPONSE TO A WEAK UPPER IMPULSE MOVING ACROSS CNTRL TX. THIS IS OCCURRING ALONG AND IMMEDIATELY N OF A SWD MOVING COLD FRONT...AND STORMS HAVE THUS FAR BEEN PRIMARILY ROOTED ABOVE THE BOUNDARY LAYER. WITH FURTHER HEATING/DESTABILIZATION EXPECTED TO YIELD MLCAPE VALUES APPROACHING 2500 J/KG ALONG/S OF THE COLD FRONT...TSTMS SHOULD CONTINUE TO INTENSIFY THROUGH THE AFTERNOON AND BECOME INCREASINGLY SFC-BASED. DESPITE A RELATIVE WEAKNESS IN LOW-LEVEL FLOW /PER REGIONAL VWP DATA/...MIDLEVEL WLYS WILL BE SUFFICIENTLY STRONG /E.G. 30-40 KTS/ TO PROMOTE ORGANIZED STORM STRUCTURES...AND POSSIBLE CONSOLIDATION /GIVEN BOUNDARY-PARALLEL ORIENTATION OF DEEP-LAYER SHEAR VECTOR/ INTO A CLUSTER OR FORWARD-PROPAGATING QLCS. THE PRIMARY HAZARDS WITH THIS ACTIVITY ARE EXPECTED TO BE DMGG WIND GUSTS AND LARGE HAIL...BUT A TORNADO CANNOT BE RULED OUT...PARTICULARLY WITH ANY DISCRETE STORMS THAT MAY DEVELOP. ..ROGERS/CORFIDI.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HGX...FWD...EWX...SJT... LAT...LON 29429832 29499958 29560118 29810144 29910158 30360125 30720034 30949922 30939807 31099703 31139612 31109547 30349530 29809534 29339648 29429832  928 ACUS11 KWNS 311932 SWOMCD SPC MCD 311932 MSZ000-LAZ000-TXZ000-312030- MESOSCALE DISCUSSION 0355 NWS STORM PREDICTION CENTER NORMAN OK 0232 PM CDT SUN MAR 31 2013 AREAS AFFECTED...SERN TX...LA...WCNTRL MS CONCERNING...SEVERE THUNDERSTORM WATCH 72... VALID 311932Z - 312030Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 72 CONTINUES. SUMMARY...ISOLATED SEVERE WIND GUSTS AND LARGE HAIL REMAIN POSSIBLE ALONG LEADING EDGE OF MCS. MAIN SEVERE THREAT IS CONFINED TO THE ERN AND SRN PERIPHERY OF WW 72. NEW WW WILL BE ISSUED SOON FOR PORTIONS OF THE UPPER TX COAST. DISCUSSION...MATURE MCS CONTINUES EXPANDING/PROPAGATING SEWD ACROSS SERN TX/LA/WCNTRL MS. EXTENSIVE PRECIPITATION SHIELD IN THE WAKE OF STRONG SQUALL LINE WILL REMAIN CONDUCIVE FOR DRIVING LEADING EDGE OF STRONGEST ACTIVITY TOWARD THE SRN/ERN EDGE OF WW 72 OVER THE NEXT FEW HOURS. AIRMASS ACROSS THE UPPER TX COAST IS ESPECIALLY MORE UNSTABLE/STEEPER LAPSE RATES THAN THE LA COASTAL PLAIN. THIS WILL PROVE FAVORABLE FOR UPSTREAM ACTIVITY OVER CNTRL TX TO SPREAD TOWARD THE UPPER TX COAST INTO THE EARLY EVENING HOURS. FOR THIS REASON A NEW WW WILL BE ISSUED FOR PORTIONS OF THE UPPER TX COAST. ..DARROW.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAN...LIX...LCH...SHV...HGX...FWD... LAT...LON 31779530 33088936 31058937 29759528 31779530  077 ACUS01 KWNS 312002 SWODY1 SPC AC 312000 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CDT SUN MAR 31 2013 VALID 312000Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS AND LOWER MS VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NRN AND CNTRL