SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Tue May 13 2025 Valid 131200Z - 141200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE DESERT SOUTHWEST.... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN NORTH DAKOTA AND NORTHWESTERN MINNESOTA... ...Synopsis... Western US trouhging will deepen and begin to spread eastward as upper-level blocking breaks down over the central US today. A lee low will aid strong southwesterly winds and dry downslope conditions across the Southwest and High Plains. With little recent rainfall and above normal temperatures overlapping the increased surface winds, critical fire-weather conditions are expected. ...Northern Plains... Hot, dry and breezy conditions are again expected across parts of the Red River Valley of the North and upper Midwest, as a strong lee low supporting dry southerly winds over the northern Plains. Ahead of a surface trough and cold front gusty southerly winds of 20-25 mph are likely across the eastern Dakotas and western MN through the afternoon. Abnormally warm temperatures and modest moisture advection should keep afternoon RH values below 30%. With very dry fuels (ERC >90th percentile), several hours of widespread elevated to critical conditions appear likely. ...Southwest... The deepening upper trough over the western US will begin to move eastward today, spreading strong westerly flow over the Southwest and southern Rockies. The accelerating mid-level flow over a deep, dry boundary layer with above normal temperatures will bring gusty west-southwest winds of 15-25 mph to much of the Southwest. Fuels continue to dry/cure farther north into eastern AZ and western NM,supporting widespread elevated and critical fire-weather conditions. ..Lyons.. 05/13/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 AM CDT Tue May 13 2025 Valid 131200Z - 141200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE DESERT SOUTHWEST.... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN NORTH DAKOTA AND NORTHWESTERN MINNESOTA... ...Synopsis... Western US trouhging will deepen and begin to spread eastward as upper-level blocking breaks down over the central US today. A lee low will aid strong southwesterly winds and dry downslope conditions across the Southwest and High Plains. With little recent rainfall and above normal temperatures overlapping the increased surface winds, critical fire-weather conditions are expected. ...Northern Plains... Hot, dry and breezy conditions are again expected across parts of the Red River Valley of the North and upper Midwest, as a strong lee low supporting dry southerly winds over the northern Plains. Ahead of a surface trough and cold front gusty southerly winds of 20-25 mph are likely across the eastern Dakotas and western MN through the afternoon. Abnormally warm temperatures and modest moisture advection should keep afternoon RH values below 30%. With very dry fuels (ERC >90th percentile), several hours of widespread elevated to critical conditions appear likely. ...Southwest... The deepening upper trough over the western US will begin to move eastward today, spreading strong westerly flow over the Southwest and southern Rockies. The accelerating mid-level flow over a deep, dry boundary layer with above normal temperatures will bring gusty west-southwest winds of 15-25 mph to much of the Southwest. Fuels continue to dry/cure farther north into eastern AZ and western NM,supporting widespread elevated and critical fire-weather conditions. ..Lyons.. 05/13/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1236 AM CDT Tue May 13 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL TO NORTHERN PLAINS... ...SUMMARY... Scattered strong to severe thunderstorms are possible mainly over parts of the Dakotas and Nebraska Wednesday afternoon and evening. A more isolated severe threat is anticipated across parts of the Southeast and Mid-Atlantic Wednesday afternoon. ...Synopsis... An upper trough evident in water-vapor imagery over the Pacific Northwest is forecast to pivot into the central and northern Plains over the next 48 hours. As this occurs, strong to severe thunderstorms are expected to develop ahead of the wave and within a narrow warm sector in place across parts of the central to northern Plains. Across the Southeast and Mid-Atlantic, a weakening upper-level low will continue to de-amplify as it meanders to the northeast. Residual 25-35 knot mid-level flow will likely contribute to some storm organization as convection develops within a moist and weakly capped environment. ...Central to Northern Plains... Continued deepening of a surface trough is anticipated through the next 48 hours across the northern Plains. This will maintain a southeasterly flow regime across the Plains with modest moisture return anticipated within a narrow plume from NE into the Dakotas by Wednesday afternoon. A Pacific cold front, evident in late-evening surface observations across the Intermountain West, is forecast to progress east and impinge on the narrow warm sector by late afternoon/early evening. Storm motions and deep-layer shear vectors largely parallel to the front will favor relatively quick upscale growth into