Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0207 AM CST Mon Nov 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... A strong 500mb jet will drift slowly south through the day across the Southwest. As this occurs, some stronger mid-level flow may overlap a dry and well-mixed airmass across portions of the Southwest. Locally elevated fire weather conditions will be possible, but given fuel states still appear to be somewhat marginal, no Elevated delineation will be added. Relative humidity in the teens with 15 to 20 mph winds will continue to cure fine fuels in the region which may lead to greater severe weather concern later in the week. Additionally, dry conditions will continue across portions of the Southeast into the Carolinas. However, winds will remain light in this region. Therefore, some increase in initial attack is likely, but large fire potential is somewhat muted by the light winds. ..Bentley.. 11/06/2023 ...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 0207 AM CST Mon Nov 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... A strong 500mb jet will drift slowly south through the day across the Southwest. As this occurs, some stronger mid-level flow may overlap a dry and well-mixed airmass across portions of the Southwest. Locally elevated fire weather conditions will be possible, but given fuel states still appear to be somewhat marginal, no Elevated delineation will be added. Relative humidity in the teens with 15 to 20 mph winds will continue to cure fine fuels in the region which may lead to greater severe weather concern later in the week. Additionally, dry conditions will continue across portions of the Southeast into the Carolinas. However, winds will remain light in this region. Therefore, some increase in initial attack is likely, but large fire potential is somewhat muted by the light winds. ..Bentley.. 11/06/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 06 2023 Valid 071200Z - 081200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis and Discussion... A shortwave trough is expected to extend from southern British Columbia to off the central CA coast early Tuesday morning. A belt of enhanced, largely zonal westerly flow is anticipated east of this system, extending from the Great Basin through the OH Valley and Northeast. The shortwave is forecast to make gradual eastward progress throughout the day, likely extending from eastern MT across the Great Basin and into southern CA by early Wednesday. Modest upper ridging will build over the eastern CONUS downstream of this system. At the surface, lee troughing is anticipated across the High Plains, with eventual cyclogenesis likely over the central High Plains Tuesday evening. Resulting surface low is then expected to progress eastward across KS. A broad warm sector, characterized by dewpoints in the low to mid 60s, will exist from south TX into MO ahead of this low. Warm-air advection will persist across this warm sector throughout the day, with some low-level convergence possible along the warm front as well. However, mid-level temperatures are expected to remain warm, resulting in substantial convective inhibition and prohibiting thunderstorm development. Dry and stable conditions are expected elsewhere across the CONUS, with no thunderstorms expected during the period. ..Mosier.. 11/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 06 2023 Valid 071200Z - 081200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis and Discussion... A shortwave trough is expected to extend from southern British Columbia to off the central CA coast early Tuesday morning. A belt of enhanced, largely zonal westerly flow is anticipated east of this system, extending from the Great Basin through the OH Valley and Northeast. The shortwave is forecast to make gradual eastward progress throughout the day, likely extending from eastern MT across the Great Basin and into southern CA by early Wednesday. Modest upper ridging will build over the eastern CONUS downstream of this system. At the surface, lee troughing is anticipated across the High Plains, with eventual cyclogenesis likely over the central High Plains Tuesday evening. Resulting surface low is then expected to progress eastward across KS. A broad warm sector, characterized by dewpoints in the low to mid 60s, will exist from south TX into MO ahead of this low. Warm-air advection will persist across this warm sector throughout the day, with some low-level convergence possible along the warm front as well. However, mid-level temperatures are expected to remain warm, resulting in substantial convective inhibition and prohibiting thunderstorm development. Dry and stable conditions are expected elsewhere across the CONUS, with no thunderstorms expected during the period. ..Mosier.. 11/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 06 2023 Valid 071200Z - 081200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis and Discussion... A shortwave trough is expected to extend from southern British Columbia to off the central CA coast early Tuesday morning. A belt of enhanced, largely zonal westerly flow is anticipated east of this system, extending from the Great Basin through the OH Valley and Northeast. The shortwave is forecast to make gradual eastward progress throughout the day, likely extending from eastern MT across the Great Basin and into southern CA by early Wednesday. Modest upper ridging will build over the eastern CONUS downstream of this system. At the surface, lee troughing is anticipated across the High Plains, with eventual cyclogenesis likely over the central High Plains Tuesday evening. Resulting surface low is then expected to progress eastward across KS. A broad warm sector, characterized by dewpoints in the low to mid 60s, will exist from south TX into MO ahead of this low. Warm-air advection will persist across this warm sector throughout the day, with some low-level convergence possible along the warm front as well. However, mid-level temperatures are expected to remain warm, resulting in substantial convective inhibition and prohibiting thunderstorm development. Dry and stable conditions are expected elsewhere across the CONUS, with no thunderstorms expected during the period. ..Mosier.. 