938 ACUS01 KWNS 110050 SWODY1 SPC AC 110048 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Sat May 10 2025 Valid 110100Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE SOUTHEAST AND NORTHERN ROCKIES... ...SUMMARY... Isolated severe gusts may persist this evening over parts of the northern Rockies. A brief tornado or two, along with locally damaging winds are possible across parts of the Southeast into Sunday morning. ...Southeast... Primary severe potential early tonight should be confined to near the slow-moving warm front across parts of south GA into far southern SC. Enhanced low-level SRH along the boundary may support a few transient supercell structures persisting this evening. Bulk of this convection should diminish though and/or shift off the Lower Savannah Valley and coastal SC by early morning. A brief tornado and localized damaging winds are the primary hazards. Afternoon guidance continued to signal scattered convection redeveloping later tonight through mid-morning Sunday from portions of the northeast Gulf across the FL Panhandle and southeast AL into far southwest GA along a north-south/oriented confluence band. This will be aided by strengthening upper-level diffluence downstream of a jetlet ejecting into the central Gulf. Given the meridional deep-layer flow regime, largely paralleling the axis of storm development, heavy rain is likely the primary threat (reference WPC ERO). Near-saturated thermodynamic profiles coupled with adequate low-level SRH suggests a brief tornado and locally damaging winds will remain possible through 12Z. ...Northern Rockies... A fairly prolific number of severe gusts have been measured this evening with a swath of high-based convection across southeast ID into central MT. With limited downstream instability, this activity should diminish after sunset. Until that time, sporadic severe gusts will be possible. ..Grams.. 05/11/2025 $$  357 ACUS02 KWNS 110442 SWODY2 SPC AC 110440 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CDT Sat May 10 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MONDAY ACROSS THE FL PENINSULA THROUGH NORTHEASTERN FL...MUCH OF GA AND SC...ADJACENT PORTIONS OF NC...NRN/ERN AL...ADJACENT SRN TN... ...SUMMARY... Scattered strong thunderstorms may impact parts of the Southeast on Monday, particularly a corridor across the Florida Peninsula into the South Carolina Piedmont, where strongest activity may pose a risk for producing a couple of tornadoes and locally strong surface gusts. ...Discussion... Latest model output remains similar to prior runs concerning the mid/upper flow evolution through this period. Within the amplified, split westerlies, one significant trough is forecast to continue digging inland of the U.S. Pacific coast, downstream of a prominent ridge now building across the mid-latitude eastern Pacific. It still appears that at least one notable smaller-scale perturbation emerging from this trough will accelerate northeast of the northern U.S. Rockies into the Canadian Prairies, around the northwestern periphery of broad downstream ridging encompassing much of the U.S. northern Great Plains through the Great Lakes and St. Lawrence Valley. In lower-levels, models indicate that deeper surface troughing will shift east of the Canadian and northern U.S. Rockies into Saskatchewan/Manitoba and the Dakotas, while deepening southward through the southern high plains. However, destabilization near this feature is likely to be significantly inhibited by warm air aloft, and the lack of appreciable low-level moisture return due to the continuing presence of a broad mid/upper low initially centered across the lower Mississippi Valley. Cut off from the stronger westerlies, to the south of the broad mid-level ridging, movement of this low is likely to remain slow; however, models indicate that it will probably elongate north-northeastward across the Mid South and lower Ohio Valley, while taking on a negative tilt east of the lower Mississippi Valley into Southeast. In lower levels, this may be accompanied by broad, weak surface troughing developing across much of the Southeast, as surface ridging slowly shifts east of the Atlantic Seaboard. ...Southeast... Differences linger among the various model output, but the gradient between the low-level ridging and troughing may continue to support a belt of modest southerly low-level flow (20-30+ kt around 850 mb) along a corridor roughly from the Florida Peninsula into the South Carolina Piedmont. It appears probable that this will coincide with a