Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Jul 24 2024 Valid 241630Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR WESTERN/CENTRAL NY INTO NORTHWEST PA...AND FROM EASTERN OR/ID INTO WESTERN MT... ...SUMMARY... Strong to severe thunderstorms may produce damaging wind gusts across western/central New York and vicinity this afternoon/evening, as well as across southern Arizona. ...Western/central NY and northwest PA this afternoon/evening... A midlevel trough will progress eastward from the upper Great Lakes toward NY as an associated surface cold front likewise moves eastward into western NY and southeastward into OH/northwest PA through this evening. Surface heating is underway in a corridor ahead of the cold front from northern OH into western NY where boundary-layer dewpoints are in the mid-upper 60s with surface temperatures warming into the lower 80s, and a band of convection has already developed from Lake Erie to western Lake Ontario. These storms may persist into the afternoon while spreading eastward, with additional development possible along convective outflow, a pre-frontal confluence zone and/or local lake breeze boundaries. Midlevel lapse rates will remain modest (roughly 6.5 C/km), but the low-level moisture/warming temperatures will drive MLCAPE in the 1000-1500 J/kg range. Deep-layer vertical shear/hodograph length will be on the lower margins for organized clusters/cells per local VWPs now sampling 30-40 kt midlevel flow, while steepening low-level lapse rates will support the potential for occasional wind damage with strong thunderstorm outflow in the 50-60 mph range. ...Southern AZ this afternoon/evening... Strong surface heating is underway near and south of the Rim, and late afternoon temperatures will peak near or above 110 F across the lower deserts into southern AZ. Moisture will be sufficient for thunderstorm development this afternoon along the Rim and the mountains in southeast AZ, while northeasterly midlevel flow of 15-20 kt will steer outflows southwestward toward the lower deserts. MLCAPE will increase to the 1000-1500 J/kg with deep inverted-V profiles favoring strong downdrafts and outflow winds of 60-75 mph capable of producing wind damage and substantial blowing dust. The relatively greater severe threat will be with the stronger/deeper convection driven by outflow mergers. ...Northern Rockies area this afternoon/evening... A plume of mainly midlevel moisture with PW values of 0.75-1 inch (per BOI and LKN 12z soundings) will persist around the northern periphery of a midlevel high over the Great Basin, and southeast of a midlevel trough approaching WA. High-based thunderstorms are expected in a few loosely organized clusters within this plume, where deep inverted-V profiles will support the potential for a few strong-severe outflow gusts 50-65 mph. ...Mid-Atlantic into NC this afternoon... Modest surface heating within small cloud breaks and boundary-layer dewpoints of 72-74 F will contribute MLCAPE approaching 1500 J/kg to the east of the Blue Ridge, though midlevel lapse rates will remain poor. Still, the southern extent of 30-40 kt midlevel flow will support a low-end wind damage threat with the stronger storm clusters this afternoon. ..Thompson/Karstens.. 07/24/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0812 AM CDT Wed Jul 24 2024 Valid 251200Z - 261200Z CORRECTED FOR MISSING ELEVATED LABEL ...Synopsis... Isolated dry thunderstorms are anticipated across portions of southern Idaho into southwestern Montana as an upper-level trough continues to progress eastward across the Northwest. Additionally, elevated fire-weather conditions are expected across the southern Cascades, portions of northern Montana, and the northern Great Plains. ...Pacific Northwest... As an upper-level trough is forecast to continue progressing eastward out of the Pacific Northwest and into Montana on Thursday, isolated dry thunderstorms are expected across much of the region over receptive fuels. While thunderstorm coverage could approach scattered criteria, current forecast guidance suggests a mix of both wet and dry thunderstorms, in addition to at least some minor potential for some wetting rainfall from the previous day's weather. This uncertainty currently precludes the expansion of the isolated dry thunder area and the inclusion of any scattered dry thunder areas, though forecast trends will continue to be monitored for subsequent updates. Elevated fire-weather conditions are expected to occur over the southern Cascades, especially where local gap flow enhanced winds could contribute to wildfire spread with existing fires. Current forecast guidance suggests that there is less potential for winds to reach elevated criteria over the northern Cascades as the upper-trough begins