Severe Storms

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Aug 15 2024 Valid 181200Z - 231200Z ...DISCUSSION... As an upper trough moves slowly eastward over the eastern CONUS, an isolated severe threat may continue on Day 4/Sunday across parts of the Mid-Atlantic into the Southeast along/ahead of a cold front. However, the potential stabilizing effects of prior convection, along with generally modest deep-layer shear, render low confidence in a more organized severe/damaging wind threat on Sunday. Lower severe potential is anticipated across the eastern states on Day 5/Monday as the upper trough progresses eastward and the cold front moves mostly offshore. Upper ridging will likely remain prominent across much of the Rockies and Plains through at least early next week, while an upper trough/low generally remains centered off the coast of the Pacific Northwest. Some chance for severe thunderstorms may exist over interior portions of the Northwest into parts of the northern Rockies/Plains and perhaps Upper Midwest next week. But, predictability of various mid-level perturbations that may encourage robust thunderstorms remains low at this extended time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Aug 15 2024 Valid 181200Z - 231200Z ...DISCUSSION... As an upper trough moves slowly eastward over the eastern CONUS, an isolated severe threat may continue on Day 4/Sunday across parts of the Mid-Atlantic into the Southeast along/ahead of a cold front. However, the potential stabilizing effects of prior convection, along with generally modest deep-layer shear, render low confidence in a more organized severe/damaging wind threat on Sunday. Lower severe potential is anticipated across the eastern states on Day 5/Monday as the upper trough progresses eastward and the cold front moves mostly offshore. Upper ridging will likely remain prominent across much of the Rockies and Plains through at least early next week, while an upper trough/low generally remains centered off the coast of the Pacific Northwest. Some chance for severe thunderstorms may exist over interior portions of the Northwest into parts of the northern Rockies/Plains and perhaps Upper Midwest next week. But, predictability of various mid-level perturbations that may encourage robust thunderstorms remains low at this extended time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Thu Aug 15 2024 Valid 181200Z - 231200Z ...DISCUSSION... As an upper trough moves slowly eastward over the eastern CONUS, an isolated severe threat may continue on Day 4/Sunday across parts of the Mid-Atlantic into the Southeast along/ahead of a cold front. However, the potential stabilizing effects of prior convection, along with generally modest deep-layer shear, render low confidence in a more organized severe/damaging wind threat on Sunday. Lower severe potential is anticipated across the eastern states on Day 5/Monday as the upper trough progresses eastward and the cold front moves mostly offshore. Upper ridging will likely remain prominent across much of the Rockies and Plains through at least early next week, while an upper trough/low generally remains centered off the coast of the Pacific Northwest. Some chance for severe thunderstorms may exist over interior portions of the Northwest into parts of the northern Rockies/Plains and perhaps Upper Midwest next week. But, predictability of various mid-level perturbations that may encourage robust thunderstorms remains low at this extended time frame. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Thu Aug 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC INTO THE OHIO VALLEY...APPALACHIANS...AND SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms may occur Saturday across parts of the Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast. ...Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast... A slow-moving upper trough/low should continue eastward across the Great Lakes and OH Valley vicinity on Saturday. A weak surface low initially over Lower MI is forecast to gradually develop into southern Ontario through the period. A weak front extending southward from this low should make gradual east-southeastward progress across much of the OH Valley/Mid-Atlantic into the Southeast through Saturday evening. This boundary, although ill-defined and having only modest low-level convergence, should still serve as a focus for strong to severe convection across parts of these regions. Diurnal heating of a moist airmass along/ahead of the front should foster weak to moderate destabilization by Saturday afternoon, even though mid-level lapse rates should remain modest. Enhanced mid-level flow associated with the upper trough/low should focus over parts of the lower OH Valley into the TN Valley and Mid-South. But, sufficient deep-layer shear to support some updraft organization should be present over much of the broad warm sector. Multiple clusters may develop along the length of the front Saturday afternoon and pose primarily an isolated strong to damaging wind threat as they spread east-southeastward through Saturday evening. Similar to Day 2/Friday, confidence in a more focused corridor of damaging wind potential remains too low to include greater wind probabilities at this time. ..Gleason.. 08/15/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Thu Aug 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC INTO THE OHIO VALLEY...APPALACHIANS...AND SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms may occur Saturday across parts of the Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast. ...Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast... A slow-moving upper trough/low should continue eastward across the Great Lakes and OH Valley vicinity on Saturday. A weak surface low initially over Lower MI is forecast to gradually develop into southern Ontario through the period. A weak front extending southward from this low should make gradual east-southeastward progress across much of the OH Valley/Mid-Atlantic into the Southeast through Saturday evening. This boundary, although ill-defined and having only modest low-level convergence, should still serve as a focus for strong to severe convection across parts of these regions. Diurnal heating of a moist airmass along/ahead of the front should foster weak to moderate destabilization by Saturday afternoon, even though mid-level lapse rates should remain modest. Enhanced mid-level flow associated with the upper trough/low should focus over parts of the lower OH Valley into the TN Valley and Mid-South. But, sufficient deep-layer shear to support some updraft organization should be present over much of the broad warm sector. Multiple clusters may develop along the length of the front Saturday afternoon and pose primarily an isolated strong to damaging wind threat as they spread east-southeastward through Saturday evening. Similar to Day 2/Friday, confidence in a more focused corridor of damaging wind potential remains too low to include greater wind probabilities at this time. ..Gleason.. 08/15/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Thu Aug 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC INTO THE OHIO VALLEY...APPALACHIANS...AND SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms may occur Saturday across parts of the Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast. ...Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast... A slow-moving upper trough/low should continue eastward across the Great Lakes and OH Valley vicinity on Saturday. A weak surface low initially over Lower MI is forecast to gradually develop into southern Ontario through the period. A weak front extending southward from this low should make gradual east-southeastward progress across much of the OH Valley/Mid-Atlantic into the Southeast through Saturday evening. This boundary, although ill-defined and having only modest low-level convergence, should still serve as a focus for strong to severe convection across parts of these regions. Diurnal heating of a moist airmass along/ahead of the front should foster weak to moderate destabilization by Saturday afternoon, even though mid-level lapse rates should remain modest. Enhanced mid-level flow associated with the upper trough/low should focus over parts of the lower OH Valley into the TN Valley and Mid-South. But, sufficient deep-layer shear to support some updraft organization should be present over much of the broad warm sector. Multiple clusters may develop along the length of the front Saturday afternoon and pose primarily an isolated strong to damaging wind threat as they spread east-southeastward through Saturday evening. Similar to Day 2/Friday, confidence in a more focused corridor of damaging wind potential remains too low to include greater wind probabilities at this time. ..Gleason.. 08/15/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Thu Aug 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC INTO THE OHIO VALLEY...APPALACHIANS...AND SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms may occur Saturday across parts of the Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast. ...Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast... A slow-moving upper trough/low should continue eastward across the Great Lakes and OH Valley vicinity on Saturday. A weak surface low initially over Lower MI is forecast to gradually develop into southern Ontario through the period. A weak front extending southward from this low should make gradual east-southeastward progress across much of the OH Valley/Mid-Atlantic into the Southeast through Saturday evening. This boundary, although ill-defined and having only modest low-level convergence, should still serve as a focus for strong to severe convection across parts of these regions. Diurnal heating of a moist airmass along/ahead of the front should foster weak to moderate destabilization by Saturday afternoon, even though mid-level lapse rates should remain modest. Enhanced mid-level flow associated with the upper trough/low should focus over parts of the lower OH Valley into the TN Valley and Mid-South. But, sufficient deep-layer shear to support some updraft organization should be present over much of the broad warm sector. Multiple clusters may develop along the length of the front Saturday afternoon and pose primarily an isolated strong to damaging wind threat as they spread east-southeastward through Saturday evening. Similar to Day 2/Friday, confidence in a more focused corridor of damaging wind potential remains too low to include greater wind probabilities at this time. ..Gleason.. 