Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1012 AM CST Fri Nov 17 2023 Valid 171700Z - 181200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 11/17/2023 .PREV DISCUSSION... /ISSUED 0145 AM CST Fri Nov 17 2023/ ...Synopsis... Fire-weather concerns are expected to remain low Friday as a broad upper trough over the eastern US shifts eastward. A second, larger trough over the West Coast will move into the Four Corners bringing increasing rain chances for the western CONUS. At the surface, a cold front accompanying the eastern trough is also forecast to bring the potential for rain to the Ohio Valley and parts of the Northeast. With only modest surface winds, little overlap of dry and breezy surface conditions are expected over the CONUS. This should keep fire-weather concerns low through the period. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Nov 17 2023 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis/Discussion... In mid/upper levels, large-scale troughing will prevail over eastern North America through the period. Associated cyclonic flow will be traversed by several shortwaves, including one evident in moisture- channel imagery from Lake Superior to eastern Kansas. The northern part of this perturbation will move southeastward to the lower Great Lakes, lower Ohio Valley and Ozarks by 00Z, then split, with the northern part being absorbed into a trailing perturbation now over the eastern Dakotas. The southern part should extend from western NC to central MS by 12Z. An associated surface cold front -- analyzed at 11Z from Lake Huron and southern Lower MI across central parts of IL/MO to southwestern OK and northwest TX -- will move southeastward by 00Z to northern NY, western PA, eastern parts of KY/TN, southern MS, central/southern LA, and southeast TX. Low-level moisture is very limited in the prefrontal return flow, which consists of mostly recycled continental/polar air behind a prior front. Still, low- density MUCAPE of 100-300 J/kg -- sometimes extending into icing layers suitable for lightning -- may support sporadic thunder within a near-frontal precip belt over parts of the Ohio Valley to southern Appalachians. Elsewhere, a southern-stream shortwave trough and associated low/ middle-level cyclone were evident over the coastal east-central FL vicinity. These will support isolated thunder potential today over parts of FL, then tonight in the NC Outer Banks area as the low-level circulation moves/redevelops northeastward to the east of the Carolinas. In the West, an initially cut-off cyclone centered near 35N132W will devolve to a progressive, open-wave trough by this evening, as heights fall to its northwest from a strongly progressive shortwave over the northeastern Pacific. The lead trough will move ashore over CA near the end of the period. Cooling/destabilization aloft will support episodic belts of convection -- including some thunderstorms, across parts of north-central to coastal southern CA today and tonight. Small hail and strong gusts may occur, but organized severe is not expected. Diurnal heating may yield MLCAPE up to about 500 J/kg, but with the trough still well offshore this afternoon, deep shear and low-level hodographs still should be limited. Colder air aloft, in the zone of strongest DCVA preceding the trough, will support showers and isolated thunderstorms this evening into tonight. Strengthening lift with low-level warm advection and collocated southwesterly moisture transport should support increasing precip late tonight over parts of AZ, including isolated to widely scattered thunderstorms. In the low-level source area, surface dewpoints already are in the 60s F from portions of south-central AZ across western Sonora, central parts of Baja and intervening waters. ..Edwards.. 11/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Nov 17 2023 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis/Discussion... In mid/upper levels, large-scale troughing will prevail over eastern North America through the period. Associated cyclonic flow will be traversed by several shortwaves, including one evident in moisture- channel imagery from Lake Superior to eastern Kansas. The northern part of this perturbation will move southeastward to the lower Great Lakes, lower Ohio Valley and Ozarks by 00Z, then split, with the northern part being absorbed into a trailing perturbation now over the eastern Dakotas. The southern part should extend from western NC to central MS by 12Z. An associated surface cold front -- analyzed at 11Z from Lake Huron and southern Lower MI across central parts of IL/MO to southwestern OK and northwest TX -- will move southeastward by 00Z to northern NY, western PA, eastern parts of KY/TN, southern MS, central/southern LA, and southeast TX. Low-level moisture is very limited in the prefrontal return flow, which consists of mostly recycled continental/polar air behind a prior front. Still, low- density MUCAPE of 100-300 J/kg -- sometimes extending into icing layers suitable for lightning -- may support sporadic thunder within a near-frontal precip belt over parts of the Ohio Valley to southern Appalachians. Elsewhere, a southern-stream shortwave trough and associated low/ middle-level cyclone were evident over the coastal east-central FL vicinity. These will support isolated thunder potential today over parts of FL, then tonight in the NC Outer Banks area as the low-level circulation moves/redevelops northeastward to the east of the Carolinas. In the West, an initially cut-off cyclone centered near 35N132W will devolve to