to leave the region, resulting in the removal of the area from the previous forecast. Some elevated fire weather conditions are also possible in portions of north-central Montana, but the overlap of stronger surface winds and receptive fuels is somewhat narrow. ...Northern Great Plains... Elevated fire-weather conditions are anticipated, particularly along portions of western Montana and Wyoming, into eastern Nebraska and the Dakotas. Strong southerly flow, coupled with hot, dry boundary layer profiles, are expected to persist for much of the afternoon and into the evening. However, current fuel guidance leaves some uncertainty on where these conditions have significant overlap with receptive fuels, particularly with eastward extent. ..Halbert/Lyons.. 07/24/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0812 AM CDT Wed Jul 24 2024 Valid 251200Z - 261200Z CORRECTED FOR MISSING ELEVATED LABEL ...Synopsis... Isolated dry thunderstorms are anticipated across portions of southern Idaho into southwestern Montana as an upper-level trough continues to progress eastward across the Northwest. Additionally, elevated fire-weather conditions are expected across the southern Cascades, portions of northern Montana, and the northern Great Plains. ...Pacific Northwest... As an upper-level trough is forecast to continue progressing eastward out of the Pacific Northwest and into Montana on Thursday, isolated dry thunderstorms are expected across much of the region over receptive fuels. While thunderstorm coverage could approach scattered criteria, current forecast guidance suggests a mix of both wet and dry thunderstorms, in addition to at least some minor potential for some wetting rainfall from the previous day's weather. This uncertainty currently precludes the expansion of the isolated dry thunder area and the inclusion of any scattered dry thunder areas, though forecast trends will continue to be monitored for subsequent updates. Elevated fire-weather conditions are expected to occur over the southern Cascades, especially where local gap flow enhanced winds could contribute to wildfire spread with existing fires. Current forecast guidance suggests that there is less potential for winds to reach elevated criteria over the northern Cascades as the upper-trough begins to leave the region, resulting in the removal of the area from the previous forecast. Some elevated fire weather conditions are also possible in portions of north-central Montana, but the overlap of stronger surface winds and receptive fuels is somewhat narrow. ...Northern Great Plains... Elevated fire-weather conditions are anticipated, particularly along portions of western Montana and Wyoming, into eastern Nebraska and the Dakotas. Strong southerly flow, coupled with hot, dry boundary layer profiles, are expected to persist for much of the afternoon and into the evening. However, current fuel guidance leaves some uncertainty on where these conditions have significant overlap with receptive fuels, particularly with eastward extent. ..Halbert/Lyons.. 07/24/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0812 AM CDT Wed Jul 24 2024 Valid 251200Z - 261200Z CORRECTED FOR MISSING ELEVATED LABEL ...Synopsis... Isolated dry thunderstorms are anticipated across portions of southern Idaho into southwestern Montana as an upper-level trough continues to progress eastward across the Northwest. Additionally, elevated fire-weather conditions are expected across the southern Cascades, portions of northern Montana, and the northern Great Plains. ...Pacific Northwest... As an upper-level trough is forecast to continue progressing eastward out of the Pacific Northwest and into Montana on Thursday, isolated dry thunderstorms are expected across much of the region over receptive fuels. While thunderstorm coverage could approach scattered criteria, current forecast guidance suggests a mix of both wet and dry thunderstorms, in addition to at least some minor potential for some wetting rainfall from the previous day's weather. This uncertainty currently precludes the expansion of the isolated dry thunder area and the inclusion of any scattered dry thunder areas, though forecast trends will continue to be monitored for subsequent updates. Elevated fire-weather conditions are expected to occur over the southern Cascades, especially where local gap flow enhanced winds could contribute to wildfire spread with existing fires. Current forecast guidance suggests that there is less potential for winds to reach elevated criteria over the northern Cascades as the upper-trough begins to leave the region, resulting in the removal of the area from the previous forecast. Some elevated fire weather conditions are also possible in portions of north-central Montana, but the overlap of stronger surface winds and receptive fuels is somewhat narrow. ...Northern Great Plains... Elevated fire-weather conditions are anticipated, particularly along portions of western Montana and Wyoming, into eastern Nebraska and the Dakotas. Strong southerly flow, coupled with hot, dry boundary layer profiles, are expected to persist for much of the afternoon and into the evening. However, current fuel guidance leaves some uncertainty on where these conditions have significant overlap with receptive fuels, particularly with eastward extent. ..Halbert/Lyons.. 