Severe Storms

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0155 AM CST Sat Dec 09 2023 Valid 111200Z - 121200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm probabilities appear to be less than 10 percent on Monday. ...Discussion... Substantial cyclogenesis late D2 should persist into early D3 with the surface low tracking near the New England coast to the Canadian Maritimes. An extremely strong low-level jet ahead of the cyclone, increasing to around 100 kts at 850 mb, may advect sufficient western Atlantic moisture to yield minimal elevated buoyancy. Both 00Z NAM and ECMWF forecast soundings indicate MUCAPE may reach 100 J/kg across Cape Cod to Downeast ME on Monday morning, but this appears to be largely inadequate for charge separation given weak lapse rates above 500 mb. Still, very strong forcing for ascent might support a few lightning flashes within heavier convective elements embedded amid a broad swath of rain. Elsewhere across the CONUS, with the surface cold front expected to clear the south FL Peninsula just prior to 12Z Monday, thunderstorm potential will be negligible. ..Grams.. 12/09/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 AM CST Sat Dec 09 2023 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FL PANHANDLE TO THE DELMARVA... ...SUMMARY... Isolated severe thunderstorms will be possible through Sunday evening across parts of the Southeast States, mainly in the form of sporadic damaging winds and a few brief tornadoes. ...Synopsis... An amplified, positive-tilt upper trough from ON to east TX at 12Z Sunday will take on a neutral to slight negative tilt as a basal shortwave impulse rapidly ejects across the Deep South to the Lower Mid-Atlantic States. Intense mid-level southerlies will become asymmetrically confined ahead of the trough by early morning Monday. Surface cyclogenesis will occur from the central/southern Appalachians across the Northeast into southern New England, with greater deepening during the latter half of the period. ...FL Panhandle to the Delmarva... Overall scenario appears similar to prior days with a broad swath of low-probability tornado and severe thunderstorm wind evident from Sunday morning to evening across the Southeast States. A mesoscale corridor of greater tornado/wind threat may be highlighted in later outlooks, seemingly within the eastern SC to southeast VA vicinity. A swath of showers and embedded thunderstorms will likely be ongoing 12Z Sunday from western/central VA to the FL Panhandle, within the warm conveyor ahead of a surface cold front steadily progressing eastward. Morning severe potential should generally be confined to the FL/GA portion of the risk area, where mid 60s surface dew points should be more common ahead of the early-day convection. Diurnal diabatic heating is still expected to be muted, with extensive low-level moistening and resultant cloudiness anticipated. Consensus of guidance still suggests that a separate low-level warm theta-e advection regime from the western Atlantic will aid in a secondary swath of convective development by late morning into the afternoon across the eastern Carolinas. A corridor of somewhat greater surface heating may occur between both regimes which could yield a mesoscale area of MLCAPE from 500-1000 J/kg. Otherwise, amid weak mid-level lapse rates, much of the region should hold with MLCAPE at or below 500 J/kg. Low-level hodographs will be more favorably enlarged from the Carolinas northward. Should this become coincident with greater than meager buoyancy, a level 2-SLGT risk may be warranted for Sunday afternoon. More prominent strengthening of low-level southerlies will occur on Sunday night as cyclogenesis intensifies. However, the thermodynamic environment may be mostly to completely overturned by this time frame, given widespread convection. Guidance varies substantially in whether scant to meager surface-based buoyancy can still linger ahead of the cold front, mainly across eastern NC. Should this occur, a brief tornado/damaging-wind threat may be sustained through late evening. ..Grams.. 12/09/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 AM CST Sat Dec 09 2023 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FL PANHANDLE TO THE DELMARVA... ...SUMMARY... Isolated severe thunderstorms will be possible through Sunday evening across parts of the Southeast States, mainly in the form of sporadic damaging winds and a few brief tornadoes. ...Synopsis... An amplified, positive-tilt upper trough from ON to east TX at 12Z Sunday will take on a neutral to slight negative tilt as a basal shortwave impulse rapidly ejects across the Deep South to the Lower Mid-Atlantic States. Intense mid-level southerlies will become asymmetrically confined ahead of the trough by early morning Monday. Surface cyclogenesis will occur from the central/southern Appalachians across the Northeast into southern New England, with greater deepening during the latter half of the period. ...FL Panhandle to the Delmarva... Overall scenario appears similar to prior days with a broad swath of low-probability tornado