Aggregator

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CDT Sat Oct 05 2024 Valid 081200Z - 131200Z ...DISCUSSION... A mature mid-latitude cyclone is forecast to gradually shift eastward across southern Quebec on D4/Tuesday and D5/Wednesday as a series of shortwave troughs rotate through the enhanced mid-level flow throughout its base. At the same time, expansive upper ridging will build eastward. By early D6/Thursday, this ridging is expected to extend from the Southwest northward across the Plains and Upper MS Valley into Ontario. Further eastward progression/expansion of this ridging is anticipated on D7/Friday, although some dampening is possible along its northern periphery over the Canadian Prairies. This pattern evolution will maintain a stable airmass across the majority of the CONUS. The only exception is across FL, where a tropical airmass will remain in place throughout the period. Additionally, medium-range guidance continues to suggest tropical cyclone development could occur over the Gulf of Mexico, with potential impacts across the FL Peninsula on D4/Tuesday and D5/Wednesday. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CDT Sat Oct 05 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Synopsis... A dry, post-frontal airmass is forecast to be in place from the northern/central Plains eastward across much of the OH and TN Valleys early Monday morning. This airmass is expected to push farther east/southeast throughout the day as a cold front continues to progress southward across the Southeast. Modest low-level moisture will precede this front, but warm mid-level temperatures will limit thunderstorm chances across the Southeast. Some isolated thunderstorms are possible across FL where deeper moisture will already be in place and low-level easterlies persist. Thunderstorm development is not anticipated elsewhere across the CONUS, aside from a few early morning flashes near Long Island and just off the NJ coast. ..Mosier.. 10/05/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CDT Sat Oct 05 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Synopsis... A dry, post-frontal airmass is forecast to be in place from the northern/central Plains eastward across much of the OH and TN Valleys early Monday morning. This airmass is expected to push farther east/southeast throughout the day as a cold front continues to progress southward across the Southeast. Modest low-level moisture will precede this front, but warm mid-level temperatures will limit thunderstorm chances across the Southeast. Some isolated thunderstorms are possible across FL where deeper moisture will already be in place and low-level easterlies persist. Thunderstorm development is not anticipated elsewhere across the CONUS, aside from a few early morning flashes near Long Island and just off the NJ coast. ..Mosier.. 10/05/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CDT Sat Oct 05 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Synopsis... A dry, post-frontal airmass is forecast to be in place from the northern/central Plains eastward across much of the OH and TN Valleys early Monday morning. This airmass is expected to push farther east/southeast throughout the day as a cold front continues to progress southward across the Southeast. Modest low-level moisture will precede this front, but warm mid-level temperatures will limit thunderstorm chances across the Southeast. Some isolated thunderstorms are possible across FL where deeper moisture will already be in place and low-level easterlies persist. Thunderstorm development is not anticipated elsewhere across the CONUS, aside from a few early morning flashes near Long Island and just off the NJ coast. ..Mosier.. 10/05/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CDT Sat Oct 05 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Synopsis... A dry, post-frontal airmass is forecast to be in place from the northern/central Plains eastward across much of the OH and TN Valleys early Monday morning. This airmass is expected to push farther east/southeast throughout the day as a cold front continues to progress southward across the Southeast. Modest low-level moisture will precede this front, but warm mid-level temperatures will limit thunderstorm chances across the Southeast. Some isolated thunderstorms are possible across FL where deeper moisture will already be in place and low-level easterlies persist. Thunderstorm development is not anticipated elsewhere across the CONUS, aside from a few early morning flashes near Long Island and just off the NJ coast. ..Mosier.. 