Aggregator

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CST Mon Nov 27 2023 Valid 301200Z - 051200Z ...DISCUSSION... On Thursday/D4, models are in good agreement depicting a shortwave trough strengthening as it moves into the southern Plains, with strong height falls over TX and a 70 kt midlevel jet. This wave is expected to pivot northeastward rapidly after 00Z, with height rises from the Rio Grande Valley to the ArkLaTex into Friday/D5 morning. Low pressure will likely develop over northern or central TX during the day, and will move with the parent trough toward the Ozarks overnight. Low-level southerly winds will aid moisture advection, with a warm front possibly into northeast TX and southern AR by evening. Predictability issues do exist due to numerous showers and thunderstorms likely to be ongoing throughout the period, focused east of I-35, which will reduce instability. However, large-scale ascent will be favorable and so will deep-layer shear, and it is not inconceivable that areas of severe storms could develop. The threat is conditional on access to the better instability plume over southern TX. Given these considerations, predictability is too low to introduce severe probabilities at this time. From Friday/D5 onward, the initial trough will lose amplitude quickly as it moves northeastward, becoming well removed from the instability plume. This will likely give way to a more generalized west/southwest flow regime over the Plains and MS Valley, as a possible large-scale trough amplification occurs over the West. The result may be scattered to numerous thunderstorms for several days from TX into the Southeast, with the overall regime characterized as that of warm advection and heavy rain. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CST Mon Nov 27 2023 Valid 301200Z - 051200Z ...DISCUSSION... On Thursday/D4, models are in good agreement depicting a shortwave trough strengthening as it moves into the southern Plains, with strong height falls over TX and a 70 kt midlevel jet. This wave is expected to pivot northeastward rapidly after 00Z, with height rises from the Rio Grande Valley to the ArkLaTex into Friday/D5 morning. Low pressure will likely develop over northern or central TX during the day, and will move with the parent trough toward the Ozarks overnight. Low-level southerly winds will aid moisture advection, with a warm front possibly into northeast TX and southern AR by evening. Predictability issues do exist due to numerous showers and thunderstorms likely to be ongoing throughout the period, focused east of I-35, which will reduce instability. However, large-scale ascent will be favorable and so will deep-layer shear, and it is not inconceivable that areas of severe storms could develop. The threat is conditional on access to the better instability plume over southern TX. Given these considerations, predictability is too low to introduce severe probabilities at this time. From Friday/D5 onward, the initial trough will lose amplitude quickly as it moves northeastward, becoming well removed from the instability plume. This will likely give way to a more generalized west/southwest flow regime over the Plains and MS Valley, as a possible large-scale trough amplification occurs over the West. The result may be scattered to numerous thunderstorms for several days from TX into the Southeast, with the overall regime characterized as that of warm advection and heavy rain. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CST Mon Nov 27 2023 Valid 301200Z - 051200Z ...DISCUSSION... On Thursday/D4, models are in good agreement depicting a shortwave trough strengthening as it moves into the southern Plains, with strong height falls over TX and a 70 kt midlevel jet. This wave is expected to pivot northeastward rapidly after 00Z, with height rises from the Rio Grande Valley to the ArkLaTex into Friday/D5 morning. Low pressure will likely develop over northern or central TX during the day, and will move with the parent trough toward the Ozarks overnight. Low-level southerly winds will aid moisture advection, with a warm front possibly into northeast TX and southern AR by evening. Predictability issues do exist due to numerous showers and thunderstorms likely to be ongoing throughout the period, focused east of I-35, which will reduce instability. However, large-scale ascent will be favorable and so will deep-layer shear, and it is not inconceivable that areas of severe storms could develop. The threat is conditional on access to the better instability plume over southern TX. Given these considerations, predictability is too low to introduce severe probabilities at this time. From Friday/D5 onward, the initial trough will lose amplitude quickly as it moves northeastward, becoming well removed from the instability plume. This will likely give way to a more generalized west/southwest flow regime over the Plains and MS Valley, as a possible large-scale trough amplification occurs over the West. The result may be scattered to numerous thunderstorms for several days from TX into the Southeast, with the overall regime characterized as that of warm advection and heavy rain. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CST Mon Nov 27 2023 Valid 301200Z - 051200Z ...DISCUSSION... On Thursday/D4, models are in good agreement depicting a shortwave trough strengthening as it moves into the southern Plains, with strong height falls over TX and a 70 kt midlevel jet. This wave is expected to pivot northeastward rapidly after 00Z, with height rises from the Rio Grande Valley to the ArkLaTex into Friday/D5 morning. Low pressure will likely develop over northern or central TX during the day, and will move with the parent trough toward the Ozarks overnight. Low-level southerly winds will aid moisture advection, with a warm front possibly into northeast TX and southern AR by evening. Predictability issues do exist due to numerous showers and thunderstorms likely to be ongoing throughout the period, focused east of I-35, which will reduce instability. However, large-scale ascent will be favorable and so will deep-layer shear, and it is not inconceivable that areas of severe storms could develop. The threat is conditional on access to the better instability plume over southern TX. Given these considerations, predictability is too low to introduce severe probabilities at this time. From Friday/D5 onward, the initial trough will lose amplitude quickly as it moves northeastward, becoming well removed from the instability plume. This will likely give way to a more generalized west/southwest flow regime over the Plains and MS Valley, as a possible large-scale trough amplification occurs over the West. The result may be scattered to numerous thunderstorms for several days from TX into the Southeast, with the overall regime characterized as that of warm advection and heavy rain. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0118 AM CST Mon Nov 27 2023 Valid 291200Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered thunderstorms will develop late Wednesday into early Thursday over much of southern and eastern Texas. Severe weather appears unlikely. ...Synopsis... On Wednesday, a shortwave trough will move east across the Great Basin, with gradual height falls by Thursday morning into the southern Plains. As the large-scale eastern trough exits the CONUS, southerly low-level return flow will develop across the western Gulf of Mexico, with mid 60s F dewpoints to the TX Coast late. Aiding moisture advection will be a developing low-level jet Wednesday night over the western Gulf of Mexico as height falls continue. The antecedent cool air mass will likely fill with low-clouds quickly with numerous showers developing. Elevated instability will favor scattered convection well north of a warm front which will remain near the TX Coastal Plain. Forecast soundings indicate poor lapse rates overall, which should both preclude severe hail, and minimize effective SRH over land. Elsewhere, isolated weak thunderstorms will be possible late in the day over the Four Corners region beneath the upper trough. ..Jewell.. 11/27/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0118 AM CST Mon Nov 27 2023 Valid 291200Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered thunderstorms will develop late Wednesday into early Thursday over much of southern and eastern Texas. Severe weather appears unlikely. ...Synopsis... On Wednesday, a shortwave trough will move east across the Great Basin, with gradual height falls by Thursday morning into the southern Plains. As the large-scale eastern trough exits the CONUS, southerly low-level return flow will develop across the western Gulf of Mexico, with mid 60s F dewpoints to the TX Coast late. Aiding moisture advection will be a developing low-level jet Wednesday night over the western Gulf of Mexico as height falls continue. The antecedent cool air mass will likely fill with low-clouds quickly with numerous showers developing. Elevated instability will favor scattered convection well north of a warm front which will remain near the TX Coastal Plain. Forecast soundings indicate poor lapse rates overall, which should both preclude severe hail, and minimize effective SRH over land. Elsewhere, isolated weak thunderstorms will be possible late in the day over the Four Corners region beneath the upper trough. ..Jewell.. 11/27/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0118 AM CST Mon Nov 27 2023 Valid 291200Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered thunderstorms will develop late Wednesday into early Thursday over much of southern and eastern Texas. Severe weather appears unlikely. ...Synopsis... On Wednesday, a shortwave trough will move east across the Great Basin, with gradual height falls by Thursday morning into the southern Plains. As the large-scale eastern trough exits the CONUS, southerly low-level return flow will develop across the western Gulf of Mexico, with mid 60s F dewpoints to the TX Coast late. Aiding moisture advection will be a developing low-level jet Wednesday night over the western Gulf of Mexico as height falls continue. The antecedent cool air mass will likely fill with low-clouds quickly with numerous showers developing. Elevated instability will favor scattered convection well north of a warm front which will remain near the TX Coastal Plain. Forecast soundings indicate poor lapse rates overall, which should both preclude severe hail, and minimize effective SRH over land. Elsewhere, isolated weak thunderstorms will be possible late in the day over the Four Corners region beneath the upper trough. ..Jewell.. 