11/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 06 2023 Valid 071200Z - 081200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis and Discussion... A shortwave trough is expected to extend from southern British Columbia to off the central CA coast early Tuesday morning. A belt of enhanced, largely zonal westerly flow is anticipated east of this system, extending from the Great Basin through the OH Valley and Northeast. The shortwave is forecast to make gradual eastward progress throughout the day, likely extending from eastern MT across the Great Basin and into southern CA by early Wednesday. Modest upper ridging will build over the eastern CONUS downstream of this system. At the surface, lee troughing is anticipated across the High Plains, with eventual cyclogenesis likely over the central High Plains Tuesday evening. Resulting surface low is then expected to progress eastward across KS. A broad warm sector, characterized by dewpoints in the low to mid 60s, will exist from south TX into MO ahead of this low. Warm-air advection will persist across this warm sector throughout the day, with some low-level convergence possible along the warm front as well. However, mid-level temperatures are expected to remain warm, resulting in substantial convective inhibition and prohibiting thunderstorm development. Dry and stable conditions are expected elsewhere across the CONUS, with no thunderstorms expected during the period. ..Mosier.. 11/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CST Sun Nov 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible from the Pacific Northwest into parts of the northern Rockies, as well as over Lower Michigan. ...Discussion... Severe thunderstorms are not forecast across the CONUS Monday; although, lightning is expected with convection across a few areas, namely the Pacific Northwest and Great Lakes region. Strong upper trough will advance inland along the WA/OR/northern CA Coast by 18z as a 500mb speed max translates across northern CA into the Great Basin. Modest midlevel height falls will spread ahead of this feature and lapse rates will steepen north of the jet such that weak buoyancy will materialize from coastal portions of the Northwest into the northern Rockies. A few flashes of lightning may accompany weak convection north of the jet. Downstream, a pronounced, fast-moving short-wave trough will eject across WI into MI by late afternoon, then into the lower Great Lakes by the end of the period. Strong LLJ will evolve ahead of this feature and warm advection is expected to encourage elevated convection within a zone of large-scale ascent. Forecast soundings suggest parcels lifted near 850mb will yield around 500mb MUCAPE, more than adequate for lightning with this activity. ..Darrow/Bentley.. 11/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CST Sun Nov 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible from the Pacific Northwest into parts of the northern Rockies, as well as over Lower Michigan. ...Discussion... Severe thunderstorms are not forecast across the CONUS Monday; although, lightning is expected with convection across a few areas, namely the Pacific Northwest and Great Lakes region. Strong upper trough will advance inland along the WA/OR/northern CA Coast by 18z as a 500mb speed max translates across northern CA into the Great Basin. Modest midlevel height falls will spread ahead of this feature and lapse rates will steepen north of the jet such that weak buoyancy will materialize from coastal portions of the Northwest into the northern Rockies. A few flashes of lightning may accompany weak convection north of the jet. Downstream, a pronounced, fast-moving short-wave trough will eject across WI into MI by late afternoon, then into the lower Great Lakes by the end of the period. Strong LLJ will evolve ahead of this feature and warm advection is expected to encourage elevated convection within a zone of large-scale ascent. Forecast soundings suggest parcels lifted near 850mb will yield around 500mb MUCAPE, more than adequate for lightning with this activity. ..Darrow/Bentley.. 11/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CST Sun Nov 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible from the Pacific Northwest into parts of the northern Rockies, as well as over Lower Michigan. ...Discussion... Severe thunderstorms are not forecast across the CONUS Monday; although, lightning is expected with convection across a few areas, namely the Pacific Northwest and Great Lakes region. Strong upper trough will advance inland along the WA/OR/northern CA Coast by 18z as a 500mb speed max translates across northern CA into the Great Basin. Modest midlevel height falls will spread ahead of this feature and lapse rates will steepen north of the jet such that weak buoyancy will materialize from coastal portions of the Northwest into the northern Rockies. A few flashes of lightning may accompany weak convection north of the jet. Downstream, a pronounced, fast-moving short-wave trough will eject across WI into MI by late afternoon, then into the lower Great Lakes by the end of the period. Strong LLJ will evolve ahead of this feature and warm advection is expected to encourage elevated convection within a zone of large-scale ascent. Forecast soundings suggest parcels lifted near 850mb will yield around 500mb MUCAPE, more than adequate for lightning with this activity. ..Darrow/Bentley.. 