07/24/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0812 AM CDT Wed Jul 24 2024 Valid 251200Z - 261200Z CORRECTED FOR MISSING ELEVATED LABEL ...Synopsis... Isolated dry thunderstorms are anticipated across portions of southern Idaho into southwestern Montana as an upper-level trough continues to progress eastward across the Northwest. Additionally, elevated fire-weather conditions are expected across the southern Cascades, portions of northern Montana, and the northern Great Plains. ...Pacific Northwest... As an upper-level trough is forecast to continue progressing eastward out of the Pacific Northwest and into Montana on Thursday, isolated dry thunderstorms are expected across much of the region over receptive fuels. While thunderstorm coverage could approach scattered criteria, current forecast guidance suggests a mix of both wet and dry thunderstorms, in addition to at least some minor potential for some wetting rainfall from the previous day's weather. This uncertainty currently precludes the expansion of the isolated dry thunder area and the inclusion of any scattered dry thunder areas, though forecast trends will continue to be monitored for subsequent updates. Elevated fire-weather conditions are expected to occur over the southern Cascades, especially where local gap flow enhanced winds could contribute to wildfire spread with existing fires. Current forecast guidance suggests that there is less potential for winds to reach elevated criteria over the northern Cascades as the upper-trough begins to leave the region, resulting in the removal of the area from the previous forecast. Some elevated fire weather conditions are also possible in portions of north-central Montana, but the overlap of stronger surface winds and receptive fuels is somewhat narrow. ...Northern Great Plains... Elevated fire-weather conditions are anticipated, particularly along portions of western Montana and Wyoming, into eastern Nebraska and the Dakotas. Strong southerly flow, coupled with hot, dry boundary layer profiles, are expected to persist for much of the afternoon and into the evening. However, current fuel guidance leaves some uncertainty on where these conditions have significant overlap with receptive fuels, particularly with eastward extent. ..Halbert/Lyons.. 07/24/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0812 AM CDT Wed Jul 24 2024 Valid 251200Z - 261200Z CORRECTED FOR MISSING ELEVATED LABEL ...Synopsis... Isolated dry thunderstorms are anticipated across portions of southern Idaho into southwestern Montana as an upper-level trough continues to progress eastward across the Northwest. Additionally, elevated fire-weather conditions are expected across the southern Cascades, portions of northern Montana, and the northern Great Plains. ...Pacific Northwest... As an upper-level trough is forecast to continue progressing eastward out of the Pacific Northwest and into Montana on Thursday, isolated dry thunderstorms are expected across much of the region over receptive fuels. While thunderstorm coverage could approach scattered criteria, current forecast guidance suggests a mix of both wet and dry thunderstorms, in addition to at least some minor potential for some wetting rainfall from the previous day's weather. This uncertainty currently precludes the expansion of the isolated dry thunder area and the inclusion of any scattered dry thunder areas, though forecast trends will continue to be monitored for subsequent updates. Elevated fire-weather conditions are expected to occur over the southern Cascades, especially where local gap flow enhanced winds could contribute to wildfire spread with existing fires. Current forecast guidance suggests that there is less potential for winds to reach elevated criteria over the northern Cascades as the upper-trough begins to leave the region, resulting in the removal of the area from the previous forecast. Some elevated fire weather conditions are also possible in portions of north-central Montana, but the overlap of stronger surface winds and receptive fuels is somewhat narrow. ...Northern Great Plains... Elevated fire-weather conditions are anticipated, particularly along portions of western Montana and Wyoming, into eastern Nebraska and the Dakotas. Strong southerly flow, coupled with hot, dry boundary layer profiles, are expected to persist for much of the afternoon and into the evening. However, current fuel guidance leaves some uncertainty on where these conditions have significant overlap with receptive fuels, particularly with eastward extent. ..Halbert/Lyons.. 