Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1137 AM CDT Fri Apr 18 2025 Valid 181700Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF SOUTHERN/EASTERN NEW MEXICO INTO FAR WEST TEXAS... ...1630 Update... A faster southward progression of a backdoor cold front across the Texas Panhandle as far south as US-70 has temporarily mitigated fire weather concerns across the area. However, some northeastward retreat and daytime mixing should allow dry southwest flow to return to portions of northeastern New Mexico and the Texas Panhandle supporting at least a brief period of Elevated fire weather conditions to emerge within this zone. The Critical fire weather threat will continue for much of southeastern New Mexico. Eastern extent of Elevated highlights were trimmed along the Florida Atlantic Coast as higher dewpoints/relative humidity accompany southeasterly onshore flow. Farther inland however, Elevated fire weather conditions expected with east-southeast winds of 10-15 mph and relative humidity dropping into the 35-40 percent range this afternoon amid increasingly dry fuels. ..Williams/Lyons.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1245 AM CDT Fri Apr 18 2025/ ...Synopsis... An upper trough initially in the Great Basin will move towards the Four Corners region today. A modest surface low in eastern New Mexico into West Texas will develop during the day. A cold front will continue to make southward progress into the southern Plains. ...New Mexico into West Texas... Elevated to critical fire weather conditions are again expected during the afternoon. Moderate mid-level flow across the Southwest and southern Plains and a modest surface low along the Texas/New Mexico border will drive 15-20 mph (up to 25 mph in the terrain) surface winds by the afternoon. RH will be slightly higher than Thursday on account of mid/upper-level clouds. Values of around 10% may occur, but will occur on a relatively local basis. 15-20% will be more common. The driest fuels will be in New Mexico and the Trans-Pecos. Farther east in the Texas Panhandle/South Plains, transitional/greening fuels will mitigate fire weather concerns even with similarly dry and windy conditions. ...Florida... Easterly winds of around 10 mph appear possible during the afternoon. RH of 25-35% can be expected along the western Peninsula. With dry fuels (current ERC data showing some locations above the 90th percentile), elevated fire weather is likely this afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1133 AM CDT Fri Apr 18 2025 Valid 181630Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND SOUTHWESTERN GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward through the mid Mississippi Valley and southwestern Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Southern Plains to the Ozarks... Strong southwesterly mid to high-level flow will extend from the southern High Plains northeastward into the Great Lakes, downstream of a mid- to upper-level low over the Four Corners states. A cold front was analyzed from the Low Rolling Plains northeastward through central OK late this morning. This portion of the front will continue southeastward into the I-44 corridor but decelerate towards late afternoon. A dryline extends southward from the front over the TX Big Country. Despite widespread mid/high-level cloudiness, filtered heating of a moist/destabilizing airmass will likely result in a weakened cap by late afternoon. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. Model forecast hodographs and ample PW suggest a strong tendency towards upscale growth into an HP supercell and linear segment this evening from south-central OK northeastward towards the western part of the Ozark Plateau. Coincident with this expected convective mode evolution, an increase in the severe/damaging wind threat is anticipated. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where surface-based supercells and mesovortex potential may still exist. ...Lower MI to Mid Mississippi Valley... In wake of weakened thunderstorm activity across Lower MI, a warm sector will attempt to spread northward and destabilize across parts of the mid MS Valley and southern/central Great Lakes this afternoon. An upper trough will only slowly encroach on the Upper Midwest through late tonight. As a result, southwesterly flow aloft will be maintained and limited southeastward progression of a cold front is forecast. Model guidance continues to indicate surface-based thunderstorm development will be inhibited until peak heating, when frontal forcing and gradual erosion of the cap leads to isolated storms developing from MO northeastward towards the southwest Great Lakes. Uncertainty remains regarding timing, overall thunderstorm coverage, and the exact evolution of this activity. Nonetheless, strong shear through a deep layer and adequate buoyancy (due in part to steep mid-level lapse rates), will support organized thunderstorms. The stronger thunderstorms will probably pose a risk for severe hail and damaging winds. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ..Smith/Thornton.. 04/18/2025 Read more

MD 0468 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF LAKE MICHIGAN THROUGH SOUTHERN AND CENTRAL LOWER MICHIGAN