and severe thunderstorm wind evident from Sunday morning to evening across the Southeast States. A mesoscale corridor of greater tornado/wind threat may be highlighted in later outlooks, seemingly within the eastern SC to southeast VA vicinity. A swath of showers and embedded thunderstorms will likely be ongoing 12Z Sunday from western/central VA to the FL Panhandle, within the warm conveyor ahead of a surface cold front steadily progressing eastward. Morning severe potential should generally be confined to the FL/GA portion of the risk area, where mid 60s surface dew points should be more common ahead of the early-day convection. Diurnal diabatic heating is still expected to be muted, with extensive low-level moistening and resultant cloudiness anticipated. Consensus of guidance still suggests that a separate low-level warm theta-e advection regime from the western Atlantic will aid in a secondary swath of convective development by late morning into the afternoon across the eastern Carolinas. A corridor of somewhat greater surface heating may occur between both regimes which could yield a mesoscale area of MLCAPE from 500-1000 J/kg. Otherwise, amid weak mid-level lapse rates, much of the region should hold with MLCAPE at or below 500 J/kg. Low-level hodographs will be more favorably enlarged from the Carolinas northward. Should this become coincident with greater than meager buoyancy, a level 2-SLGT risk may be warranted for Sunday afternoon. More prominent strengthening of low-level southerlies will occur on Sunday night as cyclogenesis intensifies. However, the thermodynamic environment may be mostly to completely overturned by this time frame, given widespread convection. Guidance varies substantially in whether scant to meager surface-based buoyancy can still linger ahead of the cold front, mainly across eastern NC. Should this occur, a brief tornado/damaging-wind threat may be sustained through late evening. ..Grams.. 12/09/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 AM CST Sat Dec 09 2023 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FL PANHANDLE TO THE DELMARVA... ...SUMMARY... Isolated severe thunderstorms will be possible through Sunday evening across parts of the Southeast States, mainly in the form of sporadic damaging winds and a few brief tornadoes. ...Synopsis... An amplified, positive-tilt upper trough from ON to east TX at 12Z Sunday will take on a neutral to slight negative tilt as a basal shortwave impulse rapidly ejects across the Deep South to the Lower Mid-Atlantic States. Intense mid-level southerlies will become asymmetrically confined ahead of the trough by early morning Monday. Surface cyclogenesis will occur from the central/southern Appalachians across the Northeast into southern New England, with greater deepening during the latter half of the period. ...FL Panhandle to the Delmarva... Overall scenario appears similar to prior days with a broad swath of low-probability tornado and severe thunderstorm wind evident from Sunday morning to evening across the Southeast States. A mesoscale corridor of greater tornado/wind threat may be highlighted in later outlooks, seemingly within the eastern SC to southeast VA vicinity. A swath of showers and embedded thunderstorms will likely be ongoing 12Z Sunday from western/central VA to the FL Panhandle, within the warm conveyor ahead of a surface cold front steadily progressing eastward. Morning severe potential should generally be confined to the FL/GA portion of the risk area, where mid 60s surface dew points should be more common ahead of the early-day convection. Diurnal diabatic heating is still expected to be muted, with extensive low-level moistening and resultant cloudiness anticipated. Consensus of guidance still suggests that a separate low-level warm theta-e advection regime from the western Atlantic will aid in a secondary swath of convective development by late morning into the afternoon across the eastern Carolinas. A corridor of somewhat greater surface heating may occur between both regimes which could yield a mesoscale area of MLCAPE from 500-1000 J/kg. Otherwise, amid weak mid-level lapse rates, much of the region should hold with MLCAPE at or below 500 J/kg. Low-level hodographs will be more favorably enlarged from the Carolinas northward. Should this become coincident with greater than meager buoyancy, a level 2-SLGT risk may be warranted for Sunday afternoon. More prominent strengthening of low-level southerlies will occur on Sunday night as cyclogenesis intensifies. However, the thermodynamic environment may be mostly to completely overturned by this time frame, given widespread convection. Guidance varies substantially in whether scant to meager surface-based buoyancy can still linger ahead of the cold front, mainly across eastern NC. Should this occur, a brief tornado/damaging-wind threat may be sustained through late evening. ..Grams.. 