a progressive, open-wave trough by this evening, as heights fall to its northwest from a strongly progressive shortwave over the northeastern Pacific. The lead trough will move ashore over CA near the end of the period. Cooling/destabilization aloft will support episodic belts of convection -- including some thunderstorms, across parts of north-central to coastal southern CA today and tonight. Small hail and strong gusts may occur, but organized severe is not expected. Diurnal heating may yield MLCAPE up to about 500 J/kg, but with the trough still well offshore this afternoon, deep shear and low-level hodographs still should be limited. Colder air aloft, in the zone of strongest DCVA preceding the trough, will support showers and isolated thunderstorms this evening into tonight. Strengthening lift with low-level warm advection and collocated southwesterly moisture transport should support increasing precip late tonight over parts of AZ, including isolated to widely scattered thunderstorms. In the low-level source area, surface dewpoints already are in the 60s F from portions of south-central AZ across western Sonora, central parts of Baja and intervening waters. ..Edwards.. 11/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Nov 17 2023 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis/Discussion... In mid/upper levels, large-scale troughing will prevail over eastern North America through the period. Associated cyclonic flow will be traversed by several shortwaves, including one evident in moisture- channel imagery from Lake Superior to eastern Kansas. The northern part of this perturbation will move southeastward to the lower Great Lakes, lower Ohio Valley and Ozarks by 00Z, then split, with the northern part being absorbed into a trailing perturbation now over the eastern Dakotas. The southern part should extend from western NC to central MS by 12Z. An associated surface cold front -- analyzed at 11Z from Lake Huron and southern Lower MI across central parts of IL/MO to southwestern OK and northwest TX -- will move southeastward by 00Z to northern NY, western PA, eastern parts of KY/TN, southern MS, central/southern LA, and southeast TX. Low-level moisture is very limited in the prefrontal return flow, which consists of mostly recycled continental/polar air behind a prior front. Still, low- density MUCAPE of 100-300 J/kg -- sometimes extending into icing layers suitable for lightning -- may support sporadic thunder within a near-frontal precip belt over parts of the Ohio Valley to southern Appalachians. Elsewhere, a southern-stream shortwave trough and associated low/ middle-level cyclone were evident over the coastal east-central FL vicinity. These will support isolated thunder potential today over parts of FL, then tonight in the NC Outer Banks area as the low-level circulation moves/redevelops northeastward to the east of the Carolinas. In the West, an initially cut-off cyclone centered near 35N132W will devolve to a progressive, open-wave trough by this evening, as heights fall to its northwest from a strongly progressive shortwave over the northeastern Pacific. The lead trough will move ashore over CA near the end of the period. Cooling/destabilization aloft will support episodic belts of convection -- including some thunderstorms, across parts of north-central to coastal southern CA today and tonight. Small hail and strong gusts may occur, but organized severe is not expected. Diurnal heating may yield MLCAPE up to about 500 J/kg, but with the trough still well offshore this afternoon, deep shear and low-level hodographs still should be limited. Colder air aloft, in the zone of strongest DCVA preceding the trough, will support showers and isolated thunderstorms this evening into tonight. Strengthening lift with low-level warm advection and collocated southwesterly moisture transport should support increasing precip late tonight over parts of AZ, including isolated to widely scattered thunderstorms. In the low-level source area, surface dewpoints already are in the 60s F from portions of south-central AZ across western Sonora, central parts of Baja and intervening waters. ..Edwards.. 11/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Nov 17 2023 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis/Discussion... In mid/upper levels, large-scale troughing will prevail over eastern North America through the period. Associated cyclonic flow will be traversed by several shortwaves, including one evident in moisture- channel imagery from Lake Superior to eastern Kansas. The northern part of this perturbation will move southeastward to the lower Great Lakes, lower Ohio Valley and Ozarks by 00Z, then split, with the northern part being absorbed into a trailing perturbation now over the eastern Dakotas. The southern part should extend from western NC to central MS by 12Z. An associated surface cold front -- analyzed at 11Z from Lake Huron and southern Lower MI across central parts of IL/MO to southwestern OK and northwest TX -- will move southeastward by 00Z to northern NY, western PA, eastern parts of KY/TN, southern MS, central/southern LA, and southeast TX. Low-level moisture is very limited in the prefrontal return flow, which consists of mostly recycled continental/polar air behind a prior front. Still, low- density MUCAPE of 100-300 J/kg -- sometimes extending into icing layers suitable for lightning -- may support sporadic thunder within a near-frontal precip belt over parts of the Ohio Valley to southern Appalachians. Elsewhere, a southern-stream shortwave trough and