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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Thu Nov 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible along the Pacific Northwest Coast Friday. Severe storms are not expected. ...Synopsis... Amplified mid-level flow is likely over much of the CONUS Friday, with a deep upper low off the East Coast and a similarly deep trough off the West Coast. Between the two lows, a shortwave ridge will slowly migrate eastward over the central Plains. At the surface, a low and trailing cold front will steadily move offshore through the day over the East. High pressure and offshore flow are likely over the central CONUS. While along the West Coast, a pronounced low and onshore flow will continue. As the upper trough continues to shift eastward, cool and stable offshore flow should limit buoyancy and deep convection over the eastern 2/3rds of the CONUS. The only exception to this could be brief, low-topped storms near Cape Cod. A few deeper convective elements embedded within broad stratiform could produce sporadic lightning before stronger offshore flow shifts any lingering buoyancy completely offshore by midday. Across the Pacific Northwest, continuous onshore flow is likely as the cold core of the upper trough (-28 to -30 C 500 mb temps) moves onshore late in the day and overnight. Scattered low-topped convection will be most likely over the ocean overnight, but a few thunderstorms with sporadic lightning could move inland. With very weak MUCAPE (100-200 J/kg) any stronger updrafts will likely be brief. Strong deep-layer shear could briefly overlap with the buoyancy supporting a sporadic strong wind gust near the coast. However, the transient nature of the updrafts should keep the severe risk negligible. ..Lyons.. 11/21/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Thu Nov 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible along the Pacific Northwest Coast Friday. Severe storms are not expected. ...Synopsis... Amplified mid-level flow is likely over much of the CONUS Friday, with a deep upper low off the East Coast and a similarly deep trough off the West Coast. Between the two lows, a shortwave ridge will slowly migrate eastward over the central Plains. At the surface, a low and trailing cold front will steadily move offshore through the day over the East. High pressure and offshore flow are likely over the central CONUS. While along the West Coast, a pronounced low and onshore flow will continue. As the upper trough continues to shift eastward, cool and stable offshore flow should limit buoyancy and deep convection over the eastern 2/3rds of the CONUS. The only exception to this could be brief, low-topped storms near Cape Cod. A few deeper convective elements embedded within broad stratiform could produce sporadic lightning before stronger offshore flow shifts any lingering buoyancy completely offshore by midday. Across the Pacific Northwest, continuous onshore flow is likely as the cold core of the upper trough (-28 to -30 C 500 mb temps) moves onshore late in the day and overnight. Scattered low-topped convection will be most likely over the ocean overnight, but a few thunderstorms with sporadic lightning could move inland. With very weak MUCAPE (100-200 J/kg) any stronger updrafts will likely be brief. Strong deep-layer shear could briefly overlap with the buoyancy supporting a sporadic strong wind gust near the coast. However, the transient nature of the updrafts should keep the severe risk negligible. ..Lyons.. 11/21/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Thu Nov 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible along the Pacific Northwest Coast Friday. Severe storms are not expected. ...Synopsis... Amplified mid-level flow is likely over much of the CONUS Friday, with a deep upper low off the East Coast and a similarly deep trough off the West Coast. Between the two lows, a shortwave ridge will slowly migrate eastward over the central Plains. At the surface, a low and trailing cold front will steadily move offshore through the day over the East. High pressure and offshore flow are likely over the central CONUS. While along the West Coast, a pronounced low and onshore flow will continue. As the upper trough continues to shift eastward, cool and stable offshore flow should limit buoyancy and deep convection over the eastern 2/3rds of the CONUS. The only exception to this could be brief, low-topped storms near Cape Cod. A few deeper convective elements embedded within broad stratiform could produce sporadic lightning before stronger offshore flow shifts any lingering buoyancy completely offshore by midday. Across the Pacific Northwest, continuous onshore flow is likely as the cold core of the upper trough (-28 to -30 C 500 mb temps) moves onshore late in the day and overnight. Scattered low-topped convection will be most likely over the ocean overnight, but a few thunderstorms with sporadic lightning could move inland. With very weak MUCAPE (100-200 J/kg) any stronger updrafts will likely be brief. Strong deep-layer shear could briefly overlap with the buoyancy supporting a sporadic strong wind gust near the coast. However, the transient nature of the updrafts should keep the severe risk negligible. ..Lyons.