12/09/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 AM CST Sat Dec 09 2023 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FL PANHANDLE TO THE DELMARVA... ...SUMMARY... Isolated severe thunderstorms will be possible through Sunday evening across parts of the Southeast States, mainly in the form of sporadic damaging winds and a few brief tornadoes. ...Synopsis... An amplified, positive-tilt upper trough from ON to east TX at 12Z Sunday will take on a neutral to slight negative tilt as a basal shortwave impulse rapidly ejects across the Deep South to the Lower Mid-Atlantic States. Intense mid-level southerlies will become asymmetrically confined ahead of the trough by early morning Monday. Surface cyclogenesis will occur from the central/southern Appalachians across the Northeast into southern New England, with greater deepening during the latter half of the period. ...FL Panhandle to the Delmarva... Overall scenario appears similar to prior days with a broad swath of low-probability tornado and severe thunderstorm wind evident from Sunday morning to evening across the Southeast States. A mesoscale corridor of greater tornado/wind threat may be highlighted in later outlooks, seemingly within the eastern SC to southeast VA vicinity. A swath of showers and embedded thunderstorms will likely be ongoing 12Z Sunday from western/central VA to the FL Panhandle, within the warm conveyor ahead of a surface cold front steadily progressing eastward. Morning severe potential should generally be confined to the FL/GA portion of the risk area, where mid 60s surface dew points should be more common ahead of the early-day convection. Diurnal diabatic heating is still expected to be muted, with extensive low-level moistening and resultant cloudiness anticipated. Consensus of guidance still suggests that a separate low-level warm theta-e advection regime from the western Atlantic will aid in a secondary swath of convective development by late morning into the afternoon across the eastern Carolinas. A corridor of somewhat greater surface heating may occur between both regimes which could yield a mesoscale area of MLCAPE from 500-1000 J/kg. Otherwise, amid weak mid-level lapse rates, much of the region should hold with MLCAPE at or below 500 J/kg. Low-level hodographs will be more favorably enlarged from the Carolinas northward. Should this become coincident with greater than meager buoyancy, a level 2-SLGT risk may be warranted for Sunday afternoon. More prominent strengthening of low-level southerlies will occur on Sunday night as cyclogenesis intensifies. However, the thermodynamic environment may be mostly to completely overturned by this time frame, given widespread convection. Guidance varies substantially in whether scant to meager surface-based buoyancy can still linger ahead of the cold front, mainly across eastern NC. Should this occur, a brief tornado/damaging-wind threat may be sustained through late evening. ..Grams.. 12/09/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 AM CST Sat Dec 09 2023 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FL PANHANDLE TO THE DELMARVA... ...SUMMARY... Isolated severe thunderstorms will be possible through Sunday evening across parts of the Southeast States, mainly in the form of sporadic damaging winds and a few brief tornadoes. ...Synopsis... An amplified, positive-tilt upper trough from ON to east TX at 12Z Sunday will take on a neutral to slight negative tilt as a basal shortwave impulse rapidly ejects across the Deep South to the Lower Mid-Atlantic States. Intense mid-level southerlies will become asymmetrically confined ahead of the trough by early morning Monday. Surface cyclogenesis will occur from the central/southern Appalachians across the Northeast into southern New England, with greater deepening during the latter half of the period. ...FL Panhandle to the Delmarva... Overall scenario appears similar to prior days with a broad swath of low-probability tornado and severe thunderstorm wind evident from Sunday morning to evening across the Southeast States. A mesoscale corridor of greater tornado/wind threat may be highlighted in later outlooks, seemingly within the eastern SC to southeast VA vicinity. A swath of showers and embedded thunderstorms will likely be ongoing 12Z Sunday from western/central VA to the FL Panhandle, within the warm conveyor ahead of a surface cold front steadily progressing eastward. Morning severe potential should generally be confined to the FL/GA portion of the risk area, where mid 60s surface dew points should be more common ahead of the early-day convection. Diurnal diabatic heating is still expected to be muted, with extensive low-level moistening and resultant cloudiness anticipated. Consensus of guidance still suggests that a separate low-level warm theta-e advection regime from the western Atlantic will aid in a secondary swath of convective development by late morning into the afternoon across the eastern Carolinas. A corridor of somewhat greater surface heating may occur between both regimes which could yield a mesoscale area of MLCAPE from 500-1000 J/kg. Otherwise, amid weak mid-level lapse rates, much of the region should hold with MLCAPE at or below 500 J/kg. Low-level hodographs will be more favorably enlarged from the Carolinas northward. Should this become coincident with greater than meager buoyancy, a level 2-SLGT risk may be warranted for Sunday afternoon. More prominent strengthening of low-level southerlies will occur on Sunday night as cyclogenesis intensifies. However, the thermodynamic environment may be mostly to completely overturned by this time frame, given widespread convection. Guidance varies substantially in whether scant to meager surface-based buoyancy can still linger ahead of the cold front, mainly across eastern NC. Should this occur, a brief tornado/damaging-wind threat may be sustained through late evening. ..Grams.. 