07/24/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0812 AM CDT Wed Jul 24 2024 Valid 251200Z - 261200Z CORRECTED FOR MISSING ELEVATED LABEL ...Synopsis... Isolated dry thunderstorms are anticipated across portions of southern Idaho into southwestern Montana as an upper-level trough continues to progress eastward across the Northwest. Additionally, elevated fire-weather conditions are expected across the southern Cascades, portions of northern Montana, and the northern Great Plains. ...Pacific Northwest... As an upper-level trough is forecast to continue progressing eastward out of the Pacific Northwest and into Montana on Thursday, isolated dry thunderstorms are expected across much of the region over receptive fuels. While thunderstorm coverage could approach scattered criteria, current forecast guidance suggests a mix of both wet and dry thunderstorms, in addition to at least some minor potential for some wetting rainfall from the previous day's weather. This uncertainty currently precludes the expansion of the isolated dry thunder area and the inclusion of any scattered dry thunder areas, though forecast trends will continue to be monitored for subsequent updates. Elevated fire-weather conditions are expected to occur over the southern Cascades, especially where local gap flow enhanced winds could contribute to wildfire spread with existing fires. Current forecast guidance suggests that there is less potential for winds to reach elevated criteria over the northern Cascades as the upper-trough begins to leave the region, resulting in the removal of the area from the previous forecast. Some elevated fire weather conditions are also possible in portions of north-central Montana, but the overlap of stronger surface winds and receptive fuels is somewhat narrow. ...Northern Great Plains... Elevated fire-weather conditions are anticipated, particularly along portions of western Montana and Wyoming, into eastern Nebraska and the Dakotas. Strong southerly flow, coupled with hot, dry boundary layer profiles, are expected to persist for much of the afternoon and into the evening. However, current fuel guidance leaves some uncertainty on where these conditions have significant overlap with receptive fuels, particularly with eastward extent. ..Halbert/Lyons.. 07/24/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed Jul 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms may produce damaging wind gusts across southern Arizona, and from parts of Iowa and Illinois into Pennsylvania/New York. Other locally strong storms are possible in parts of the Northwest, northern Rockies and Mid-Atlantic regions. ...Arizona... A relatively active scenario for thunderstorms is expected later today with the potential for thunderstorms/outflows to spread generally south-southwestward onto the desert floor by evening. The upper-level ridge over the western states will remain centered over parts of Nevada/Utah today, with 15-20 kt of northeasterly mid-level flow across central/eastern Arizona. This should help steer storms onto the desert flow where a moist/deeply mixed boundary layer environment will exist, with the potential for severe-caliber wind gusts and considerable blowing dust late this afternoon into evening. ...Midwest including Iowa/Illinois/Indiana... The region will be influenced by the western cyclonically curved portion of the upper-level trough over the Great Lakes/Ontario, with a cold front moving southward across Iowa/Illinois and into Indiana/Ohio, with very warm and humid conditions south of the front. Some thunderstorms are ongoing this morning across eastern Iowa and northern Illinois, but a greater coverage and intensity of storms is expected later this afternoon near/south of the front. Moderately strong west-northwesterly flow aloft, steep lapse rates, and ample buoyancy suggest the potential for strong/isolated severe storms capable of damaging winds and some hail. ...Northeast including Pennsylvania/New York.... As a front sags into western New York, modestly enhanced southwesterly low-level winds will strengthen warm advection and lift over the region. This will likely lead to scattered thunderstorms through the afternoon. Forecast soundings show MLCAPE values over 1000 J/kg and sufficient deep-layer shear for a few organized storm clusters capable of locally gusty/damaging winds. ...North Carolina/Virginia... Deep west-southwesterly winds will strengthen by this