CA... SEVERAL CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR THIS ISSUANCE. THE FIRST CHANGE IS TO TRIM THE NRN PART OF THE SLIGHT RISK AREA FROM PARTS OF ECNTRL TX AND NRN LA BEHIND A LINEAR MCS WHICH IS STABILIZING THE AIRMASS. A COLD FRONT ADVANCING SWD ACROSS PARTS OF CNTRL AND EAST TX IS ALSO ADVECTING DRY AIR SWD. FOR THUNDERSTORMS THAT CAN DEVELOP ON THE NORTH SIDE OF THE BOUNDARY...THE DRY AIR SHOULD HELP KEEP THE CONVECTION BELOW SEVERE LIMITS. THE SECOND CHANGE TO THE OUTLOOK IS TO REMOVE THUNDER FROM MOST OF AR...SRN OK AND NORTH TX WHERE THE ATMOSPHERE IS BECOMING INCREASINGLY STABLE AS DRY AIR IS ADVECTED SWD. THE THIRD CHANGE TO THE OUTLOOK IS TO EXTEND THE 5 PERCENT WIND DAMAGE AND HAIL PROBABILITIES EWD ACROSS SRN GA WHERE CELLS ARE DEVELOPING IN A MODERATELY UNSTABLE AIRMASS AND LOW-LEVEL LAPSE RATES HAVE BECOME STEEP. THE FOURTH AND FINAL CHANGE TO THE OUTLOOK IS TO ADD A 2 PERCENT TORNADO PROBABILITY INTO THE SACRAMENTO VALLEY WHERE A FEW ROTATING STORMS WILL BE POSSIBLE THIS AFTERNOON. ..BROYLES.. 03/31/2013 .PREV DISCUSSION... /ISSUED 1129 AM CDT SUN MAR 31 2013/ ...SYNOPSIS... PROGRESSIVE SPLIT PATTERN WILL PREVAIL THIS PERIOD AS E PACIFIC UPR LOW SLOWLY WEAKENS AND MOVES EWD INTO NV EARLY MON. DOWNSTREAM FROM THE SPLIT...THE NRN STREAM WILL BECOME MORE DOMINANT AS A SERIES OF DISTURBANCES CONTINUE TO AMPLIFY SEWD ACROSS THE UPR GRT LKS....AND THE SRN STREAM IS SUPPRESSED FARTHER S ACROSS S TX AND THE NRN GULF OF MEXICO. AN IMPULSE IN THE SRN STREAM...NOW ENTERING SW TX...SHOULD REACH THE S TX CSTL PLN BY EVE AND MAY ENHANCE TSTM POTENTIAL OVER CNTRL...SRN...AND ERN TX LATER TODAY. AT THE SFC...STRONG COLD FRONT ASSOCIATED WITH AMPLIFYING NRN STREAM TROUGH WILL CONTINUE S AND SE ACROSS CNTRL PLNS...MID MS VLY...AND GRT LKS...BUT OF THE MAIN BOUNDARY OF NOTE FOR SVR WEATHER POTENTIAL WILL REMAIN LEAD FRONT/WIND SHIFT NOW ARCING FROM WRN AR S AND SW INTO CNTRL TX. ...CNTRL/E TX INTO LWR MS VLY TODAY/TNGT... NE TX/NW LA SQLN APPEARS WELL-ORGANIZED AND IS SUPPORTED BY AN APPRECIABLE COLD POOL. THE MCS SHOULD CONTINUE ESE INTO E CNTRL TX...CNTRL LA...AND WRN/SRN MS THROUGH THIS AFTN. SOME INTENSIFICATION SEEMS LIKELY DUE TO DIURNAL DESTABILIZATION...PERSISTENT MOISTURE INFLOW /30+ KT WSWLY LLJ WITH PW AOA 1 INCH/...AND MODEST UPR LVL DIVERGENCE. WHILE THE MAIN SVR THREATS SHOULD BE HAIL AND LOCALLY DMGG WIND...A TORNADO CANNOT BE RULED OUT...ESPECIALLY IN THE WRN PART OF THE CONVECTIVE SYSTEM. A SEPARATE AREA OF TSTMS MAY FORM LATER TODAY OVER CNTRL TX...ALONG WRN EXTENSION OF THE SAME FRONT ALONG WHICH THE NE TX SQLN FORMED DURING THE OVERNIGHT. WITH SFC HEATING...THERMODYNAMIC PROFILES SHOULD BECOME FAVORABLE FOR STRONG UPDRAFTS ALONG AND S OF BOUNDARY GIVEN SFC