12/09/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 AM CST Sat Dec 09 2023 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FL PANHANDLE TO THE DELMARVA... ...SUMMARY... Isolated severe thunderstorms will be possible through Sunday evening across parts of the Southeast States, mainly in the form of sporadic damaging winds and a few brief tornadoes. ...Synopsis... An amplified, positive-tilt upper trough from ON to east TX at 12Z Sunday will take on a neutral to slight negative tilt as a basal shortwave impulse rapidly ejects across the Deep South to the Lower Mid-Atlantic States. Intense mid-level southerlies will become asymmetrically confined ahead of the trough by early morning Monday. Surface cyclogenesis will occur from the central/southern Appalachians across the Northeast into southern New England, with greater deepening during the latter half of the period. ...FL Panhandle to the Delmarva... Overall scenario appears similar to prior days with a broad swath of low-probability tornado and severe thunderstorm wind evident from Sunday morning to evening across the Southeast States. A mesoscale corridor of greater tornado/wind threat may be highlighted in later outlooks, seemingly within the eastern SC to southeast VA vicinity. A swath of showers and embedded thunderstorms will likely be ongoing 12Z Sunday from western/central VA to the FL Panhandle, within the warm conveyor ahead of a surface cold front steadily progressing eastward. Morning severe potential should generally be confined to the FL/GA portion of the risk area, where mid 60s surface dew points should be more common ahead of the early-day convection. Diurnal diabatic heating is still expected to be muted, with extensive low-level moistening and resultant cloudiness anticipated. Consensus of guidance still suggests that a separate low-level warm theta-e advection regime from the western Atlantic will aid in a secondary swath of convective development by late morning into the afternoon across the eastern Carolinas. A corridor of somewhat greater surface heating may occur between both regimes which could yield a mesoscale area of MLCAPE from 500-1000 J/kg. Otherwise, amid weak mid-level lapse rates, much of the region should hold with MLCAPE at or below 500 J/kg. Low-level hodographs will be more favorably enlarged from the Carolinas northward. Should this become coincident with greater than meager buoyancy, a level 2-SLGT risk may be warranted for Sunday afternoon. More prominent strengthening of low-level southerlies will occur on Sunday night as cyclogenesis intensifies. However, the thermodynamic environment may be mostly to completely overturned by this time frame, given widespread convection. Guidance varies substantially in whether scant to meager surface-based buoyancy can still linger ahead of the cold front, mainly across eastern NC. Should this occur, a brief tornado/damaging-wind threat may be sustained through late evening. ..Grams.. 12/09/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI VALLEY NORTHEASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms, capable of producing a few tornadoes, scattered damaging winds, and large hail, will be possible from the lower Mississippi Valley northeastward into the Tennessee Valley this afternoon and evening. Marginally severe storms could also develop in parts of the Ohio Valley and in the central Gulf Coast region. ...Lower Mississippi Valley/Tennessee Valley/Ohio Valley... A positively-tilted mid-level trough and an associated belt of strong flow will move eastward into the mid Mississippi Valley today. At the surface, a cold front will advance southeastward into the mid Mississippi Valley as a moist air mass advects northward across the central Gulf Coast states and Tennessee Valley. Surface dewpoints are forecast to increase into the 60s F across northern Mississippi, northern Alabama and in the western half of Tennessee. During the day, elevated thunderstorms appear likely to develop on the northern edge of the moist air mass, with a cluster of storms moving east-northeastward across northern Arkansas and western Tennessee. This cluster may be associated with a marginal threat for hail and wind damage. To the south of this cluster, the airmass should become moderately unstable by early afternoon, with MLCAPE peaking in the 1500 to 1800 J/kg range, according to RAP forecast soundings. During the mid to late afternoon, thunderstorms are expected to initiate along and ahead of the front, with a gradual increase in storm coverage taking place across the region. The eastern edge of the mid-level jet will overspread the warm sector this afternoon, creating strong deep-layer shear favorable for severe storms. 