Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1145 AM CDT Wed Nov 01 2023 Valid 011700Z - 021200Z ...17z Update... No changes will be made to the currently valid forecast. Offshore flow being observed this morning is forecast to slowly weaken through the day. However, unusually dry conditions will briefly overlap with the gusty winds supporting a few hours of elevated fire-weather concerns across the Gulf Coast and southeast states. See the previous discussion. ..Lyons.. 11/01/2023 .PREV DISCUSSION... /ISSUED 1132 PM CDT Tue Oct 31 2023/ ...Synopsis... Surface high pressure and associated cooler temperatures will drift eastward from the Plains States to the Eastern Seaboard in tandem with an upper trough that is poised to eject into the Atlantic today. Dry northerly flow will persist across the Gulf Coast states into the Southeast, overspreading drought-stricken fuels that have received minimal rainfall over the last few weeks. Elevated highlights remain in place since RH should drop below 30 percent by afternoon peak heating, with winds potentially gusting over 15 mph. Dry and breezy downslope flow may also occur across portions of northeast New Mexico into the northern Texas Panhandle. However, fuels appear to be too marginal in receptiveness to warrant fire weather highlights this outlook. ...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 1145 AM CDT Wed Nov 01 2023 Valid 011700Z - 021200Z ...17z Update... No changes will be made to the currently valid forecast. Offshore flow being observed this morning is forecast to slowly weaken through the day. However, unusually dry conditions will briefly overlap with the gusty winds supporting a few hours of elevated fire-weather concerns across the Gulf Coast and southeast states. See the previous discussion. ..Lyons.. 11/01/2023 .PREV DISCUSSION... /ISSUED 1132 PM CDT Tue Oct 31 2023/ ...Synopsis... Surface high pressure and associated cooler temperatures will drift eastward from the Plains States to the Eastern Seaboard in tandem with an upper trough that is poised to eject into the Atlantic today. Dry northerly flow will persist across the Gulf Coast states into the Southeast, overspreading drought-stricken fuels that have received minimal rainfall over the last few weeks. Elevated highlights remain in place since RH should drop below 30 percent by afternoon peak heating, with winds potentially gusting over 15 mph. Dry and breezy downslope flow may also occur across portions of northeast New Mexico into the northern Texas Panhandle. However, fuels appear to be too marginal in receptiveness to warrant fire weather highlights this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CDT Wed Nov 01 2023 Valid 011630Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorm areas are forecast today. A few lightning flashes have been noted this morning with snow showers in the lee of Lakes Erie and Ontario. The associated mid-level shortwave trough is rapidly departing this area, suggesting the risk of further lightning is diminishing rapidly. Elsewhere, no thunderstorms are forecast today. ..Hart/Thornton.. 11/01/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CDT Wed Nov 01 2023 Valid 011630Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorm areas are forecast today. A few lightning flashes have been noted this morning with snow showers in the lee of Lakes Erie and Ontario. The associated mid-level shortwave trough is rapidly departing this area, suggesting the risk of further lightning is diminishing rapidly. Elsewhere, no thunderstorms are forecast today. ..Hart/Thornton.. 11/01/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CDT Wed Nov 01 2023 Valid 011630Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorm areas are forecast today. A few lightning flashes have been noted this morning with snow showers in the lee of Lakes Erie and Ontario. The associated mid-level shortwave trough is rapidly departing this area, suggesting the risk of further lightning is diminishing rapidly. Elsewhere, no thunderstorms are forecast today. ..Hart/Thornton.. 11/01/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CDT Wed Nov 01 2023 Valid 011630Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorm areas are forecast today. A few lightning flashes have been noted this morning with snow showers in the lee of Lakes Erie and Ontario. The associated mid-level shortwave trough is rapidly departing this area, suggesting the risk of further lightning is diminishing rapidly. Elsewhere, no thunderstorms are forecast today. ..Hart/Thornton.. 11/01/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Wed Nov 01 2023 Valid 011300Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No overland thunderstorm areas are forecast today. ...Synopsis/Discussion... In mid/upper levels, a longwave trough will persist over eastern North America, though its amplitude will decrease somewhat, due to the ejection/weakening of a strong shortwave trough now over Lake Ontario and the central Appalachians. Ridging aloft will prevail over the Pacific Coast States, before a day-2 trough's moving ashore. Following a major low-level cold-frontal intrusion across the central/eastern CONUS and Gulf, and with a lack of moisture and lift in the West as well, the air mass will be unfavorable for thunderstorm areas across the CONUS. ..Edwards.. 11/01/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Wed Nov 01 2023 Valid 011300Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No overland thunderstorm areas are forecast today. ...Synopsis/Discussion... In mid/upper levels, a longwave trough will persist over eastern North America, though its amplitude will decrease somewhat, due to the ejection/weakening of a strong shortwave trough now over Lake Ontario and the central Appalachians. Ridging aloft will prevail over the Pacific Coast States, before a day-2 trough's moving ashore. Following a major low-level cold-frontal intrusion across the central/eastern CONUS and Gulf, and with a lack of moisture and lift in the West as well, the air mass will be unfavorable for thunderstorm areas across the CONUS. ..Edwards.. 