Mesoscale Discussion 0468 NWS Storm Prediction Center Norman OK 0936 AM CDT Fri Apr 18 2025 Areas affected...portions of Lake Michigan through southern and central Lower Michigan Concerning...Severe potential...Watch unlikely Valid 181436Z - 181630Z Probability of Watch Issuance...20 percent SUMMARY...A continuing risk for severe hail and/or increasing potential for strong, damaging wind gusts appears low, as a small, organizing cluster of storms, or its remnants, spreads inland of Lake Michigan across parts of central/southern Lower Michigan through midday. A new watch is not anticipated, but trends are being monitored. DISCUSSION...Strongest convection has become focused above the convectively generated cold pool, within forcing associated with low-level warm advection, trailing to the southwest of a weakening MCV now approaching Michigan coastal areas near/north of Muskegon. Currently moving eastward at speeds of 45-50 kt, the small, organizing cluster is on track to overspread the Grand Rapids, Lansing and Flint vicinities of south central Lower Michigan through 15-17Z. However, the latest Rapid Refresh suggests that southerly low-level wind fields and associated forcing for ascent will weaken through mid to late morning, while warmer and more strongly capping elevated mixed layer air advects northeastward across the region. So, it remains uncertain how much longer ongoing activity will be maintained. Furthermore, while an initially cool, dry and stable boundary-layer across southern into central Lower Michigan is in the process of gradually warming and moistening ahead of the approaching convection, the extent to which low-level thermodynamic profiles become unstable to downdrafts and/or downward mixing of stronger momentum aloft remains unclear. Currently, potential for a continuing risk for severe hail and/or an increasing risk for damaging wind gusts appears low, at least in the near term, but trends will continue to be monitored. ..Kerr/Smith.. 04/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX...IWX...GRR...MKX... LAT...LON 43918706 44048635 43378327 42268295 41998647 42718813 43918706 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

WW 0142 Status Updates
STATUS REPORT ON WW 142 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 SSE RAC TO 25 ENE RAC. REMAINING VALID PORTION OF WW MAY BE CANCELLED PRIOR TO THE SCHEDULED 16Z EXPIRATION. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 468. ..KERR..04/18/25 ATTN...WFO...MKX... STATUS REPORT FOR WS 142 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LMZ673-675-181540- CW . ADJACENT COASTAL WATERS INCLUDED ARE THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 142 SEVERE TSTM WI LM 181055Z - 181600Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 142 NWS Storm Prediction Center Norman OK 555 AM CDT Fri Apr 18 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Wisconsin Lake Michigan * Effective this Friday morning from 555 AM until 1100 AM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Multiple supercells and bowing structures will spread quickly eastward this morning across southern Wisconsin. Scattered large hail around 1-2 inches in diameter and 60-70 mph wind gusts may occur with this activity. The severe thunderstorm watch area is approximately along and 30 statute miles north and south of a line from 40 miles west of Madison WI to 30 miles east northeast of Racine WI. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27050. ...Gleason Read more

WW 0142 Status Updates
STATUS REPORT ON WW 142 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 E JVL TO 35 N MKE. ..KERR..04/18/25 ATTN...WFO...MKX... STATUS REPORT FOR WS 142 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS WIC059-079-089-101-127-133-181440- WI . WISCONSIN COUNTIES INCLUDED ARE KENOSHA MILWAUKEE OZAUKEE RACINE WALWORTH WAUKESHA LMZ644-645-646-671-673-675-181440- CW . ADJACENT COASTAL WATERS INCLUDED ARE PORT WASHINGTON TO NORTH POINT LIGHT WI NORTH POINT LIGHT TO WIND POINT WI WIND POINT WI TO WINTHROP HARBOR IL LAKE MICHIGAN FROM PORT WASHINGTON TO NORTH POINT LIGHT WI 5NM OFFSHORE TO MID LAKE LAKE MICHIGAN FROM NORTH POINT LIGHT TO WIND POINT WI 5NM Read more

MD 0467 CONCERNING SEVERE THUNDERSTORM WATCH 142... FOR SOUTHERN WISCONSIN...LAKE MICHIGAN
Mesoscale Discussion 0467 NWS Storm Prediction Center Norman OK 0722 AM CDT Fri Apr 18 2025 Areas affected...Southern Wisconsin...Lake Michigan Concerning...Severe Thunderstorm Watch 142... Valid 181222Z - 181415Z The severe weather threat for Severe Thunderstorm Watch 142 continues. SUMMARY...A severe threat will likely continue over the next couple of hours from parts of southern Wisconsin eastward over Lake Michigan. Significant wind gusts and large hail will be possible with the strongest of cells. DISCUSSION...The latest high-resolution radar imagery from KMKX shows a cluster of strong to severe storms over southern Wisconsin, with a severe short line segment located about 40 statute miles to the west of Milwaukee, Wisconsin. The storms are located along an east-to-west gradient of instability, where the RAP is estimating MUCAPE around 1000 J/kg. RAP forecast soundings to the west of Milwaukee still have a temperature inversion from the surface to 850 mb, with strong effective shear above the inversion. This will continue to support elevated supercell development. In addition, forecast soundings have steep lapse rates in the 700 to 500 mb layer, which will aid a threat for large hail with supercells. Hailstones greater than 2 inches in diameter will be possible in the more intense cores. The stronger and faster moving line segments could also produce severe gusts, with 70+ mph gusts possible. The severe threat is expected to become more isolated later this morning. To the east of the current watch, watch issuance probably won't be needed. Trends will be monitored. ..Broyles/Gleason.. 