11/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CST Sun Nov 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible from the Pacific Northwest into parts of the northern Rockies, as well as over Lower Michigan. ...Discussion... Severe thunderstorms are not forecast across the CONUS Monday; although, lightning is expected with convection across a few areas, namely the Pacific Northwest and Great Lakes region. Strong upper trough will advance inland along the WA/OR/northern CA Coast by 18z as a 500mb speed max translates across northern CA into the Great Basin. Modest midlevel height falls will spread ahead of this feature and lapse rates will steepen north of the jet such that weak buoyancy will materialize from coastal portions of the Northwest into the northern Rockies. A few flashes of lightning may accompany weak convection north of the jet. Downstream, a pronounced, fast-moving short-wave trough will eject across WI into MI by late afternoon, then into the lower Great Lakes by the end of the period. Strong LLJ will evolve ahead of this feature and warm advection is expected to encourage elevated convection within a zone of large-scale ascent. Forecast soundings suggest parcels lifted near 850mb will yield around 500mb MUCAPE, more than adequate for lightning with this activity. ..Darrow/Bentley.. 11/06/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0616 PM CST Sun Nov 05 2023 Valid 060100Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ALONG THE PACIFIC NORTHWEST COAST... ...SUMMARY... A brief tornado or two, isolated damaging winds, and small hail are possible into tonight over parts of western Oregon and the far northern California coast. ...01z Update... Strong midlevel height falls will develop across much of the Pacific Northwest into northern CA tonight ahead a pronounced short-wave trough that will approach the coast around sunrise. 500mb jet is forecast to gradually sag south across northern CA by the end of the period which will allow lapse rates to steepen at lower latitudes and permit deeper convection to evolve south along the northern CA Coast later tonight. Latest satellite imagery and lightning data suggest scattered thunderstorms are approaching the WA/OR Coast early this evening. Some organization has been noted with this activity about 60mi west-northwest of Astoria OR, but gradual weakening is currently observed. An arcing band of convection, roughly 90mi long, will move onshore into southwest WA in the next hour. Gusty winds and small hail should be the main threats with this activity along the coast. Otherwise, cooling/steepening lapse rates will continue to support renewed development ahead of the short wave through the overnight hours. ..Darrow.. 11/06/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0616 PM CST Sun Nov 05 2023 Valid 060100Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ALONG THE PACIFIC NORTHWEST COAST... ...SUMMARY... A brief tornado or two, isolated damaging winds, and small hail are possible into tonight over parts of western Oregon and the far northern California coast. ...01z Update... Strong midlevel height falls will develop across much of the Pacific Northwest into northern CA tonight ahead a pronounced short-wave trough that will approach the coast around sunrise. 500mb jet is forecast to gradually sag south across northern CA by the end of the period which will allow lapse rates to steepen at lower latitudes and permit deeper convection to evolve south along the northern CA Coast later tonight. Latest satellite imagery and lightning data suggest scattered thunderstorms are approaching the WA/OR Coast early this evening. Some organization has been noted with this activity about 60mi west-northwest of Astoria OR, but gradual weakening is currently observed. An arcing band of convection, roughly 90mi long, will move onshore into southwest WA in the next hour. Gusty winds and small hail should be the main threats with this activity along the coast. Otherwise, cooling/steepening lapse rates will continue to support renewed development ahead of the short wave through the overnight hours. ..Darrow.. 11/06/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0616 PM CST Sun Nov 05 2023 Valid 060100Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ALONG THE PACIFIC NORTHWEST COAST... ...SUMMARY... A brief tornado or two, isolated damaging winds, and small hail are possible into tonight over parts of western Oregon and the far northern California coast. ...01z Update... Strong midlevel height falls will develop across much of the Pacific Northwest into northern CA tonight ahead a pronounced short-wave trough that will approach the coast around sunrise. 500mb jet is forecast to gradually sag south across northern CA by the end of the period which will allow lapse rates to steepen at lower latitudes and permit deeper convection to evolve south along the northern CA Coast later tonight. Latest satellite imagery and lightning data suggest scattered thunderstorms are approaching the WA/OR Coast early this evening. Some organization has been noted with this activity about 60mi west-northwest of Astoria OR, but gradual weakening is currently observed. An arcing band of convection, roughly 90mi long, will move onshore into southwest WA in the next hour. Gusty winds and small hail should be the main threats with this activity along the coast. Otherwise, cooling/steepening lapse rates will continue to support renewed development ahead of the short wave through the overnight hours. ..Darrow.. 11/06/2023 Read more

No watches are valid as of Sun Nov 5 22:18:02 UTC 2023.

