SPC Nov 20, 2023 Day 4-8 Severe Weather Outlook

1 year 8 months ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0301 AM CST Mon Nov 20 2023 Valid 231200Z - 281200Z ...DISCUSSION... While there is notable spread amongst extended-range guidance regarding synoptic-scale details, there is general agreement that a substantial large-scale upper-level trough will cover most of the CONUS through next weekend. Periodic frontal passages will suppress low-level moisture return and result in generally cool and stable conditions for most areas. There remains some potential for a frontal wave to develop over the Gulf of Mexico on D5/Friday, as a cutoff mid/upper-level low over Mexico finally ejects northeastward. Most guidance has trended toward a more suppressed solution with this scenario, though some potential remains for a frontal wave to move over Florida, accompanied by a moist and favorably sheared warm sector. Aside from this relatively low-probability scenario, the severe-thunderstorm threat appears very limited into early next week. Read more

SPC Nov 20, 2023 Day 4-8 Severe Weather Outlook

1 year 8 months ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0301 AM CST Mon Nov 20 2023 Valid 231200Z - 281200Z ...DISCUSSION... While there is notable spread amongst extended-range guidance regarding synoptic-scale details, there is general agreement that a substantial large-scale upper-level trough will cover most of the CONUS through next weekend. Periodic frontal passages will suppress low-level moisture return and result in generally cool and stable conditions for most areas. There remains some potential for a frontal wave to develop over the Gulf of Mexico on D5/Friday, as a cutoff mid/upper-level low over Mexico finally ejects northeastward. Most guidance has trended toward a more suppressed solution with this scenario, though some potential remains for a frontal wave to move over Florida, accompanied by a moist and favorably sheared warm sector. Aside from this relatively low-probability scenario, the severe-thunderstorm threat appears very limited into early next week. Read more

SPC Nov 20, 2023 Day 4-8 Severe Weather Outlook

1 year 8 months ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0301 AM CST Mon Nov 20 2023 Valid 231200Z - 281200Z ...DISCUSSION... While there is notable spread amongst extended-range guidance regarding synoptic-scale details, there is general agreement that a substantial large-scale upper-level trough will cover most of the CONUS through next weekend. Periodic frontal passages will suppress low-level moisture return and result in generally cool and stable conditions for most areas. There remains some potential for a frontal wave to develop over the Gulf of Mexico on D5/Friday, as a cutoff mid/upper-level low over Mexico finally ejects northeastward. Most guidance has trended toward a more suppressed solution with this scenario, though some potential remains for a frontal wave to move over Florida, accompanied by a moist and favorably sheared warm sector. Aside from this relatively low-probability scenario, the severe-thunderstorm threat appears very limited into early next week. Read more

SPC Nov 20, 2023 Day 4-8 Severe Weather Outlook

1 year 8 months ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0301 AM CST Mon Nov 20 2023 Valid 231200Z - 281200Z ...DISCUSSION... While there is notable spread amongst extended-range guidance regarding synoptic-scale details, there is general agreement that a substantial large-scale upper-level trough will cover most of the CONUS through next weekend. Periodic frontal passages will suppress low-level moisture return and result in generally cool and stable conditions for most areas. There remains some potential for a frontal wave to develop over the Gulf of Mexico on D5/Friday, as a cutoff mid/upper-level low over Mexico finally ejects northeastward. Most guidance has trended toward a more suppressed solution with this scenario, though some potential remains for a frontal wave to move over Florida, accompanied by a moist and favorably sheared warm sector. Aside from this relatively low-probability scenario, the severe-thunderstorm threat appears very limited into early next week. Read more

SPC Nov 20, 2023 Day 4-8 Severe Weather Outlook

1 year 8 months ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0301 AM CST Mon Nov 20 2023 Valid 231200Z - 281200Z ...DISCUSSION... While there is notable spread amongst extended-range guidance regarding synoptic-scale details, there is general agreement that a substantial large-scale upper-level trough will cover most of the CONUS through next weekend. Periodic frontal passages will suppress low-level moisture return and result in generally cool and stable conditions for most areas. There remains some potential for a frontal wave to develop over the Gulf of Mexico on D5/Friday, as a cutoff mid/upper-level low over Mexico finally ejects northeastward. Most guidance has trended toward a more suppressed solution with this scenario, though some potential remains for a frontal wave to move over Florida, accompanied by a moist and favorably sheared warm sector. Aside from this relatively low-probability scenario, the severe-thunderstorm threat appears very limited into early next week. Read more