10/05/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CDT Sat Oct 05 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Synopsis... A dry, post-frontal airmass is forecast to be in place from the northern/central Plains eastward across much of the OH and TN Valleys early Monday morning. This airmass is expected to push farther east/southeast throughout the day as a cold front continues to progress southward across the Southeast. Modest low-level moisture will precede this front, but warm mid-level temperatures will limit thunderstorm chances across the Southeast. Some isolated thunderstorms are possible across FL where deeper moisture will already be in place and low-level easterlies persist. Thunderstorm development is not anticipated elsewhere across the CONUS, aside from a few early morning flashes near Long Island and just off the NJ coast. ..Mosier.. 10/05/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0158 AM CDT Sat Oct 05 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Monday. ...Synopsis... A dry, post-frontal airmass is forecast to be in place from the northern/central Plains eastward across much of the OH and TN Valleys early Monday morning. This airmass is expected to push farther east/southeast throughout the day as a cold front continues to progress southward across the Southeast. Modest low-level moisture will precede this front, but warm mid-level temperatures will limit thunderstorm chances across the Southeast. Some isolated thunderstorms are possible across FL where deeper moisture will already be in place and low-level easterlies persist. Thunderstorm development is not anticipated elsewhere across the CONUS, aside from a few early morning flashes near Long Island and just off the NJ coast. ..Mosier.. 10/05/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0123 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...Synopsis... A mid-level trough will traverse the Great Lakes area as a surface cold front moves across the Mississippi/Ohio Valleys and high pressure ushers in across the central CONUS tomorrow (Sunday). Behind the cold front, sustained northwesterly surface winds approaching 15 mph in spots, will coincide with 20-30 percent RH from the Ohio and Upper Mississippi Valleys into the southern Plains by afternoon. Fuel receptiveness across these regions range from modest across the Ohio Valley, to high across the Mississippi Valley into the Plains, warranting broad Elevated highlights over these areas. ..Squitieri.. 10/05/2024 ...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 0123 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...Synopsis... A mid-level trough will traverse the Great Lakes area as a surface cold front moves across the Mississippi/Ohio Valleys and high pressure ushers in across the central CONUS tomorrow (Sunday). Behind the cold front, sustained northwesterly surface winds approaching 15 mph in spots, will coincide with 20-30 percent RH from the Ohio and Upper Mississippi Valleys into the southern Plains by afternoon. Fuel receptiveness across these regions range from modest across the Ohio Valley, to high across the Mississippi Valley into the Plains, warranting broad Elevated highlights over these areas. ..Squitieri.. 10/05/2024 ...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 0123 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...Synopsis... A mid-level trough will traverse the Great Lakes area as a surface cold front moves across the Mississippi/Ohio Valleys and high pressure ushers in across the central CONUS tomorrow (Sunday). Behind the cold front, sustained northwesterly surface winds approaching 15 mph in spots, will coincide with 20-30 percent RH from the Ohio and Upper Mississippi Valleys into the southern Plains by afternoon. Fuel receptiveness across these regions range from modest across the Ohio Valley, to high across the Mississippi Valley into the Plains, warranting broad Elevated highlights over these areas. ..Squitieri.. 10/05/2024 ...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 0123 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...Synopsis... A mid-level trough will traverse the Great Lakes area as a surface cold front moves across the Mississippi/Ohio Valleys and high pressure ushers in across the central CONUS tomorrow (Sunday). Behind the cold front, sustained northwesterly surface winds approaching 15 mph in spots, will coincide with 20-30 percent RH from the Ohio and Upper Mississippi Valleys into the southern Plains by afternoon. Fuel receptiveness across these regions range from modest across the Ohio Valley, to high across the Mississippi Valley into the Plains, warranting broad Elevated highlights over these areas. ..Squitieri.. 10/05/2024 ...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 0123 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...Synopsis... A mid-level trough will traverse the Great Lakes area as a surface cold front moves across the Mississippi/Ohio Valleys and high pressure ushers in across the central CONUS tomorrow (Sunday). Behind the cold front, sustained northwesterly surface winds approaching 15 mph in spots, will coincide with 20-30 percent RH from the Ohio and Upper Mississippi Valleys into the southern Plains by afternoon. Fuel receptiveness across these regions range from modest across the Ohio Valley, to high across the Mississippi Valley into the Plains, warranting broad Elevated highlights over these areas. ..Squitieri.. 10/05/2024 ...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 0123 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...Synopsis... A mid-level trough will traverse the Great Lakes area as a surface cold front moves across the Mississippi/Ohio Valleys and high pressure ushers in across the central CONUS tomorrow (Sunday). Behind the cold front, sustained northwesterly surface winds approaching 15 mph in spots, will coincide with 20-30 percent RH from the Ohio and Upper Mississippi Valleys into the southern Plains by afternoon. Fuel receptiveness across these regions range from modest across the Ohio Valley, to high across the Mississippi Valley into the Plains, warranting broad Elevated highlights over these areas. ..Squitieri.. 10/05/2024 ...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 1238 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO INTO MUCH OF WEST VIRGINIA...WESTERN PENNSYLVANIA AND WESTERN NEW YORK... ...SUMMARY... Isolated strong to severe thunderstorms are possible Sunday afternoon and evening across parts of the western New York and Pennsylvania into West Virginia. ...Upper Ohio Valley/Lower Great Lakes vicinity... A mid-latitude cyclone is forecast to begin the period over central Ontario, with enhanced mid-level flow extending throughout the base of this system from the Upper Midwest into the Upper Great Lakes and OH Valley. A pair of shortwave troughs are expected to progress quickly eastward/northeastward within this belt of stronger flow, helping to pull the cyclone eastward while also inducing a negative tilt to the system. By early Sunday, upper troughing will likely extend from the Ontario/Quebec border southeastward into the northern Mid-Atlantic. Primary surface low associated with this system will remain occluded over Ontario throughout the period. However, a secondary triple-point low will likely be over central Ontario early Sunday, with its associated cold front extending southwestward through the Mid MS Valley. This low is forecast to push eastward across eastern Ontario during the day, with the cold front progressing eastward/southeastward as well. A narrow corridor of low 60s dewpoints is anticipated just ahead of the cold front, which is expected to combine with cooling mid-level temperatures and foster modest buoyancy. Initial thunderstorm development along the front is anticipated across eastern OH, where a favorable combination of daytime heating and low-level moisture will destabilize the pre-frontal airmass. Moderate to strong mid-level flow will extend across the region as well, which should allow updrafts to stay ahead of the quick-moving cold front for at least a few hours. Cold mid-level temperatures and moderate deep-layer vertical shear will support a hail risk with the strongest updrafts, particularly with initial development. Bowing line segments will contribute to a threat for damaging gusts as well. Surface winds will likely veer ahead of the front, limiting the low-level curvature. Even so, forecast soundings show southwesterlies strengthening from 15 kt at the surface to 40 kt at 700 mb, which does result in enough storm-relative helicity for some tornado potential if a discrete mode can be maintained. ...Gulf Coast into the Coastal GA and FL Peninsula... Easterly/northeasterly low-level flow will persist for another day across the northern Gulf of Mexico, as a broad area of low pressure remains in place. Showers and thunderstorms are possible within the moist airmass, but weak shear should keep storm severity low. ..Mosier.. 10/05/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO INTO MUCH OF WEST VIRGINIA...WESTERN PENNSYLVANIA AND WESTERN NEW YORK... ...SUMMARY... Isolated strong to severe thunderstorms are possible Sunday afternoon and evening across parts of the western New York and Pennsylvania into West Virginia. ...Upper Ohio Valley/Lower Great Lakes vicinity... A mid-latitude cyclone is forecast to begin the period over central Ontario, with enhanced mid-level flow extending throughout the base of this system from the Upper Midwest into the Upper Great Lakes and OH Valley. A pair of shortwave troughs are expected to progress quickly eastward/northeastward within this belt of stronger flow, helping to pull the cyclone eastward while also inducing a negative tilt to the system. By early Sunday, upper troughing will likely extend from the Ontario/Quebec border southeastward into the northern Mid-Atlantic. Primary surface low associated with this system will remain occluded over Ontario throughout the period. However, a secondary triple-point low will likely be over central Ontario early Sunday, with its associated cold front extending southwestward through the Mid MS Valley. This low is forecast to push eastward across eastern Ontario during the day, with the cold front progressing eastward/southeastward as well. A narrow corridor of low 60s dewpoints is anticipated just ahead of the cold front, which is expected to combine with cooling mid-level temperatures and foster modest buoyancy. Initial thunderstorm development along the front is anticipated across eastern OH, where a favorable combination of daytime heating and low-level moisture will destabilize the pre-frontal airmass. Moderate to strong mid-level flow will extend across the region as well, which should allow updrafts to stay ahead of the quick-moving cold front for at least a few hours. Cold mid-level temperatures and moderate deep-layer vertical shear will support a hail risk with the strongest updrafts, particularly with initial development. Bowing line segments will contribute to a threat for damaging gusts as well. Surface winds will likely veer ahead of the front, limiting the low-level curvature. Even so, forecast soundings show southwesterlies strengthening from 15 kt at the surface to 40 kt at 700 mb, which does result in enough storm-relative helicity for some tornado potential if a discrete mode can be maintained. ...Gulf Coast into the Coastal GA and FL Peninsula... Easterly/northeasterly low-level flow will persist for another day across the northern Gulf of Mexico, as a broad area of low pressure remains in place. Showers and thunderstorms are possible within the moist airmass, but weak shear should keep storm severity low. ..Mosier.. 10/05/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO INTO MUCH OF WEST VIRGINIA...WESTERN PENNSYLVANIA AND WESTERN NEW YORK... ...SUMMARY... Isolated strong to severe thunderstorms are possible Sunday afternoon and evening across parts of the western New York and Pennsylvania into West Virginia. ...Upper Ohio Valley/Lower Great Lakes vicinity... A mid-latitude cyclone is forecast to begin the period over central Ontario, with enhanced mid-level flow extending throughout the base of this system from the Upper Midwest into the Upper Great Lakes and OH Valley. A pair of shortwave troughs are expected to progress quickly eastward/northeastward within this belt of stronger flow, helping to pull the cyclone eastward while also inducing a negative tilt to the system. By early Sunday, upper troughing will likely extend from the Ontario/Quebec border southeastward into the northern Mid-Atlantic. Primary surface low associated with this system will remain occluded over Ontario throughout the period. However, a secondary triple-point low will likely be over central Ontario early Sunday, with its associated cold front extending southwestward through the Mid MS Valley. This low is forecast to push eastward across eastern Ontario during the day, with the cold front progressing eastward/southeastward as well. A narrow corridor of low 60s dewpoints is anticipated just ahead of the cold front, which is expected to combine with cooling mid-level temperatures and foster modest buoyancy. Initial thunderstorm development along the front is anticipated across eastern OH, where a favorable combination of daytime heating and low-level moisture will destabilize the pre-frontal airmass. Moderate to strong mid-level flow will extend across the region as well, which should allow updrafts to stay ahead of the quick-moving cold front for at least a few hours. Cold mid-level temperatures and moderate deep-layer vertical shear will support a hail risk with the strongest updrafts, particularly with initial development. Bowing line segments will contribute to a threat for damaging gusts as well. Surface winds will likely veer ahead of the front, limiting the low-level curvature. Even so, forecast soundings show southwesterlies strengthening from 15 kt at the surface to 40 kt at 700 mb, which does result in enough storm-relative helicity for some tornado potential if a discrete mode can be maintained. ...Gulf Coast into the Coastal GA and FL Peninsula... Easterly/northeasterly low-level flow will persist for another day across the northern Gulf of Mexico, as a broad area of low pressure remains in place. Showers and thunderstorms are possible within the moist airmass, but weak shear should keep storm severity low. ..Mosier.. 10/05/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO INTO MUCH OF WEST VIRGINIA...WESTERN PENNSYLVANIA AND WESTERN NEW YORK... ...SUMMARY... Isolated strong to severe thunderstorms are possible Sunday afternoon and evening across parts of the western New York and Pennsylvania into West Virginia. ...Upper Ohio Valley/Lower Great Lakes vicinity... A mid-latitude cyclone is forecast to begin the period over central Ontario, with enhanced mid-level flow extending throughout the base of this system from the Upper Midwest into the Upper Great Lakes and OH Valley. A pair of shortwave troughs are expected to progress quickly eastward/northeastward within this belt of stronger flow, helping to pull the cyclone eastward while also inducing a negative tilt to the system. By early Sunday, upper troughing will likely extend from the Ontario/Quebec border southeastward into the northern Mid-Atlantic. Primary surface low associated with this system will remain occluded over Ontario throughout the period. However, a secondary triple-point low will likely be over central Ontario early Sunday, with its associated cold front extending southwestward through the Mid MS Valley. This low is forecast to push eastward across eastern Ontario during the day, with the cold front progressing eastward/southeastward as well. A narrow corridor of low 60s dewpoints is anticipated just ahead of the cold front, which is expected to combine with cooling mid-level temperatures and foster modest buoyancy. Initial thunderstorm development along the front is anticipated across eastern OH, where a favorable combination of daytime heating and low-level moisture will destabilize the pre-frontal airmass. Moderate to strong mid-level flow will extend across the region as well, which should allow updrafts to stay ahead of the quick-moving cold front for at least a few hours. Cold mid-level temperatures and moderate deep-layer vertical shear will support a hail risk with the strongest updrafts, particularly with initial development. Bowing line segments will contribute to a threat for damaging gusts as well. Surface winds will likely veer ahead of the front, limiting the low-level curvature. Even so, forecast soundings show southwesterlies strengthening from 15 kt at the surface to 40 kt at 700 mb, which does result in enough storm-relative helicity for some tornado potential if a discrete mode can be maintained. ...Gulf Coast into the Coastal GA and FL Peninsula... Easterly/northeasterly low-level flow will persist for another day across the northern Gulf of Mexico, as a broad area of low pressure remains in place. Showers and thunderstorms are possible within the moist airmass, but weak shear should keep storm severity low. ..Mosier.. 10/05/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Sat Oct 05 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO INTO MUCH OF WEST VIRGINIA...WESTERN PENNSYLVANIA AND WESTERN NEW YORK... ...SUMMARY... Isolated strong to severe thunderstorms are possible Sunday afternoon and evening across parts of the western New York and Pennsylvania into West Virginia. ...Upper Ohio Valley/Lower Great Lakes vicinity... A mid-latitude cyclone is forecast to begin the period over central Ontario, with enhanced mid-level flow extending throughout the base of this system from the Upper Midwest into the Upper Great Lakes and OH Valley. A pair of shortwave troughs are expected to progress quickly eastward/northeastward within this belt of stronger flow, helping to pull the cyclone eastward while also inducing a negative tilt to the system. By early Sunday, upper troughing will likely extend from the Ontario/Quebec border southeastward into the northern Mid-Atlantic. Primary surface low associated with this system will remain occluded over Ontario throughout the period. However, a secondary triple-point low will likely be over central Ontario early Sunday, with its associated cold front extending southwestward through the Mid MS Valley. This low is forecast to push eastward across eastern Ontario during the day, with the cold front progressing eastward/southeastward as well. A narrow corridor of low 60s dewpoints is anticipated just ahead of the cold front, which is expected to combine with cooling mid-level temperatures and foster modest buoyancy. Initial thunderstorm development along the front is anticipated across eastern OH, where a favorable combination of daytime heating and low-level moisture will destabilize the pre-frontal airmass. Moderate to strong mid-level flow will extend across the region as well, which should allow updrafts to stay ahead of the quick-moving cold front for at least a few hours. Cold mid-level temperatures and moderate deep-layer vertical shear will support a hail risk with the strongest updrafts, particularly with initial development. Bowing line segments will contribute to a threat for damaging gusts as well. Surface winds will likely veer ahead of the front, limiting the low-level curvature. Even so, forecast soundings show southwesterlies strengthening from 15 kt at the surface to 40 kt at 700 mb, which does result in enough storm-relative helicity for some tornado potential if a discrete mode can be maintained. ...Gulf Coast into the Coastal GA and FL Peninsula... Easterly/northeasterly low-level flow will persist for another day across the northern Gulf of Mexico, as a broad area of low pressure remains in place. Showers and thunderstorms are possible within the moist airmass, but weak shear should keep storm severity low. ..Mosier.. 10/05/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Oct 05 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF NORTHERN WISCONSIN AND ADJACENT PORTIONS OF SOUTHERN UPPER MICHIGAN... ...SUMMARY... Isolated strong to severe thunderstorms may produce hail and gusty winds across parts of northern Wisconsin into the Upper Peninsula of Michigan this evening. ...Synopsis... Flow aloft will remain generally weak over the southern half of the U.S. today, where upper ridging will prevail. This ridging will -- however -- be interrupted by an elongated/weak trough comprised of several smaller-scale vorticity maxima, extending from the southeastern states west-southwestward across the Gulf of Mexico to northern Mexico. Farther north, a faster belt of westerly flow will prevail, with an embedded/potent short-wave trough forecast to move across the northern Plains through the day, and then the Upper Mississippi Valley/Upper Great Lakes region overnight. Accompanying the upper trough, a surface low is forecast to advance east-northeastward across the Canadian Prairie, and into northwestern Ontario through latter stages of the period. A trailing cold front will shift eastward across the north-central U.S. and southward across the Plains -- reaching a position from Lower Michigan southwestward to the Ozarks, and then west-southwestward across Oklahoma to Far West Texas by Sunday morning. ...Central and northern Wisconsin north to Lake Michigan... As a cold front advances across the Upper Midwest area through the afternoon, a capped boundary layer should hinder convective development. As the boundary crosses the Upper Mississippi Valley around sunset, and the upper system advances, the combination of strong ascent and steepening lapse rates aloft should permit eventual development of showers and scattered thunderstorms. With a rather dry -- and nocturnally stabilizing -- boundary layer expected ahead of the front, convection should evolve within a slightly elevated but amply unstable layer. Strong southwesterly flow aloft will provide sufficient shear for organized/rotating storms -- and thus risk for hail is evident. Additionally, the strongly dynamic upper system/strong mass response suggests potential for downward transport of strong flow aloft -- potentially manifesting as severe-caliber wind gusts at the surface. Given the overall severe risk, will introduce a small SLGT/level 2 risk across this area, with the primary risk expected to be hail. However, potential for strong/gusty surface winds may also -- depending upon boundary-layer evolution -- warrant upgrade to 15% probability in later outlooks. ..Goss/Squitieri.. 10/05/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Oct 05 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF NORTHERN WISCONSIN AND ADJACENT PORTIONS OF SOUTHERN UPPER MICHIGAN... ...SUMMARY... Isolated strong to severe thunderstorms may produce hail and gusty winds across parts of northern Wisconsin into the Upper Peninsula of Michigan this evening. ...Synopsis... Flow aloft will remain generally weak over the southern half of the U.S. today, where upper ridging will prevail. This ridging will -- however -- be interrupted by an elongated/weak trough comprised of several smaller-scale vorticity maxima, extending from the southeastern states west-southwestward across the Gulf of Mexico to northern Mexico. Farther north, a faster belt of westerly flow will prevail, with an embedded/potent short-wave trough forecast to move across the northern Plains through the day, and then the Upper Mississippi Valley/Upper Great Lakes region overnight. Accompanying the upper trough, a surface low is forecast to advance east-northeastward across the Canadian Prairie, and into northwestern Ontario through latter stages of the period. A trailing cold front will shift eastward across the north-central U.S. and southward across the Plains -- reaching a position from Lower Michigan southwestward to the Ozarks, and then west-southwestward across Oklahoma to Far West Texas by Sunday morning. ...Central and northern Wisconsin north to Lake Michigan... As a cold front advances across the Upper Midwest area through the afternoon, a capped boundary layer should hinder convective development. As the boundary crosses the Upper Mississippi Valley around sunset, and the upper system advances, the combination of strong ascent and steepening lapse rates aloft should permit eventual development of showers and scattered thunderstorms. With a rather dry -- and nocturnally stabilizing -- boundary layer expected ahead of the front, convection should evolve within a slightly elevated but amply unstable layer. Strong southwesterly flow aloft will provide sufficient shear for organized/rotating storms -- and thus risk for hail is evident. Additionally, the strongly dynamic upper system/strong mass response suggests potential for downward transport of strong flow aloft -- potentially manifesting as severe-caliber wind gusts at the surface. Given the overall severe risk, will introduce a small SLGT/level 2 risk across this area, with the primary risk expected to be hail. However, potential for strong/gusty surface winds may also -- depending upon boundary-layer evolution -- warrant upgrade to 15% probability in later outlooks. ..Goss/Squitieri.. 10/05/2024 Read more