associated low/ middle-level cyclone were evident over the coastal east-central FL vicinity. These will support isolated thunder potential today over parts of FL, then tonight in the NC Outer Banks area as the low-level circulation moves/redevelops northeastward to the east of the Carolinas. In the West, an initially cut-off cyclone centered near 35N132W will devolve to a progressive, open-wave trough by this evening, as heights fall to its northwest from a strongly progressive shortwave over the northeastern Pacific. The lead trough will move ashore over CA near the end of the period. Cooling/destabilization aloft will support episodic belts of convection -- including some thunderstorms, across parts of north-central to coastal southern CA today and tonight. Small hail and strong gusts may occur, but organized severe is not expected. Diurnal heating may yield MLCAPE up to about 500 J/kg, but with the trough still well offshore this afternoon, deep shear and low-level hodographs still should be limited. Colder air aloft, in the zone of strongest DCVA preceding the trough, will support showers and isolated thunderstorms this evening into tonight. Strengthening lift with low-level warm advection and collocated southwesterly moisture transport should support increasing precip late tonight over parts of AZ, including isolated to widely scattered thunderstorms. In the low-level source area, surface dewpoints already are in the 60s F from portions of south-central AZ across western Sonora, central parts of Baja and intervening waters. ..Edwards.. 11/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Nov 17 2023 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis/Discussion... In mid/upper levels, large-scale troughing will prevail over eastern North America through the period. Associated cyclonic flow will be traversed by several shortwaves, including one evident in moisture- channel imagery from Lake Superior to eastern Kansas. The northern part of this perturbation will move southeastward to the lower Great Lakes, lower Ohio Valley and Ozarks by 00Z, then split, with the northern part being absorbed into a trailing perturbation now over the eastern Dakotas. The southern part should extend from western NC to central MS by 12Z. An associated surface cold front -- analyzed at 11Z from Lake Huron and southern Lower MI across central parts of IL/MO to southwestern OK and northwest TX -- will move southeastward by 00Z to northern NY, western PA, eastern parts of KY/TN, southern MS, central/southern LA, and southeast TX. Low-level moisture is very limited in the prefrontal return flow, which consists of mostly recycled continental/polar air behind a prior front. Still, low- density MUCAPE of 100-300 J/kg -- sometimes extending into icing layers suitable for lightning -- may support sporadic thunder within a near-frontal precip belt over parts of the Ohio Valley to southern Appalachians. Elsewhere, a southern-stream shortwave trough and associated low/ middle-level cyclone were evident over the coastal east-central FL vicinity. These will support isolated thunder potential today over parts of FL, then tonight in the NC Outer Banks area as the low-level circulation moves/redevelops northeastward to the east of the Carolinas. In the West, an initially cut-off cyclone centered near 35N132W will devolve to a progressive, open-wave trough by this evening, as heights fall to its northwest from a strongly progressive shortwave over the northeastern Pacific. The lead trough will move ashore over CA near the end of the period. Cooling/destabilization aloft will support episodic belts of convection -- including some thunderstorms, across parts of north-central to coastal southern CA today and tonight. Small hail and strong gusts may occur, but organized severe is not expected. Diurnal heating may yield MLCAPE up to about 500 J/kg, but with the trough still well offshore this afternoon, deep shear and low-level hodographs still should be limited. Colder air aloft, in the zone of strongest DCVA preceding the trough, will support showers and isolated thunderstorms this evening into tonight. Strengthening lift with low-level warm advection and collocated southwesterly moisture transport should support increasing precip late tonight over parts of AZ, including isolated to widely scattered thunderstorms. In the low-level source area, surface dewpoints already are in the 60s F from portions of south-central AZ across western Sonora, central parts of Baja and intervening waters. ..Edwards.. 11/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Nov 17 2023 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis/Discussion... In mid/upper levels, large-scale troughing will prevail over eastern North America through the period. Associated cyclonic flow will be traversed by several shortwaves, including one evident in moisture- channel imagery from Lake Superior to eastern Kansas. The northern part of this perturbation will move southeastward to the lower Great Lakes, lower Ohio Valley and Ozarks by 00Z, then split, with the northern part being absorbed into a trailing perturbation now over the eastern Dakotas. The southern part should extend from western NC to central MS by 12Z. An associated surface cold front -- analyzed at 11Z from Lake Huron and southern Lower MI across central parts of IL/MO to southwestern OK and northwest TX -- will move southeastward by 00Z to northern NY, western PA, eastern parts of KY/TN, southern MS, central/southern LA, and southeast TX. Low-level moisture is very limited in the