DEWPOINTS IN THE LWR 60S AND CONTINUING PRESENCE OF DEEP EML. DEVELOPMENT MAY BE FOSTERED BY APPROACH OF SW TX UPR IMPULSE. PROXIMITY OF SRN STREAM JET /WITH 500 MB WNW FLOW AROUND 40 KTS/ WILL PROMOTE STORM ORGANIZATION/SUSTENANCE...WITH DEVELOPMENT OF A FORWARD-PROPAGATING SQLN POSSIBLE BY LATE IN THE DAY. SUCH A SYSTEM...IF IT WERE TO DEVELOP...COULD EXTEND A RISK FOR SVR HAIL AND WIND E TO THE MIDDLE AND UPR TX GULF CSTL PLN BY EVE. ...CNTRL CA CST AND INTERIOR VLY THIS AFTN/EARLY EVE... MID-LVL COLD CORE /-22 TO -24C AT 500 MB/ ASSOCIATED WITH E PAC UPR LOW WILL MOVE INLAND THIS AFTN. IN CONJUNCTION WITH SFC HEATING AND SFC DEWPOINTS AROUND 50 F...THERMODYNAMIC PROFILES MAY BECOME FAVORABLE FOR HAIL AS CONVECTION/TSTMS FORM OVER REGION. SOME STRONGER CELLS COULD BRIEFLY BECOME SVR...AND A TORNADO IS NOT TOTALLY OUT OF THE QUESTION. THE OVERALL SVR THREAT SHOULD...HOWEVER REMAIN LIMITED BY RELATIVELY MODEST VERTICAL SHEAR.  788 ACUS11 KWNS 312022 SWOMCD SPC MCD 312021 ALZ000-MSZ000-LAZ000-312115- MESOSCALE DISCUSSION 0356 NWS STORM PREDICTION CENTER NORMAN OK 0321 PM CDT SUN MAR 31 2013 AREAS AFFECTED...SERN LA AND SRN AL CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 312021Z - 312115Z PROBABILITY OF WATCH ISSUANCE...60 PERCENT SUMMARY...NEW WW MAY BE REQUIRED FOR PORTIONS OF SERN LA INTO SRN AL. DISCUSSION...A NARROW CORRIDOR OF ENHANCED INSTABILITY HAS DEVELOPED FROM SERN LA INTO SRN AL WHERE SFC-3KM LAPSE RATES ARE NOW IN EXCESS OF 8 C/KM. WITH SFC DEW POINTS IN THE LOWER 60S MUCAPE IS ON THE ORDER OF 1500 J/KG. OF PARTICULAR NOTE IS THE SW-NE ORIENTED LINE SEGMENT FROM IBERVILLE PARISH TO EAST FELICIAN PARISH AND ITS MORE FAVORABLE ORIENTATION TO THE DEEPER MEAN WIND CURRENTS. THERE IS INCREASING CONCERN THAT THIS ACTIVITY MAY INTENSIFY AS IT SPREADS DOWNSTREAM INTO THE AFOREMENTIONED INSTABILITY AXIS. LOCALLY DAMAGING WINDS AND PERHAPS SOME HAIL MAY BE OBSERVED. ..DARROW/CORFIDI.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX... LAT...LON 29999116 31798885 30678836 29469008 29999116  290 ACUS11 KWNS 312152 SWOMCD SPC MCD 312151 GAZ000-FLZ000-ALZ000-312315- MESOSCALE DISCUSSION 0357 NWS STORM PREDICTION CENTER NORMAN OK 0451 PM CDT SUN MAR 31 2013 AREAS AFFECTED...SRN AL/GA...FL PANHANDLE CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 312151Z - 312315Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...CLUSTERS OF TSTMS INTENSIFYING ALONG THE MERGING OF CONVECTIVE OUTFLOW/CONFLUENCE BANDS WILL POSE A RISK FOR ISOLATED SEVERE HAIL THROUGH ABOUT SUNSET. ACTIVITY MAY MERGE WITH THE BROADER QLCS ACROSS LA/MS WHICH COULD NECESSITATE A WW ISSUANCE DOWNSTREAM OF WW 75. DISCUSSION...VIS SATELLITE/RADAR IMAGERY HAVE DEPICTED THE COLLISION OF TWO DISTINCT