Severe Storms

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Wed Jul 09 2025 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE HIGH PLAINS OF THE SOUTHERN AND CENTRAL ROCKIES NORTHEAST TO THE UPPER GREAT LAKES AND FROM THE CAROLINAS TO CENTRAL PENNSYLVANIA... ...SUMMARY... A few strong to severe thunderstorms capable of producing large hail and damaging winds will be possible across portions of the central Great Plains. Additional strong storms capable of producing sporadic wind damage will be possible from the Carolinas to central Pennsylvania. ... Central Plains ... A low-amplitude short-wave trough across the central Great Plains will begin to phase with / be absorbed by a larger scale trough moving across the northern Great Plains. At the surface, a cold front will slowly push southeast through much of Iowa during the day. At the start of the forecast period, convection from the previous day should still be ongoing across portions of the area. The overall pattern would suggest that one or more mesoscale convective vortices (MCVs) may accompany this ongoing convection. Guidance consensus and the overall pattern would support this convection persisting through much of the day. To the south of this convection, diurnal heating of a moist airmass below steep mid-level lapse rates will result in a strongly unstable atmosphere by mid afternoon. Additional thunderstorms should develop within this strongly unstable atmosphere and be capable of producing large hail and damaging winds. At present, the combination of a weakening mid-level wind field and uncertainty associated with the location of any ongoing/persistent convection prevents the inclusion of higher probabilities with this forecast. However, locally enhanced effective-layer shear associated with any remnant MCVs should support some organization of a severe threat such that an upgrade to Level 2/Slight Risk may be warranted as the details of such features become clear. ... Carolinas to central Pennsylvania ... Diurnal heating of a moist and weakly capped boundary layer will result in afternoon thunderstorms. Precipitable water values look to be less on Friday than previous days, but still should be sufficient for widely scattered to scattered wet downbursts. Wind damage will be possible with the stronger downbursts. ... Eastern Colorado into the southern Great Plains ... Thunderstorms are expected to develop across northeast Colorado during the afternoon. Large-scale flow should result in these storms moving southeast through the evening and overnight hours as they grow upscale into a large MCS. The overall pattern would suggest the potential for at least a couple of severe wind reports associated with this southeastward moving MCS. ..Marsh.. 07/09/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Wed Jul 09 2025 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE HIGH PLAINS OF THE SOUTHERN AND CENTRAL ROCKIES NORTHEAST TO THE UPPER GREAT LAKES AND FROM THE CAROLINAS TO CENTRAL PENNSYLVANIA... ...SUMMARY... A few strong to severe thunderstorms capable of producing large hail and damaging winds will be possible across portions of the central Great Plains. Additional strong storms capable of producing sporadic wind damage will be possible from the Carolinas to central Pennsylvania. ... Central Plains ... A low-amplitude short-wave trough across the central Great Plains will begin to phase with / be absorbed by a larger scale trough moving across the northern Great Plains. At the surface, a cold front will slowly push southeast through much of Iowa during the day. At the start of the forecast period, convection from the previous day should still be ongoing across portions of the area. The overall pattern would suggest that one or more mesoscale convective vortices (MCVs) may accompany this ongoing convection. Guidance consensus and the overall pattern would support this convection persisting through much of the day. To the south of this convection, diurnal heating of a moist airmass below steep mid-level lapse rates will result in a strongly unstable atmosphere by mid afternoon. Additional thunderstorms should develop within this strongly unstable atmosphere and be capable of producing large hail and damaging winds. At present, the combination of a weakening mid-level wind field and uncertainty associated with the location of any ongoing/persistent convection prevents the inclusion of higher probabilities with this forecast. However, locally enhanced effective-layer shear associated with any remnant MCVs should support some organization of a severe threat such that an upgrade to Level 2/Slight Risk may be warranted as the details of such features become clear. ... Carolinas to central Pennsylvania ... Diurnal heating of a moist and weakly capped boundary layer will result in afternoon thunderstorms. Precipitable water values look to be less on Friday than previous days, but still should be sufficient for widely scattered to scattered wet downbursts. Wind damage will be possible with the stronger downbursts. ... Eastern Colorado into the southern Great Plains ... Thunderstorms are expected to develop across northeast Colorado during the afternoon. Large-scale flow should result in these storms moving southeast through the evening and overnight hours as they grow upscale into a large MCS. The overall pattern would suggest the potential for at least a couple of severe wind reports associated with this southeastward moving MCS. ..Marsh.. 