SPC Nov 20, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook

1 year 8 months ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CST Mon Nov 20 2023 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are currently not expected on Wednesday. ...Synopsis... Guidance varies with respect to upper-level pattern evolution on Wednesday, with recent GFS runs and the 20/00Z ECMWF depicting a relatively amplified shortwave trough moving eastward from the TN Valley toward the Carolinas, while other guidance depicts a broader positively tilted trough moving offshore earlier in the forecast period. Despite these differences, most guidance agrees that a cold front will be near or just offshore of coastal NC at the start of the period Wednesday morning, with the trailing portion of the front expected to move across the FL Peninsula through the day. ...Eastern NC and the Outer Banks... While some severe threat could evolve late in the D2/Tuesday period across eastern NC into the Outer Banks, most guidance suggests the effective warm sector will be very near the coast or offshore by the start of the D3/Wednesday period. As a result, severe probabilities were not included with this outlook. However, if the front is slower than currently anticipated, then some threat for isolated damaging wind and/or a brief tornado could briefly persist after 12Z Wednesday morning, within a weakly unstable but moist and strongly sheared environment. ..Dean.. 11/20/2023 Read more

SPC Nov 20, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook

1 year 8 months ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CST Mon Nov 20 2023 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are currently not expected on Wednesday. ...Synopsis... Guidance varies with respect to upper-level pattern evolution on Wednesday, with recent GFS runs and the 20/00Z ECMWF depicting a relatively amplified shortwave trough moving eastward from the TN Valley toward the Carolinas, while other guidance depicts a broader positively tilted trough moving offshore earlier in the forecast period. Despite these differences, most guidance agrees that a cold front will be near or just offshore of coastal NC at the start of the period Wednesday morning, with the trailing portion of the front expected to move across the FL Peninsula through the day. ...Eastern NC and the Outer Banks... While some severe threat could evolve late in the D2/Tuesday period across eastern NC into the Outer Banks, most guidance suggests the effective warm sector will be very near the coast or offshore by the start of the D3/Wednesday period. As a result, severe probabilities were not included with this outlook. However, if the front is slower than currently anticipated, then some threat for isolated damaging wind and/or a brief tornado could briefly persist after 12Z Wednesday morning, within a weakly unstable but moist and strongly sheared environment. ..Dean.. 11/20/2023 Read more

SPC Nov 20, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook

1 year 8 months ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CST Mon Nov 20 2023 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are currently not expected on Wednesday. ...Synopsis... Guidance varies with respect to upper-level pattern evolution on Wednesday, with recent GFS runs and the 20/00Z ECMWF depicting a relatively amplified shortwave trough moving eastward from the TN Valley toward the Carolinas, while other guidance depicts a broader positively tilted trough moving offshore earlier in the forecast period. Despite these differences, most guidance agrees that a cold front will be near or just offshore of coastal NC at the start of the period Wednesday morning, with the trailing portion of the front expected to move across the FL Peninsula through the day. ...Eastern NC and the Outer Banks... While some severe threat could evolve late in the D2/Tuesday period across eastern NC into the Outer Banks, most guidance suggests the effective warm sector will be very near the coast or offshore by the start of the D3/Wednesday period. As a result, severe probabilities were not included with this outlook. However, if the front is slower than currently anticipated, then some threat for isolated damaging wind and/or a brief tornado could briefly persist after 12Z Wednesday morning, within a weakly unstable but moist and strongly sheared environment. ..Dean.. 11/20/2023 Read more

SPC Nov 20, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook

1 year 8 months ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CST Mon Nov 20 2023 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are currently not expected on Wednesday. ...Synopsis... Guidance varies with respect to upper-level pattern evolution on Wednesday, with recent GFS runs and the 20/00Z ECMWF depicting a relatively amplified shortwave trough moving eastward from the TN Valley toward the Carolinas, while other guidance depicts a broader positively tilted trough moving offshore earlier in the forecast period. Despite these differences, most guidance agrees that a cold front will be near or just offshore of coastal NC at the start of the period Wednesday morning, with the trailing portion of the front expected to move across the FL Peninsula through the day. ...Eastern NC and the Outer Banks... While some severe threat could evolve late in the D2/Tuesday period across eastern NC into the Outer Banks, most guidance suggests the effective warm sector will be very near the coast or offshore by the start of the D3/Wednesday period. As a result, severe probabilities were not included with this outlook. However, if the front is slower than currently anticipated, then some threat for isolated damaging wind and/or a brief tornado could briefly persist after 12Z Wednesday morning, within a weakly unstable but moist and strongly sheared environment. ..Dean.. 11/20/2023 Read more