clusters/linear segments. Although shear will initially be modest, the high-based nature of the storms should promote a strong/severe wind threat. With time, strengthening mid to upper-level flow will elongate hodographs and may support an increasing hail threat into the evening hours as convection develops southward along the front. Some guidance hints at a second round of convection late evening into the overnight hours across southeast SD into NE as the primary vorticity maximum ejects into the Plains and promotes additional thunderstorm development along the advancing cold front. ...Carolinas to Mid-Atlantic... A moist air mass will remain in place across the Southeast and Mid-Atlantic through the next 48 hours in the absence of any synoptic fronts or influential gradient winds. Rich moisture through the lowest 100-200 mb will maintain weak capping and support diurnally driven convection by late afternoon as surface temperatures warm into the mid 70s under broken cloud cover. Similar to previous days, which have produced isolated damaging winds, weak low-level winds under 25-35 knot mid-level flow will promote transient storm organization. While a similar thermodynamic/kinematic environment will be in place across much of the Southeast on Wednesday, latest CAM guidance suggests the best severe potential resides across portions of the Carolinas into the DelMarVa region where thunderstorm coverage should be greatest ahead of the mid-level vorticity maximum. ..Moore.. 05/13/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Tue May 13 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE NC/VA/WV VICINITY...NORTHERN GREAT PLAINS...AND DEEP SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible: 1) today in vicinity of Virginia-North Carolina-West Virginia, 2) during the late afternoon to mid-evening over a portion of the Deep South, and 3) this evening into early morning Wednesday in parts of the northern Great Plains. ...NC/VA/WV vicinity... A mid/upper trough centered on the Mid to Deep South will gradually shift east-northeastward, reaching the OH Valley to FL Peninsula by early Wednesday. The low-level warm conveyor will remain displaced well downstream across eastern NC and advance north across the Mid-Atlantic States towards the Lower Great Lakes. Early-day severe potential will be tied to this conveyor in eastern NC/VA where low-topped convection is anticipated. While instability will remain quite limited, enlarged low-level hodograph curvature and near-saturated thermodynamic profiles will offer potential for a brief tornado. West of the warm conveyor, more pronounced boundary-layer heating will occur, likely resulting in moderate buoyancy by early to mid afternoon with MLCAPE of 1000-1500 J/kg. This coupled with weak mid-level height falls should support scattered thunderstorms. Deep-layer shear is expected to remain moderate across the Piedmont, with decreasing values westward towards the trough. This renders a nebulous transition between loosely organized to pulse convection. For now, have delineated the MRGL risk where at least modest values of deep-layer shear could support multicell clusters. Isolated severe hail and damaging winds are the expected hazards, west of the coastal plain. ...AL/MS/TN vicinity... Some guidance suggests a supercell or two may develop on the backside of the departing mid-level trough. A mesoscale corridor of differential boundary-layer heating, coincident with the eastward expansion of the southern Great Plains EML across the Lower MS Valley, may support a favored corridor for late afternoon to mid-evening storm development. Despite weak low-level winds, some veering of the wind profile should yield modest hodograph curvature. This coupled with moderate mid-level west-northwesterlies will favor a conditional supercell threat. ...Northern Great Plains... A broad, but more amplified mid/upper trough will gradually shift east across the West. A downstream split in the stronger flow regime is expected over the southern Rockies to adjacent High Plains in the wake of the prior blocking pattern over the central states. This will yield a meridional mid/upper wind profile across the northern Great Plains. At the surface, a Pacific cold front will stall in the western to central Dakotas vicinity. Strong mid/upper winds will remain displaced west of this boundary, where strengthening large-scale ascent is anticipated tonight as an embedded shortwave impulse rotates through the eastern portion of the western trough. Elevated buoyancy is expected to remain weak given poor-quality low-level moisture. Still, with the strengthening effective bulk shear and forcing for ascent, a few elevated supercells are possible tonight into early morning Wednesday. Isolated severe hail should be the primary hazard, with potential for strong (but sub-severe) gusts closer to the surface front. ..Grams/Lyons.. 