deep lower/mid-tropospheric moist plume emanating from the lower latitudes, beneath a belt of moderate to strong, difluent southwesterly high-level flow Much of this corridor may be impacted by considerable remnant convectively generated cloud cover, and perhaps continuing scattered thunderstorm development, at the outset of the period. However, the environment appears at least conditionally supportive of organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. And breaks in the cloud cover during the day may allow for sufficient insolation and boundary-layer destabilization to allow for some of this potential to be realized. Otherwise, closer to the mid-level cold core, models suggest that forcing for ascent downstream of an embedded cyclonic vorticity center may aid thunderstorm development across the northern/eastern Alabama into western Georgia vicinity. Despite at least some low-level drying in the wake of the aforementioned moist plume, thermodynamic profiles might still become conducive to small to marginally severe hail in widely scattered stronger cells, in the presence of modest deep-layer shear. ..Kerr.. 05/11/2025 $$  971 ACUS01 KWNS 110543 SWODY1 SPC AC 110542 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Sun May 11 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST ID TO CENTRAL/EASTERN MT... ...SUMMARY... Scattered severe gusts are possible across a part of the Northwest from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...Northern Rockies/High Plains and northeast Great Basin... A broad upper trough, consisting of multiple embedded shortwave impulses, will largely remain anchored off the BC and Pacific Northwest Coast. A fast mid-level jet, in excess of 70 kts at 500 mb, will overspread northern CA today and expand towards the northern Rockies through 12Z Monday. Displaced northeast of this strong flow regime, a broad swath of isolated to scattered thunderstorms is expected to peak during the late afternoon and early evening. Similar to Sunday, sporadic severe gusts appear to be the primary hazard owing to deeply mixed boundary layers, especially with eastern extent from southeast ID to central/eastern MT. Pockets of modest buoyancy, coupled with moderate to strong deep-layer southwesterly speed shear, could yield a few high-based supercell structures producing small to marginally severe hail. This should be focused from the OR/WA/ID border area into central MT, and separately over southeast ID into Yellowstone. These structures may further aid in the downstream severe wind threat in MT. ...Southeast... A mid/upper cyclone will drift east across the Sabine to Lower MS Valleys through early Monday. The belt of stronger mid/upper flow will largely remain centered over the northeast Gulf Coast, with weaker branches curling northwest towards the Mid-South and the other continuing across the South Atlantic Coast. Thunderstorm clusters are expected to be ongoing across the northeast Gulf through the FL Panhandle into southeast AL/southwest GA and near coastal SC. The primary concern with the Panhandle to Chattahoochee Valley convection is for potential of a tornado or two and locally damaging winds through late morning. A 30-40 kt low-level jet is expected to sustain adequately enlarged low-level hodographs, especially towards the coast. But convection is expected to be within a messy, outflow-dominated mode by 12Z given near-parallel alignment of the deep-layer shear vector and initial north/south-oriented convective swath. More widespread convection should form along large-scale outflow into the afternoon, which will tend to push east-northeast, and sea breeze boundaries. Downstream wind profiles appear less favorable for organized storms. Weak mid-level lapse rates should further marginalize/maintain an isolated severe threat towards the South Atlantic States. Farther west in AL to MS, despite somewhat cooler mid-level temperatures closer to the upper cyclone, lapse rates still appear modest. But deep-layer speed shear will be moderately favorable amid a nearly unidirectional southeasterly wind profile. A few cells may briefly produce marginally severe hail and locally strong gusts, mainly from late afternoon into mid-evening. ..Grams/Lyons.. 