0-6 km shear values are forecast to increase into the 50 to 60 knot range, suggesting supercells will be possible. Storm-relative helicity in the 200 to 300 m2/s2 range will support a tornado threat, especially with cells that remain discrete. Although a tornado threat is expected to develop over a broad area from far eastern Arkansas northeastward into middle Tennessee, the most focused tornado potential may be from northwest Alabama into southern Tennessee. In this area, the combination of low-level shear and instability is expected to become maximized during the late afternoon and early evening. In addition to supercells, multicell clusters and line segments will be likely. The stronger rotating storms and multicell line segments may be capable of damaging wind gusts. The large hail threat will likely be associated with the more widely scattered supercells that develop further west into parts of the lower Mississippi Valley, where mid-level lapse rates are forecast to be steeper. The severe threat over the Tennessee Valley should persist into the mid to late evening as a line segment gradually develops ahead of the cold front. Further north into the Ohio Valley, instability is forecast remain weak in the afternoon and evening with RAP forecast soundings having MLCAPE peak in the 500 to 800 J/kg range. In spite of this, 0-6 km shear from 60 to 70 knots will support an isolated severe threat. Any potential for tornadoes, wind damage and hail is expected to remain isolated and marginal. ..Broyles/Wendt.. 12/09/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI VALLEY NORTHEASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms, capable of producing a few tornadoes, scattered damaging winds, and large hail, will be possible from the lower Mississippi Valley northeastward into the Tennessee Valley this afternoon and evening. Marginally severe storms could also develop in parts of the Ohio Valley and in the central Gulf Coast region. ...Lower Mississippi Valley/Tennessee Valley/Ohio Valley... A positively-tilted mid-level trough and an associated belt of strong flow will move eastward into the mid Mississippi Valley today. At the surface, a cold front will advance southeastward into the mid Mississippi Valley as a moist air mass advects northward across the central Gulf Coast states and Tennessee Valley. Surface dewpoints are forecast to increase into the 60s F across northern Mississippi, northern Alabama and in the western half of Tennessee. During the day, elevated thunderstorms appear likely to develop on the northern edge of the moist air mass, with a cluster of storms moving east-northeastward across northern Arkansas and western Tennessee. This cluster may be associated with a marginal threat for hail and wind damage. To the south of this cluster, the airmass should become moderately unstable by early afternoon, with MLCAPE peaking in the 1500 to 1800 J/kg range, according to RAP forecast soundings. During the mid to late afternoon, thunderstorms are expected to initiate along and ahead of the front, with a gradual increase in storm coverage taking place across the region. The eastern edge of the mid-level jet will overspread the warm sector this afternoon, creating strong deep-layer shear favorable for severe storms. 0-6 km shear values are forecast to increase into the 50 to 60 knot range, suggesting supercells will be possible. Storm-relative helicity in the 200 to 300 m2/s2 range will support a tornado threat, especially with cells that remain discrete. Although a tornado threat is expected to develop over a broad area from far eastern Arkansas northeastward into middle Tennessee, the most focused tornado potential may be from northwest Alabama into southern Tennessee. In this area, the combination of low-level shear and instability is expected to become maximized during the late afternoon and early evening. In addition to supercells, multicell clusters and line segments will be likely. The stronger rotating storms and multicell line segments may be capable of damaging wind gusts. The large hail threat will likely be associated with the more widely scattered supercells that develop further west into parts of the lower Mississippi Valley, where mid-level lapse rates are forecast to be steeper. The severe threat over the Tennessee Valley should persist into the mid to late evening as a line segment gradually develops ahead of the cold front. Further north into the Ohio Valley, instability is forecast remain weak in the afternoon and evening with RAP forecast soundings having MLCAPE peak in the 500 to 800 J/kg range. In spite of this, 0-6 km shear from 60 to 70 knots will support an isolated severe threat. Any potential for tornadoes, wind damage and hail is expected to remain isolated and marginal. ..Broyles/Wendt.. 