07/09/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Wed Jul 09 2025 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE HIGH PLAINS OF THE SOUTHERN AND CENTRAL ROCKIES NORTHEAST TO THE UPPER GREAT LAKES AND FROM THE CAROLINAS TO CENTRAL PENNSYLVANIA... ...SUMMARY... A few strong to severe thunderstorms capable of producing large hail and damaging winds will be possible across portions of the central Great Plains. Additional strong storms capable of producing sporadic wind damage will be possible from the Carolinas to central Pennsylvania. ... Central Plains ... A low-amplitude short-wave trough across the central Great Plains will begin to phase with / be absorbed by a larger scale trough moving across the northern Great Plains. At the surface, a cold front will slowly push southeast through much of Iowa during the day. At the start of the forecast period, convection from the previous day should still be ongoing across portions of the area. The overall pattern would suggest that one or more mesoscale convective vortices (MCVs) may accompany this ongoing convection. Guidance consensus and the overall pattern would support this convection persisting through much of the day. To the south of this convection, diurnal heating of a moist airmass below steep mid-level lapse rates will result in a strongly unstable atmosphere by mid afternoon. Additional thunderstorms should develop within this strongly unstable atmosphere and be capable of producing large hail and damaging winds. At present, the combination of a weakening mid-level wind field and uncertainty associated with the location of any ongoing/persistent convection prevents the inclusion of higher probabilities with this forecast. However, locally enhanced effective-layer shear associated with any remnant MCVs should support some organization of a severe threat such that an upgrade to Level 2/Slight Risk may be warranted as the details of such features become clear. ... Carolinas to central Pennsylvania ... Diurnal heating of a moist and weakly capped boundary layer will result in afternoon thunderstorms. Precipitable water values look to be less on Friday than previous days, but still should be sufficient for widely scattered to scattered wet downbursts. Wind damage will be possible with the stronger downbursts. ... Eastern Colorado into the southern Great Plains ... Thunderstorms are expected to develop across northeast Colorado during the afternoon. Large-scale flow should result in these storms moving southeast through the evening and overnight hours as they grow upscale into a large MCS. The overall pattern would suggest the potential for at least a couple of severe wind reports associated with this southeastward moving MCS. ..Marsh.. 07/09/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...Synopsis... Along the northern periphery of a large-scale ridge over the Southwest, a midlevel shortwave trough will move eastward from the Great Basin into the central Rockies. Enhanced westerly flow aloft accompanying this feature will overspread a deeply mixed boundary layer during the afternoon. As a result, an expansive area of 15 percent RH and 15-20 mph sustained westerly surface winds will favor elevated to locally critical fire-weather conditions across the Four Corners region. ..Weinman.. 07/09/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...Synopsis... Along the northern periphery of a large-scale ridge over the Southwest, a midlevel shortwave trough will move eastward from the Great Basin into the central Rockies. Enhanced westerly flow aloft accompanying this feature will overspread a deeply mixed boundary layer during the afternoon. As a result, an expansive area of 15 percent RH and 15-20 mph sustained westerly surface winds will favor elevated to locally critical fire-weather conditions across the Four Corners region. ..Weinman.. 07/09/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...Synopsis... Along the northern periphery of a large-scale ridge over the Southwest, a midlevel shortwave trough will move eastward from the Great Basin into the central Rockies. Enhanced westerly flow aloft accompanying this feature will overspread a deeply mixed boundary layer during the afternoon. As a result, an expansive area of 15 percent RH and 15-20 mph sustained westerly surface winds will favor elevated to locally critical fire-weather conditions across the Four Corners region. ..Weinman.. 07/09/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...Synopsis... Along the northern periphery of a large-scale ridge over the Southwest, a midlevel shortwave trough will move eastward from the Great Basin into the central Rockies. Enhanced westerly flow aloft accompanying this feature will overspread a deeply mixed boundary layer during the afternoon. As a result, an expansive area of 15 percent RH and 15-20 mph sustained westerly surface winds will favor elevated to locally critical fire-weather conditions across the Four Corners region. ..Weinman.. 07/09/2025 ...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 0156 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL NEVADA INTO WESTERN UTAH... ...Synopsis... A compact midlevel trough will advance eastward across the northern Great Basin during the day. At the same time, a separate large-scale trough will move eastward across western Canada. ...Great Basin... Preceding the compact midlevel trough, moderate deep-layer southwesterly flow will overspread the Great Basin during peak heating. Deep boundary-layer mixing into this strengthening flow aloft will result in an expansive area of lower-teens RH and 20-25 mph sustained west-southwesterly surface winds. Given increasingly dry fuels across the region, critical fire-weather conditions are expected from central NV into western UT (with elevated conditions surrounding this area across the Great Basin). ...Northwest... Large-scale ascent accompanying the compact midlevel trough will aid in isolated to widely scattered thunderstorm development over southeastern OR, southwestern ID, and far northeastern CA during the afternoon/evening hours. Deep inverted-V soundings and 0.5-0.7 inch PW will favor dry thunderstorms -- with a risk of lightning-induced ignitions and strong/erratic outflow winds. Additionally, strong westerly flow in the base of the large-scale trough moving across western Canada will persist across the Cascades. Despite slightly higher RH than previous days, strong downslope/westerly surface winds will favor elevated to locally critical fire-weather conditions in the Columbia Basin. ..Weinman.. 