05/11/2025 $$  091 ACUS03 KWNS 110729 SWODY3 SPC AC 110728 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Sun May 11 2025 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms currently appears negligible across the U.S. Tuesday through Tuesday night. ...Discussion... It appears that significant mid/upper-level troughing progressing inland of the U.S. Pacific coast may dig as far south as the lower Colorado Valley, and suppress ridging within a belt of westerlies emanating from the subtropical eastern Pacific, across the southwestern international border area. Thereafter, models indicate that the perturbation will turn eastward across the Intermountain West later Tuesday through Tuesday night, with intensifying difluent west-southwesterly mid/upper flow overspreading the southern Rockies by 12Z Wednesday. In lower levels, modestly deep surface troughing to the lee of the Rockies may continue to slowly shift eastward across the Great Plains. However, in the wake of broad, weak negatively tilted mid/upper troughing shifting east of the Mississippi Valley, toward the Atlantic coast at a slower pace than the upstream trough, strengthening low-level flow (up to 30-40 kt around 850 mb) is forecast to maintain a pronounced westerly component across the southern Great Plains into lower Mississippi Valley. This will continue to impede boundary-layer moisture return off the Gulf into the Great Plains, though evapotranspiration may contribute to moistening beneath the leading edge of a plume of warm elevated mixed-layer air advecting eastward across the central and southern Great Plains. Downstream, models indicate that there will be gradual further deepening of broad, weak surface troughing across much of the Southeast. However, the plume of seasonably high moisture content air emanating from the lower latitudes is forecast to generally shift east of the south Atlantic coast during the day Tuesday, though this may be slower to occur across southeast coastal areas of the Florida Peninsula. ...Intermountain West into Great Plains... Models suggest that destabilization beneath an elongated mid-level cold pool, trailing the surface cold front, may contribute to scattered, generally weak/diurnal thunderstorm activity across the northern Rockies and intermountain region, into the vicinity of the northern Sierra Nevada. Near the surface troughing across the Dakotas, it appears that a strongly heated and deeply mixed boundary may become characterized by 40-50 F surface temperature/dew point spreads, but with thermodynamic profiles still supportive of CAPE on the order of 500-1000 J/kg. High-based thunderstorm development appears possible near/after peak heating, which could pose some risk for locally strong surface gusts. However, the extent of this potential remains unclear, and too uncertain to introduce even low severe probabilities at the present time. ...Ohio Valley/Mid Atlantic/Southeast... Scattered, largely diurnal thunderstorm activity will again be possible beneath the weak/weakening mid-level troughing. Stronger convection may focus along the sea breeze near southeastern Florida coastal areas, and perhaps across parts of the mid and southern Atlantic Piedmont, where at least modest boundary-layer destabilization may occur. However, it is not yet clear that this will be accompanied by an appreciable risk for severe weather. ..Kerr.. 05/11/2025 $$  167 ACUS48 KWNS 110902 SWOD48 SPC AC 110900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sun May 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Latest medium-range output remains generally similar to prior runs concerning the pattern evolution Wednesday into Thursday. A significant short wave trough emerging from the Intermountain West is forecast to support modest cyclogenesis across the central and northern Great Plains through the mid/upper Mississippi Valley vicinity. It appears that this probably will be accompanied by increasing potential for strong to severe thunderstorm development, with severe probabilities maximizing across parts of the Midwest late Thursday into Thursday night, as the stronger large-scale forcing for ascent becomes better coupled with substantive boundary-layer moistening and destabilization. Aided by steep lower/mid-tropospheric lapse rates associated with elevated mixed-layer air, and moderate to strong low-level and deep-layer shear, it appears that the environment will become conducive to the evolution of an upscale growing and organizing convective system. But initial convection may include supercells posing a risk for large hail and a couple of tornadoes, before damaging wind gusts become the predominate severe hazard. Based on the subsequent pattern evolution, it appears that this convection could persist into, or re-intensify, Friday across parts of the mid/upper Ohio Valley, with additional