12/09/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI VALLEY NORTHEASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms, capable of producing a few tornadoes, scattered damaging winds, and large hail, will be possible from the lower Mississippi Valley northeastward into the Tennessee Valley this afternoon and evening. Marginally severe storms could also develop in parts of the Ohio Valley and in the central Gulf Coast region. ...Lower Mississippi Valley/Tennessee Valley/Ohio Valley... A positively-tilted mid-level trough and an associated belt of strong flow will move eastward into the mid Mississippi Valley today. At the surface, a cold front will advance southeastward into the mid Mississippi Valley as a moist air mass advects northward across the central Gulf Coast states and Tennessee Valley. Surface dewpoints are forecast to increase into the 60s F across northern Mississippi, northern Alabama and in the western half of Tennessee. During the day, elevated thunderstorms appear likely to develop on the northern edge of the moist air mass, with a cluster of storms moving east-northeastward across northern Arkansas and western Tennessee. This cluster may be associated with a marginal threat for hail and wind damage. To the south of this cluster, the airmass should become moderately unstable by early afternoon, with MLCAPE peaking in the 1500 to 1800 J/kg range, according to RAP forecast soundings. During the mid to late afternoon, thunderstorms are expected to initiate along and ahead of the front, with a gradual increase in storm coverage taking place across the region. The eastern edge of the mid-level jet will overspread the warm sector this afternoon, creating strong deep-layer shear favorable for severe storms. 0-6 km shear values are forecast to increase into the 50 to 60 knot range, suggesting supercells will be possible. Storm-relative helicity in the 200 to 300 m2/s2 range will support a tornado threat, especially with cells that remain discrete. Although a tornado threat is expected to develop over a broad area from far eastern Arkansas northeastward into middle Tennessee, the most focused tornado potential may be from northwest Alabama into southern Tennessee. In this area, the combination of low-level shear and instability is expected to become maximized during the late afternoon and early evening. In addition to supercells, multicell clusters and line segments will be likely. The stronger rotating storms and multicell line segments may be capable of damaging wind gusts. The large hail threat will likely be associated with the more widely scattered supercells that develop further west into parts of the lower Mississippi Valley, where mid-level lapse rates are forecast to be steeper. The severe threat over the Tennessee Valley should persist into the mid to late evening as a line segment gradually develops ahead of the cold front. Further north into the Ohio Valley, instability is forecast remain weak in the afternoon and evening with RAP forecast soundings having MLCAPE peak in the 500 to 800 J/kg range. In spite of this, 0-6 km shear from 60 to 70 knots will support an isolated severe threat. Any potential for tornadoes, wind damage and hail is expected to remain isolated and marginal. ..Broyles/Wendt.. 12/09/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI VALLEY NORTHEASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms, capable of producing a few tornadoes, scattered damaging winds, and large hail, will be possible from the lower Mississippi Valley northeastward into the Tennessee Valley this afternoon and evening. Marginally severe storms could also develop in parts of the Ohio Valley and in the central Gulf Coast region. ...Lower Mississippi Valley/Tennessee Valley/Ohio Valley... A positively-tilted mid-level trough and an associated belt of strong flow will move eastward into the mid Mississippi Valley today. At the surface, a cold front will advance southeastward into the mid Mississippi Valley as a moist air mass advects northward across the central Gulf Coast states and Tennessee Valley. Surface dewpoints are forecast to increase into the 60s F across northern Mississippi, northern Alabama and in the western half of Tennessee. During the day, elevated thunderstorms appear likely to develop on the northern edge of the moist air mass, with a cluster of storms moving east-northeastward across northern Arkansas and western Tennessee. This cluster may be associated with a marginal threat for hail and wind damage. To the south of this cluster, the airmass should become moderately unstable by early afternoon, with MLCAPE peaking in the 1500 to 1800 J/kg range, according to RAP forecast soundings. During the mid to late afternoon, thunderstorms are expected to initiate along and ahead of the front, with a gradual increase in storm coverage taking place across the region. The eastern edge of the mid-level jet will overspread the warm sector this afternoon, creating strong deep-layer shear favorable for severe storms. 