afternoon along a corridor from the southern Appalachians into the Mid-Atlantic states. This enhanced flow/shear profile will aid in helping to organize scattered diurnal thunderstorm development from western North Carolina into parts of southern/eastern Virginia. Mid-level lapse rates will be poor, but strong heating and high PWAT values will promote a risk of a few intense storm clusters capable of gusty/damaging winds. ...Northwest... Relatively fast cyclonic flow aloft will remain over the Pacific Northwest states into the northern Great Basin. Mid-level moisture will spread eastward and aid in afternoon thunderstorm development from Oregon into parts of Idaho/Montana. Forecast soundings show weak CAPE, but a few of the stronger cells could produce locally gusty/damaging winds. ...Coastal Texas/southern Louisiana... Aided by the possibility of weak surface low development, some guidance suggests that a modest strengthening of low-level flow may occur today. However, mid-level winds will remain weak, with inland destabilization expected to be limited. This should minimize the potential for anything beyond a few very weak/transient mesocyclones. ..Guyer/Jewell.. 07/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed Jul 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms may produce damaging wind gusts across southern Arizona, and from parts of Iowa and Illinois into Pennsylvania/New York. Other locally strong storms are possible in parts of the Northwest, northern Rockies and Mid-Atlantic regions. ...Arizona... A relatively active scenario for thunderstorms is expected later today with the potential for thunderstorms/outflows to spread generally south-southwestward onto the desert floor by evening. The upper-level ridge over the western states will remain centered over parts of Nevada/Utah today, with 15-20 kt of northeasterly mid-level flow across central/eastern Arizona. This should help steer storms onto the desert flow where a moist/deeply mixed boundary layer environment will exist, with the potential for severe-caliber wind gusts and considerable blowing dust late this afternoon into evening. ...Midwest including Iowa/Illinois/Indiana... The region will be influenced by the western cyclonically curved portion of the upper-level trough over the Great Lakes/Ontario, with a cold front moving southward across Iowa/Illinois and into Indiana/Ohio, with very warm and humid conditions south of the front. Some thunderstorms are ongoing this morning across eastern Iowa and northern Illinois, but a greater coverage and intensity of storms is expected later this afternoon near/south of the front. Moderately strong west-northwesterly flow aloft, steep lapse rates, and ample buoyancy suggest the potential for strong/isolated severe storms capable of damaging winds and some hail. ...Northeast including Pennsylvania/New York.... As a front sags into western New York, modestly enhanced southwesterly low-level winds will strengthen warm advection and lift over the region. This will likely lead to scattered thunderstorms through the afternoon. Forecast soundings show MLCAPE values over 1000 J/kg and sufficient deep-layer shear for a few organized storm clusters capable of locally gusty/damaging winds. ...North Carolina/Virginia... Deep west-southwesterly winds will strengthen by this afternoon along a corridor from the southern Appalachians into the Mid-Atlantic states. This enhanced flow/shear profile will aid in helping to organize scattered diurnal thunderstorm development from western North Carolina into parts of southern/eastern Virginia. Mid-level lapse rates will be poor, but strong heating and high PWAT values will promote a risk of a few intense storm clusters capable of gusty/damaging winds. ...Northwest... Relatively fast cyclonic flow aloft will remain over the Pacific Northwest states into the northern Great Basin. Mid-level moisture will spread eastward and aid in afternoon thunderstorm development from Oregon into parts of Idaho/Montana. Forecast soundings show weak CAPE, but a few of the stronger cells could produce locally gusty/damaging winds. ...Coastal Texas/southern Louisiana... Aided by the possibility of weak surface low development, some guidance suggests that a modest strengthening of low-level flow may occur today. However, mid-level winds will remain weak, with inland destabilization expected to be limited. This should minimize the potential for anything beyond a few very weak/transient mesocyclones. ..Guyer/Jewell.. 