prefrontal return flow, which consists of mostly recycled continental/polar air behind a prior front. Still, low- density MUCAPE of 100-300 J/kg -- sometimes extending into icing layers suitable for lightning -- may support sporadic thunder within a near-frontal precip belt over parts of the Ohio Valley to southern Appalachians. Elsewhere, a southern-stream shortwave trough and associated low/ middle-level cyclone were evident over the coastal east-central FL vicinity. These will support isolated thunder potential today over parts of FL, then tonight in the NC Outer Banks area as the low-level circulation moves/redevelops northeastward to the east of the Carolinas. In the West, an initially cut-off cyclone centered near 35N132W will devolve to a progressive, open-wave trough by this evening, as heights fall to its northwest from a strongly progressive shortwave over the northeastern Pacific. The lead trough will move ashore over CA near the end of the period. Cooling/destabilization aloft will support episodic belts of convection -- including some thunderstorms, across parts of north-central to coastal southern CA today and tonight. Small hail and strong gusts may occur, but organized severe is not expected. Diurnal heating may yield MLCAPE up to about 500 J/kg, but with the trough still well offshore this afternoon, deep shear and low-level hodographs still should be limited. Colder air aloft, in the zone of strongest DCVA preceding the trough, will support showers and isolated thunderstorms this evening into tonight. Strengthening lift with low-level warm advection and collocated southwesterly moisture transport should support increasing precip late tonight over parts of AZ, including isolated to widely scattered thunderstorms. In the low-level source area, surface dewpoints already are in the 60s F from portions of south-central AZ across western Sonora, central parts of Baja and intervening waters. ..Edwards.. 11/17/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Fri Nov 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... ...D4/Monday - ArkLaTex into parts of the Southeast... Extended-range guidance is in general agreement regarding the synoptic-scale pattern across the CONUS on D4/Monday. A vigorous mid/upper-level shortwave trough is forecast to pivot eastward across the southern Plains/ArkLaTex region, to the south of a weakening midlevel cyclone over the central Plains. However, considerable uncertainty (with regard to both run-to-run deterministic changes and ensemble spread) remains regarding the details, which will impact the magnitude and placement of the primary severe-thunderstorm threat on D4/Monday. Generally speaking, mid 60s F dewpoints are expected to advance northward across parts of east TX into the lower MS Valley, east of a surface cyclone and trailing cold front that will approach the ArkLaTex/ArkLaMiss regions by early evening. Initial thunderstorm development is expected by late afternoon across parts of east TX, with an increase in storm coverage Monday night as the shortwave pivots through the base of the positively tilted trough. Strong deep-layer shear will support organized convection and at least some severe-thunderstorm threat where sufficient destabilization can occur. The threat is likely to be maximized near and just south of the surface-low track, which remains somewhat uncertain at this time. ...D5/Tuesday - Parts of the Southeast... Depending on the timing and intensity of the primary mid/upper-level shortwave trough and surface cyclone, some severe threat may linger into Tuesday across parts of the Southeast, within an environment characterized by relatively rich low-level moisture, strong deep-layer flow/shear, and weak instability. A separate area of threat could materialize across parts of the Carolinas Tuesday night, in association with a secondary low-level moisture surge, but uncertainty regarding instability remains too high to include any 15% areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Fri Nov 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... ...D4/Monday - ArkLaTex into parts of the Southeast... Extended-range guidance is in general agreement regarding the synoptic-scale pattern across the CONUS on D4/Monday. A vigorous mid/upper-level shortwave trough is forecast to pivot eastward across the southern Plains/ArkLaTex region, to the south of a weakening midlevel cyclone over the central Plains. However, considerable uncertainty (with regard to both run-to-run deterministic changes and ensemble spread) remains regarding the details, which will impact the magnitude and placement of the primary severe-thunderstorm threat on D4/Monday. Generally speaking, mid 60s F dewpoints are expected to advance northward across parts of east TX into the lower MS Valley, east of a surface cyclone and trailing cold front that will approach the ArkLaTex/ArkLaMiss regions by early evening. Initial thunderstorm development is expected by late afternoon across parts of east TX, with an increase in storm coverage Monday night as the shortwave pivots through the base of the positively tilted trough. Strong deep-layer shear will support organized convection and at least some severe-thunderstorm threat where sufficient destabilization can occur. The threat is likely to be maximized near and just south of the surface-low track, which remains somewhat uncertain at this time. ...D5/Tuesday - Parts of the Southeast... Depending on the timing and intensity of the primary mid/upper-level shortwave trough and surface cyclone, some severe threat may