0-6 km shear values are forecast to increase into the 50 to 60 knot range, suggesting supercells will be possible. Storm-relative helicity in the 200 to 300 m2/s2 range will support a tornado threat, especially with cells that remain discrete. Although a tornado threat is expected to develop over a broad area from far eastern Arkansas northeastward into middle Tennessee, the most focused tornado potential may be from northwest Alabama into southern Tennessee. In this area, the combination of low-level shear and instability is expected to become maximized during the late afternoon and early evening. In addition to supercells, multicell clusters and line segments will be likely. The stronger rotating storms and multicell line segments may be capable of damaging wind gusts. The large hail threat will likely be associated with the more widely scattered supercells that develop further west into parts of the lower Mississippi Valley, where mid-level lapse rates are forecast to be steeper. The severe threat over the Tennessee Valley should persist into the mid to late evening as a line segment gradually develops ahead of the cold front. Further north into the Ohio Valley, instability is forecast remain weak in the afternoon and evening with RAP forecast soundings having MLCAPE peak in the 500 to 800 J/kg range. In spite of this, 0-6 km shear from 60 to 70 knots will support an isolated severe threat. Any potential for tornadoes, wind damage and hail is expected to remain isolated and marginal. ..Broyles/Wendt.. 12/09/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI VALLEY NORTHEASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms, capable of producing a few tornadoes, scattered damaging winds, and large hail, will be possible from the lower Mississippi Valley northeastward into the Tennessee Valley this afternoon and evening. Marginally severe storms could also develop in parts of the Ohio Valley and in the central Gulf Coast region. ...Lower Mississippi Valley/Tennessee Valley/Ohio Valley... A positively-tilted mid-level trough and an associated belt of strong flow will move eastward into the mid Mississippi Valley today. At the surface, a cold front will advance southeastward into the mid Mississippi Valley as a moist air mass advects northward across the central Gulf Coast states and Tennessee Valley. Surface dewpoints are forecast to increase into the 60s F across northern Mississippi, northern Alabama and in the western half of Tennessee. During the day, elevated thunderstorms appear likely to develop on the northern edge of the moist air mass, with a cluster of storms moving east-northeastward across northern Arkansas and western Tennessee. This cluster may be associated with a marginal threat for hail and wind damage. To the south of this cluster, the airmass should become moderately unstable by early afternoon, with MLCAPE peaking in the 1500 to 1800 J/kg range, according to RAP forecast soundings. During the mid to late afternoon, thunderstorms are expected to initiate along and ahead of the front, with a gradual increase in storm coverage taking place across the region. The eastern edge of the mid-level jet will overspread the warm sector this afternoon, creating strong deep-layer shear favorable for severe storms. 0-6 km shear values are forecast to increase into the 50 to 60 knot range, suggesting supercells will be possible. Storm-relative helicity in the 200 to 300 m2/s2 range will support a tornado threat, especially with cells that remain discrete. Although a tornado threat is expected to develop over a broad area from far eastern Arkansas northeastward into middle Tennessee, the most focused tornado potential may be from northwest Alabama into southern Tennessee. In this area, the combination of low-level shear and instability is expected to become maximized during the late afternoon and early evening. In addition to supercells, multicell clusters and line segments will be likely. The stronger rotating storms and multicell line segments may be capable of damaging wind gusts. The large hail threat will likely be associated with the more widely scattered supercells that develop further west into parts of the lower Mississippi Valley, where mid-level lapse rates are forecast to be steeper. The severe threat over the Tennessee Valley should persist into the mid to late evening as a line segment gradually develops ahead of the cold front. Further north into the Ohio Valley, instability is forecast remain weak in the afternoon and evening with RAP forecast soundings having MLCAPE peak in the 500 to 800 J/kg range. In spite of this, 0-6 km shear from 60 to 70 knots will support an isolated severe threat. Any potential for tornadoes, wind damage and hail is expected to remain isolated and marginal. ..Broyles/Wendt.. 