SPC Nov 20, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook

1 year 8 months ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CST Mon Nov 20 2023 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are currently not expected on Wednesday. ...Synopsis... Guidance varies with respect to upper-level pattern evolution on Wednesday, with recent GFS runs and the 20/00Z ECMWF depicting a relatively amplified shortwave trough moving eastward from the TN Valley toward the Carolinas, while other guidance depicts a broader positively tilted trough moving offshore earlier in the forecast period. Despite these differences, most guidance agrees that a cold front will be near or just offshore of coastal NC at the start of the period Wednesday morning, with the trailing portion of the front expected to move across the FL Peninsula through the day. ...Eastern NC and the Outer Banks... While some severe threat could evolve late in the D2/Tuesday period across eastern NC into the Outer Banks, most guidance suggests the effective warm sector will be very near the coast or offshore by the start of the D3/Wednesday period. As a result, severe probabilities were not included with this outlook. However, if the front is slower than currently anticipated, then some threat for isolated damaging wind and/or a brief tornado could briefly persist after 12Z Wednesday morning, within a weakly unstable but moist and strongly sheared environment. ..Dean.. 11/20/2023 Read more

SPC Nov 20, 2023 0830 UTC Day 3 Severe Thunderstorm Outlook

1 year 8 months ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CST Mon Nov 20 2023 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are currently not expected on Wednesday. ...Synopsis... Guidance varies with respect to upper-level pattern evolution on Wednesday, with recent GFS runs and the 20/00Z ECMWF depicting a relatively amplified shortwave trough moving eastward from the TN Valley toward the Carolinas, while other guidance depicts a broader positively tilted trough moving offshore earlier in the forecast period. Despite these differences, most guidance agrees that a cold front will be near or just offshore of coastal NC at the start of the period Wednesday morning, with the trailing portion of the front expected to move across the FL Peninsula through the day. ...Eastern NC and the Outer Banks... While some severe threat could evolve late in the D2/Tuesday period across eastern NC into the Outer Banks, most guidance suggests the effective warm sector will be very near the coast or offshore by the start of the D3/Wednesday period. As a result, severe probabilities were not included with this outlook. However, if the front is slower than currently anticipated, then some threat for isolated damaging wind and/or a brief tornado could briefly persist after 12Z Wednesday morning, within a weakly unstable but moist and strongly sheared environment. ..Dean.. 11/20/2023 Read more

SPC Day 2 Fire Weather Outlook

1 year 8 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... The mid-level pattern over the CONUS is forecast to continue amplifying as the upper low over the central US slides eastward. An attendant surface cyclone is projected to weaken as it moves northeastward across the TN Valley and into the eastern OH Valley by Tuesday evening. Widespread precipitation and cooler temperatures will overspread the eastern half of the US, limiting fire-weather concerns. To the west, eastern Pacific ridging will also intensify with strong high pressure developing within the Great Basin and the Intermountain West. Offshore flow will continue over parts of southern CA for the first half of the period, before weakening as the high pressure moves onto the Plains. Dry northerly winds are also expected over much of the central and southern High Plains. However, with limited fuels owing to cooler temperatures and recent precipitation, fire-weather concerns are expected to remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

1 year 8 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... The mid-level pattern over the CONUS is forecast to continue amplifying as the upper low over the central US slides eastward. An attendant surface cyclone is projected to weaken as it moves northeastward across the TN Valley and into the eastern OH Valley by Tuesday evening. Widespread precipitation and cooler temperatures will overspread the eastern half of the US, limiting fire-weather concerns. To the west, eastern Pacific ridging will also intensify with strong high pressure developing within the Great Basin and the Intermountain West. Offshore flow will continue over parts of southern CA for the first half of the period, before weakening as the high pressure moves onto the Plains. Dry northerly winds are also expected over much of the central and southern High Plains. However, with limited fuels owing to cooler temperatures and recent precipitation, fire-weather concerns are expected to remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