07/09/2025 ...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 0156 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL NEVADA INTO WESTERN UTAH... ...Synopsis... A compact midlevel trough will advance eastward across the northern Great Basin during the day. At the same time, a separate large-scale trough will move eastward across western Canada. ...Great Basin... Preceding the compact midlevel trough, moderate deep-layer southwesterly flow will overspread the Great Basin during peak heating. Deep boundary-layer mixing into this strengthening flow aloft will result in an expansive area of lower-teens RH and 20-25 mph sustained west-southwesterly surface winds. Given increasingly dry fuels across the region, critical fire-weather conditions are expected from central NV into western UT (with elevated conditions surrounding this area across the Great Basin). ...Northwest... Large-scale ascent accompanying the compact midlevel trough will aid in isolated to widely scattered thunderstorm development over southeastern OR, southwestern ID, and far northeastern CA during the afternoon/evening hours. Deep inverted-V soundings and 0.5-0.7 inch PW will favor dry thunderstorms -- with a risk of lightning-induced ignitions and strong/erratic outflow winds. Additionally, strong westerly flow in the base of the large-scale trough moving across western Canada will persist across the Cascades. Despite slightly higher RH than previous days, strong downslope/westerly surface winds will favor elevated to locally critical fire-weather conditions in the Columbia Basin. ..Weinman.. 07/09/2025 ...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 0156 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL NEVADA INTO WESTERN UTAH... ...Synopsis... A compact midlevel trough will advance eastward across the northern Great Basin during the day. At the same time, a separate large-scale trough will move eastward across western Canada. ...Great Basin... Preceding the compact midlevel trough, moderate deep-layer southwesterly flow will overspread the Great Basin during peak heating. Deep boundary-layer mixing into this strengthening flow aloft will result in an expansive area of lower-teens RH and 20-25 mph sustained west-southwesterly surface winds. Given increasingly dry fuels across the region, critical fire-weather conditions are expected from central NV into western UT (with elevated conditions surrounding this area across the Great Basin). ...Northwest... Large-scale ascent accompanying the compact midlevel trough will aid in isolated to widely scattered thunderstorm development over southeastern OR, southwestern ID, and far northeastern CA during the afternoon/evening hours. Deep inverted-V soundings and 0.5-0.7 inch PW will favor dry thunderstorms -- with a risk of lightning-induced ignitions and strong/erratic outflow winds. Additionally, strong westerly flow in the base of the large-scale trough moving across western Canada will persist across the Cascades. Despite slightly higher RH than previous days, strong downslope/westerly surface winds will favor elevated to locally critical fire-weather conditions in the Columbia Basin. ..Weinman.. 07/09/2025 ...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 0156 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL NEVADA INTO WESTERN UTAH... ...Synopsis... A compact midlevel trough will advance eastward across the northern Great Basin during the day. At the same time, a separate large-scale trough will move eastward across western Canada. ...Great Basin... Preceding the compact midlevel trough, moderate deep-layer southwesterly flow will overspread the Great Basin during peak heating. Deep boundary-layer mixing into this strengthening flow aloft will result in an expansive area of lower-teens RH and 20-25 mph sustained west-southwesterly surface winds. Given increasingly dry fuels across the region, critical fire-weather conditions are expected from central NV into western UT (with elevated conditions surrounding this area across the Great Basin). ...Northwest... Large-scale ascent accompanying the compact midlevel trough will aid in isolated to widely scattered thunderstorm development over southeastern OR, southwestern ID, and far northeastern CA during the afternoon/evening hours. Deep inverted-V soundings and 0.5-0.7 inch PW will favor dry thunderstorms -- with a risk of lightning-induced ignitions and strong/erratic outflow winds. Additionally, strong westerly flow in the base of the large-scale trough moving across western Canada will persist across the Cascades. Despite slightly higher RH than previous days, strong downslope/westerly surface winds will favor elevated to locally critical fire-weather conditions in the Columbia Basin. ..Weinman.. 07/09/2025 ...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 1258 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL AND NORTHERN GREAT PLAINS AS WELL AS PORTIONS OF THE SOUTHEAST... ...SUMMARY... Scattered severe thunderstorms are possible over parts of the central and northern Great Plains, mainly during the late afternoon and evening on Thursday. Additional severe thunderstorms will be possible during the afternoon across portions of the Southeast. ... Synopsis ... A complex evolution of the mid-to-upper level pattern is expected to unfold on Thursday across the central United States. A de-amplifying short-wave trough will move from northern Utah into the central Great Plains. At the same time, a larger-scale, positive-tilt trough will amplify during the period across southern Canada as it pushes east. This will result in an effective split-flow pattern across the north-central US. ... Central and Northern Great Plains ... Thunderstorms are expected at the start of the period across eastern portions of the central and northern Great Plains, driven primarily by warm, moist low-level advection. In the wake of this