11/01/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Wed Nov 01 2023 Valid 011300Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No overland thunderstorm areas are forecast today. ...Synopsis/Discussion... In mid/upper levels, a longwave trough will persist over eastern North America, though its amplitude will decrease somewhat, due to the ejection/weakening of a strong shortwave trough now over Lake Ontario and the central Appalachians. Ridging aloft will prevail over the Pacific Coast States, before a day-2 trough's moving ashore. Following a major low-level cold-frontal intrusion across the central/eastern CONUS and Gulf, and with a lack of moisture and lift in the West as well, the air mass will be unfavorable for thunderstorm areas across the CONUS. ..Edwards.. 11/01/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0339 AM CDT Wed Nov 01 2023 Valid 041200Z - 091200Z ...DISCUSSION... Medium-range models continue to suggest a pattern evolution which could support at least increasing potential for thunderstorm activity during the early through middle portion of next week. It appears that a belt of strong mid/upper flow will emerge from the southern mid-latitude Pacific and undergo amplification while crossing the U.S. Latest output, including the ECENS/ECMWF and GEFS, has trended faster and less amplified (compared to 24 hours ago) with an initial perturbation progressing east of the Rockies late Sunday into early Monday. Forcing for ascent and surface cyclone development are also focused farther north, along a stalling surface front across the middle Missouri Valley through southern/lower Great Lakes region by late Monday afternoon, and across New England on Tuesday. While it does not appear out of the question that vertical shear and lift within the warm sector of this system may become sufficient to support a risk for severe thunderstorms given enough destabilization, it still appears that weak moisture return in the wake of the recent cold intrusion through the Gulf of Mexico will be a limiting factor. Spread is larger among the various models concerning renewed cyclogenesis to the lee of southern Rockies by next Wednesday, associated with a trailing short wave trough. Barring more substantive amplification than current guidance suggests is most probable, low-level moisture return might still not support more than very limited severe weather potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0339 AM CDT Wed Nov 01 2023 Valid 041200Z - 091200Z ...DISCUSSION... Medium-range models continue to suggest a pattern evolution which could support at least increasing potential for thunderstorm activity during the early through middle portion of next week. It appears that a belt of strong mid/upper flow will emerge from the southern mid-latitude Pacific and undergo amplification while crossing the U.S. Latest output, including the ECENS/ECMWF and GEFS, has trended faster and less amplified (compared to 24 hours ago) with an initial perturbation progressing east of the Rockies late Sunday into early Monday. Forcing for ascent and surface cyclone development are also focused farther north, along a stalling surface front across the middle Missouri Valley through southern/lower Great Lakes region by late Monday afternoon, and across New England on Tuesday. While it does not appear out of the question that vertical shear and lift within the warm sector of this system may become sufficient to support a risk for severe thunderstorms given enough destabilization, it still appears that weak moisture return in the wake of the recent cold intrusion through the Gulf of Mexico will be a limiting factor. Spread is larger among the various models concerning renewed cyclogenesis to the lee of southern Rockies by next Wednesday, associated with a trailing short wave trough. Barring more substantive amplification than current guidance suggests is most probable, low-level moisture return might still not support more than very limited severe weather potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0339 AM CDT Wed Nov 01 2023 Valid 041200Z - 091200Z ...DISCUSSION... Medium-range models continue to suggest a pattern evolution which could support at least increasing potential for thunderstorm activity during the early through middle portion of next week. It appears that a belt of strong mid/upper flow will emerge from the southern mid-latitude Pacific and undergo amplification while crossing the U.S. Latest output, including the ECENS/ECMWF and GEFS, has trended faster and less amplified (compared to 24 hours ago) with an initial perturbation progressing east of the Rockies late Sunday into early Monday. Forcing for ascent and surface cyclone development are also focused farther north, along a stalling surface front across the middle Missouri Valley through southern/lower Great Lakes region by late Monday afternoon, and across New England on Tuesday. While it does not appear out of the question that vertical shear and lift within the warm sector of this system may become sufficient to support a risk for severe thunderstorms given enough destabilization, it still appears that weak moisture return in the wake of the recent cold intrusion through the Gulf of Mexico will be a limiting factor. Spread is larger among the various models concerning renewed cyclogenesis to the lee of southern Rockies by next Wednesday, associated with a trailing short wave trough. Barring more substantive amplification than current guidance suggests is most probable, low-level moisture return might still not support more than very limited severe weather potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0339 AM CDT Wed Nov 01 2023 Valid 041200Z - 091200Z ...DISCUSSION... Medium-range