11/27/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0118 AM CST Mon Nov 27 2023 Valid 291200Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered thunderstorms will develop late Wednesday into early Thursday over much of southern and eastern Texas. Severe weather appears unlikely. ...Synopsis... On Wednesday, a shortwave trough will move east across the Great Basin, with gradual height falls by Thursday morning into the southern Plains. As the large-scale eastern trough exits the CONUS, southerly low-level return flow will develop across the western Gulf of Mexico, with mid 60s F dewpoints to the TX Coast late. Aiding moisture advection will be a developing low-level jet Wednesday night over the western Gulf of Mexico as height falls continue. The antecedent cool air mass will likely fill with low-clouds quickly with numerous showers developing. Elevated instability will favor scattered convection well north of a warm front which will remain near the TX Coastal Plain. Forecast soundings indicate poor lapse rates overall, which should both preclude severe hail, and minimize effective SRH over land. Elsewhere, isolated weak thunderstorms will be possible late in the day over the Four Corners region beneath the upper trough. ..Jewell.. 11/27/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0104 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... ...Synopsis... A mid/upper-level ridge over the western CONUS will deamplify as it continues eastward across the Rockies. Upstream, a pronounced midlevel trough will approach the California coast. This evolution will lead to a weakening of the offshore pressure gradient over southern California, with weaker surface winds compared to previous days. Elsewhere across the CONUS, cool and/or moist surface conditions will limit the fire-weather risk. ..Weinman.. 11/27/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0104 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... ...Synopsis... A mid/upper-level ridge over the western CONUS will deamplify as it continues eastward across the Rockies. Upstream, a pronounced midlevel trough will approach the California coast. This evolution will lead to a weakening of the offshore pressure gradient over southern California, with weaker surface winds compared to previous days. Elsewhere across the CONUS, cool and/or moist surface conditions will limit the fire-weather risk. ..Weinman.. 11/27/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0104 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... ...Synopsis... A mid/upper-level ridge over the western CONUS will deamplify as it continues eastward across the Rockies. Upstream, a pronounced midlevel trough will approach the California coast. This evolution will lead to a weakening of the offshore pressure gradient over southern California, with weaker surface winds compared to previous days. Elsewhere across the CONUS, cool and/or moist surface conditions will limit the fire-weather risk. ..Weinman.. 11/27/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0104 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... ...Synopsis... A mid/upper-level ridge over the western CONUS will deamplify as it continues eastward across the Rockies. Upstream, a pronounced midlevel trough will approach the California coast. This evolution will lead to a weakening of the offshore pressure gradient over southern California, with weaker surface winds compared to previous days. Elsewhere across the CONUS, cool and/or moist surface conditions will limit the fire-weather risk. ..Weinman.. 11/27/2023 ...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 0103 AM CST Mon Nov 27 2023 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... An amplified mid/upper-level ridge will move slowly eastward across the western CONUS, maintaining surface high pressure over the Intermountain West. This pattern will continue to support an enhanced offshore pressure gradient over southern California. Over portions of Ventura and Los Angeles Counties, a belt of breezy/gusty east-northeasterly surface winds will overlap 15-25 percent minimum RH. While locally elevated fire-weather conditions are possible here, recent rainfall and a marginal overlap of the strongest winds and low RH should limit the overall threat. Elsewhere across the CONUS, fire-weather concerns are minimal owing to cool and/or moist surface conditions. ..Weinman.. 11/27/2023 ...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 0103 AM CST Mon Nov 27 2023 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... An amplified mid/upper-level ridge will move slowly eastward across the western CONUS, maintaining surface high pressure over the Intermountain West. This pattern will continue to support an enhanced offshore pressure gradient over southern California. Over portions of Ventura and Los Angeles Counties, a belt of breezy/gusty east-northeasterly surface winds will overlap 15-25 percent minimum RH. While locally elevated fire-weather conditions are possible here, recent rainfall and a marginal overlap of the strongest winds and low RH should limit the overall threat. Elsewhere across the CONUS, fire-weather concerns are minimal owing to cool and/or moist surface conditions. ..Weinman.. 11/27/2023 ...