convection, the airmass is expected to quickly recover yielding moderate to extreme instability. By late afternoon, thunderstorms are expected to develop across the terrain of northeast Colorado and eastern Wyoming. As the aforementioned low-amplitude short-wave trough begins to eject into the central Great Plains, these thunderstorms should quickly move off the terrain and into the Plains. Damaging winds will be possible with these storms as the quickly grow upscale in response to the increasing large-scale ascent. The overall degree of instability will also support the potential for sporadic large hail. To the north across North Dakota, convective evolution is more uncertain. The atmosphere will be extremely unstable in the presence of a surface boundary and approaching large-scale ascent. Despite the absence of a more robust signal in the convective allowing guidance for afternoon convection, coarser-scale guidance suggests at least scattered thunderstorm development will occur during the evening and overnight hours. These thunderstorms will be capable of damaging thunderstorm winds with at least some potential for large hail. ... Portions of the Southeast ... Thunderstorms will once again develop within a warm, moist, and weakly capped environment. High precipitable water value (locally in excess of 2 inches) will support water loaded downdrafts giving way to wet downbursts capable of wind damage. A Level 2/Slight Risk was added to highlight the area of highest coverage of potential wet downbursts. ... Portions of the Northeast ... Diurnal heating of a moist boundary layer will result in scattered thunderstorm development across the region. Most-unstable CAPE values greater than 1000 J/kg and modest effective-layer shear should support the potential for scattered wind damage. Should coverage of thunderstorms be greater than currently anticipated an upgrade to Level 2/Slight Risk may be warranted in subsequent forecasts. ..Marsh.. 07/09/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL AND NORTHERN GREAT PLAINS AS WELL AS PORTIONS OF THE SOUTHEAST... ...SUMMARY... Scattered severe thunderstorms are possible over parts of the central and northern Great Plains, mainly during the late afternoon and evening on Thursday. Additional severe thunderstorms will be possible during the afternoon across portions of the Southeast. ... Synopsis ... A complex evolution of the mid-to-upper level pattern is expected to unfold on Thursday across the central United States. A de-amplifying short-wave trough will move from northern Utah into the central Great Plains. At the same time, a larger-scale, positive-tilt trough will amplify during the period across southern Canada as it pushes east. This will result in an effective split-flow pattern across the north-central US. ... Central and Northern Great Plains ... Thunderstorms are expected at the start of the period across eastern portions of the central and northern Great Plains, driven primarily by warm, moist low-level advection. In the wake of this convection, the airmass is expected to quickly recover yielding moderate to extreme instability. By late afternoon, thunderstorms are expected to develop across the terrain of northeast Colorado and eastern Wyoming. As the aforementioned low-amplitude short-wave trough begins to eject into the central Great Plains, these thunderstorms should quickly move off the terrain and into the Plains. Damaging winds will be possible with these storms as the quickly grow upscale in response to the increasing large-scale ascent. The overall degree of instability will also support the potential for sporadic large hail. To the north across North Dakota, convective evolution is more uncertain. The atmosphere will be extremely unstable in the presence of a surface boundary and approaching large-scale ascent. Despite the absence of a more robust signal in the convective allowing guidance for afternoon convection, coarser-scale guidance suggests at least scattered thunderstorm development will occur during the evening and overnight hours. These thunderstorms will be capable of damaging thunderstorm winds with at least some potential for large hail. ... Portions of the Southeast ... Thunderstorms will once again develop within a warm, moist, and weakly capped environment. High precipitable water value (locally in excess of 2 inches) will support water loaded downdrafts giving way to wet downbursts capable of wind damage. A Level 2/Slight Risk was added to highlight the area of highest coverage of potential wet downbursts. ... Portions of the Northeast ... Diurnal heating of a moist boundary layer will result in scattered thunderstorm development across the region. Most-unstable CAPE values greater than 1000 J/kg and modest effective-layer shear should support the potential for scattered wind damage. Should coverage of thunderstorms be greater than currently anticipated an upgrade to Level 2/Slight Risk may be warranted in subsequent forecasts. ..Marsh.. 07/09/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL AND NORTHERN GREAT PLAINS AS WELL AS PORTIONS OF THE SOUTHEAST... ...SUMMARY... Scattered severe thunderstorms are possible over parts of the central and northern Great Plains, mainly during the late afternoon and evening on Thursday. Additional severe thunderstorms will be possible during the afternoon across portions of the Southeast. ... Synopsis ... A complex evolution of the mid-to-upper level pattern is expected to unfold on Thursday across the central United States. A de-amplifying short-wave trough will move from northern Utah into the central Great Plains. At the same time, a larger-scale, positive-tilt trough will amplify during the period across southern Canada as it pushes east. This will result in an effective split-flow pattern across the north-central US. ... Central and Northern Great Plains ... Thunderstorms are expected at the start of the period across eastern portions of the central and northern Great