07/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed Jul 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms may produce damaging wind gusts across southern Arizona, and from parts of Iowa and Illinois into Pennsylvania/New York. Other locally strong storms are possible in parts of the Northwest, northern Rockies and Mid-Atlantic regions. ...Arizona... A relatively active scenario for thunderstorms is expected later today with the potential for thunderstorms/outflows to spread generally south-southwestward onto the desert floor by evening. The upper-level ridge over the western states will remain centered over parts of Nevada/Utah today, with 15-20 kt of northeasterly mid-level flow across central/eastern Arizona. This should help steer storms onto the desert flow where a moist/deeply mixed boundary layer environment will exist, with the potential for severe-caliber wind gusts and considerable blowing dust late this afternoon into evening. ...Midwest including Iowa/Illinois/Indiana... The region will be influenced by the western cyclonically curved portion of the upper-level trough over the Great Lakes/Ontario, with a cold front moving southward across Iowa/Illinois and into Indiana/Ohio, with very warm and humid conditions south of the front. Some thunderstorms are ongoing this morning across eastern Iowa and northern Illinois, but a greater coverage and intensity of storms is expected later this afternoon near/south of the front. Moderately strong west-northwesterly flow aloft, steep lapse rates, and ample buoyancy suggest the potential for strong/isolated severe storms capable of damaging winds and some hail. ...Northeast including Pennsylvania/New York.... As a front sags into western New York, modestly enhanced southwesterly low-level winds will strengthen warm advection and lift over the region. This will likely lead to scattered thunderstorms through the afternoon. Forecast soundings show MLCAPE values over 1000 J/kg and sufficient deep-layer shear for a few organized storm clusters capable of locally gusty/damaging winds. ...North Carolina/Virginia... Deep west-southwesterly winds will strengthen by this afternoon along a corridor from the southern Appalachians into the Mid-Atlantic states. This enhanced flow/shear profile will aid in helping to organize scattered diurnal thunderstorm development from western North Carolina into parts of southern/eastern Virginia. Mid-level lapse rates will be poor, but strong heating and high PWAT values will promote a risk of a few intense storm clusters capable of gusty/damaging winds. ...Northwest... Relatively fast cyclonic flow aloft will remain over the Pacific Northwest states into the northern Great Basin. Mid-level moisture will spread eastward and aid in afternoon thunderstorm development from Oregon into parts of Idaho/Montana. Forecast soundings show weak CAPE, but a few of the stronger cells could produce locally gusty/damaging winds. ...Coastal Texas/southern Louisiana... Aided by the possibility of weak surface low development, some guidance suggests that a modest strengthening of low-level flow may occur today. However, mid-level winds will remain weak, with inland destabilization expected to be limited. This should minimize the potential for anything beyond a few very weak/transient mesocyclones. ..Guyer/Jewell.. 07/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed Jul 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms may produce damaging wind gusts across southern Arizona, and from parts of Iowa and Illinois into Pennsylvania/New York. Other locally strong storms are possible in parts of the Northwest, northern Rockies and Mid-Atlantic regions. ...Arizona... A relatively active scenario for thunderstorms is expected later today with the potential for thunderstorms/outflows to spread generally south-southwestward onto the desert floor by evening. The upper-level ridge over the western states will remain centered over parts of Nevada/Utah today, with 15-20 kt of northeasterly mid-level flow across central/eastern Arizona. This should help steer storms onto the desert flow where a moist/deeply mixed boundary layer environment will exist, with the potential for severe-caliber wind gusts and considerable blowing dust late this afternoon into evening. ...Midwest including Iowa/Illinois/Indiana... The region will be influenced by the western cyclonically curved portion of the upper-level trough over the Great Lakes/Ontario, with a cold front moving southward across Iowa/Illinois and into Indiana/Ohio, with very warm and humid conditions south of the front. Some thunderstorms are ongoing this morning across eastern Iowa and northern Illinois, but a greater coverage and intensity of storms is expected later this afternoon near/south of the front. Moderately strong west-northwesterly flow aloft, steep lapse rates, and ample buoyancy suggest the potential for strong/isolated severe storms capable of damaging winds and some hail. ...Northeast including Pennsylvania/New York.... As a front sags into western New York, modestly