04/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRR...LOT...MKX...ARX... LAT...LON 43328623 42978610 42648625 42508658 42488814 42558932 42619011 42769037 43059037 43369020 43578977 43598821 43528671 43328623 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN Read more

WW 0142 Status Updates
STATUS REPORT ON WW 142 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 WNW RFD TO 15 SW MSN TO 25 NE MSN TO 20 S OSH. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0467 ..GLEASON..04/18/25 ATTN...WFO...MKX... STATUS REPORT FOR WS 142 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS WIC025-027-045-055-059-079-089-101-105-127-131-133-181340- WI . WISCONSIN COUNTIES INCLUDED ARE DANE DODGE GREEN JEFFERSON KENOSHA MILWAUKEE OZAUKEE RACINE ROCK WALWORTH WASHINGTON WAUKESHA LMZ644-645-646-671-673-675-181340- CW . ADJACENT COASTAL WATERS INCLUDED ARE PORT WASHINGTON TO NORTH POINT LIGHT WI NORTH POINT LIGHT TO WIND POINT WI WIND POINT WI TO WINTHROP HARBOR IL Read more

MD 0466 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEAST IOWA...SOUTHERN WISCONSIN
Mesoscale Discussion 0466 NWS Storm Prediction Center Norman OK 0505 AM CDT Fri Apr 18 2025 Areas affected...Northeast Iowa...Southern Wisconsin Concerning...Severe potential...Watch unlikely Valid 181005Z - 181230Z Probability of Watch Issuance...20 percent SUMMARY...An isolated threat for large hail and severe gusts will likely continue across parts of northeast Iowa over the next few hours. The threat is also expected to affect parts of southern Wisconsin. Weather watch issuance is unlikely. DISCUSSION...The latest high-resolution radar imagery from Des Moines shows a cluster of thunderstorms across northeast Iowa and far southwest Wisconsin. Some of these storms have produced severe reports over the last couple of hours. The cluster will continue to move eastward into southern Wisconsin this morning. RAP forecast soundings from northeast Iowa into southern Wisconsin have a temperature inversion up to about 850 mb. Across northeast Iowa, MUCAPE is estimated by the RAP in the 1000 to 2000 J/kg range. Instability further to the east is considerably less, but an increase in instability could still occur as warm advection continues through the morning. In addition, RAP analysis across northeast Iowa has effective shear generally in the 40 to 50 knot range. This environment should support elevated supercells capable of producing isolated large hail. In spite of the low-level temperature inversion, a strong to severe gust will also be possible. The severe threat should develop eastward across southern Wisconsin but may become more isolated as the storms outrun the instability further to the west. ..Broyles/Gleason.. 04/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX...DMX... LAT...LON 42458882 42479059 42539253 42669327 43109340 43499266 43488999 43368824 42768793 42508828 42458882 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 AM CDT Fri Apr 18 2025 Valid 181300Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND UPPER GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward toward the upper Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Upper Great Lakes to Mid Mississippi Valley... Ongoing, mostly elevated thunderstorms aided by persistent low-level warm/moist advection and steep mid-level lapse rates should continue to pose a large hail and damaging wind threat as they spread quickly eastward across southern WI this morning. This activity should eventually weaken later this morning as it continues moving across Lower MI into a less unstable environment. Behind this initial activity, the surface warm sector will attempt to spread northward across parts of the Upper Midwest and Great Lakes today, as longwave troughing gradually develops eastward over the northern/central Plains and Southwest. Given the positive tilt/orientation of this upper troughing and enhanced southwesterly flow aloft expected to persist through the period, a strong cold front should make only slow southeastward progress. A cap will likely inhibit surface-based convective development until peak afternoon heating and frontal forcing can help lift parcels to their LFC. Given nebulous forcing aloft, there is still a fair amount of uncertainty regarding overall convective coverage this afternoon/evening. Even so, any thunderstorms that can develop along or ahead of the front could pose a threat for severe hail and damaging winds, with strong deep-layer shear aiding updraft organization. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ...Southern Plains to the Ozarks... The southern portion of the cold front is forecast to decelerate and eventually stall over parts of OK later today. A dryline will extend southward from a weak frontal low across northwest to west-central TX by late afternoon. Even with widespread mid/high-level cloudiness present, robust daytime heating of the moist warm sector is anticipated across the southern Plains today. The low-level cap should eventually be breached by late afternoon/early evening (around 22-00Z), particularly along/near the cold front, and perhaps the front/dryline intersection as well. Strong southwesterly flow aloft and related deep-layer shear will likely support organized severe convection. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. With time, upscale growth into multiple clusters/short line segments is expected through the evening into early Saturday morning, as a south-southwesterly low-level jet gradually strengthens. An increase in the severe/damaging wind threat is anticipated as this mode transition occurs. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where supercells may still exist. Even with a higher concentration of thunderstorms expected across the southern Plains, the messy convective mode this evening and tendency for convection to be undercut by the cold front currently limit confidence in delineating a corridor of greater severe hail/wind potential. ..Gleason/Broyles.. 04/18/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 AM CDT Fri Apr 18 2025 Valid 181300Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND UPPER GREAT LAKES... ...SUMMARY... Scattered severe thunderstorms are possible from parts of the southern Plains northeastward toward the upper Great Lakes, mainly from late afternoon into early Saturday morning. Large to very large hail and severe wind gusts should be the main hazards, especially across the southern Plains where storms will be more concentrated. A few tornadoes also appear possible. ...Upper Great Lakes to Mid Mississippi Valley... Ongoing, mostly elevated thunderstorms aided by persistent low-level warm/moist advection and steep mid-level lapse rates should continue to pose a large hail and damaging wind threat as they spread quickly eastward across southern WI this morning. This activity should eventually weaken later this morning as it continues moving across Lower MI into a less unstable environment. Behind this initial activity, the surface warm sector will attempt to spread northward across parts of the Upper Midwest and Great Lakes today, as longwave troughing gradually develops eastward over the northern/central Plains and Southwest. Given the positive tilt/orientation of this upper troughing and enhanced southwesterly flow aloft expected to persist through the period, a strong cold front should make only slow southeastward progress. A cap will likely inhibit surface-based convective development until peak afternoon heating and frontal forcing can help lift parcels to their LFC. Given nebulous forcing aloft, there is still a fair amount of uncertainty regarding overall convective coverage this afternoon/evening. Even so, any thunderstorms that can develop along or ahead of the front could pose a threat for severe hail and damaging winds, with strong deep-layer shear aiding updraft organization. This severe threat may persist for much of the evening, and perhaps continuing into the early overnight hours. ...Southern Plains to the Ozarks... The southern portion of the cold front is forecast to decelerate and eventually stall over parts of OK later today. A dryline will extend southward from a weak frontal low across northwest to west-central TX by late afternoon. Even with widespread mid/high-level cloudiness present, robust daytime heating of the moist warm sector is anticipated across the southern Plains today. The low-level cap should eventually be breached by late afternoon/early evening (around 22-00Z), particularly along/near the cold front, and perhaps the front/dryline intersection as well. Strong southwesterly flow aloft and related deep-layer shear will likely support organized severe convection. Initial supercell development should pose a threat for large to very large hail, potentially up to 2-3 inches in diameter. With time, upscale growth into multiple clusters/short line segments is expected through the evening into early Saturday morning, as a south-southwesterly low-level jet gradually strengthens. An increase in the severe/damaging wind threat is anticipated as this mode transition occurs. The threat for a few tornadoes remains apparent, especially across parts of OK along/south of the front, as favorable low-level shear will be present this evening where supercells may still exist. Even with a higher concentration of thunderstorms expected across the southern Plains, the messy convective mode this evening and tendency for convection to be undercut by the cold front currently limit confidence in delineating a corridor of greater severe hail/wind potential. ..Gleason/Broyles.. 04/18/2025 Read more