BOUNDARIES...WHICH HAS SUPPORTED RECENT TSTM INTENSIFICATION ACROSS SRN AL/GA. RAP-BASED 1-H FORECAST SOUNDINGS APPEAR PARTICULARLY TOO COOL/DRY IN THE BOUNDARY LAYER COMPARED TO SURFACE OBSERVATIONS WHICH IS LIKELY YIELDING SUBSTANTIALLY LESSER BUOYANCY THAN REALITY IN SPC MESOANALYSIS. GIVEN UPPER 70S TO NEAR 80 SURFACE TEMPERATURES AND MIDDLE TO UPPER 50S DEW POINTS S OF THE BOUNDARY COLLISION...AIR MASS IS PROBABLY AT LEAST MODESTLY UNSTABLE. AREA VWP DATA SAMPLED 30-40 KT IN THE 3-6 KM AGL LAYER WHICH SHOULD SUPPORT OCCASIONAL UPDRAFT ROTATION AND A CONTINUED PRIMARY RISK OF SEVERE HAIL. SOME CONSOLIDATION OF THIS DEVELOPMENT IN PARTS OF SWRN/S-CNTRL AL MAY OCCUR WITH THE BROADER QLCS AND ASSOCIATED COLD POOL EVOLVING EWD FROM SERN LA/MS. THIS MAY LEAD TO AN INCREASING DAMAGING WIND RISK ACROSS PARTS OF SWRN AL/WRN FL PANHANDLE BY 00Z. ..GRAMS/MEAD.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAX...FFC...TAE...BMX...MOB... LAT...LON 31368828 32138667 32188436 32218290 32078256 31828249 31218285 30698363 30548596 30358728 30288832 31368828  708 ACUS11 KWNS 312200 SWOMCD SPC MCD 312159 CAZ000-010000- MESOSCALE DISCUSSION 0358 NWS STORM PREDICTION CENTER NORMAN OK 0459 PM CDT SUN MAR 31 2013 AREAS AFFECTED...A LARGE PART OF CNTRL/NRN CA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 312159Z - 010000Z PROBABILITY OF WATCH ISSUANCE...5 PERCENT SUMMARY...THUNDERSTORMS WILL CONTINUE TO INCREASE IN COVERAGE ACROSS CNTRL/NRN CA THROUGH THE AFTERNOON. SMALL HAIL WILL BE POSSIBLE WITH THIS ACTIVITY...AND ONE OR TWO STORMS MAY PRODUCE MARGINALLY SVR HAIL. A WW WILL NOT BE NEEDED. DISCUSSION...DIURNAL DIABATIC HEATING WITHIN THE BOUNDARY LAYER...BENEATH COOLING MID-LEVEL TEMPERATURES PRECEDING A MID-LEVEL VORT MAX APPROACHING THE CNTRL CA COAST...IS YIELDING MARGINAL INSTABILITY. MODIFIED FORECAST SOUNDINGS TO ACCOUNT FOR CURRENT SFC OBSERVATIONS SUGGEST THAT MLCAPE VALUES OF 250-800 J/KG ARE COMMON ACROSS THE AREA. THE GREATEST INSTABILITY IS OVER THE SAN JOAQUIN AND SACRAMENTO VALLEYS...WHERE INSOLATION HAS BEEN MAXIMIZED WITH SFC TEMPERATURES HAVING CLIMBED INTO THE UPPER 60S AND LOWER 70S. OROGRAPHIC ASCENT AUGMENTED BY DCVA LEADING THE MID-LEVEL VORT MAX CONTINUES SUPPORTING CONVECTIVE DEVELOPMENT OVER THE COASTAL RANGES...AND SOME OF THIS ACTIVITY IS BEGINNING TO SPREAD OVER THE ADJACENT LOWER ELEVATIONS ACROSS THE CNTRL CA INTERIOR. AS THE DCVA MAKES ADDITIONAL PROGRESS INLAND DURING THE NEXT SEVERAL HOURS...THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE. THE AFOREMENTIONED DEGREE OF BUOYANCY AMID 500-MB TEMPERATURES FROM -25C TO -20C WILL LIKELY YIELD A THREAT FOR SMALL HAIL. ONE OR TWO OF THE STRONGEST STORMS COULD ALSO PRODUCE MARGINALLY SVR HAIL...ESPECIALLY INVOF THE