08/15/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Thu Aug 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID-ATLANTIC INTO THE OHIO VALLEY...APPALACHIANS...AND SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms may occur Saturday across parts of the Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast. ...Mid-Atlantic into the Ohio Valley, Appalachians, and Southeast... A slow-moving upper trough/low should continue eastward across the Great Lakes and OH Valley vicinity on Saturday. A weak surface low initially over Lower MI is forecast to gradually develop into southern Ontario through the period. A weak front extending southward from this low should make gradual east-southeastward progress across much of the OH Valley/Mid-Atlantic into the Southeast through Saturday evening. This boundary, although ill-defined and having only modest low-level convergence, should still serve as a focus for strong to severe convection across parts of these regions. Diurnal heating of a moist airmass along/ahead of the front should foster weak to moderate destabilization by Saturday afternoon, even though mid-level lapse rates should remain modest. Enhanced mid-level flow associated with the upper trough/low should focus over parts of the lower OH Valley into the TN Valley and Mid-South. But, sufficient deep-layer shear to support some updraft organization should be present over much of the broad warm sector. Multiple clusters may develop along the length of the front Saturday afternoon and pose primarily an isolated strong to damaging wind threat as they spread east-southeastward through Saturday evening. Similar to Day 2/Friday, confidence in a more focused corridor of damaging wind potential remains too low to include greater wind probabilities at this time. ..Gleason.. 08/15/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Friday will be characterized by west-southwesterly mid-level flow across the Western U.S., with a shortwave trough approaching the Oregon/Washington coasts late in the period. This will support some dry/windy conditions across portions of southern Nevada and western Utah, with relative humidity dropping to 10-15% with winds reaching 20-25 MPH. However, these conditions will largely occur over fuels that have received recent wetting rainfall or are only modestly dry, precluding highlights at this time. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Friday will be characterized by west-southwesterly mid-level flow across the Western U.S., with a shortwave trough approaching the Oregon/Washington coasts late in the period. This will support some dry/windy conditions across portions of southern Nevada and western Utah, with relative humidity dropping to 10-15% with winds reaching 20-25 MPH. However, these conditions will largely occur over fuels that have received recent wetting rainfall or are only modestly dry, precluding highlights at this time. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Friday will be characterized by west-southwesterly mid-level flow across the Western U.S., with a shortwave trough approaching the Oregon/Washington coasts late in the period. This will support some dry/windy conditions across portions of southern Nevada and western Utah, with relative humidity dropping to 10-15% with winds reaching 20-25 MPH. However, these conditions will largely occur over fuels that have received recent wetting rainfall or are only modestly dry, precluding highlights at this time. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Friday will be characterized by west-southwesterly mid-level flow across the Western U.S., with a shortwave trough approaching the Oregon/Washington coasts late in the period. This will support some dry/windy conditions across portions of southern Nevada and western Utah, with relative humidity dropping to 10-15% with winds reaching 20-25 MPH. However, these conditions will largely occur over fuels that have received recent wetting rainfall or are only modestly dry, precluding highlights at this time. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Friday will be characterized by west-southwesterly mid-level flow across the Western U.S., with a shortwave trough approaching the Oregon/Washington coasts late in the period. This will support some dry/windy conditions across portions of southern Nevada and western Utah, with relative humidity dropping to 10-15% with winds reaching 20-25 MPH. However, these conditions will largely occur over fuels that have received recent wetting rainfall or are only modestly dry, precluding highlights at this time. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0111 AM CDT Thu Aug 15 2024 Valid 151200Z - 161200Z ...Synopsis... A mid-level trough is forecast to move across the Northwest, bringing two different rounds of a mix of scattered wet/dry thunderstorms to portions of Oregon and Idaho. ...Dry Thunderstorms... Overnight elevated convection is expected to persist into beginning of the forecast period over Oregon. However, the greatest chance for thunderstorm development will be later in the afternoon (20-21Z), when a mix of scattered wet/dry thunderstorms is forecast to develop over south-central Oregon and progress northeastward into western Idaho. Fuels guidance shows ERCs are at or exceeding the 90th percentile, so even though PWAT values of 0.6-0.9 inches and relatively slow storm motions of 20 kts will support at least some wetting rainfall, lightning-based ignitions will still be possible. ...Dry/Windy... Localized elevated conditions are possible across eastern Nevada and western Utah, but will mostly be confined to diurnally/terrain-driven corridors. These conditions also overlap with recent wetting rainfall and fuels that are only modestly dry. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0111 AM CDT Thu Aug 15 2024 Valid 151200Z - 161200Z ...Synopsis... A mid-level trough is forecast to move across the Northwest, bringing two different rounds of a mix of scattered wet/dry thunderstorms to portions of Oregon and Idaho. ...Dry Thunderstorms... Overnight elevated convection is expected to persist into beginning of the forecast period over Oregon. However, the greatest chance for thunderstorm development will be later in the afternoon (20-21Z), when a mix of scattered wet/dry thunderstorms is forecast to develop over south-central Oregon and progress northeastward into western Idaho. Fuels guidance shows ERCs are at or exceeding the 90th percentile, so even though PWAT values of 0.6-0.9 inches and relatively slow storm motions of 20 kts will support at least some wetting rainfall, lightning-based ignitions will still be possible. ...Dry/Windy... Localized elevated conditions are possible across eastern Nevada and western Utah, but will mostly be confined to diurnally/terrain-driven corridors. These conditions also overlap with recent wetting rainfall and fuels that are only modestly dry. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0111 AM CDT Thu Aug 15 2024 Valid 151200Z - 161200Z ...Synopsis... A mid-level trough is forecast to move across the Northwest, bringing two different rounds of a mix of scattered wet/dry thunderstorms to portions of Oregon and Idaho. ...Dry Thunderstorms... Overnight elevated convection is expected to persist into beginning of the forecast period over Oregon. However, the greatest chance for thunderstorm development will be later in the afternoon (20-21Z), when a mix of scattered wet/dry thunderstorms is forecast to develop over south-central Oregon and progress northeastward into western Idaho. Fuels guidance shows ERCs are at or exceeding the 90th percentile, so even though PWAT values of 0.6-0.9 inches and relatively slow storm motions of 20 kts will support at least some wetting rainfall, lightning-based ignitions will still be possible. ...Dry/Windy... Localized elevated conditions are possible across eastern Nevada and western Utah, but will mostly be confined to diurnally/terrain-driven corridors. These conditions also overlap with recent wetting rainfall and fuels that are only modestly dry. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0111 AM CDT Thu Aug 15 2024 Valid 151200Z - 161200Z ...Synopsis... A mid-level trough is forecast to move across the Northwest, bringing two different rounds of a mix of scattered wet/dry thunderstorms to portions of Oregon and Idaho. ...Dry Thunderstorms... Overnight elevated convection is expected to persist into beginning of the forecast period over Oregon. However, the greatest chance for thunderstorm development will be later in the afternoon (20-21Z), when a mix of scattered wet/dry thunderstorms is forecast to develop over south-central Oregon and progress northeastward into western Idaho. Fuels guidance shows ERCs are at or exceeding the 90th percentile, so even though PWAT values of 0.6-0.9 inches and relatively slow storm motions of 20 kts will support at least some wetting rainfall, lightning-based ignitions will still be possible. ...Dry/Windy... Localized elevated conditions are possible across eastern Nevada and western Utah, but will mostly be confined to diurnally/terrain-driven corridors. These conditions also overlap with recent wetting rainfall and fuels that are only modestly dry. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0111 AM CDT Thu Aug 15 2024 Valid 151200Z - 161200Z ...Synopsis... A mid-level trough is forecast to move across the Northwest, bringing two different rounds of a mix of scattered wet/dry thunderstorms to portions of Oregon and Idaho. ...Dry Thunderstorms... Overnight elevated convection is expected to persist into beginning of the forecast period over Oregon. However, the greatest chance for thunderstorm development will be later in the afternoon (20-21Z), when a mix of scattered wet/dry thunderstorms is forecast to develop over south-central Oregon and progress northeastward into western Idaho. Fuels guidance shows ERCs are at or exceeding the 90th percentile, so even though PWAT values of 0.6-0.9 inches and relatively slow storm motions of 20 kts will support at least some wetting rainfall, lightning-based ignitions will still be possible. ...Dry/Windy... Localized elevated conditions are possible across eastern Nevada and western Utah, but will mostly be confined to diurnally/terrain-driven corridors. These conditions also overlap with recent wetting rainfall and fuels that are only modestly dry. ..Halbert/Wendt.. 08/15/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES INTO THE OHIO/TENNESSEE VALLEYS AND THE OZARKS INTO THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... At least isolated strong to severe thunderstorms may develop Friday over portions of the Great Lakes into the Ohio/Tennessee Valleys, and potentially across parts of the Ozarks into the central/southern Plains. Damaging winds and occasional large hail should be the main threats. ...Great Lakes into the Ohio/Tennessee Valleys and Mid-South... A mid/upper-level trough will move slowly eastward across parts of the Great Lakes, Midwest, and OH Valley on Friday. A belt of enhanced mid-level flow should be present from the east-central Plains to parts of the mid MS Valley into the OH Valley. Related deep-layer shear should be sufficient for some updraft organization with thunderstorms that can develop through the period. A weak surface low should likewise move slowly eastward over the Upper Great Lakes vicinity. A weak front/wind shift is forecast to extend south-southwestward from this surface low. Extensive convection will probably be ongoing Friday morning across the OH Valley vicinity. Some intensification of morning storms may occur through the day, though the primary severe threat is expected with separate thunderstorms that will develop in the wake of early-day convection during the afternoon and evening. Diurnal heating of a rather moist low-level airmass across a broad area will support pockets of moderate to locally strong instability by late afternoon across parts of the Midwest and OH/TN Valleys. Moderate mid-level flow will support sufficient deep-layer shear for updraft organization, and a conditionally favorable severe environment should eventually develop over a broad region near/ahead of the front. However, details of thunderstorm initiation and evolution remain rather unclear, due to the influence of morning convection and generally weak low-level convergence near the surface front. However, a few stronger cells/clusters may evolve during the afternoon and evening, posing a threat of damaging winds and severe hail. Greater severe probabilities may eventually be needed, if confidence increases in the location of one or more favored corridors of severe potential within the broader Marginal Risk area. ...Ozarks into the Central/Southern Plains... The trailing portion of the cold front should extend from southern MO into southern KS/northern OK by late Friday afternoon. Isolated to widely scattered thunderstorm development may occur in the vicinity of the front, with some signal for convection to persist into Friday night as it moves east-southeastward. Other isolated activity may develop across the central High Plains in eastern CO into western KS. Moderate to strong buoyancy and supportive deep-layer shear across these areas should foster a threat of isolated strong/damaging gusts and large hail with the more robust storms from late Friday afternoon through the evening. ...Northern High Plains... High-based convection may develop over the northern Rockies in advance of a mid-level shortwave trough, and subsequently move across the northern High Plains. Low-level moisture and instability are forecast to remain limited, but steepened low-level lapse rates could allow for isolated strong/gusty winds as this activity moves east-northeastward through the early evening. At this point, the overall severe threat appears too isolated/marginal to include low severe wind probabilities. ..Gleason.. 08/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Aug 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES INTO THE OHIO/TENNESSEE VALLEYS AND THE OZARKS INTO THE SOUTHERN/CENTRAL PLAINS... ...SUMMARY... At least isolated strong to severe thunderstorms may develop Friday over portions of the Great Lakes into the Ohio/Tennessee Valleys, and potentially across parts of the Ozarks into the central/southern Plains. Damaging winds and occasional large hail should be the main threats. ...Great Lakes into the Ohio/Tennessee Valleys and Mid-South... A mid/upper-level trough will move slowly eastward across parts of the Great Lakes, Midwest, and OH Valley on Friday. A belt of enhanced mid-level flow should be present from the east-central Plains to parts of the mid MS Valley into the OH Valley. Related deep-layer shear should be sufficient for some updraft organization with thunderstorms that can develop through the period. A weak surface low should likewise move slowly eastward over the Upper Great Lakes vicinity. A weak front/wind shift is forecast to extend south-southwestward from this surface low. Extensive convection will probably be ongoing Friday morning across the OH Valley vicinity. Some intensification of morning storms may occur through the day, though the primary severe threat is expected with separate thunderstorms that will develop in the wake of early-day convection during the afternoon and evening. Diurnal heating of a rather moist low-level airmass across a broad area will support pockets of moderate to locally strong instability by late afternoon across parts of the Midwest and OH/TN Valleys. Moderate mid-level flow will support sufficient deep-layer shear for updraft organization, and a conditionally favorable severe environment should eventually develop over a broad region near/ahead of the front. However, details of thunderstorm initiation and evolution remain rather unclear, due to the influence of morning convection and generally weak low-level convergence near the surface front. However, a few stronger cells/clusters may evolve during the afternoon and evening, posing a threat of damaging winds and severe hail. Greater severe probabilities may eventually be needed, if confidence increases in the location of one or more favored corridors of severe potential within the broader Marginal Risk area. ...Ozarks into the Central/Southern Plains... The trailing portion of the cold front should extend from southern MO into southern KS/northern OK by late Friday afternoon. Isolated to widely scattered thunderstorm development may occur in the vicinity of the front, with some signal for convection to persist into Friday night as it moves east-southeastward. Other isolated activity may develop across the central High Plains in eastern CO into western KS. Moderate to strong buoyancy and supportive deep-layer shear across these areas should foster a threat of isolated strong/damaging gusts and large hail with the more robust storms from late Friday afternoon through the evening. ...Northern High Plains... High-based convection may develop over the northern Rockies in advance of a mid-level shortwave trough, and subsequently move across the northern High Plains. Low-level moisture and instability are forecast to remain limited, but steepened low-level lapse rates could allow for isolated strong/gusty winds as this activity moves east-northeastward through the early evening. At this point, the overall severe threat appears too isolated/marginal to include low severe wind probabilities. ..Gleason.. 08/15/2024 Read more