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SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0434 PM CDT Fri Apr 18 2025 Valid 201200Z - 261200Z Active mid-level flow is expected over much of the US through the extended forecast period. An upper trough will migrate across the Plains and central US this weekend, as an area of low pressure and cold front move east with it. As the cold front over the plains stalls, the trailing portion will move westward, increasing RH and overnight recoveries for several days across the Southwest and southern High Plains. This will keep fire-weather conditions relatively limited until the next larger trough begins to approach midweek next week. ...Southern Great Basin into the Southwest... Midweek next week, the cooler air mass behind the aforementioned cold front will begin to modify as the next upper trough approaches the West Coast. Increasingly strong southwesterly flow aloft will overspread the drying and warming air mass, supporting some increase in fire-weather potential. Model timing differences remain substantial, though ensembles shows elevated conditions emerging by D6/Thurs. More substantial fire-weather conditions are possible into next weekend, as the main trough overspreads the southern Rockies and High Plains. ...FL... Very dry conditions are expected to persist across south FL through the middle of next week as high pressure continues to intensify over the eastern Atlantic this weekend. Relatively dry east/southeasterly flow is expected along with very warm temperatures. The combination of warm temperatures and modest moisture will support elevated fire-weather conditions given dry fuels D3/Sunday. Further drying of fuels is also expected over southern FL next week. Some risk for locally elevated fire weather conditions remains possible for the inland and western Peninsula much of next week. ...Central High Plains... A period of westerly downslope flow is likely from this weekend into early next week as flow aloft becomes more zonal. Downslope winds may reach critical criteria behind the cold front, but substantial uncertainty remains on diurnal RH minimums given the cooler surface temperatures. Additionally, widespread precipitation is expected over the next several days, likely tempering fuels and supporting only localized fire-weather concerns. ..Lyons.. 04/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0469 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SWRN THROUGH MUCH OF ERN MO...CNTRL AND NRN IL
Mesoscale Discussion 0469 NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Apr 18 2025 Areas affected...swrn through much of ern MO...cntrl and nrn IL Concerning...Severe potential...Watch possible Valid 181953Z - 182230Z Probability of Watch Issuance...40 percent SUMMARY...The initiation of thunderstorms probably will begin to increase by 5-7 PM, but this may be slow and rather widely scattered in nature, resulting in uncertainty concerning severe weather watch issuance. Storms that do develop may include supercells with severe hail, locally strong surface gusts, and at least some risk for a tornado. DISCUSSION...Much of the region remains beneath strong, but broadly anticyclonic mid/upper flow, on the northwestern periphery of prominent large-scale ridging within a stagnant to slowly progressive regime. However, one weak embedded mid-level perturbation has been slowly shifting into/across the middle Mississippi Valley vicinity, with associated lift contributing to a gradual erosion of mid-level inhibition associated with elevated mixed-layer air across Missouri into Illinois. This is coinciding with diurnal destabilization of a modestly moist boundary layer within lee surface troughing across the region. Although this has been slowed by broken layers of cloudiness, mixed-layer CAPE appears on the order of 1000-1500 J/kg, with at least some further increase through 22-00Z. At the same time, low-level hodographs may enlarge beneath southwesterly 850 mb flow forecast to strengthen to 30-40+ kt. As the environment becomes conditionally supportive of supercell development across a sizable area, the focus for and extent of thunderstorm initiation remains more unclear. Guidance suggests that inhibition will become weakest within a relatively narrow corridor near/just ahead of the cold front now still west of the Rockford and Quincy IL, Columbia and Joplin MO, vicinities. However, better mid/upper forcing for ascent continues to spread ahead of the front across parts of northern/central Illinois and east central into south central Missouri. Currently, it appears that thunderstorm initiation will be gradual and rather widely scattered into late afternoon. ..Kerr/Smith.. 04/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...MKX...LSX...DVN...SGF...EAX... LAT...LON 37419464 38309378 39779206 41979026 42578840 41888716 40268803 39338896 37639076 36699384 37419464 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Fri Apr 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS NORTHEASTWARD TO THE UPPER GREAT LAKES AREA... ...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. ...Discussion... Aside from some minor trimming of the MRGL risk area across southern Wisconsin, and from the western Oklahoma vicinity into southern Kansas, no changes appear necessary at this time. Extensive cloud cover along the frontal zone -- from the southern Plains to Wisconsin -- continues to modulate heating/destabilization in the near-frontal warm sector. These effects include a persistent, stout cap across the southern Plains area early this afternoon (per the 18Z OUN RAOB). Still, storm development is expected late this afternoon, as reflected in previous forecasts, with all-hazards severe potential with more vigorous convection. ..Goss.. 04/18/2025 .PREV DISCUSSION... /ISSUED 1133 AM CDT Fri Apr 18 2025/ ...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. Read more