05/13/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0729 PM CDT Mon May 12 2025 Valid 130100Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SAVANNAH VALLEY TO THE COASTAL CAROLINAS...AND IN NORTHEAST MT TO FAR NORTHWEST ND... ...SUMMARY... Isolated severe thunderstorms remain possible tonight from the Savannah Valley to the coastal Carolinas, and through the rest of this evening in northeast Montana to far northwest North Dakota. ...Savannah Valley to the coastal Carolinas... Potential for strong to severe storms will remain limited across the Southeast tonight. One area of low-probability tornado/wind threat that may persist is downstream of an arc of ongoing convection across eastern GA to upstate SC. While downstream instability is weak, enough of a gap exists between this arc and the persistent warm-conveyor rain swath across eastern NC. Adequate low to deep-layer shear should be maintained for transient weak rotation through 12Z Tuesday. This might support a brief tornado or localized wet microburst. These threats should tend to become more confined towards the SC to southern NC coastal plain overnight. ...Northeast MT and far northwest ND... High-based convection persists along and rearward of an undercutting Pacific cold front marching east into northeast MT. Despite meager MLCAPE, as sampled by the 00Z GGW sounding, 45-55 F surface temperature-dew points spreads ahead of the front will promote potential for a few gusts of 55-70 mph through late evening. ..Grams.. 05/13/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0729 PM CDT Mon May 12 2025 Valid 130100Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SAVANNAH VALLEY TO THE COASTAL CAROLINAS...AND IN NORTHEAST MT TO FAR NORTHWEST ND... ...SUMMARY... Isolated severe thunderstorms remain possible tonight from the Savannah Valley to the coastal Carolinas, and through the rest of this evening in northeast Montana to far northwest North Dakota. ...Savannah Valley to the coastal Carolinas... Potential for strong to severe storms will remain limited across the Southeast tonight. One area of low-probability tornado/wind threat that may persist is downstream of an arc of ongoing convection across eastern GA to upstate SC. While downstream instability is weak, enough of a gap exists between this arc and the persistent warm-conveyor rain swath across eastern NC. Adequate low to deep-layer shear should be maintained for transient weak rotation through 12Z Tuesday. This might support a brief tornado or localized wet microburst. These threats should tend to become more confined towards the SC to southern NC coastal plain overnight. ...Northeast MT and far northwest ND... High-based convection persists along and rearward of an undercutting Pacific cold front marching east into northeast MT. Despite meager MLCAPE, as sampled by the 00Z GGW sounding, 45-55 F surface temperature-dew points spreads ahead of the front will promote potential for a few gusts of 55-70 mph through late evening. ..Grams.. 05/13/2025 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Mon May 12 2025 Valid 141200Z - 201200Z An upper-level trough over the Intermountain West on Day 3/Wednesday will translate northeastward into the Great Lakes region by Day 6/Friday bringing dry and breezy conditions to portions of the Southwest, with needed rainfall to portions of the Northern Plains and Upper-Midwest. The cutoff low across the Southeast will shift northeastward as an open wave, bringing more rainfall to the Mid-Atlantic and Northeast through Day 3-4/Wednesday-Thursday. Overall pattern remains active with another upper-trough entering the western U.S. by the weekend (Day 6-7/Saturday-Sunday) bringing more fire weather concerns to portions of the Southwest. ...Upper-Midwest... A residual dry boundary layer along with pre-frontal winds of 15-20 mph could allow for period of elevated fire weather conditions across western Minnesota/eastern Dakotas. However, moist return flow from the Missouri Valley could keep relative humidity above critical thresholds before expected cold front and associated rainfall/cooler air mass moves in for the end of the Day 3/Wednesday period. ...Southwest... A persistent fire weather threat will continue for portions of Southwest. Southeastern Arizona and central/southern New Mexico will be the threat focal point where fuels have been more receptive to fire spread. Modest to strong mid-level flow at the base of the upper-trough will be the primary contributor to 20-25 mph west-southwest surface winds across southern New Mexico on Day3/Wednesday. A 70 percent Critical probability area was added to far southern New Mexico with the increased forecast confidence from latest model guidance. Fuels should remain available with no appreciable rainfall across the Southwest through Day 5/Friday before the next upper-trough arrives for the weekend. Some forecast uncertainty persists with the timing of the next upper-trough and arrival of enhanced mid-level flow, precluding addition of Critical probabilities for the weekend time frame for now. ..Williams.. 