upscale growing convection evolving along a stalling trailing cold front near the southern edge of the stronger westerlies. Into next weekend, renewed cyclogenesis appears possible along the trailing flank of the front across the south central Great Plains, where additional strong to severe thunderstorm development may focus along a developing warm front, and a developing dryline southward through the plains, as the warm sector destabilizes with increasing Gulf moisture return. However, by late Thursday into Friday, and beyond, these developments remain much more unclear, as spread among and within the various medium-range models begins to increase. Substantive differences begin to develop concerning the progressiveness of the lead trough, and a trailing short wave trough emerging from the mid-latitude Pacific. The uncertain impacts of potentially multiple evolving large convective clusters on succeeding days adds to low predictability. ..Kerr.. 05/11/2025  399 ACUS01 KWNS 111255 SWODY1 SPC AC 111254 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0754 AM CDT Sun May 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies to Montana High Plains fom mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...Northern Rockies/High Plains and northeast Great Basin... The leading portion of an eastward-transitioning upper-level trough will overspread the northern Rockies and northern Great Basin later today and tonight, with preceding height falls and a regionally strengthening 60-80 kt southwesterly mid-level jet. These trends in conjunction with orographic influences/differential heating will lead to another round of isolated to scattered thunderstorms by mid/late afternoon. Similar to Saturday, severe-caliber wind gusts will be the primary hazard as storms develop in association with deeply mixed boundary layers, especially with eastward extent from southeast Idaho to central/eastern Montana. Corridors of modest buoyancy, coupled with moderate to strong deep-layer southwesterly speed shear, could yield a few high-based supercell structures producing small to marginally severe hail. This should be focused from the Oregon/Washington/Idaho border vicinity into central Montana, and separately over southeast Idaho into Yellowstone. ...Southeast States... A persistent, slow-moving, and essentially vertically stacked low will persist, centered over the ArkLaMiss vicinity, with a preceding belt of moderately strong mid-level winds extending over the northeast Gulf to the coastal Southeast. This will overlie a moderately moist warm sector to the east of the surface cyclone and along/south of the eastward-extending stationary front (or slow-moving warm front). Scattered thunderstorms are ongoing regionally this morning, including semi-extensively over the northeast Gulf. A 30-40 kt southerly low-level jet is expected to sustain adequately enlarged low-level hodographs within this corridor, but especially towards the coast and near the warm front. But convection is expected to be within a messy, outflow-dominated mode at times. Regardless, isolated damaging wind and tornado potential is apparent. While the severe risk does not appear as semi-focused as yesterday, portions of far northern Florida to southern/southeast Georgia in vicinity of the stationary/warm front will be reevaluated for a potential Slight Risk upgrade. Farther west in Alabama and Mississippi, despite somewhat cooler mid-level temperatures closer to the upper cyclone, lapse rates still appear modest. But deep-layer speed shear will be moderately favorable amid a nearly unidirectional southeasterly wind profile. A few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, mainly from late afternoon through early/mid-evening. ..Guyer/Dean.. 05/11/2025 $$  861 ACUS11 KWNS 111300 SWOMCD SPC MCD 111259 SCZ000-GAZ000-FLZ000-ALZ000-111500- Mesoscale Discussion 0763 NWS Storm Prediction Center Norman OK 0759 AM CDT Sun May 11 2025 Areas affected...FL Panhandle/north FL into southeast AL...south GA...and southern SC Concerning...Severe potential...Watch unlikely Valid 111259Z - 111500Z Probability of Watch Issuance...20 percent SUMMARY...The threat for strong to locally severe storms may increase through the morning. DISCUSSION...Scattered storms are ongoing this morning from southeast GA into the FL Panhandle. Other than an MCS now moving off the Carolina coast, convection has largely been disorganized thus far. However, modest diurnal heating/destabilization could lead to increasingly vigorous storms with time this morning. Some increase in deep-layer flow/shear is also possible as a vorticity maximum rotates around a midlevel low centered over LA. Locally damaging winds and perhaps some hail could accompany the stronger storms through the morning. Effective SRH of 100-150 m2/s2 could also support at least transient supercell structures, with localized tornado potential, especially from the FL Panhandle into adjacent parts of southeast AL and south GA. ..Dean/Guyer.