linger into Tuesday across parts of the Southeast, within an environment characterized by relatively rich low-level moisture, strong deep-layer flow/shear, and weak instability. A separate area of threat could materialize across parts of the Carolinas Tuesday night, in association with a secondary low-level moisture surge, but uncertainty regarding instability remains too high to include any 15% areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Fri Nov 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... ...D4/Monday - ArkLaTex into parts of the Southeast... Extended-range guidance is in general agreement regarding the synoptic-scale pattern across the CONUS on D4/Monday. A vigorous mid/upper-level shortwave trough is forecast to pivot eastward across the southern Plains/ArkLaTex region, to the south of a weakening midlevel cyclone over the central Plains. However, considerable uncertainty (with regard to both run-to-run deterministic changes and ensemble spread) remains regarding the details, which will impact the magnitude and placement of the primary severe-thunderstorm threat on D4/Monday. Generally speaking, mid 60s F dewpoints are expected to advance northward across parts of east TX into the lower MS Valley, east of a surface cyclone and trailing cold front that will approach the ArkLaTex/ArkLaMiss regions by early evening. Initial thunderstorm development is expected by late afternoon across parts of east TX, with an increase in storm coverage Monday night as the shortwave pivots through the base of the positively tilted trough. Strong deep-layer shear will support organized convection and at least some severe-thunderstorm threat where sufficient destabilization can occur. The threat is likely to be maximized near and just south of the surface-low track, which remains somewhat uncertain at this time. ...D5/Tuesday - Parts of the Southeast... Depending on the timing and intensity of the primary mid/upper-level shortwave trough and surface cyclone, some severe threat may linger into Tuesday across parts of the Southeast, within an environment characterized by relatively rich low-level moisture, strong deep-layer flow/shear, and weak instability. A separate area of threat could materialize across parts of the Carolinas Tuesday night, in association with a secondary low-level moisture surge, but uncertainty regarding instability remains too high to include any 15% areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Fri Nov 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... ...D4/Monday - ArkLaTex into parts of the Southeast... Extended-range guidance is in general agreement regarding the synoptic-scale pattern across the CONUS on D4/Monday. A vigorous mid/upper-level shortwave trough is forecast to pivot eastward across the southern Plains/ArkLaTex region, to the south of a weakening midlevel cyclone over the central Plains. However, considerable uncertainty (with regard to both run-to-run deterministic changes and ensemble spread) remains regarding the details, which will impact the magnitude and placement of the primary severe-thunderstorm threat on D4/Monday. Generally speaking, mid 60s F dewpoints are expected to advance northward across parts of east TX into the lower MS Valley, east of a surface cyclone and trailing cold front that will approach the ArkLaTex/ArkLaMiss regions by early evening. Initial thunderstorm development is expected by late afternoon across parts of east TX, with an increase in storm coverage Monday night as the shortwave pivots through the base of the positively tilted trough. Strong deep-layer shear will support organized convection and at least some severe-thunderstorm threat where sufficient destabilization can occur. The threat is likely to be maximized near and just south of the surface-low track, which remains somewhat uncertain at this time. ...D5/Tuesday - Parts of the Southeast... Depending on the timing and intensity of the primary mid/upper-level shortwave trough and surface cyclone, some severe threat may linger into Tuesday across parts of the Southeast, within an environment characterized by relatively rich low-level moisture, strong deep-layer flow/shear, and weak instability. A separate area of threat could materialize across parts of the Carolinas Tuesday night, in association with a secondary low-level moisture surge, but uncertainty regarding instability remains too high to include any 15% areas at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Fri Nov 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... ...D4/Monday - ArkLaTex into parts of the Southeast... Extended-range guidance is in general agreement regarding the synoptic-scale pattern across the CONUS on D4/Monday. A vigorous mid/upper-level shortwave trough is forecast to pivot eastward across the southern Plains/ArkLaTex region, to the south of a weakening midlevel cyclone over the central Plains. However, considerable uncertainty (with regard to both run-to-run deterministic changes and ensemble spread) remains regarding the details, which will impact the magnitude and placement of the primary severe-thunderstorm threat on D4/Monday. Generally speaking, mid 60s F dewpoints are expected to advance northward across parts of east TX into the lower MS Valley, east of a surface cyclone and trailing cold front that will approach the ArkLaTex/ArkLaMiss regions by early evening. Initial thunderstorm development is expected by late afternoon across parts of east TX, with an increase in storm coverage Monday night as the shortwave pivots through the base of the