Plains, driven primarily by warm, moist low-level advection. In the wake of this convection, the airmass is expected to quickly recover yielding moderate to extreme instability. By late afternoon, thunderstorms are expected to develop across the terrain of northeast Colorado and eastern Wyoming. As the aforementioned low-amplitude short-wave trough begins to eject into the central Great Plains, these thunderstorms should quickly move off the terrain and into the Plains. Damaging winds will be possible with these storms as the quickly grow upscale in response to the increasing large-scale ascent. The overall degree of instability will also support the potential for sporadic large hail. To the north across North Dakota, convective evolution is more uncertain. The atmosphere will be extremely unstable in the presence of a surface boundary and approaching large-scale ascent. Despite the absence of a more robust signal in the convective allowing guidance for afternoon convection, coarser-scale guidance suggests at least scattered thunderstorm development will occur during the evening and overnight hours. These thunderstorms will be capable of damaging thunderstorm winds with at least some potential for large hail. ... Portions of the Southeast ... Thunderstorms will once again develop within a warm, moist, and weakly capped environment. High precipitable water value (locally in excess of 2 inches) will support water loaded downdrafts giving way to wet downbursts capable of wind damage. A Level 2/Slight Risk was added to highlight the area of highest coverage of potential wet downbursts. ... Portions of the Northeast ... Diurnal heating of a moist boundary layer will result in scattered thunderstorm development across the region. Most-unstable CAPE values greater than 1000 J/kg and modest effective-layer shear should support the potential for scattered wind damage. Should coverage of thunderstorms be greater than currently anticipated an upgrade to Level 2/Slight Risk may be warranted in subsequent forecasts. ..Marsh.. 07/09/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Wed Jul 09 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL AND NORTHERN GREAT PLAINS AS WELL AS PORTIONS OF THE SOUTHEAST... ...SUMMARY... Scattered severe thunderstorms are possible over parts of the central and northern Great Plains, mainly during the late afternoon and evening on Thursday. Additional severe thunderstorms will be possible during the afternoon across portions of the Southeast. ... Synopsis ... A complex evolution of the mid-to-upper level pattern is expected to unfold on Thursday across the central United States. A de-amplifying short-wave trough will move from northern Utah into the central Great Plains. At the same time, a larger-scale, positive-tilt trough will amplify during the period across southern Canada as it pushes east. This will result in an effective split-flow pattern across the north-central US. ... Central and Northern Great Plains ... Thunderstorms are expected at the start of the period across eastern portions of the central and northern Great Plains, driven primarily by warm, moist low-level advection. In the wake of this convection, the airmass is expected to quickly recover yielding moderate to extreme instability. By late afternoon, thunderstorms are expected to develop across the terrain of northeast Colorado and eastern Wyoming. As the aforementioned low-amplitude short-wave trough begins to eject into the central Great Plains, these thunderstorms should quickly move off the terrain and into the Plains. Damaging winds will be possible with these storms as the quickly grow upscale in response to the increasing large-scale ascent. The overall degree of instability will also support the potential for sporadic large hail. To the north across North Dakota, convective evolution is more uncertain. The atmosphere will be extremely unstable in the presence of a surface boundary and approaching large-scale ascent. Despite the absence of a more robust signal in the convective allowing guidance for afternoon convection, coarser-scale guidance suggests at least scattered thunderstorm development will occur during the evening and overnight hours. These thunderstorms will be capable of damaging thunderstorm winds with at least some potential for large hail. ... Portions of the Southeast ... Thunderstorms will once again develop within a warm, moist, and weakly capped environment. High precipitable water value (locally in excess of 2 inches) will support water loaded downdrafts giving way to wet downbursts capable of wind damage. A Level 2/Slight Risk was added to highlight the area of highest coverage of potential wet downbursts. ... Portions of the Northeast ... Diurnal heating of a moist boundary layer will result in scattered thunderstorm development across the region. Most-unstable CAPE values greater than 1000 J/kg and modest effective-layer shear should support the potential for scattered wind damage. Should coverage of thunderstorms be greater than currently anticipated an upgrade to Level 2/Slight Risk may be warranted in subsequent forecasts. ..Marsh.. 