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...JAX...FFC...TAE...BMX...MOB... LAT...LON 31788641 31978448 32518218 32698132 32868047 32128049 31308136 30688165 30358196 30138240 29848374 29468505 29728594 29908620 30148676 30608672 31078661 31788641 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  143 ACUS01 KWNS 111620 SWODY1 SPC AC 111619 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1119 AM CDT Sun May 11 2025 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies to Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. ..Mosier/Wendt.. 05/11/2025 $$  113 ACUS02 KWNS 111658 SWODY2 SPC AC 111656 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1156 AM CDT Sun May 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE TENNESSEE VALLEY AND THE SOUTHEAST... ...SUMMARY... Scattered strong thunderstorms may impact parts of the Southeast on Monday. The strongest activity may pose a risk for a couple of tornadoes, locally strong surface gusts, and isolated hail. ...Southeast... The mid/upper low over the lower MS Valley will pivot northeast toward the TN Valley on Monday. A belt of enhanced south/southwesterly flow aloft will overspread portions of the Southeast. Vertically veering wind profiles, with 30-45 kt of flow between 700-500 mb, will support effective shear magnitude greater than 30 kt across much of the risk area. South/southeasterly low-level flow will maintain a moist airmass. Meanwhile, cool temperatures aloft will support modest midlevel lapse rates. Pockets of stronger daytime heating with aid in modest destabilization, with MLCAPE around 500-1000 J/kg forecast. Similar to the previous couple of days, bands of cells/clusters are expected through the day. This activity will pose an isolated risk for locally damaging gusts, marginal hail, and a tornado or two. ..Leitman.. 05/11/2025 $$  527 ACUS11 KWNS 111830 SWOMCD SPC MCD 111830 UTZ000-IDZ000-112030- Mesoscale Discussion 0764 NWS Storm Prediction Center Norman OK 0130 PM CDT Sun May 11 2025 Areas affected...Salt Lake Vicinity Concerning...Severe potential...Watch unlikely Valid 111830Z - 112030Z Probability of Watch Issuance...20 percent SUMMARY...Severe wind gusts will be possible this afternoon with high-based showers and embedded thunderstorms. DISCUSSION...With temperatures rising into the low/mid 80s F in the vicinity of Salt Lake, high-based showers and isolated thunderstorms have deepened over the last hour. A few of these storms have produced 58-63 mph measured gusts in Tooele/Salt Lake Counties. While low-level wind fields are not overly strong, the 9.2 C/km 700-500 mb lapse rate observed in this mornings 12Z SLC sounding, coupled with steep low-level lapse rates and high surface dewpoint depressions, will continue to support strong diabatically driven downdrafts. Severe wind gusts will remain possible through the afternoon in association with this weak, disorganized convection. ..Wendt/Mosier.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SLC...PIH... LAT...LON 40601390 40971401 41411368 41841283 42061198 41861165 40971159 40241175 40011215 39861291 39981339 40601390 MOST PROBABLE PEAK WIND GUST...65-80 MPH  430 ACUS11 KWNS 111840 SWOMCD SPC MCD 111839 WYZ000-MTZ000-IDZ000-112115- Mesoscale Discussion 0765 NWS Storm Prediction Center Norman OK 0139 PM CDT Sun May 11 2025 Areas affected...eastern Idaho into western Wyoming and southwest Montana Concerning...Severe potential...Watch possible Valid 111839Z - 112115Z Probability of Watch Issuance...40 percent SUMMARY...Storms should gradually increase in coverage and intensity from eastern Idaho into southwest Montana, with both hail and gust potential. DISCUSSION...A line of convection continue to increase in intensity over the upper Snake River Plain, with both strong heating and low-level warm advection ahead of it. Continued steepening of deep-layer lapse rates as the upper trough moves in the from the west and more heating should support further strengthening of this convection. Strong deep-layer shear will favor hail production with these storms over eastern ID. A brief/weak tornado cannot be ruled out with the stronger cells this afternoon, as low-level stretching is maximized. Farther north toward the Bitterroots, stronger cooling aloft is occurring, and areas of heating persist ahead of this activity as well. Long hodographs and cold midlevel temperatures will favor hail with these storms through the day. ..Jewell/Mosier.