1 year 8 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... The mid-level pattern over the CONUS is forecast to continue amplifying as the upper low over the central US slides eastward. An attendant surface cyclone is projected to weaken as it moves northeastward across the TN Valley and into the eastern OH Valley by Tuesday evening. Widespread precipitation and cooler temperatures will overspread the eastern half of the US, limiting fire-weather concerns. To the west, eastern Pacific ridging will also intensify with strong high pressure developing within the Great Basin and the Intermountain West. Offshore flow will continue over parts of southern CA for the first half of the period, before weakening as the high pressure moves onto the Plains. Dry northerly winds are also expected over much of the central and southern High Plains. However, with limited fuels owing to cooler temperatures and recent precipitation, fire-weather concerns are expected to remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

1 year 8 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... The mid-level pattern over the CONUS is forecast to continue amplifying as the upper low over the central US slides eastward. An attendant surface cyclone is projected to weaken as it moves northeastward across the TN Valley and into the eastern OH Valley by Tuesday evening. Widespread precipitation and cooler temperatures will overspread the eastern half of the US, limiting fire-weather concerns. To the west, eastern Pacific ridging will also intensify with strong high pressure developing within the Great Basin and the Intermountain West. Offshore flow will continue over parts of southern CA for the first half of the period, before weakening as the high pressure moves onto the Plains. Dry northerly winds are also expected over much of the central and southern High Plains. However, with limited fuels owing to cooler temperatures and recent precipitation, fire-weather concerns are expected to remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

1 year 8 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... The mid-level pattern over the CONUS is forecast to continue amplifying as the upper low over the central US slides eastward. An attendant surface cyclone is projected to weaken as it moves northeastward across the TN Valley and into the eastern OH Valley by Tuesday evening. Widespread precipitation and cooler temperatures will overspread the eastern half of the US, limiting fire-weather concerns. To the west, eastern Pacific ridging will also intensify with strong high pressure developing within the Great Basin and the Intermountain West. Offshore flow will continue over parts of southern CA for the first half of the period, before weakening as the high pressure moves onto the Plains. Dry northerly winds are also expected over much of the central and southern High Plains. However, with limited fuels owing to cooler temperatures and recent precipitation, fire-weather concerns are expected to remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

1 year 8 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... The mid-level pattern over the CONUS is forecast to continue amplifying as the upper low over the central US slides eastward. An attendant surface cyclone is projected to weaken as it moves northeastward across the TN Valley and into the eastern OH Valley by Tuesday evening. Widespread precipitation and cooler temperatures will overspread the eastern half of the US, limiting fire-weather concerns. To the west, eastern Pacific ridging will also intensify with strong high pressure developing within the Great Basin and the Intermountain West. Offshore flow will continue over parts of southern CA for the first half of the period, before weakening as the high pressure moves onto the Plains. Dry northerly winds are also expected over much of the central and southern High Plains. However, with limited fuels owing to cooler temperatures and recent precipitation, fire-weather concerns are expected to remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook

1 year 8 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0158 AM CST Mon Nov 20 2023 Valid 201200Z - 211200Z ...Synopsis... A deep mid-level trough over the central US will drive strong flow aloft southward over parts of southern CA and the lower CO River Valley while ridging develops over the eastern Pacific. High pressure over the northern Great Basin should support offshore flow over parts of southern CA through tonight and into early D2/Tuesday. ...Central Appalachians... Breezy easterly flow is expected over parts of western NC and eastern TN ahead of the surface low as it moves from OK into the mid MS Valley tonight. North of the stalled warm front, the low-level air mass remains relatively dry from the prior frontal passage. While RH values are not expected to reach critical levels, very strong low- and mid-level winds ahead of the surface low are expected to overspread areas of 90th percentile ERCs. Ongoing wildfire activity within the higher terrain could be impacted by strong east/southeast winds and mountain waves for several hours this afternoon into the evening. With this in mind, have opted to include a small elevated on the downwind side of the Smoky Mountains where strong winds could overlap with the driest fuels. Later tonight, widespread rain should develop and end the fire-weather threat. ...Southern High Plains... Very strong flow aloft is expected to overspread parts of the Southern High Plains and eastern NM as the deep mid-level trough begins to move east. Aided by the low over OK, gusty northwest surface winds are possible across west TX and eastern NM Monday afternoon and evening. However, recent rainfall and cooler temperatures in the wake of the passing Pacific front should keep RH above critical levels. Gusty winds still may support brief local fire-weather concerns through the afternoon. ...Southern California... Strong flow aloft along the backside of the central US trough will overspread parts of southern CA late this weekend into early Monday. High pressure over the Great Basin will tighten offshore surface pressure gradients, enhancing surface winds across Point Conception and the lee of the Peninsular Ranges. A few hours of gusty winds and low humidity are likely through tonight before winds begin to weaken into D2/Tuesday morning. However, marginally receptive fuels and the relatively brief period of offshore winds suggest any fire-weather concerns will remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook

1 year 8 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0158 AM CST Mon Nov 20 2023 Valid 201200Z - 211200Z ...Synopsis... A deep mid-level trough over the central US will drive strong flow aloft southward over parts of southern CA and the lower CO River Valley while ridging develops over the eastern Pacific. High pressure over the northern Great Basin should support offshore flow over parts of southern CA through tonight and into early D2/Tuesday. ...Central Appalachians... Breezy easterly flow is expected over parts of western NC and eastern TN ahead of the surface low as it moves from OK into the mid MS Valley tonight. North of the stalled warm front, the low-level air mass remains relatively dry from the prior frontal passage. While RH values are not expected to reach critical levels, very strong low- and mid-level winds ahead of the surface low are expected to overspread areas of 90th percentile ERCs. Ongoing wildfire activity within the higher terrain could be impacted by strong east/southeast winds and mountain waves for several hours this afternoon into the evening. With this in mind, have opted to include a small elevated on the downwind side of the Smoky Mountains where strong winds could overlap with the driest fuels. Later tonight, widespread rain should develop and end the fire-weather threat. ...Southern High Plains... Very strong flow aloft is expected to overspread parts of the Southern High Plains and eastern NM as the deep mid-level trough begins to move east. Aided by the low over OK, gusty northwest surface winds are possible across west TX and eastern NM Monday afternoon and evening. However, recent rainfall and cooler temperatures in the wake of the passing Pacific front should keep RH above critical levels. Gusty winds still may support brief local fire-weather concerns through the afternoon. ...Southern California... Strong flow aloft along the backside of the central US trough will overspread parts of southern CA late this weekend into early Monday. High pressure over the Great Basin will tighten offshore surface pressure gradients, enhancing surface winds across Point Conception and the lee of the Peninsular Ranges. A few hours of gusty winds and low humidity are likely through tonight before winds begin to weaken into D2/Tuesday morning. However, marginally receptive fuels and the relatively brief period of offshore winds suggest any fire-weather concerns will remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook

1 year 8 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0158 AM CST Mon Nov 20 2023 Valid 201200Z - 211200Z ...Synopsis... A deep mid-level trough over the central US will drive strong flow aloft southward over parts of southern CA and the lower CO River Valley while ridging develops over the eastern Pacific. High pressure over the northern Great Basin should support offshore flow over parts of southern CA through tonight and into early D2/Tuesday. ...Central Appalachians... Breezy easterly flow is expected over parts of western NC and eastern TN ahead of the surface low as it moves from OK into the mid MS Valley tonight. North of the stalled warm front, the low-level air mass remains relatively dry from the prior frontal passage. While RH values are not expected to reach critical levels, very strong low- and mid-level winds ahead of the surface low are expected to overspread areas of 90th percentile ERCs. Ongoing wildfire activity within the higher terrain could be impacted by strong east/southeast winds and mountain waves for several hours this afternoon into the evening. With this in mind, have opted to include a small elevated on the downwind side of the Smoky Mountains where strong winds could overlap with the driest fuels. Later tonight, widespread rain should develop and end the fire-weather threat. ...Southern High Plains... Very strong flow aloft is expected to overspread parts of the Southern High Plains and eastern NM as the deep mid-level trough begins to move east. Aided by the low over OK, gusty northwest surface winds are possible across west TX and eastern NM Monday afternoon and evening. However, recent rainfall and cooler temperatures in the wake of the passing Pacific front should keep RH above critical levels. Gusty winds still may support brief local fire-weather concerns through the afternoon. ...Southern California... Strong flow aloft along the backside of the central US trough will overspread parts of southern CA late this weekend into early Monday. High pressure over the Great Basin will tighten offshore surface pressure gradients, enhancing surface winds across Point Conception and the lee of the Peninsular Ranges. A few hours of gusty winds and low humidity are likely through tonight before winds begin to weaken into D2/Tuesday morning. However, marginally receptive fuels and the relatively brief period of offshore winds suggest any fire-weather concerns will remain localized. ..Lyons.. 11/20/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more