07/09/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS INTO THE MID-ATLANTIC...AND PORTIONS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered damaging winds are possible this afternoon to early evening from parts of the Carolinas to the Mid-Atlantic. Large hail and severe gusts are also possible across parts of the northern/central Plains beginning late this afternoon and continuing into the evening. ...Southeast into the Mid-Atlantic... A weak mid-level trough will move slowly eastward today across the Great Lakes/OH Valley. A belt of modestly enhanced southwesterly mid-level flow will remain over the Mid-Atlantic through this evening, diminishing with southward extent in the Southeast. Scattered to numerous thunderstorms are once again expected to develop this afternoon over the southern Appalachians and Blue Ridge Mountains, and then spread eastward towards the coast. The presence of rich low-level moisture will compensate for poor lapse rates aloft to support MLCAPE generally around 1500-3000 J/kg across lower elevations. A few loosely organized clusters may eventually develop from parts of VA towards the DelMarVa Peninsula and vicinity owing to somewhat more favorable deep-layer shear across these regions. Isolated hail may occur initially with the more cellular/discrete convection, before scattered severe/damaging winds becomes the primary risk with eastward extent as multiple clusters potentially develop. Generally minor adjustments have been made to the ongoing Marginal/Slight Risk areas to account for latest guidance trends. ...Northern/Central Plains... Downstream of a low-amplitude mid-level ridge emanating from an upper-level anticyclone over the Southwest, most guidance continues to suggest that isolated to scattered thunderstorms should form by late this afternoon along a weak surface trough. Ample low-level moisture ahead of this trough will gradually build beneath a stout EML. A corridor of strong to very strong instability will likely exist by late afternoon/early evening from parts of western/central ND into NE, aided by daytime heating and steep lapse rates aloft. Despite modest mid-level west-northwesterlies owing to the proximity of the upper ridge, stronger upper-level westerlies will support adequate deep-layer shear for a few supercells initially, with associated threat for large to isolated very large hail. Outflow-dominated downdrafts should foster clustering east-southeastward across the Dakotas and perhaps parts of NE, with a risk for scattered severe gusts, some of which could be 75+ mph on an isolated basis given the rather favorable thermodynamic environment forecast. While confidence is somewhat lower regarding convective coverage with southward extent across the central Plains (into KS and vicinity), a conditionally favorable environment for at least isolated severe convection will be in place. Have therefore expanded the Marginal Risk southward to account for this potential. ...Interior Northwest/Northern Rockies... Downstream of a shortwave trough moving eastward across northern CA into the northwest Great Basin, an elongated belt of enhanced southwesterly mid-level flow will exist across the northern Great Basin/Rockies. Within this favorable flow regime amid steepened low-level lapse rates through daytime heating, scattered thunderstorms should foster strong to isolated severe gusts from parts of eastern OR into MT. ...Lower Michigan into Northwest Ohio... Isolated/marginally severe hail and locally damaging winds appear possible this afternoon across parts of Lower Michigan and northwest OH as scattered thunderstorms develop beneath a weak upper trough, supported by a modest combination of instability and deep-layer shear. ..Gleason/Weinman.. 07/09/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS INTO THE MID-ATLANTIC...AND PORTIONS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered damaging winds are possible this afternoon to early evening from parts of the Carolinas to the Mid-Atlantic. Large hail and severe gusts are also possible across parts of the northern/central Plains beginning late this afternoon and continuing into the evening. ...Southeast into the Mid-Atlantic... A weak mid-level trough will move slowly eastward today across the Great Lakes/OH Valley. A belt of modestly enhanced southwesterly mid-level flow will remain over the Mid-Atlantic through this evening, diminishing with southward extent in the Southeast. Scattered to numerous thunderstorms are once again expected to develop this afternoon over the southern Appalachians and Blue Ridge Mountains, and then spread eastward towards the coast. The presence of rich low-level moisture will compensate for poor lapse rates aloft to support MLCAPE generally around 1500-3000 J/kg across lower elevations. A few loosely organized clusters may eventually develop from parts of VA towards the DelMarVa Peninsula and vicinity owing to somewhat more favorable deep-layer shear across these regions. Isolated hail may occur initially with the more cellular/discrete convection, before scattered severe/damaging winds becomes the primary risk with eastward extent as multiple clusters potentially develop. Generally minor adjustments have been made to the ongoing Marginal/Slight Risk areas to account for latest guidance trends. ...Northern/Central Plains... Downstream of a low-amplitude mid-level ridge emanating from an upper-level anticyclone over the Southwest, most guidance continues to suggest that isolated to scattered thunderstorms should form by late this afternoon along a weak surface trough. Ample low-level moisture ahead of this trough will gradually build beneath a stout EML. A corridor of strong to very strong instability will likely exist by late afternoon/early evening from parts of western/central ND into NE, aided by daytime heating and steep lapse rates aloft. Despite modest mid-level west-northwesterlies owing to the proximity of the upper ridge, stronger upper-level westerlies will support adequate deep-layer shear for a few supercells initially, with associated threat for large to isolated very large hail. Outflow-dominated downdrafts should foster clustering east-southeastward across the Dakotas and perhaps parts of NE, with a risk for scattered severe gusts, some of which could be 75+ mph on an isolated basis given the rather favorable thermodynamic environment forecast. While confidence is somewhat lower regarding convective coverage with southward extent across the central Plains (into KS and vicinity), a conditionally favorable environment for at least isolated severe convection will be in place. Have therefore expanded the Marginal Risk southward to account for this potential. ...Interior Northwest/Northern Rockies... Downstream of a shortwave trough moving eastward across northern CA into the northwest Great Basin, an elongated belt of enhanced southwesterly mid-level flow will exist across the northern Great Basin/Rockies. Within this favorable flow regime amid steepened low-level lapse rates through daytime heating, scattered thunderstorms should foster strong to isolated severe gusts from parts of eastern OR into MT. ...Lower Michigan into Northwest Ohio... Isolated/marginally severe hail and locally damaging winds appear possible this afternoon across parts of Lower Michigan and northwest OH as scattered thunderstorms develop beneath a weak upper trough, supported by a modest combination of instability and deep-layer shear. ..Gleason/Weinman.. 