No Mesoscale Discussions are in effect as of Sun Nov 5 22:18:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0355 PM CST Sun Nov 05 2023 Valid 071200Z - 131200Z ...Days 3-4/Tue-Wed - Southern High Plains and Southwest... Preceding a large-scale trough over the West, a belt of strong deep-layer west-southwesterly flow will overspread the central/southern Rockies and adjacent High Plains on Day 3/Tue. This will promote the development of a lee cyclone over the central High Plains, with a dryline extending southward across the southern Plains. Downslope warming/drying and diurnal heating west of the dryline will favor 10-15 percent RH across the southern High Plains. At the same time, a tightening pressure gradient and deep boundary-layer mixing into the strong flow aloft will yield 20+ mph sustained west-southwesterly surface winds (with higher gusts). The best overlap of the strong/gusty winds and low RH will extend from eastern NM into the TX Panhandle, generally along the I-40 corridor. Given marginally receptive fuels here, elevated to locally critical fire-weather conditions are expected. Dry/breezy conditions will also develop over the Southwest, though fuels are generally not supportive of large fires at this time. On Day 4/Wed, dry/breezy conditions are possible across the southern High Plains ahead of an approaching cold front, though these conditions appear too brief for an appreciable fire-weather threat. ...Day 4/Wed - Southern California... An upper-level ridge will move slowly eastward across the Northwest, favoring the development of surface high pressure over the Great Basin. In response, the offshore pressure gradient will tighten across parts of southern CA on Day 4/Wed. Offshore/continental trajectories will support 15-25 percent RH amid breezy/gusty north-northeasterly surface winds. While elevated fire-weather conditions are likely (especially for parts of Ventura and northwest LA Counties), confidence in the development of any more than locally/briefly critical conditions is too low to introduce probabilities at this time. ..Weinman.. 11/05/2023 ...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 0355 PM CST Sun Nov 05 2023 Valid 071200Z - 131200Z ...Days 3-4/Tue-Wed - Southern High Plains and Southwest... Preceding a large-scale trough over the West, a belt of strong deep-layer west-southwesterly flow will overspread the central/southern Rockies and adjacent High Plains on Day 3/Tue. This will promote the development of a lee cyclone over the central High Plains, with a dryline extending southward across the southern Plains. Downslope warming/drying and diurnal heating west of the dryline will favor 10-15 percent RH across the southern High Plains. At the same time, a tightening pressure gradient and deep boundary-layer mixing into the strong flow aloft will yield 20+ mph sustained west-southwesterly surface winds (with higher gusts). The best overlap of the strong/gusty winds and low RH will extend from eastern NM into the TX Panhandle, generally along the I-40 corridor. Given marginally receptive fuels here, elevated to locally critical fire-weather conditions are expected. Dry/breezy conditions will also develop over the Southwest, though fuels are generally not supportive of large fires at this time. On Day 4/Wed, dry/breezy conditions are possible across the southern High Plains ahead of an approaching cold front, though these conditions appear too brief for an appreciable fire-weather threat. ...Day 4/Wed - Southern California... An upper-level ridge will move slowly eastward across the Northwest, favoring the development of surface high pressure over the Great Basin. In response, the offshore pressure gradient will tighten across parts of southern CA on Day 4/Wed. Offshore/continental trajectories will support 15-25 percent RH amid breezy/gusty north-northeasterly surface winds. While elevated fire-weather conditions are likely (especially for parts of Ventura and northwest LA Counties), confidence in the development of any more than locally/briefly critical conditions is too low to introduce probabilities at this time. ..Weinman.. 11/05/2023 ...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 0355 PM CST Sun Nov 05 2023 Valid 071200Z - 131200Z ...Days 3-4/Tue-Wed - Southern High Plains and Southwest... Preceding a large-scale trough over the West, a belt of strong deep-layer west-southwesterly flow will overspread the central/southern Rockies and adjacent High Plains on Day 3/Tue. This will promote the development of a lee cyclone over the central High Plains, with a dryline extending southward across the southern Plains. Downslope warming/drying and diurnal heating west of the dryline will favor 10-15 percent RH across the southern High Plains. At the same time, a tightening pressure gradient and deep boundary-layer mixing into the strong flow aloft will yield 20+ mph sustained west-southwesterly surface winds (with higher gusts). The best overlap of the strong/gusty winds and low RH will extend from eastern NM into the TX Panhandle, generally along the I-40 corridor. Given marginally receptive fuels here, elevated to locally critical fire-weather conditions are expected. Dry/breezy conditions will