models continue to suggest a pattern evolution which could support at least increasing potential for thunderstorm activity during the early through middle portion of next week. It appears that a belt of strong mid/upper flow will emerge from the southern mid-latitude Pacific and undergo amplification while crossing the U.S. Latest output, including the ECENS/ECMWF and GEFS, has trended faster and less amplified (compared to 24 hours ago) with an initial perturbation progressing east of the Rockies late Sunday into early Monday. Forcing for ascent and surface cyclone development are also focused farther north, along a stalling surface front across the middle Missouri Valley through southern/lower Great Lakes region by late Monday afternoon, and across New England on Tuesday. While it does not appear out of the question that vertical shear and lift within the warm sector of this system may become sufficient to support a risk for severe thunderstorms given enough destabilization, it still appears that weak moisture return in the wake of the recent cold intrusion through the Gulf of Mexico will be a limiting factor. Spread is larger among the various models concerning renewed cyclogenesis to the lee of southern Rockies by next Wednesday, associated with a trailing short wave trough. Barring more substantive amplification than current guidance suggests is most probable, low-level moisture return might still not support more than very limited severe weather potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0339 AM CDT Wed Nov 01 2023 Valid 041200Z - 091200Z ...DISCUSSION... Medium-range models continue to suggest a pattern evolution which could support at least increasing potential for thunderstorm activity during the early through middle portion of next week. It appears that a belt of strong mid/upper flow will emerge from the southern mid-latitude Pacific and undergo amplification while crossing the U.S. Latest output, including the ECENS/ECMWF and GEFS, has trended faster and less amplified (compared to 24 hours ago) with an initial perturbation progressing east of the Rockies late Sunday into early Monday. Forcing for ascent and surface cyclone development are also focused farther north, along a stalling surface front across the middle Missouri Valley through southern/lower Great Lakes region by late Monday afternoon, and across New England on Tuesday. While it does not appear out of the question that vertical shear and lift within the warm sector of this system may become sufficient to support a risk for severe thunderstorms given enough destabilization, it still appears that weak moisture return in the wake of the recent cold intrusion through the Gulf of Mexico will be a limiting factor. Spread is larger among the various models concerning renewed cyclogenesis to the lee of southern Rockies by next Wednesday, associated with a trailing short wave trough. Barring more substantive amplification than current guidance suggests is most probable, low-level moisture return might still not support more than very limited severe weather potential. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0130 AM CDT Wed Nov 01 2023 Valid 031200Z - 041200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk of thunderstorms appears negligible across the U.S., Friday through Friday night. ...Discussion... Models indicate that another substantive short wave trough will emerge from a strong mid/upper jet over the southern mid-latitude Pacific, and approach the southern British Columbia/Pacific Northwest coast by late Friday night. This perturbation is forecast to support the development of a significant surface cyclone, which may begin occluding while approaching the coast. The occluding front may progress into Pacific Northwest coastal areas prior to 12Z Saturday, with an associated band of precipitation. Layers of very weak elevated instability may contribute to embedded convection, but forecast soundings suggest minimal potential for lightning, due to relatively warm air/weak lapse rates farther aloft. East of the Rockies, cold surface ridging is forecast to generally be maintained across much of the northwestern Gulf of Mexico and Gulf Coast vicinity, through the southern Appalachians and Mid Atlantic. It is possible that boundary layer modification and moistening near the Gulf Stream may support sufficient destabilization for scattered weak thunderstorm activity, but this likely will remain confined offshore. Farther north, a reinforcing intrusion of cool/dry and stable air appears likely to overspread the Upper Midwest/Great Lakes region and northern Great Plains, associated with a deep cyclone centered over Hudson Bay. ..Kerr.. 11/01/2023 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0130 AM CDT Wed Nov 01 2023 Valid 031200Z - 041200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk of thunderstorms appears negligible across the U.S., Friday through Friday night. ...Discussion... Models indicate that another substantive short wave trough will emerge from a strong mid/upper jet over the southern mid-latitude Pacific, and approach the southern British Columbia/Pacific Northwest coast by late Friday night. This perturbation is forecast to support the development of a significant surface cyclone, which may begin occluding while approaching the coast. The occluding front may progress into Pacific Northwest coastal areas prior to 12Z Saturday, with an associated band of precipitation. Layers of very weak elevated instability may contribute to embedded convection, but forecast soundings suggest minimal potential for lightning, due to relatively warm air/weak lapse rates farther aloft. East of the Rockies, cold surface ridging is forecast to generally be maintained across much of the northwestern Gulf of Mexico and Gulf Coast vicinity, through the southern Appalachians and Mid Atlantic. It is possible that boundary layer modification and