07/09/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS INTO THE MID-ATLANTIC...AND PORTIONS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered damaging winds are possible this afternoon to early evening from parts of the Carolinas to the Mid-Atlantic. Large hail and severe gusts are also possible across parts of the northern/central Plains beginning late this afternoon and continuing into the evening. ...Southeast into the Mid-Atlantic... A weak mid-level trough will move slowly eastward today across the Great Lakes/OH Valley. A belt of modestly enhanced southwesterly mid-level flow will remain over the Mid-Atlantic through this evening, diminishing with southward extent in the Southeast. Scattered to numerous thunderstorms are once again expected to develop this afternoon over the southern Appalachians and Blue Ridge Mountains, and then spread eastward towards the coast. The presence of rich low-level moisture will compensate for poor lapse rates aloft to support MLCAPE generally around 1500-3000 J/kg across lower elevations. A few loosely organized clusters may eventually develop from parts of VA towards the DelMarVa Peninsula and vicinity owing to somewhat more favorable deep-layer shear across these regions. Isolated hail may occur initially with the more cellular/discrete convection, before scattered severe/damaging winds becomes the primary risk with eastward extent as multiple clusters potentially develop. Generally minor adjustments have been made to the ongoing Marginal/Slight Risk areas to account for latest guidance trends. ...Northern/Central Plains... Downstream of a low-amplitude mid-level ridge emanating from an upper-level anticyclone over the Southwest, most guidance continues to suggest that isolated to scattered thunderstorms should form by late this afternoon along a weak surface trough. Ample low-level moisture ahead of this trough will gradually build beneath a stout EML. A corridor of strong to very strong instability will likely exist by late afternoon/early evening from parts of western/central ND into NE, aided by daytime heating and steep lapse rates aloft. Despite modest mid-level west-northwesterlies owing to the proximity of the upper ridge, stronger upper-level westerlies will support adequate deep-layer shear for a few supercells initially, with associated threat for large to isolated very large hail. Outflow-dominated downdrafts should foster clustering east-southeastward across the Dakotas and perhaps parts of NE, with a risk for scattered severe gusts, some of which could be 75+ mph on an isolated basis given the rather favorable thermodynamic environment forecast. While confidence is somewhat lower regarding convective coverage with southward extent across the central Plains (into KS and vicinity), a conditionally favorable environment for at least isolated severe convection will be in place. Have therefore expanded the Marginal Risk southward to account for this potential. ...Interior Northwest/Northern Rockies... Downstream of a shortwave trough moving eastward across northern CA into the northwest Great Basin, an elongated belt of enhanced southwesterly mid-level flow will exist across the northern Great Basin/Rockies. Within this favorable flow regime amid steepened low-level lapse rates through daytime heating, scattered thunderstorms should foster strong to isolated severe gusts from parts of eastern OR into MT. ...Lower Michigan into Northwest Ohio... Isolated/marginally severe hail and locally damaging winds appear possible this afternoon across parts of Lower Michigan and northwest OH as scattered thunderstorms develop beneath a weak upper trough, supported by a modest combination of instability and deep-layer shear. ..Gleason/Weinman.. 07/09/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS INTO THE MID-ATLANTIC...AND PORTIONS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered damaging winds are possible this afternoon to early evening from parts of the Carolinas to the Mid-Atlantic. Large hail and severe gusts are also possible across parts of the northern/central Plains beginning late this afternoon and continuing into the evening. ...Southeast into the Mid-Atlantic... A weak mid-level trough will move slowly eastward today across the Great Lakes/OH Valley. A belt of modestly enhanced southwesterly mid-level flow will remain over the Mid-Atlantic through this evening, diminishing with southward extent in the Southeast. Scattered to numerous thunderstorms are once again expected to develop this afternoon over the southern Appalachians and Blue Ridge Mountains, and then spread eastward towards the coast. The presence of rich low-level moisture will compensate for poor lapse rates aloft to support MLCAPE generally around 1500-3000 J/kg across lower elevations. A few loosely organized clusters may eventually develop from parts of VA towards the DelMarVa Peninsula and vicinity owing to somewhat more favorable deep-layer shear across these regions. Isolated hail may occur initially with the more cellular/discrete convection, before scattered severe/damaging winds becomes the primary risk with eastward extent as multiple clusters potentially develop. Generally minor adjustments have been made to the ongoing Marginal/Slight Risk areas to account for latest guidance trends. ...Northern/Central