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1029 AM CST Thu Nov 21 2024 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis... A deep midlevel low, characterized by 500-mb temperatures around -32C, will move from the Great Lakes into the Mid-Atlantic through the period. These cold midlevel temperatures and strong height falls accompanying the midlevel low may promote isolated lightning flashes embedded in showers across the central Appalachians this afternoon. Over coastal southern New England, low-level warm advection north of a related occluded surface low will also support isolated thunderstorms, given weak elevated instability. Most of this activity should remain offshore. Isolated thunderstorms are also possible over immediate coastal areas of WA, where forcing for ascent in the left exit region of a jet streak is overlapping deep tropospheric moisture/weak instability. ..Weinman.. 11/21/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...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 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...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 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...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 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...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 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...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 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...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 0926 AM CST Thu Nov 21 2024 Valid 211700Z - 221200Z The previous forecast remains on track with no changes required. Recent 15 UTC surface observations show winds increasing to around 15 mph with occasionally stronger gusts and RH falling into the 30-40% range. This aligns well with recent guidance and supports the ongoing forecast (outlined in the discussion below). ..Moore.. 11/21/2024 .PREV DISCUSSION... /ISSUED 1150 PM CST Wed Nov 20 2024/ ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2238 CONCERNING HEAVY SNOW FOR PORTIONS OF EASTERN WISCONSIN INTO ADJACENT NORTHEASTERN ILLINOIS
Mesoscale Discussion 2238 NWS Storm Prediction Center Norman OK 0409 AM CST Thu Nov 21 2024 Areas affected...portions of eastern Wisconsin into adjacent northeastern Illinois Concerning...Heavy snow Valid 211009Z - 211345Z SUMMARY...An hour or two period of 1-2+ inch per hour snow rates appears possible early this morning, coincident with strong gusty winds resulting in blowing snow and reduced visibilities. This appears most likely to spread from near or just west of Green Bay southward through the Oshkosh vicinity and areas west of Milwaukee by around 8-9 AM CST. DISCUSSION...To the southwest of the lingering occluded surface cyclone over the upper peninsula of Michigan, sub-freezing thermodynamic profiles remain entrenched across much of Wisconsin, in the presence of strengthening lower/mid-tropospheric warm advection. This is occurring in advance of a southwestward then southward pivoting mid-level cyclonic vorticity center, which is forecast to be accompanied by strengthening northerly flow to 50-60 kt in the 850-700 mb layer across much of eastern Wisconsin. Associated strengthening of large-scale ascent is likely to continue contributing to saturation of thermodynamic profiles and the development of snow through 13-15Z. Models suggest that lift may become strong and focused near and just ahead of the mid-level cyclonic vorticity center, maximized within a layer near/above 700 mb with temperatures around -15C, and conducive to large dendritic ice crystal growth. It appears that this may be accompanied by a period of heavy snow rates on the order of 1-2+ inches per hour, coincident with strengthening, gusty surface winds. ..Kerr.. 11/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...LOT...MKX... LAT...LON 45018918 44728772 43868764 42428826 43148946 45018918 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Thu Nov 21 2024 Valid 211300Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis and Discussion... A mature mid/upper-level cyclone will move from the Great Lakes/OH Valley to the East Coast today. Modest low-level warm advection may support occasional elevated thunderstorms to the north of a front near Long Island NY. This activity should generally remain offshore. Otherwise, isolated lightning flashes may be noted with shallow convection today across parts of the central Appalachians, beneath cold mid-level temperatures associated with the upper low. Although low-level moisture and related MUCAPE are both forecast to remain meager, some of this activity may acquire sufficient depth to support charge separation. Finally, isolated convection producing occasional lightning may brush parts of the WA Coast through this afternoon. ..Gleason/Kerr.. 11/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Thu Nov 21 2024 Valid 211300Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today and tonight. ...Synopsis and Discussion... A mature mid/upper-level cyclone will move from the Great Lakes/OH Valley to the East Coast today. Modest low-level warm advection may support occasional elevated thunderstorms to the north of a front near Long Island NY. This activity should generally remain offshore. Otherwise, isolated lightning flashes may be noted with shallow convection today across parts of the central Appalachians, beneath cold mid-level temperatures associated with the upper low. Although low-level moisture and related MUCAPE are both forecast to remain meager, some of this activity may acquire sufficient depth to support charge separation. Finally, isolated convection producing occasional lightning may brush parts of the WA Coast through this afternoon. ..Gleason/Kerr.. 11/21/2024 Read more