enhanced southwesterly low-level winds will strengthen warm advection and lift over the region. This will likely lead to scattered thunderstorms through the afternoon. Forecast soundings show MLCAPE values over 1000 J/kg and sufficient deep-layer shear for a few organized storm clusters capable of locally gusty/damaging winds. ...North Carolina/Virginia... Deep west-southwesterly winds will strengthen by this afternoon along a corridor from the southern Appalachians into the Mid-Atlantic states. This enhanced flow/shear profile will aid in helping to organize scattered diurnal thunderstorm development from western North Carolina into parts of southern/eastern Virginia. Mid-level lapse rates will be poor, but strong heating and high PWAT values will promote a risk of a few intense storm clusters capable of gusty/damaging winds. ...Northwest... Relatively fast cyclonic flow aloft will remain over the Pacific Northwest states into the northern Great Basin. Mid-level moisture will spread eastward and aid in afternoon thunderstorm development from Oregon into parts of Idaho/Montana. Forecast soundings show weak CAPE, but a few of the stronger cells could produce locally gusty/damaging winds. ...Coastal Texas/southern Louisiana... Aided by the possibility of weak surface low development, some guidance suggests that a modest strengthening of low-level flow may occur today. However, mid-level winds will remain weak, with inland destabilization expected to be limited. This should minimize the potential for anything beyond a few very weak/transient mesocyclones. ..Guyer/Jewell.. 07/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed Jul 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms may produce damaging wind gusts across southern Arizona, and from parts of Iowa and Illinois into Pennsylvania/New York. Other locally strong storms are possible in parts of the Northwest, northern Rockies and Mid-Atlantic regions. ...Arizona... A relatively active scenario for thunderstorms is expected later today with the potential for thunderstorms/outflows to spread generally south-southwestward onto the desert floor by evening. The upper-level ridge over the western states will remain centered over parts of Nevada/Utah today, with 15-20 kt of northeasterly mid-level flow across central/eastern Arizona. This should help steer storms onto the desert flow where a moist/deeply mixed boundary layer environment will exist, with the potential for severe-caliber wind gusts and considerable blowing dust late this afternoon into evening. ...Midwest including Iowa/Illinois/Indiana... The region will be influenced by the western cyclonically curved portion of the upper-level trough over the Great Lakes/Ontario, with a cold front moving southward across Iowa/Illinois and into Indiana/Ohio, with very warm and humid conditions south of the front. Some thunderstorms are ongoing this morning across eastern Iowa and northern Illinois, but a greater coverage and intensity of storms is expected later this afternoon near/south of the front. Moderately strong west-northwesterly flow aloft, steep lapse rates, and ample buoyancy suggest the potential for strong/isolated severe storms capable of damaging winds and some hail. ...Northeast including Pennsylvania/New York.... As a front sags into western New York, modestly enhanced southwesterly low-level winds will strengthen warm advection and lift over the region. This will likely lead to scattered thunderstorms through the afternoon. Forecast soundings show MLCAPE values over 1000 J/kg and sufficient deep-layer shear for a few organized storm clusters capable of locally gusty/damaging winds. ...North Carolina/Virginia... Deep west-southwesterly winds will strengthen by this afternoon along a corridor from the southern Appalachians into the Mid-Atlantic states. This enhanced flow/shear profile will aid in helping to organize scattered diurnal thunderstorm development from western North Carolina into parts of southern/eastern Virginia. Mid-level lapse rates will be poor, but strong heating and high PWAT values will promote a risk of a few intense storm clusters capable of gusty/damaging winds. ...Northwest... Relatively fast cyclonic flow aloft will remain over the Pacific Northwest states into the northern Great Basin. Mid-level moisture will spread eastward and aid in afternoon thunderstorm development from Oregon into parts of Idaho/Montana. Forecast soundings show weak CAPE, but a few of the stronger cells could produce locally gusty/damaging winds. ...Coastal Texas/southern Louisiana... Aided by the possibility of weak surface low development, some guidance suggests that a modest strengthening of low-level flow may occur today. However, mid-level winds will remain weak, with inland destabilization expected to be limited. This should minimize the potential for anything beyond a few very weak/transient mesocyclones. ..Guyer/Jewell.. 