Plains... Downstream of a low-amplitude mid-level ridge emanating from an upper-level anticyclone over the Southwest, most guidance continues to suggest that isolated to scattered thunderstorms should form by late this afternoon along a weak surface trough. Ample low-level moisture ahead of this trough will gradually build beneath a stout EML. A corridor of strong to very strong instability will likely exist by late afternoon/early evening from parts of western/central ND into NE, aided by daytime heating and steep lapse rates aloft. Despite modest mid-level west-northwesterlies owing to the proximity of the upper ridge, stronger upper-level westerlies will support adequate deep-layer shear for a few supercells initially, with associated threat for large to isolated very large hail. Outflow-dominated downdrafts should foster clustering east-southeastward across the Dakotas and perhaps parts of NE, with a risk for scattered severe gusts, some of which could be 75+ mph on an isolated basis given the rather favorable thermodynamic environment forecast. While confidence is somewhat lower regarding convective coverage with southward extent across the central Plains (into KS and vicinity), a conditionally favorable environment for at least isolated severe convection will be in place. Have therefore expanded the Marginal Risk southward to account for this potential. ...Interior Northwest/Northern Rockies... Downstream of a shortwave trough moving eastward across northern CA into the northwest Great Basin, an elongated belt of enhanced southwesterly mid-level flow will exist across the northern Great Basin/Rockies. Within this favorable flow regime amid steepened low-level lapse rates through daytime heating, scattered thunderstorms should foster strong to isolated severe gusts from parts of eastern OR into MT. ...Lower Michigan into Northwest Ohio... Isolated/marginally severe hail and locally damaging winds appear possible this afternoon across parts of Lower Michigan and northwest OH as scattered thunderstorms develop beneath a weak upper trough, supported by a modest combination of instability and deep-layer shear. ..Gleason/Weinman.. 07/09/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Jul 09 2025 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS INTO THE MID-ATLANTIC...AND PORTIONS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Scattered damaging winds are possible this afternoon to early evening from parts of the Carolinas to the Mid-Atlantic. Large hail and severe gusts are also possible across parts of the northern/central Plains beginning late this afternoon and continuing into the evening. ...Southeast into the Mid-Atlantic... A weak mid-level trough will move slowly eastward today across the Great Lakes/OH Valley. A belt of modestly enhanced southwesterly mid-level flow will remain over the Mid-Atlantic through this evening, diminishing with southward extent in the Southeast. Scattered to numerous thunderstorms are once again expected to develop this afternoon over the southern Appalachians and Blue Ridge Mountains, and then spread eastward towards the coast. The presence of rich low-level moisture will compensate for poor lapse rates aloft to support MLCAPE generally around 1500-3000 J/kg across lower elevations. A few loosely organized clusters may eventually develop from parts of VA towards the DelMarVa Peninsula and vicinity owing to somewhat more favorable deep-layer shear across these regions. Isolated hail may occur initially with the more cellular/discrete convection, before scattered severe/damaging winds becomes the primary risk with eastward extent as multiple clusters potentially develop. Generally minor adjustments have been made to the ongoing Marginal/Slight Risk areas to account for latest guidance trends. ...Northern/Central Plains... Downstream of a low-amplitude mid-level ridge emanating from an upper-level anticyclone over the Southwest, most guidance continues to suggest that isolated to scattered thunderstorms should form by late this afternoon along a weak surface trough. Ample low-level moisture ahead of this trough will gradually build beneath a stout EML. A corridor of strong to very strong instability will likely exist by late afternoon/early evening from parts of western/central ND into NE, aided by daytime heating and steep lapse rates aloft. Despite modest mid-level west-northwesterlies owing to the proximity of the upper ridge, stronger upper-level westerlies will support adequate deep-layer shear for a few supercells initially, with associated threat for large to isolated very large hail. Outflow-dominated downdrafts should foster clustering east-southeastward across the Dakotas and perhaps parts of NE, with a risk for scattered severe gusts, some of which could be 75+ mph on an isolated basis given the rather favorable thermodynamic environment forecast. While confidence is somewhat lower regarding convective coverage with southward extent across the central Plains (into KS and vicinity), a conditionally favorable environment for at least isolated severe convection will be in place. Have therefore expanded the Marginal Risk southward to account for this potential. ...Interior Northwest/Northern Rockies... Downstream of a shortwave trough moving eastward across northern CA into the northwest Great Basin, an elongated belt of enhanced southwesterly mid-level flow will exist across the northern Great Basin/Rockies. Within this favorable flow regime amid steepened low-level lapse rates through daytime heating, scattered thunderstorms should foster strong to isolated severe gusts from parts of eastern OR into MT. ...Lower Michigan into Northwest Ohio... Isolated/marginally severe hail and locally damaging winds appear possible this afternoon across parts of Lower Michigan and northwest OH as scattered thunderstorms develop beneath a weak upper trough, supported by a modest combination of instability and deep-layer shear. ..Gleason/Weinman.. 07/09/2025 Read more