05/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0456 PM CDT Mon May 12 2025 Valid 141200Z - 201200Z An upper-level trough over the Intermountain West on Day 3/Wednesday will translate northeastward into the Great Lakes region by Day 6/Friday bringing dry and breezy conditions to portions of the Southwest, with needed rainfall to portions of the Northern Plains and Upper-Midwest. The cutoff low across the Southeast will shift northeastward as an open wave, bringing more rainfall to the Mid-Atlantic and Northeast through Day 3-4/Wednesday-Thursday. Overall pattern remains active with another upper-trough entering the western U.S. by the weekend (Day 6-7/Saturday-Sunday) bringing more fire weather concerns to portions of the Southwest. ...Upper-Midwest... A residual dry boundary layer along with pre-frontal winds of 15-20 mph could allow for period of elevated fire weather conditions across western Minnesota/eastern Dakotas. However, moist return flow from the Missouri Valley could keep relative humidity above critical thresholds before expected cold front and associated rainfall/cooler air mass moves in for the end of the Day 3/Wednesday period. ...Southwest... A persistent fire weather threat will continue for portions of Southwest. Southeastern Arizona and central/southern New Mexico will be the threat focal point where fuels have been more receptive to fire spread. Modest to strong mid-level flow at the base of the upper-trough will be the primary contributor to 20-25 mph west-southwest surface winds across southern New Mexico on Day3/Wednesday. A 70 percent Critical probability area was added to far southern New Mexico with the increased forecast confidence from latest model guidance. Fuels should remain available with no appreciable rainfall across the Southwest through Day 5/Friday before the next upper-trough arrives for the weekend. Some forecast uncertainty persists with the timing of the next upper-trough and arrival of enhanced mid-level flow, precluding addition of Critical probabilities for the weekend time frame for now. ..Williams.. 05/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Mon May 12 22:02:02 UTC 2025.

No Mesoscale Discussions are in effect as of Mon May 12 22:02:02 UTC 2025.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Mon May 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND NORTHWEST NORTH DAKOTA...PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Southeast today, where a tornado or two, localized damaging winds, and hail could occur. Isolated severe wind gusts are also possible in northeast Montana to northwest North Dakota around early evening. ...20Z Update... Minor adjustments were made in the Southeast based on observed convective trends. Greater buoyancy has developed in southeast to east-central Georgia. This zone could have locally higher potential for strong to severe storms. However, mid-level dry air is evident on water vapor imagery. Updrafts may tend to struggle to intensify due to dry air entrainment. Elsewhere, the forecast remains unchanged. ..Wendt.. 05/12/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Mon May 12 2025/ ...Southeast... Vertically stacked cyclone persists over the Mid-South this morning. Expectation is for this system to become more progressive today, ejecting into western TN by early tomorrow morning. A moist airmass remains in place downstream of this cyclone across the Southeast, and numerous showers and thunderstorms are currently ongoing within the warm conveyor of this system from FL into GA and the Carolina. Moderate southwesterly/southerly will persist within this warm sector, and effective shear should be sufficient for multicell clusters and transient updraft rotation. However, only modest destabilization is anticipated across much of the region, limiting the overall severe potential. Expectation is for occasionally strong storms in areas of sufficient destabilization, with damaging downbursts and hail as the primary risk. A corridor of greater severe potential could be developing across southern GA and northern FL where some heating is occurring. ...Northeast Montana/northwest North Dakota... Deep shortwave trough will continue to push eastward across the Pacific Northwest today, with associated southwesterly flow aloft extending from northern CA into the northern High Plains. Deeply mixed thermodynamic profiles are expected across the region as the airmass destabilizes this afternoon. Isolated thunderstorms are most probable from mid-afternoon into evening with development near/behind an eastward-advancing front. Convective coverage off the higher terrain of southern Montana should be less than in recent days. However, the potential will still exist for a few dry microbursts producing localized severe-caliber wind gusts as the storms move off the terrain into more of eastern MT. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Mon May 12 2025 Valid 131200Z - 141200Z ...CRITICAL FIRE WEATHER AREA FOR EASTERN NORTH DAKOTA AND WESTERN MINNESOTA... ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE DESERT SOUTHWEST... ...Northern Plains and Upper-Midwest... Hot, dry and breezy conditions ahead of a surface trough and cold front will continue for Tuesday across portions of the Northern Plains. Fuels continue to dry after several days of well above normal temperatures with ERC values in the 90-97th percentile across the area. Critical highlights were added to much of the Red River Valley of the North for this persistent fire weather threat. ...Southwest... An approaching upper-level trough and accelerating mid-level flow over a deep, dry boundary layer is still expected to bring gusty west-southwest winds to much of the Southwest. Fuels continue to dry/cure farther north into eastern Arizona and western New Mexico, heightening fire spread potential. Slight adjustments to Elevated and Critical highlights were needed to account for additional available fuels. ..Williams.. 