also develop over the Southwest, though fuels are generally not supportive of large fires at this time. On Day 4/Wed, dry/breezy conditions are possible across the southern High Plains ahead of an approaching cold front, though these conditions appear too brief for an appreciable fire-weather threat. ...Day 4/Wed - Southern California... An upper-level ridge will move slowly eastward across the Northwest, favoring the development of surface high pressure over the Great Basin. In response, the offshore pressure gradient will tighten across parts of southern CA on Day 4/Wed. Offshore/continental trajectories will support 15-25 percent RH amid breezy/gusty north-northeasterly surface winds. While elevated fire-weather conditions are likely (especially for parts of Ventura and northwest LA Counties), confidence in the development of any more than locally/briefly critical conditions is too low to introduce probabilities at this time. ..Weinman.. 11/05/2023 ...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 0355 PM CST Sun Nov 05 2023 Valid 071200Z - 131200Z ...Days 3-4/Tue-Wed - Southern High Plains and Southwest... Preceding a large-scale trough over the West, a belt of strong deep-layer west-southwesterly flow will overspread the central/southern Rockies and adjacent High Plains on Day 3/Tue. This will promote the development of a lee cyclone over the central High Plains, with a dryline extending southward across the southern Plains. Downslope warming/drying and diurnal heating west of the dryline will favor 10-15 percent RH across the southern High Plains. At the same time, a tightening pressure gradient and deep boundary-layer mixing into the strong flow aloft will yield 20+ mph sustained west-southwesterly surface winds (with higher gusts). The best overlap of the strong/gusty winds and low RH will extend from eastern NM into the TX Panhandle, generally along the I-40 corridor. Given marginally receptive fuels here, elevated to locally critical fire-weather conditions are expected. Dry/breezy conditions will also develop over the Southwest, though fuels are generally not supportive of large fires at this time. On Day 4/Wed, dry/breezy conditions are possible across the southern High Plains ahead of an approaching cold front, though these conditions appear too brief for an appreciable fire-weather threat. ...Day 4/Wed - Southern California... An upper-level ridge will move slowly eastward across the Northwest, favoring the development of surface high pressure over the Great Basin. In response, the offshore pressure gradient will tighten across parts of southern CA on Day 4/Wed. Offshore/continental trajectories will support 15-25 percent RH amid breezy/gusty north-northeasterly surface winds. While elevated fire-weather conditions are likely (especially for parts of Ventura and northwest LA Counties), confidence in the development of any more than locally/briefly critical conditions is too low to introduce probabilities at this time. ..Weinman.. 11/05/2023 ...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 0149 PM CST Sun Nov 05 2023 Valid 052000Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL NORTHERN CALIFORNIA AND OREGON... ...SUMMARY... A brief tornado or two, isolated damaging winds, and small hail will be possible into tonight over parts of western Oregon and the far northern California coast. ...20z Update... No changes have been made to the Marginal (level 1 of 5) risk area along the Pacific Northwest coast. See discussion below for forecast details. Otherwise, the 10 percent general thunderstorm area has been removed from the eastern Dakotas and MN. Thunderstorm chances appear most likely near the end of the period further east across northeast WI/northern Lake Michigan. Deeper moisture and greater, though still modest, instability will be in place ahead of the eastward progressing surface low, supporting a few lightning flashes. ..Leitman.. 11/05/2023 .PREV DISCUSSION... /ISSUED 1023 AM CST Sun Nov 05 2023/ ...Western OR and far northern CA coast... Minor expansion of the level 1 risk with this outlook as a long-duration, low-probability tornado/wind threat remains apparent beginning around midday. Observational imagery depicts a series of embedded shortwave troughs moving generally eastward towards the Pacific Northwest coast today into tonight, with relatively prolific lightning production amid several convective clusters. A feed of conditionally unstable low to mid-level lapse rates and meager buoyancy (200-300 J/kg SBCAPE) will favor low-topped convection and occasional lightning flashes over land this afternoon into tonight as the waves progress inland. Low to mid-level wind profiles will strengthen somewhat, yielding sufficient hodograph length and low-level curvature for a few low-topped supercells. These cells will be capable of producing a brief tornado or two, isolated strong gusts, and small hail up to nickel size. The longest duration threat should exist along the coast, mainly in OR with a gradual north to south shift towards far northern CA tonight. The eastern extent of the low-probability severe threat into parts of the Willamette Valley should be confined from mid-afternoon to early evening. Read more