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...RIW...TFX...PIH...MSO... LAT...LON 42041299 42051382 42701393 43631329 44321328 45071381 45711419 46261407 46871302 46801187 46511101 45681004 45310990 44360984 42881087 42041299 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  712 ACUS11 KWNS 111849 SWOMCD SPC MCD 111849 SCZ000-GAZ000-112045- Mesoscale Discussion 0766 NWS Storm Prediction Center Norman OK 0149 PM CDT Sun May 11 2025 Areas affected...Portions of southeast Georgia Concerning...Severe potential...Watch unlikely Valid 111849Z - 112045Z Probability of Watch Issuance...20 percent SUMMARY...A locally greater risk for damaging winds and perhaps a tornado is evident in southeast Georgia near a local warm front feature. DISCUSSION...A small corridor in southeast Georgia has heated into the low 80s F. A few weak discrete cells exist near the Georgia/South Carolina state line. One cell has recently intensified and shown signs of low-level rotation. The localized warm front feature will promote at least marginal potential for a brief tornado with southeasterly winds near the boundary. Nearby KCLX radar accordingly shows modest 0-1 km SRH. Over the next hour or two this environment will support a locally greater risk for damaging winds and perhaps a tornado. The discrete cells will have the greatest potential, but stronger updrafts within the linear segment farther southwest could also acquire low-level rotation as well. ..Wendt/Mosier.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...JAX...FFC... LAT...LON 31138191 31648223 32088233 32288211 32298142 32188097 31928092 31258140 31018156 30958174 31138191 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH  282 ACUS03 KWNS 111912 SWODY3 SPC AC 111911 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 PM CDT Sun May 11 2025 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms currently appears low across the U.S. Tuesday through Tuesday night. ...Ohio Valley into the Southeast... The persistent mid/upper low over the Mid-South and attendant trough extending into the Gulf will likely weaken as the system shift east toward the Atlantic coast on Tuesday. While some modest vertical shear will remain over portions of the region, overall wind field is expected to be weaker. Nevertheless, a seasonally moist airmass will modestly destabilize diurnally in pockets of heating. Isolated strong storms producing locally gusty winds and perhaps small hail are possible, though overall severe potential appears less compared to previous days. ...Intermountain West into the Great Plains... A deepening upper trough near the Pacific coast will shift east over the West on Tuesday. A belt of enhanced southwesterly flow will overspread the Rockies to the High Plains. Diurnal thunderstorms may develop over the northern Great Basin and northern Rockies. Instability and heating are expected to remain modest, limiting severe potential across the higher terrain of the Intermountain West. Further east into the Plains, lee troughing along the High Plains will sharpen with the approach of the upper trough. The upper low over the southeastern U.S. will limit northwest moisture return across much of the Plains. Nevertheless, strong heating and steep midlevel lapse rates will support weak to moderate destabilization. However, capping will likely limit much in the way of thunderstorm development. A surface cold front is forecast to move east/southeast across the Dakotas during the evening and overnight. This may allow for a storm or two to develop after peak heating. This activity would likely be either elevated or high-based. If a storm develops, hail would be possible. Uncertainty in storm development/coverage precludes severe probabilities at this time. ..Leitman.. 