07/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed Jul 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms may produce damaging wind gusts across southern Arizona, and from parts of Iowa and Illinois into Pennsylvania/New York. Other locally strong storms are possible in parts of the Northwest, northern Rockies and Mid-Atlantic regions. ...Arizona... A relatively active scenario for thunderstorms is expected later today with the potential for thunderstorms/outflows to spread generally south-southwestward onto the desert floor by evening. The upper-level ridge over the western states will remain centered over parts of Nevada/Utah today, with 15-20 kt of northeasterly mid-level flow across central/eastern Arizona. This should help steer storms onto the desert flow where a moist/deeply mixed boundary layer environment will exist, with the potential for severe-caliber wind gusts and considerable blowing dust late this afternoon into evening. ...Midwest including Iowa/Illinois/Indiana... The region will be influenced by the western cyclonically curved portion of the upper-level trough over the Great Lakes/Ontario, with a cold front moving southward across Iowa/Illinois and into Indiana/Ohio, with very warm and humid conditions south of the front. Some thunderstorms are ongoing this morning across eastern Iowa and northern Illinois, but a greater coverage and intensity of storms is expected later this afternoon near/south of the front. Moderately strong west-northwesterly flow aloft, steep lapse rates, and ample buoyancy suggest the potential for strong/isolated severe storms capable of damaging winds and some hail. ...Northeast including Pennsylvania/New York.... As a front sags into western New York, modestly enhanced southwesterly low-level winds will strengthen warm advection and lift over the region. This will likely lead to scattered thunderstorms through the afternoon. Forecast soundings show MLCAPE values over 1000 J/kg and sufficient deep-layer shear for a few organized storm clusters capable of locally gusty/damaging winds. ...North Carolina/Virginia... Deep west-southwesterly winds will strengthen by this afternoon along a corridor from the southern Appalachians into the Mid-Atlantic states. This enhanced flow/shear profile will aid in helping to organize scattered diurnal thunderstorm development from western North Carolina into parts of southern/eastern Virginia. Mid-level lapse rates will be poor, but strong heating and high PWAT values will promote a risk of a few intense storm clusters capable of gusty/damaging winds. ...Northwest... Relatively fast cyclonic flow aloft will remain over the Pacific Northwest states into the northern Great Basin. Mid-level moisture will spread eastward and aid in afternoon thunderstorm development from Oregon into parts of Idaho/Montana. Forecast soundings show weak CAPE, but a few of the stronger cells could produce locally gusty/damaging winds. ...Coastal Texas/southern Louisiana... Aided by the possibility of weak surface low development, some guidance suggests that a modest strengthening of low-level flow may occur today. However, mid-level winds will remain weak, with inland destabilization expected to be limited. This should minimize the potential for anything beyond a few very weak/transient mesocyclones. ..Guyer/Jewell.. 07/24/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Wed Jul 24 2024 Valid 271200Z - 011200Z ...DISCUSSION... The beginning of the Day 4-8 period will see the central U.S. upper ridge shunted east over the eastern third of the CONUS. A weak upper shortwave trough within broader westerly flow will develop northeast from the Ozarks toward the Great Lakes/Midwest through Day 5/Sun. The remainder of the period will be characterized by a building upper ridge over the Rockies and shifting east over the Plains Days 6-8/Mon-Wed. The late period upper ridge will be flanked by shortwave troughs over the Pacific Northwest and the lower Great Lakes/Northeast. Overall, deep-layer flow will remain weak in this regime. However, a reservoir of rich boundary layer moisture will persist from eastern portions of the Plains to the MS Valley. Large-scale ascent will remain nebulous, and capping beneath the upper ridge may ultimate limit severe potential. However, mesoscale features not well resolved at long time scales may support some risk of severe thunderstorms across the warm sector given rich boundary layer moisture and large instability in a northwesterly flow regime on the eastern periphery of the upper ridge Day 6/Mon-Day 8/Wed. Confidence is too low to introduce 15 percent probabilities at this time. Read more