positively tilted trough. Strong deep-layer shear will support organized convection and at least some severe-thunderstorm threat where sufficient destabilization can occur. The threat is likely to be maximized near and just south of the surface-low track, which remains somewhat uncertain at this time. ...D5/Tuesday - Parts of the Southeast... Depending on the timing and intensity of the primary mid/upper-level shortwave trough and surface cyclone, some severe threat may linger into Tuesday across parts of the Southeast, within an environment characterized by relatively rich low-level moisture, strong deep-layer flow/shear, and weak instability. A separate area of threat could materialize across parts of the Carolinas Tuesday night, in association with a secondary low-level moisture surge, but uncertainty regarding instability remains too high to include any 15% areas at this time. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 AM CST Fri Nov 17 2023 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OKLAHOMA INTO NORTH TEXAS... ...SUMMARY... Isolated strong to potentially severe thunderstorms are possible on Sunday across parts of Oklahoma into north Texas, mainly during the late afternoon and evening. ...Synopsis... A mid/upper-level shortwave trough that emerges over the central High Plains late on D2/Saturday is forecast to slow down and potentially evolve into a midlevel cyclone over the central Plains on Sunday. A vigorous upstream shortwave trough is forecast to dig southeastward from the Great Basin toward the Four Corners region and southern Rockies by early Monday morning. A surface cyclone initially over the central High Plains is forecast to shift slowly southeastward toward western OK, with a developing dryline expected to extend southward into parts of northwest and west-central TX. ...Southern Plains... While favorable wind profiles will overspread the warm sector across parts of TX/OK on Sunday, most guidance suggests that diurnal heating/destabilization will be quite limited east of the dryline, rendering severe-thunderstorm potential uncertain. East of the surface cyclone and developing dryline, modest low-level moisture return is expected, with mid/upper 50s F dewpoints extending into western/central OK, and low 60s F dewpoints potentially advancing into north TX. However, with initially cool conditions expected in the wake of an earlier frontal passage, diurnal heating may be hampered by early-day precipitation and persistent low cloudiness. MLCAPE could approach 500 J/kg immediately east of the dryline, where modest heating is possible, but residual capping may tend to limit the potential for surface-based storm development. A supercell or two (with an attendant large-hail threat) cannot be ruled out near the dryline in the presence of favorable deep-layer shear, but confidence in more than isolated coverage is low. Regardless of any diurnal surface-based storm development (or lack thereof), an increase in elevated convection will be possible Sunday evening within a low-level warm advection regime. Cold temperatures aloft, combined with favorable deep-layer shear, could support an isolated hail threat with the strongest elevated storms across parts of central/eastern OK and potentially north TX. ..Dean.. 11/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 AM CST Fri Nov 17 2023 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OKLAHOMA INTO NORTH TEXAS... ...SUMMARY... Isolated strong to potentially severe thunderstorms are possible on Sunday across parts of Oklahoma into north Texas, mainly during the late afternoon and evening. ...Synopsis... A mid/upper-level shortwave trough that emerges over the central High Plains late on D2/Saturday is forecast to slow down and potentially evolve into a midlevel cyclone over the central Plains on Sunday. A vigorous upstream shortwave trough is forecast to dig southeastward from the Great Basin toward the Four Corners region and southern Rockies by early Monday morning. A surface cyclone initially over the central High Plains is forecast to shift slowly southeastward toward western OK, with a developing dryline expected to extend southward into parts of northwest and west-central TX. ...Southern Plains... While favorable wind profiles will overspread the warm sector across parts of TX/OK on Sunday, most guidance suggests that diurnal heating/destabilization will be quite limited east of the dryline, rendering severe-thunderstorm potential uncertain. East of the surface cyclone and developing dryline, modest low-level moisture return is expected, with mid/upper 50s F dewpoints extending into western/central OK, and low 60s F dewpoints potentially advancing into north TX. However, with initially cool conditions expected in the wake of an earlier frontal passage, diurnal heating may be hampered by early-day precipitation and persistent low cloudiness. MLCAPE could approach 500 J/kg immediately east of the dryline, where modest heating is possible, but residual capping may tend to limit the potential for surface-based storm development. A supercell or two (with an attendant large-hail threat) cannot be ruled out near the dryline in the presence of favorable deep-layer shear, but confidence in more than isolated coverage is low. Regardless of any diurnal surface-based storm development (or lack thereof), an increase in elevated convection will be possible Sunday evening within a low-level warm advection regime. Cold temperatures aloft, combined with favorable deep-layer shear, could support an isolated hail threat with