05/12/2025 .PREV DISCUSSION... /ISSUED 0154 AM CDT Mon May 12 2025/ ...Synopsis... An upper-level trough across the western U.S. will translate eastward across the Rockies with strong mid-level flow overspreading much of the Southwest. Lee troughing will encourage strong westerly winds and dry downslope conditions across the Southwest and High Plains. With little recent rainfall and above normal temperatures overlapping the increased surface winds, elevated fire-weather conditions are likely. ...Southwest... The upper trough and attendant mid-level jet are forecast to intensify and aid in the development of stronger winds within a well-mixed boundary layer across much of the Southwest. Westerly downslope flow of 20-30 mph amid RH values below 15% will support widespread dry and windy conditions across southeastern AZ into southern NM Tuesday. Several days of above-normal temperatures and poor humidity recoveries suggest additional drying of already receptive fuels is likely. Widespread elevated to critical fire weather conditions are likely across parts of the Southwest Tuesday afternoon and evening. ...Red River of the North... As the upper trough intensifies to the west, an elongated area of low pressure will deepen near the international border. Strong southerly winds are likely for another day east of the surface trough/low. Persistent above-normal temperatures should maintain low RH below 30% and dry fuels. With southerly gusts to 20 mph, several hours of elevated fire-weather conditions appear likely across the eastern Dakotas and western MN. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 PM CDT Mon May 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER CENTRAL AND EASTERN PARTS OF THE DAKOTAS AND NEBRASKA... ...SUMMARY... Scattered strong to severe thunderstorms are possible mainly over parts of the Dakotas and Nebraska Wednesday afternoon and evening. ...Synopsis... On Wednesday, a potent shortwave trough will move from the Four Corners region into the central Plains, with a 70+ kt midlevel speed max over KS by 12Z Thursday. The primary upper low will deepen over eastern MT, with most of the cooling aloft north of a line from northern NM into eastern NE. Ahead of this system, heights will rise over the MS Valley and Southeast, while the lingering upper trough over the East dissipates further. At the surface, a trough will stretch roughly from the central Dakotas into KS at 00Z, with a surface low taking shape and deepening overnight into eastern NE and IA. Modest moisture return will occur ahead of the surface trough, with 50s to near 60 F dewpoints to the Dakotas portion of the boundary. A more robust plume of moisture with mid 60s F dewpoints is likely from the lower MO to middle MS Valleys. Overnight, winds around 850 mb will strengthen as the low develops, but will also veer from southwest through northwest, resulting in advection of drier air. ...Northern and central Plains... Northern portions of the upper trough will emerge into the northern Plains in meridional fashion through early evening, with the primary speed max well to the south until early Thursday. Gradual cooling aloft will overspread the surface trough and wind shift, where strong heating will occur. The result will be moderate instability, with scattered storms erupting within the north-south zone from the Dakotas into NE. Coincident with the storm development, a cold frontal surge will occur over the northern High Plains, which should help push this activity perhaps into western MN and IA by 12Z Thursday. Shear profiles will not be particularly strong initially, but may become increasingly favorable overnight to support corridors of severe wind and hail. ..Jewell.. 05/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 PM CDT Mon May 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER CENTRAL AND EASTERN PARTS OF THE DAKOTAS AND NEBRASKA... ...SUMMARY... Scattered strong to severe thunderstorms are possible mainly over parts of the Dakotas and Nebraska Wednesday afternoon and evening. ...Synopsis... On Wednesday, a potent shortwave trough will move from the Four Corners region into the central Plains, with a 70+ kt midlevel speed max over KS by 12Z Thursday. The primary upper low will deepen over eastern MT, with most of the cooling aloft north of a line from northern NM into eastern NE. Ahead of this system, heights will rise over the MS Valley and Southeast, while the lingering upper trough over the East dissipates further. At the surface, a trough will stretch roughly from the central Dakotas into KS at 00Z, with a surface low taking shape and deepening overnight into eastern NE and IA. Modest moisture return will occur ahead of the surface trough, with 50s to near 60 F dewpoints to the Dakotas portion of the boundary. A