moistening near the Gulf Stream may support sufficient destabilization for scattered weak thunderstorm activity, but this likely will remain confined offshore. Farther north, a reinforcing intrusion of cool/dry and stable air appears likely to overspread the Upper Midwest/Great Lakes region and northern Great Plains, associated with a deep cyclone centered over Hudson Bay. ..Kerr.. 11/01/2023 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0130 AM CDT Wed Nov 01 2023 Valid 031200Z - 041200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk of thunderstorms appears negligible across the U.S., Friday through Friday night. ...Discussion... Models indicate that another substantive short wave trough will emerge from a strong mid/upper jet over the southern mid-latitude Pacific, and approach the southern British Columbia/Pacific Northwest coast by late Friday night. This perturbation is forecast to support the development of a significant surface cyclone, which may begin occluding while approaching the coast. The occluding front may progress into Pacific Northwest coastal areas prior to 12Z Saturday, with an associated band of precipitation. Layers of very weak elevated instability may contribute to embedded convection, but forecast soundings suggest minimal potential for lightning, due to relatively warm air/weak lapse rates farther aloft. East of the Rockies, cold surface ridging is forecast to generally be maintained across much of the northwestern Gulf of Mexico and Gulf Coast vicinity, through the southern Appalachians and Mid Atlantic. It is possible that boundary layer modification and moistening near the Gulf Stream may support sufficient destabilization for scattered weak thunderstorm activity, but this likely will remain confined offshore. Farther north, a reinforcing intrusion of cool/dry and stable air appears likely to overspread the Upper Midwest/Great Lakes region and northern Great Plains, associated with a deep cyclone centered over Hudson Bay. ..Kerr.. 11/01/2023 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0130 AM CDT Wed Nov 01 2023 Valid 031200Z - 041200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk of thunderstorms appears negligible across the U.S., Friday through Friday night. ...Discussion... Models indicate that another substantive short wave trough will emerge from a strong mid/upper jet over the southern mid-latitude Pacific, and approach the southern British Columbia/Pacific Northwest coast by late Friday night. This perturbation is forecast to support the development of a significant surface cyclone, which may begin occluding while approaching the coast. The occluding front may progress into Pacific Northwest coastal areas prior to 12Z Saturday, with an associated band of precipitation. Layers of very weak elevated instability may contribute to embedded convection, but forecast soundings suggest minimal potential for lightning, due to relatively warm air/weak lapse rates farther aloft. East of the Rockies, cold surface ridging is forecast to generally be maintained across much of the northwestern Gulf of Mexico and Gulf Coast vicinity, through the southern Appalachians and Mid Atlantic. It is possible that boundary layer modification and moistening near the Gulf Stream may support sufficient destabilization for scattered weak thunderstorm activity, but this likely will remain confined offshore. Farther north, a reinforcing intrusion of cool/dry and stable air appears likely to overspread the Upper Midwest/Great Lakes region and northern Great Plains, associated with a deep cyclone centered over Hudson Bay. ..Kerr.. 11/01/2023 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1151 PM CDT Tue Oct 31 2023 Valid 021200Z - 031200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk of thunderstorms appears negligible across the U.S., Thursday through Thursday night. ...Discussion... After emerging from a strong jet nosing across the southern mid-latitude Pacific, a short wave trough, approaching the British Columbia/Pacific Northwest coast by 12Z Thursday, is forecast to continue inland through the period. As it progresses through the crest of lingering larger-scale mid-level ridging along the North American Pacific coast, models indicate that an associated surface cyclone and trailing front will continue to occlude and rapidly weaken while advancing onshore. Little appreciable destabilization is forecast, with thermodynamic profiles largely remaining unsupportive of convection capable of producing lightning. East of the Rockies, although temperatures may begin to moderate, cold surface ridging is forecast to be maintained across the northwestern Gulf coast, lower Mississippi Valley, and much of the Southeast into the northwestern Atlantic. ..Kerr.. 11/01/2023 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1151 PM CDT Tue Oct 31 2023 Valid 021200Z - 031200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk of thunderstorms appears negligible across the U.S., Thursday through Thursday night. ...Discussion... After emerging from a strong jet nosing across the southern mid-latitude Pacific, a short wave trough, approaching the British Columbia/Pacific Northwest coast by 12Z Thursday, is forecast to continue inland through the period. As it progresses through the crest of lingering larger-scale mid-level ridging along the North American Pacific coast, models indicate that an associated surface cyclone and trailing front will continue to occlude and rapidly weaken while advancing onshore. Little appreciable destabilization is forecast, with thermodynamic profiles largely remaining unsupportive of convection capable of producing lightning. East of the Rockies, although temperatures may begin to moderate, cold surface ridging is forecast to be maintained across the northwestern Gulf coast, lower Mississippi Valley, and much of the Southeast into the northwestern Atlantic. ..Kerr.. 11/01/2023 Read more