the strongest elevated storms across parts of central/eastern OK and potentially north TX. ..Dean.. 11/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 AM CST Fri Nov 17 2023 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OKLAHOMA INTO NORTH TEXAS... ...SUMMARY... Isolated strong to potentially severe thunderstorms are possible on Sunday across parts of Oklahoma into north Texas, mainly during the late afternoon and evening. ...Synopsis... A mid/upper-level shortwave trough that emerges over the central High Plains late on D2/Saturday is forecast to slow down and potentially evolve into a midlevel cyclone over the central Plains on Sunday. A vigorous upstream shortwave trough is forecast to dig southeastward from the Great Basin toward the Four Corners region and southern Rockies by early Monday morning. A surface cyclone initially over the central High Plains is forecast to shift slowly southeastward toward western OK, with a developing dryline expected to extend southward into parts of northwest and west-central TX. ...Southern Plains... While favorable wind profiles will overspread the warm sector across parts of TX/OK on Sunday, most guidance suggests that diurnal heating/destabilization will be quite limited east of the dryline, rendering severe-thunderstorm potential uncertain. East of the surface cyclone and developing dryline, modest low-level moisture return is expected, with mid/upper 50s F dewpoints extending into western/central OK, and low 60s F dewpoints potentially advancing into north TX. However, with initially cool conditions expected in the wake of an earlier frontal passage, diurnal heating may be hampered by early-day precipitation and persistent low cloudiness. MLCAPE could approach 500 J/kg immediately east of the dryline, where modest heating is possible, but residual capping may tend to limit the potential for surface-based storm development. A supercell or two (with an attendant large-hail threat) cannot be ruled out near the dryline in the presence of favorable deep-layer shear, but confidence in more than isolated coverage is low. Regardless of any diurnal surface-based storm development (or lack thereof), an increase in elevated convection will be possible Sunday evening within a low-level warm advection regime. Cold temperatures aloft, combined with favorable deep-layer shear, could support an isolated hail threat with the strongest elevated storms across parts of central/eastern OK and potentially north TX. ..Dean.. 11/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 AM CST Fri Nov 17 2023 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OKLAHOMA INTO NORTH TEXAS... ...SUMMARY... Isolated strong to potentially severe thunderstorms are possible on Sunday across parts of Oklahoma into north Texas, mainly during the late afternoon and evening. ...Synopsis... A mid/upper-level shortwave trough that emerges over the central High Plains late on D2/Saturday is forecast to slow down and potentially evolve into a midlevel cyclone over the central Plains on Sunday. A vigorous upstream shortwave trough is forecast to dig southeastward from the Great Basin toward the Four Corners region and southern Rockies by early Monday morning. A surface cyclone initially over the central High Plains is forecast to shift slowly southeastward toward western OK, with a developing dryline expected to extend southward into parts of northwest and west-central TX. ...Southern Plains... While favorable wind profiles will overspread the warm sector across parts of TX/OK on Sunday, most guidance suggests that diurnal heating/destabilization will be quite limited east of the dryline, rendering severe-thunderstorm potential uncertain. East of the surface cyclone and developing dryline, modest low-level moisture return is expected, with mid/upper 50s F dewpoints extending into western/central OK, and low 60s F dewpoints potentially advancing into north TX. However, with initially cool conditions expected in the wake of an earlier frontal passage, diurnal heating may be hampered by early-day precipitation and persistent low cloudiness. MLCAPE could approach 500 J/kg immediately east of the dryline, where modest heating is possible, but residual capping may tend to limit the potential for surface-based storm development. A supercell or two (with an attendant large-hail threat) cannot be ruled out near the dryline in the presence of favorable deep-layer shear, but confidence in more than isolated coverage is low. Regardless of any diurnal surface-based storm development (or lack thereof), an increase in elevated convection will be possible Sunday evening within a low-level warm advection regime. Cold temperatures aloft, combined with favorable deep-layer shear, could support an isolated hail threat with the strongest elevated storms across parts of central/eastern OK and potentially north TX. ..Dean.. 11/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 AM CST Fri Nov 17 2023 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OKLAHOMA INTO NORTH TEXAS... ...SUMMARY... Isolated strong to potentially severe thunderstorms are possible on Sunday across parts of Oklahoma into north Texas, mainly during the late afternoon and evening. ...Synopsis... A mid/upper-level shortwave trough that emerges over the central High Plains late on D2/Saturday is forecast to slow down and potentially evolve into a midlevel cyclone over the central Plains on Sunday. A vigorous upstream shortwave trough is forecast to dig southeastward from the Great Basin toward the Four Corners region and southern Rockies by early Monday morning. A surface cyclone initially over the central High Plains is forecast to shift slowly southeastward toward western OK, with a developing dryline expected to extend southward into parts of northwest and west-central TX. ...Southern Plains... While favorable wind profiles will overspread the warm sector across parts of TX/OK on Sunday, most guidance suggests that diurnal heating/destabilization will be quite limited east of the dryline, rendering severe-thunderstorm potential uncertain. East of the surface cyclone and developing dryline, modest low-level moisture return is expected, with mid/upper 50s F dewpoints extending into western/central OK, and low 60s F dewpoints potentially advancing into north TX. However, with initially cool conditions expected in the wake of an earlier frontal passage, diurnal heating may be hampered by early-day precipitation and persistent low cloudiness. MLCAPE could approach 500 J/kg immediately east of the dryline, where modest heating is possible, but residual capping may tend to limit the potential for surface-based storm development. A supercell or two (with an attendant large-hail threat) cannot be ruled out near the dryline in the presence of favorable deep-layer shear, but confidence in more than isolated coverage is low. Regardless of any diurnal surface-based storm development (or lack thereof), an increase in elevated convection will be possible Sunday evening within a low-level warm advection regime. Cold temperatures aloft, combined with favorable deep-layer shear, could support an isolated hail threat with the strongest elevated storms across parts of central/eastern OK and potentially north TX. ..Dean.. 11/17/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0147 AM CST Fri Nov 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... The broad upper trough over the eastern US is forecast to move offshore as moderate to strong cyclonic flow aloft overspreads the northeastern US. At the same time, broad toughing to the west will shift eastward into the Four Corners and southern Plains deepening a lee low east of the Rockies. To the east, high pressure over the MS and OH Valleys will force gusty northerly winds over parts of the Appalachians as a cold front moves into the Southeast. Localized dry and breezy conditions are possible over parts of VA and NC Saturday, but broader fire-weather concerns should remain limited. ...Central Appalachians... In the wake of the cold front, surface high pressure is forecast to develop over the lower OH Valley. The increase in the surface pressure gradient will help bolster northwesterly surface winds across parts of western VA and NC Saturday afternoon. While slightly cooler given the post-frontal air mass, downslope drying with RH values below 30% and occasional gusts to 15 mph may support a few hours of locally elevated fire-weather conditions given, unseasonably dry fuels and recent fire activity. ..Lyons.. 11/17/2023 ...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 0147 AM CST Fri Nov 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... The broad upper trough over the eastern US is forecast to move offshore as moderate to strong cyclonic flow aloft overspreads the northeastern US. At the same time, broad toughing to the west will shift eastward into the Four Corners and southern Plains deepening a lee low east of the Rockies. To the east, high pressure over the MS and OH Valleys will force gusty northerly winds over parts of the Appalachians as a cold front moves into the Southeast. Localized dry and breezy conditions are possible over parts of VA and NC Saturday, but broader fire-weather concerns should remain limited. ...Central Appalachians... In the wake of the cold front, surface high pressure is forecast to develop over the lower OH Valley. The increase in the surface pressure gradient will help bolster northwesterly surface winds across parts of western VA and NC Saturday afternoon. While slightly cooler given the post-frontal air mass, downslope drying with RH values below 30% and occasional gusts to 15 mph may support a few hours of locally elevated fire-weather conditions given, unseasonably dry fuels and recent fire activity. ..Lyons.. 11/17/2023 ...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 0147 AM CST Fri Nov 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... The broad upper trough over the eastern US is forecast to move offshore as moderate to strong cyclonic flow aloft overspreads the northeastern US. At the same time, broad toughing to the west will shift eastward into the Four Corners and southern Plains deepening a lee low east of the Rockies. To the east, high pressure over the MS and OH Valleys will force gusty northerly winds over parts of the Appalachians as a cold front moves into the Southeast. Localized dry and breezy conditions are possible over parts of VA and NC Saturday, but broader fire-weather concerns should remain limited. ...Central Appalachians... In the wake of the cold front, surface high pressure is forecast to develop over the lower OH Valley. The increase in the surface pressure gradient will help bolster northwesterly surface winds across parts of western VA and NC Saturday afternoon. While slightly cooler given the post-frontal air mass, downslope drying with RH values below 30% and occasional gusts to 15 mph may support a few hours of locally elevated fire-weather conditions given, unseasonably dry fuels and recent fire activity. ..Lyons.. 11/17/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more