more robust plume of moisture with mid 60s F dewpoints is likely from the lower MO to middle MS Valleys. Overnight, winds around 850 mb will strengthen as the low develops, but will also veer from southwest through northwest, resulting in advection of drier air. ...Northern and central Plains... Northern portions of the upper trough will emerge into the northern Plains in meridional fashion through early evening, with the primary speed max well to the south until early Thursday. Gradual cooling aloft will overspread the surface trough and wind shift, where strong heating will occur. The result will be moderate instability, with scattered storms erupting within the north-south zone from the Dakotas into NE. Coincident with the storm development, a cold frontal surge will occur over the northern High Plains, which should help push this activity perhaps into western MN and IA by 12Z Thursday. Shear profiles will not be particularly strong initially, but may become increasingly favorable overnight to support corridors of severe wind and hail. ..Jewell.. 05/12/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1156 AM CDT Mon May 12 2025 Valid 121700Z - 131200Z ...CRITICAL FIRE WEATHER AREA FOR THE NORTHERN PLAINS AND UPPER MIDWEST... ...Northern Plains and Midwest... An approaching upper-level trough and advancing cold front will support shower and thunderstorm development across northeastern Montana late this afternoon into the evening hours. Forward motion of precipitation cores will limit rainfall to likely less than one tenth of an inch. However, a cooler air mass and higher humidity will infiltrate into eastern Montana tonight, with additional widespread rainfall expected Tuesday across the area. Before convection commences late this afternoon, a well-mixed boundary layer and dry downslope flow ahead of the upper-trough should support a few hours of elevated fire weather conditions across the area, necessitating and westward expansion of Elevated highlights. ...Southwest... Latest fuels guidance indicates increased fire spread potential across portions of eastern Arizona and western New Mexico. With a broad area of stronger winds and dry conditions across the region, expanded Elevated highlights northward to encompass drier fuels along the Arizona and New Mexico border. ..Williams.. 05/12/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Mon May 12 2025/ ...Synopsis... As the blocking within the upper-air pattern begins to breakdown a trough will deepens over the western US. Strong mid-level flow will gradually move into the Plains, as upper ridging moves eastward. Strong lee troughing/cyclogenesis will support gusty south/westerly winds over the High Plains. Fire-weather conditions are expected across the Northern Great Plains and Southwest this afternoon and evening. ...Northern Plains and Midwest... Another day of strong southerly winds are likely across the northern Plains and Midwest as ascent from the western US trough overspreads the region. A lee cyclone will support southerly gusts of 20-30 mph over a A broad area amid fuels with ERC values above the 97th percentile. While afternoon RH minimums may not be as low as prior days, record-setting temperatures in the lower to upper 90s are again expected across the region supporting dry surface conditions with RH below 30%. This will support widespread critical fire-weather concerns given the state of drought and recent fire activity. ...Southwest... As the western US trough begins to eject, strong westerly flow aloft will overspread parts of the Southwest from southern AZ into NM. Downslope winds of 15-25 mph along with low RH below 15% will support several hours of elevated to locally critical fire-weather conditions within dry fuels, that have supported recent fire activity. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Mon May 12 2025 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not forecast on Tuesday. ...Synopsis and Discussion... On Tuesday, an upper low will proceed northward across the TN and OH Valleys, beneath the larger-scale upper ridge extending from the Northeast into eastern Canada. As this occurs, winds aloft will generally weaken from FL into the Mid Atlantic, but cool temperatures aloft will maintain thunderstorm chances over much of the East. Severe chances will be limited by poor lapse rates aloft in most areas. To the west, a deep upper trough will move eastward across the Great Basin, with a intense midlevel speed max moving from southern CA toward the Four Corners area. Moderate southwest flow aloft will exist over the central and northern Rockies, with increasing west/northwest flow aloft from NM into TX north of a Mexican upper ridge. Beneath the upper trough, cold air aloft will favor daytime thunderstorms from the Sierra into the northern Rockies, and into the evening across the western Dakotas. ..Jewell.. 05/12/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon May 12 2025 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND NORTHWEST NORTH DAKOTA... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Southeast today, where a tornado or two, localized damaging winds, and hail could occur. Isolated severe wind gusts are also possible in northeast Montana to northwest North Dakota around early evening. ...Southeast... Vertically stacked cyclone persists over the Mid-South this morning. Expectation is for this system to become more progressive today, ejecting into western TN by early tomorrow morning. A moist airmass remains in place downstream of this cyclone across the Southeast, and numerous showers and thunderstorms are currently ongoing within the warm conveyor of this system from FL into GA and the Carolina. Moderate southwesterly/southerly will persist within this warm sector, and effective shear should be sufficient for multicell clusters and transient updraft rotation. However, only modest destabilization is anticipated across much of the region, limiting the overall severe potential. Expectation is for occasionally strong storms in areas of sufficient destabilization, with damaging downbursts and hail as the primary risk. A corridor of greater severe potential could be developing across southern GA and northern FL where some heating is occurring. ...Northeast Montana/northwest North Dakota... Deep shortwave trough will continue to push eastward across the Pacific Northwest today, with associated southwesterly flow aloft extending from northern CA into the northern High Plains. Deeply mixed thermodynamic profiles are expected across the region as the airmass destabilizes this afternoon. Isolated thunderstorms are most probable from mid-afternoon into evening with development near/behind an eastward-advancing front. Convective coverage off the higher terrain of southern Montana should be less than in recent days. However, the potential will still exist for a few dry microbursts producing localized severe-caliber wind gusts as the storms move off the terrain into more of eastern MT. ..Mosier/Halbert.. 05/12/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 AM CDT Mon May 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND NORTHWEST NORTH DAKOTA... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Southeast today, where a tornado or two, localized damaging winds, and hail could occur. Isolated severe wind gusts are also possible in northeast Montana to northwest North Dakota around early evening. ...Southeast States... The persistent vertically stacked mid/upper low that has been nearly stationary over the Sabine Valley/Lower Mississippi River Valley will finally accelerate northeastward towards western Tennessee through tonight. A jetlet of cyclonically curved mid-level southerlies over the northeast Gulf and Florida Panhandle will dampen somewhat as it becomes centered on north Florida to southeast Georgia vicinity this afternoon. More probable diurnal thunderstorm development is anticipated from the left-exit region of this jetlet westward towards the cold-core of the stacked low. Deep-layer vertical shear will relax with westward extent, yielding more of a pulse strong-storm environment from Middle Tennessee to western Alabama and Mississippi. Despite the meridional deep-layer wind profile, effective shear should be sufficient for multicell clusters and transient updraft rotation centered on eastern Alabama and Georgia into north Florida. Pockets of modest buoyancy should support a mix of small to marginally severe hail and strong gusts capable of isolated damaging winds. Along the eastern periphery of this activity, a tornado or two is possible where there remains some overlap with the western belt of enhanced low-level flow, including South Carolina into both western and near-coastal North Carolina. Farther south, a more nebulous convective scenario is anticipated amid extensive ongoing convection across the Florida Peninsula and Keys. Guidance differs markedly with the degree of destabilization, as adequate boundary-layer heating will be required amid poor mid-level lapse rates near 5 C/km. But some guidance suggests south-central/southern Florida has the best chance at recovery by afternoon, although low-level winds will tend to be veering with a likely diminishing trend of low-level SRH. ...Northeast Montana/northwest North Dakota... Another day of rather deeply mixed thermodynamic profiles is expected across the region. Isolated thunderstorms are most probable from mid-afternoon into evening with development near/behind an eastward-advancing front. Overall convective coverage off the higher terrain of southern Montana should be substantially less than in recent days, amid deep-layer southwesterly wind profiles. The potential will exist for a few dry microbursts producing localized severe-caliber wind gusts. ..Guyer/Dean.. 05/12/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0741 AM CDT Mon May 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND NORTHWEST NORTH DAKOTA... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the Southeast today, where a tornado or two, localized damaging winds, and hail could occur. Isolated severe wind gusts are also possible in northeast Montana to northwest North Dakota around early evening. ...Southeast States... The persistent vertically stacked mid/upper low that has been nearly stationary over the Sabine Valley/Lower Mississippi River Valley will finally accelerate northeastward towards western Tennessee through tonight. A jetlet of cyclonically curved mid-level southerlies over the northeast Gulf and Florida Panhandle will dampen somewhat as it becomes centered on north Florida to southeast Georgia vicinity this afternoon. More probable diurnal thunderstorm development is anticipated from the left-exit region of this jetlet westward towards the cold-core of the stacked low. Deep-layer vertical shear will relax with westward extent, yielding more of a pulse strong-storm environment from Middle Tennessee to western Alabama and Mississippi. Despite the meridional deep-layer wind profile, effective shear should be sufficient for multicell clusters and transient updraft rotation centered on eastern Alabama and Georgia into north Florida. Pockets of modest buoyancy should support a mix of small to marginally severe hail and strong gusts capable of isolated damaging winds. Along the eastern periphery of this activity, a tornado or two is possible where there remains some overlap with the western belt of enhanced low-level flow, including South Carolina into both western and near-coastal North Carolina. Farther south, a more nebulous convective scenario is anticipated amid extensive ongoing convection across the Florida Peninsula and Keys. Guidance differs markedly with the degree of destabilization, as adequate boundary-layer heating will be required amid poor mid-level lapse rates near 5 C/km. But some guidance suggests south-central/southern Florida has the best chance at recovery by afternoon, although low-level winds will tend to be veering with a likely diminishing trend of low-level SRH. ...Northeast Montana/northwest North Dakota... Another day of rather deeply mixed thermodynamic profiles is expected across the region. Isolated thunderstorms are most probable from mid-afternoon into evening with development near/behind an eastward-advancing front. Overall convective coverage off the higher terrain of southern Montana should be substantially less than in recent days, amid deep-layer southwesterly wind profiles. The potential will exist for a few dry microbursts producing localized severe-caliber wind gusts. ..Guyer/Dean.. 05/12/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Mon May 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... An active period of severe weather is anticipated through early next week based on recent trends in long-range guidance. A transition to a progressive upper-level regime is expected over the next seven days as a series of upper waves traverse the CONUS with favorable wavelengths for air mass/moisture recovery into central portions of the CONUS. Although both the GFS and ECMWF (and their respective ensemble families) show similar synoptic evolutions through the extended period, predictability in any severe threat currently appears greatest on D4/Thursday and D5/Friday. ...D4/Thursday... The upper-level trough currently over the Pacific Northwest is forecast to eject into the upper MS River Valley through the day Thursday with an attendant surface low deepening across the upper MS Valley. A Pacific front is forecast to push east into an expanding warm sector that should span from the MS River into the upper Great Lakes and OH River Valley. Strong mid-level flow orthogonal to the front should generally promote discrete/semi-discrete convection by late afternoon on the eastern fringe of a stout EML. The consistent signal for QPF within the warm sector coincident with 50-60 knot mid-level flow and the intensifying nature of the synoptic low suggests that a widespread severe weather event is possible and may expand further east than depicted in previous forecasts. Despite these trends, regional discrepancies among guidance limit confidence in where the more robust severe corridors will become established. Notable factors limiting confidence are the potential for strong capping across much of the OH Valley and a faster progression of the surface low/front in recent GFS/GEFS solutions (which typically exhibit a fast bias at this range). ...D5/Friday... The Pacific front/outflow associated with D4/Thursday's convection is expected to stall across the lower OH Valley/mid-MS Valley before gradually returning north as an effective warm front on Friday. Ensemble guidance shows a reasonably strong signal for dewpoints in the mid/upper 60s (potentially into the low 70s) along and south of this boundary by peak heating. A mid-level impulse propagating over the region should maintain elongated hodographs and provide sufficient lift for thunderstorm development along the boundary. This synoptic regime suggests that one or more organized clusters/linear segments may propagate along the boundary and into parts of the mid-MS Valley, lower OH Valley, and potentially into the TN Valley. Given the thermodynamic and kinematic environment forecast by ensemble guidance, such a cluster/line will likely pose a severe threat. A 15% risk area has been introduced where the QPF signal associated with this regime has been most consistent over recent model runs, but further forecast refinements are expected. Read more