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 0103 AM CST Mon Nov 27 2023 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... An amplified mid/upper-level ridge will move slowly eastward across the western CONUS, maintaining surface high pressure over the Intermountain West. This pattern will continue to support an enhanced offshore pressure gradient over southern California. Over portions of Ventura and Los Angeles Counties, a belt of breezy/gusty east-northeasterly surface winds will overlap 15-25 percent minimum RH. While locally elevated fire-weather conditions are possible here, recent rainfall and a marginal overlap of the strongest winds and low RH should limit the overall threat. Elsewhere across the CONUS, fire-weather concerns are minimal owing to cool and/or moist surface conditions. ..Weinman.. 11/27/2023 ...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 0103 AM CST Mon Nov 27 2023 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... An amplified mid/upper-level ridge will move slowly eastward across the western CONUS, maintaining surface high pressure over the Intermountain West. This pattern will continue to support an enhanced offshore pressure gradient over southern California. Over portions of Ventura and Los Angeles Counties, a belt of breezy/gusty east-northeasterly surface winds will overlap 15-25 percent minimum RH. While locally elevated fire-weather conditions are possible here, recent rainfall and a marginal overlap of the strongest winds and low RH should limit the overall threat. Elsewhere across the CONUS, fire-weather concerns are minimal owing to cool and/or moist surface conditions. ..Weinman.. 11/27/2023 ...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 1225 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated weak thunderstorms may approach coastal northern California into Wednesday morning. Severe storms are unlikely. ...Synopsis and Discussion... On Tuesday, a large but progressive upper trough will move from the Great Lakes across the Northeast, with rapid height rises on the back side of the trough. Cool air aloft will exist over the lower Great Lakes early in the day, and a rogue lightning flash cannot be ruled out. However, veering low-level winds and decreasing surface convergence suggest less than 10% coverage. To the west, a shortwave trough will affect the West Coast overnight, with cool air aloft into northern CA by 12Z Wednesday. Convergence along an associated cold front and large-scale ascent may result in 100-200 J/kg MUCAPE beneath the upper trough, with lighting possibly over land prior to 12Z Wednesday. Severe weather is unlikely given weak and elevated instability. ..Jewell.. 11/27/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated weak thunderstorms may approach coastal northern California into Wednesday morning. Severe storms are unlikely. ...Synopsis and Discussion... On Tuesday, a large but progressive upper trough will move from the Great Lakes across the Northeast, with rapid height rises on the back side of the trough. Cool air aloft will exist over the lower Great Lakes early in the day, and a rogue lightning flash cannot be ruled out. However, veering low-level winds and decreasing surface convergence suggest less than 10% coverage. To the west, a shortwave trough will affect the West Coast overnight, with cool air aloft into northern CA by 12Z Wednesday. Convergence along an associated cold front and large-scale ascent may result in 100-200 J/kg MUCAPE beneath the upper trough, with lighting possibly over land prior to 12Z Wednesday. Severe weather is unlikely given weak and elevated instability. ..Jewell.. 11/27/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated weak thunderstorms may approach coastal northern California into Wednesday morning. Severe storms are unlikely. ...Synopsis and Discussion... On Tuesday, a large but progressive upper trough will move from the Great Lakes across the Northeast, with rapid height rises on the back side of the trough. Cool air aloft will exist over the lower Great Lakes early in the day, and a rogue lightning flash cannot be ruled out. However, veering low-level winds and decreasing surface convergence suggest less than 10% coverage. To the west, a shortwave trough will affect the West Coast overnight, with cool air aloft into northern CA by 12Z Wednesday. Convergence along an associated cold front and large-scale ascent may result in 100-200 J/kg MUCAPE beneath the upper trough, with lighting possibly over land prior to 12Z Wednesday. Severe weather is unlikely given weak and elevated instability. ..Jewell.. 11/27/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CST Mon Nov 27 2023 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated weak thunderstorms may approach coastal northern California into Wednesday morning. Severe storms are unlikely. ...Synopsis and Discussion... On Tuesday, a large but progressive upper trough will move from the Great Lakes across the Northeast, with rapid height rises on the back side of the trough. Cool air aloft will exist over the lower Great Lakes early in the day, and a rogue lightning flash cannot be ruled out. However, veering low-level winds and decreasing surface convergence suggest less than 10% coverage. To the west, a shortwave trough will affect the West Coast overnight, with cool air aloft into northern CA by 12Z Wednesday. Convergence along an associated cold front and large-scale ascent may result in 100-200 J/kg MUCAPE beneath the upper trough, with lighting possibly over land prior to 12Z Wednesday. Severe weather is unlikely given weak and elevated instability. ..Jewell.. 11/27/2023 Read more