05/11/2025 $$  540 ACUS11 KWNS 111922 SWOMCD SPC MCD 111921 FLZ000-GAZ000-112145- Mesoscale Discussion 0767 NWS Storm Prediction Center Norman OK 0221 PM CDT Sun May 11 2025 Areas affected...central Florida northward toward southeast Georgia Concerning...Severe potential...Watch unlikely Valid 111921Z - 112145Z Probability of Watch Issuance...20 percent SUMMARY...Storms are forecast to increase in coverage throughout the afternoon from the central Florida Peninsula into northeast Florida and southeast Georgia. DISCUSSION...Storms are currently increasing east of Tampa to west of Okeechobee where strong heating has led to strong instability. The southerly flow regime should support a north/northeast movement to this development, affecting the remainder of central into northeastern Florida. Breaks in the clouds in those downstream areas are developing, and this should further increase instability. Although temperatures aloft are not as cool as previous days, MUCAPE over 2000 J/kg and deep-layer shear of 35-40 kt will support cellular storm mode with sporadic hail > 1.00" expected. Locally strong to damaging gusts cannot be ruled out as well, especially with any merging outflows. ..Jewell/Mosier.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...TBW...JAX... LAT...LON 27158103 27348165 27658206 28098211 30438218 30958218 31328183 31328151 31148134 30518136 29698113 29078080 28408044 27888038 27308059 27158103 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  307 ACUS01 KWNS 112000 SWODY1 SPC AC 111959 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. $$  674 ACUS11 KWNS 112157 SWOMCD SPC MCD 112157 NDZ000-SDZ000-MTZ000-WYZ000-120000- Mesoscale Discussion 0768 NWS Storm Prediction Center Norman OK 0457 PM CDT Sun May 11 2025 Areas affected...central and eastern Montana into western North Dakota Concerning...Severe potential...Watch possible Valid 112157Z - 120000Z Probability of Watch Issuance...60 percent SUMMARY...Severe wind gusts possible across central and eastern Montana into western North Dakota this evening. DISCUSSION...A few storm clusters have developed this evening, one in north-central Montana and another in southeast Montana. A very deeply mixed environment ahead of this activity will support severe wind gusts. These winds will be most likely in a belt from north-central Montana to northeast Montana and another across southeast Montana into western North Dakota. MLCAPE is only around 500 to 750 J/kg, but is sufficient to support strengthening convection a some additional storms. The most likely corridor for a watch is the southeast Montana corridor where the region of greater instability is larger and where temperatures are warmer (away from the cloudcover). In addition, the HRRR has a consistent signal showing 70-80 mph surface wind gusts from the convection that is currently in southeast Montana as it moves northeast and eventually into western North Dakota. Additional convection developing across far southeast Montana may also pose a severe wind threat as it congeals and moves north-east/north this evening. ..Bentley/Hart.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...UNR...BYZ...GGW...RIW...TFX... LAT...LON 49110182 47530198 46050267 45860393 45150514 44870784 45550932 46201120 46851177 47691158 49101033 49060400 49110182 MOST PROBABLE PEAK WIND GUST...75-90 MPH  572 ACUS11 KWNS 112235 SWOMCD SPC MCD 112234 WYZ000-MTZ000-UTZ000-IDZ000-120030- Mesoscale Discussion 0769 NWS Storm Prediction Center Norman OK 0534 PM CDT Sun May 11 2025 Areas affected...parts of northern UT...western WY and southwest MT Concerning...Severe Thunderstorm Watch 245... Valid 112234Z - 120030Z The severe weather threat for Severe Thunderstorm Watch 245 continues. SUMMARY...Scattered high-based showers and storms will remain capable of damaging gusts to 60-80 mph this evening. DISCUSSION...As of 2225 UTC, regional radar and satellite imagery showed scattered high-based showers and thunderstorms have developed across WW245 this afternoon. Numerous reports of severe/damaging gusts have been noted over UT and ID so far indicating an environment supportive of severe gusts. This is expected to continue as storms gradually expand northeastward into western WY and southern MT this evening with 500-1000 J/kg of MLCAPE and 40+ kt of effective shear. While some redevelopment is possible farther south through this evening, decreasing MU and DCAPE from SPC mesoanalysis indicate some air mass overturning has occurred across southern portions of the watch in northern UT. This may limit the best storm coverage to area farther north, but given the environment remains broadly favorable, severe gusts remain possible over much of the watch area this evening. ..Lyons.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...RIW...TFX...SLC...PIH...MSO... LAT...LON 40861390 44251326 45111060 44900833 43710908 43370924 40861102 40431136 40631276 40861390 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN