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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible across southern New England Thursday morning. ...Southern New England... Strong upper low will shift southeast from the Great Lakes into the upper Ohio Valley by late afternoon. This evolution will encourage low-level warm advection across southern New England as a surface low repositions itself off the middle Atlantic coast, south of Long Island. Forecast soundings suggest weak elevated buoyancy will develop north of this boundary as mid-level lapse rates will steepen as 500mb temperatures cool in advance of the approaching trough. Strongest elevated updrafts may exceed levels necessary for lightning discharge, but this should mainly be prior to 18z. Thereafter, deepest convection will focus offshore. ..Darrow/Wendt.. 11/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible across southern New England Thursday morning. ...Southern New England... Strong upper low will shift southeast from the Great Lakes into the upper Ohio Valley by late afternoon. This evolution will encourage low-level warm advection across southern New England as a surface low repositions itself off the middle Atlantic coast, south of Long Island. Forecast soundings suggest weak elevated buoyancy will develop north of this boundary as mid-level lapse rates will steepen as 500mb temperatures cool in advance of the approaching trough. Strongest elevated updrafts may exceed levels necessary for lightning discharge, but this should mainly be prior to 18z. Thereafter, deepest convection will focus offshore. ..Darrow/Wendt.. 11/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible across southern New England Thursday morning. ...Southern New England... Strong upper low will shift southeast from the Great Lakes into the upper Ohio Valley by late afternoon. This evolution will encourage low-level warm advection across southern New England as a surface low repositions itself off the middle Atlantic coast, south of Long Island. Forecast soundings suggest weak elevated buoyancy will develop north of this boundary as mid-level lapse rates will steepen as 500mb temperatures cool in advance of the approaching trough. Strongest elevated updrafts may exceed levels necessary for lightning discharge, but this should mainly be prior to 18z. Thereafter, deepest convection will focus offshore. ..Darrow/Wendt.. 11/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible across southern New England Thursday morning. ...Southern New England... Strong upper low will shift southeast from the Great Lakes into the upper Ohio Valley by late afternoon. This evolution will encourage low-level warm advection across southern New England as a surface low repositions itself off the middle Atlantic coast, south of Long Island. Forecast soundings suggest weak elevated buoyancy will develop north of this boundary as mid-level lapse rates will steepen as 500mb temperatures cool in advance of the approaching trough. Strongest elevated updrafts may exceed levels necessary for lightning discharge, but this should mainly be prior to 18z. Thereafter, deepest convection will focus offshore. ..Darrow/Wendt.. 11/21/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Wed Nov 20 2024 Valid 210100Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected tonight; although, a few strong storms may be noted along the immediate Washington/Oregon Coast this evening. ...01z Update... Strong upper low off the BC/WA coast should gradually fill tonight as it occludes offshore. As a result, mid-level heights will gradually rise through sunrise, and onshore flow should weaken. Until then, a few longer-lived showers/supercells developed about 100mi offshore and are now moving inland, especially over northwest Pacific County WA. This convection was aided by marine-influenced buoyancy, but this activity will quickly weaken as it encounters a poor air mass inland. Some near-term risk for gusty winds, and perhaps an offshore water spout, exist for the next few hours. However, severe threat does not appear to be enough to warrant severe probabilities overnight. Downstream across the middle Atlantic, strong height falls will spread across this region (180m in 12hr) ahead of a pronounced upper low shifting southeast across the Great Lakes. A plume of modest 0-3km lapse rates developed across the Ohio Valley earlier this afternoon which appeared to aid shallow convection across eastern OH into western PA, where some localized damaging winds were noted. However, this convection has spread well east of this steeper plume and poor low-level lapse rates downstream do not support robust updrafts overnight. ..Darrow.. 11/21/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Wed Nov 20 2024 Valid 210100Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected tonight; although, a few strong storms may be noted along the immediate Washington/Oregon Coast this evening. ...01z Update... Strong upper low off the BC/WA coast should gradually fill tonight as it occludes offshore. As a result, mid-level heights will gradually rise through sunrise, and onshore flow should weaken. Until then, a few longer-lived showers/supercells developed about 100mi offshore and are now moving inland, especially over northwest Pacific County WA. This convection was aided by marine-influenced buoyancy, but this activity will quickly weaken as it encounters a poor air mass inland. Some near-term risk for gusty winds, and perhaps an offshore water spout, exist for the next few hours. However, severe threat does not appear to be enough to warrant severe probabilities overnight. Downstream across the middle Atlantic, strong height falls will spread across this region (180m in 12hr) ahead of a pronounced upper low shifting southeast across the Great Lakes. A plume of modest 0-3km lapse rates developed across the Ohio Valley earlier this afternoon which appeared to aid shallow convection across eastern OH into western PA, where some localized damaging winds were noted. However, this convection has spread well east of this steeper plume and poor low-level lapse rates downstream do not support robust updrafts overnight. ..Darrow.. 11/21/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Wed Nov 20 2024 Valid 210100Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected tonight; although, a few strong storms may be noted along the immediate Washington/Oregon Coast this evening. ...01z Update... Strong upper low off the BC/WA coast should gradually fill tonight as it occludes offshore. As a result, mid-level heights will gradually rise through sunrise, and onshore flow should weaken. Until then, a few longer-lived showers/supercells developed about 100mi offshore and are now moving inland, especially over northwest Pacific County WA. This convection was aided by marine-influenced buoyancy, but this activity will quickly weaken as it encounters a poor air mass inland. Some near-term risk for gusty winds, and perhaps an offshore water spout, exist for the next few hours. However, severe threat does not appear to be enough to warrant severe probabilities overnight. Downstream across the middle Atlantic, strong height falls will spread across this region (180m in 12hr) ahead of a pronounced upper low shifting southeast across the Great Lakes. A plume of modest 0-3km lapse rates developed across the Ohio Valley earlier this afternoon which appeared to aid shallow convection across eastern OH into western PA, where some localized damaging winds were noted. However, this convection has spread well east of this steeper plume and poor low-level lapse rates downstream do not support robust updrafts overnight. ..Darrow.. 11/21/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Wed Nov 20 2024 Valid 210100Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected tonight; although, a few strong storms may be noted along the immediate Washington/Oregon Coast this evening. ...01z Update... Strong upper low off the BC/WA coast should gradually fill tonight as it occludes offshore. As a result, mid-level heights will gradually rise through sunrise, and onshore flow should weaken. Until then, a few longer-lived showers/supercells developed about 100mi offshore and are now moving inland, especially over northwest Pacific County WA. This convection was aided by marine-influenced buoyancy, but this activity will quickly weaken as it encounters a poor air mass inland. Some near-term risk for gusty winds, and perhaps an offshore water spout, exist for the next few hours. However, severe threat does not appear to be enough to warrant severe probabilities overnight. Downstream across the middle Atlantic, strong height falls will spread across this region (180m in 12hr) ahead of a pronounced upper low shifting southeast across the Great Lakes. A plume of modest 0-3km lapse rates developed across the Ohio Valley earlier this afternoon which appeared to aid shallow convection across eastern OH into western PA, where some localized damaging winds were noted. However, this convection has spread well east of this steeper plume and poor low-level lapse rates downstream do not support robust updrafts overnight. ..Darrow.. 11/21/2024 Read more

No Mesoscale Discussions are in effect as of Wed Nov 20 23:41:02 UTC 2024.

No watches are valid as of Wed Nov 20 23:41:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Wed Nov 20 2024 Valid 202000Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms appear unlikely through tonight across the contiguous United States. ...20z Update... No changes are needed to the current D1 Convective Outlook. See previous discussion below for more information. ..Thornton/Smith.. 11/20/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Wed Nov 20 2024/ ...Mid-Atlantic into North Carolina... Midday water-vapor imagery shows a cyclone over the Upper Midwest that will move eastward across the Great Lakes through tonight. A cold front will advance eastward over these regions. While low-level moisture will gradually increase across NC into the southern Mid-Atlantic by early evening, considerable cloud cover and relatively meager lapse rates will only result in pockets of weak instability. Nonetheless, low-topped convection should still form along or just ahead of the cold front across eastern OH into western PA and WV by late this afternoon according to the latest guidance. This elevated convection is forecast to continue moving eastward over the southern Mid-Atlantic this evening and overnight. However, boundary-layer instability is forecast to remain minimal with eastward extent, which should limit the storm intensity. ...Coastal Pacific Northwest... A powerful upper cyclone west of British Columbia will occlude and gradually move away from the coast. Low-level warm advection will support intermittent low-topped convection across coastal portions of the Pacific Northwest. With surface dewpoints generally in the low to mid 40s over land, instability will remain scant---precluding a severe risk. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Wed Nov 20 2024 Valid 202000Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms appear unlikely through tonight across the contiguous United States. ...20z Update... No changes are needed to the current D1 Convective Outlook. See previous discussion below for more information. ..Thornton/Smith.. 11/20/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Wed Nov 20 2024/ ...Mid-Atlantic into North Carolina... Midday water-vapor imagery shows a cyclone over the Upper Midwest that will move eastward across the Great Lakes through tonight. A cold front will advance eastward over these regions. While low-level moisture will gradually increase across NC into the southern Mid-Atlantic by early evening, considerable cloud cover and relatively meager lapse rates will only result in pockets of weak instability. Nonetheless, low-topped convection should still form along or just ahead of the cold front across eastern OH into western PA and WV by late this afternoon according to the latest guidance. This elevated convection is forecast to continue moving eastward over the southern Mid-Atlantic this evening and overnight. However, boundary-layer instability is forecast to remain minimal with eastward extent, which should limit the storm intensity. ...Coastal Pacific Northwest... A powerful upper cyclone west of British Columbia will occlude and gradually move away from the coast. Low-level warm advection will support intermittent low-topped convection across coastal portions of the Pacific Northwest. With surface dewpoints generally in the low to mid 40s over land, instability will remain scant---precluding a severe risk. Read more