COLDEST MID-LEVEL TEMPERATURES AND STRONGEST BOUNDARY-LAYER BUOYANCY -- FROM THE CNTRL CA COASTAL RANGES TO THE ADJACENT CNTRL CA VALLEY. HOWEVER...WITH AOB 25 KT OF DEEP SHEAR AND WITH WEAK LOW-LEVEL FLOW DEPICTED BY REGIONAL VWP DATA...THUNDERSTORMS WILL LIKELY LACK ANY SUBSTANTIAL ORGANIZATION/PERSISTENCE...GREATLY LIMITING ANY SVR THREAT. STORMS SHOULD WEAKEN AFTER SUNSET AS THE BOUNDARY LAYER STABILIZES. ..COHEN/MEAD.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HNX...STO...MTR...EKA... LAT...LON 39192375 39792394 40162414 40552359 40562251 39272076 37411901 36861871 36071928 35792066 36192164 36772202 37772253 38582331 39192375  975 ACUS11 KWNS 312224 SWOMCD SPC MCD 312224 TXZ000-010000- MESOSCALE DISCUSSION 0359 NWS STORM PREDICTION CENTER NORMAN OK 0524 PM CDT SUN MAR 31 2013 AREAS AFFECTED...PARTS OF S TX CONCERNING...SEVERE THUNDERSTORM WATCH 73...74... VALID 312224Z - 010000Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 73...74...CONTINUES. SUMMARY...GREATEST RISK FOR LARGE HAIL WILL PERSIST WITH DISCRETE SUPERCELLS ACROSS THE WRN PORTION OF WW 73...WHICH SHOULD EVENTUALLY EVOLVE SEWD AND NECESSITATE A NEW WW ISSUANCE IN PARTS OF THE BRUSH COUNTY THIS EVENING. RISK FOR A COMBINATION OF MARGINALLY SEVERE HAIL/DAMAGING WINDS EXISTS INVOF GALVESTON BAY AREA BEFORE QLCS MOVES COMPLETELY OFFSHORE. DISCUSSION...CLUSTERS OF TSTMS CONTINUE TO EVOLVE SWD ALONG A SAGGING W/E-ORIENTED COMPOSITE COLD FRONT/OUTFLOW. THE MOST INTENSE REFLECTIVITY ALONG THE WRN PORTION OF A LARGE-SCALE QLCS WAS LOCATED INVOF GALVESTON BAY. THE PRIMARY LIMITING FACTOR TO MORE ROBUST SEVERE POTENTIAL HERE IS THE NEARLY PARALLEL NATURE OF THE DEEP-LAYER FLOW WITH THE ORIENTATION OF THE LINE ALONG WITH WEAK LOW-LEVEL WINDS AHEAD OF IT /AS SAMPLED BY THE HGX VWP/. STILL WITH INFLOW OF LOW TO MIDDLE 80S SURFACE TEMPERATURES TO THE SW AMIDST STEEP MID-LEVEL LAPSE RATES SUPPORTS A MIXED RISK OF MARGINALLY SEVERE HAIL/DAMAGING WINDS. FARTHER WEST...A PAIR OF SUPERCELLS ACROSS UVALDE AND KINNEY COUNTIES WILL CONTINUE TO POSE A PRIMARY RISK FOR LARGE HAIL /POSSIBLY SIGNIFICANT/ WITHIN A STRONGLY UNSTABLE AIR MASS. TSTM ACTIVITY HERE SHOULD CONTINUE TO EVOLVE SEWD JUST BEHIND THE COMPOSITE OUTFLOW/FRONT WHICH WILL PROBABLY LIMIT SEVERE WIND POTENTIAL TO SOME EXTENT SHORT-TERM. HOWEVER...GIVEN DOWNSTREAM CU AGITATION TO ZAVALA COUNTY...CONSOLIDATION OF UPDRAFTS IS POSSIBLE THAT MIGHT EVOLVE INTO AN ACCELERATING SEWD-CLUSTER INTO PARTS OF DEEP S TX LATER THIS EVENING. ..GRAMS.. 03/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LCH...HGX...CRP...EWX... LAT...LON 29939397 29489381 29069508 28929620 28489773 27999823 27769902 27949988 28870053 29510102 29750088 29650014 29479925 29419722 29639517 29939397