12/09/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1157 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI VALLEY NORTHEASTWARD INTO THE TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms, capable of producing a few tornadoes, scattered damaging winds, and large hail, will be possible from the lower Mississippi Valley northeastward into the Tennessee Valley this afternoon and evening. Marginally severe storms could also develop in parts of the Ohio Valley and in the central Gulf Coast region. ...Lower Mississippi Valley/Tennessee Valley/Ohio Valley... A positively-tilted mid-level trough and an associated belt of strong flow will move eastward into the mid Mississippi Valley today. At the surface, a cold front will advance southeastward into the mid Mississippi Valley as a moist air mass advects northward across the central Gulf Coast states and Tennessee Valley. Surface dewpoints are forecast to increase into the 60s F across northern Mississippi, northern Alabama and in the western half of Tennessee. During the day, elevated thunderstorms appear likely to develop on the northern edge of the moist air mass, with a cluster of storms moving east-northeastward across northern Arkansas and western Tennessee. This cluster may be associated with a marginal threat for hail and wind damage. To the south of this cluster, the airmass should become moderately unstable by early afternoon, with MLCAPE peaking in the 1500 to 1800 J/kg range, according to RAP forecast soundings. During the mid to late afternoon, thunderstorms are expected to initiate along and ahead of the front, with a gradual increase in storm coverage taking place across the region. The eastern edge of the mid-level jet will overspread the warm sector this afternoon, creating strong deep-layer shear favorable for severe storms. 0-6 km shear values are forecast to increase into the 50 to 60 knot range, suggesting supercells will be possible. Storm-relative helicity in the 200 to 300 m2/s2 range will support a tornado threat, especially with cells that remain discrete. Although a tornado threat is expected to develop over a broad area from far eastern Arkansas northeastward into middle Tennessee, the most focused tornado potential may be from northwest Alabama into southern Tennessee. In this area, the combination of low-level shear and instability is expected to become maximized during the late afternoon and early evening. In addition to supercells, multicell clusters and line segments will be likely. The stronger rotating storms and multicell line segments may be capable of damaging wind gusts. The large hail threat will likely be associated with the more widely scattered supercells that develop further west into parts of the lower Mississippi Valley, where mid-level lapse rates are forecast to be steeper. The severe threat over the Tennessee Valley should persist into the mid to late evening as a line segment gradually develops ahead of the cold front. Further north into the Ohio Valley, instability is forecast remain weak in the afternoon and evening with RAP forecast soundings having MLCAPE peak in the 500 to 800 J/kg range. In spite of this, 0-6 km shear from 60 to 70 knots will support an isolated severe threat. Any potential for tornadoes, wind damage and hail is expected to remain isolated and marginal. ..Broyles/Wendt.. 12/09/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1142 PM CST Fri Dec 08 2023 Valid 101200Z - 111200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level trough will continue through the Southeast before lifting into the Mid-Atlantic on Sunday. The surface high in the West will move into the southern Plains and Gulf of Mexico. A belt of strong mid-level northwesterly winds will remain in the central Rockies. Modest lee troughing may occur in the southern/central High Plains as a result. ...Southern California... Offshore pressure gradients will continue to diminish. The strongest winds will again be early in the day. RH recovery during Saturday night may only be modest. Though some elevated fire weather may occur early in the period, diminishing coverage and intensity of winds, a slight offset of the lowest RH with the strongest winds, and winds becoming more confined to the terrain where fuels are less receptive should keep the bulk of fire weather concerns localized. ...Southern High Plains... As the surface high shifts east and a weak lee trough develops, some modestly dry and breezy conditions are possible in parts of eastern New Mexico into the Texas Panhandle/South Plains. With both winds and RH being marginal, fire weather concerns that exist should remain rather localized. ..Wendt.. 12/09/2023 ...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 1142 PM CST Fri Dec 08 2023 Valid 101200Z - 111200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level trough will continue through the Southeast before lifting into the Mid-Atlantic on Sunday. The surface high in the West will move into the southern Plains and Gulf of Mexico. A belt of strong mid-level northwesterly winds will remain in the central Rockies. Modest lee troughing may occur in the southern/central High Plains as a result. ...Southern California... Offshore pressure gradients will continue to diminish. The strongest winds will again be early in the day. RH recovery during Saturday night may only be modest. Though some elevated fire weather may occur early in the period, diminishing coverage and intensity of winds, a slight offset of the lowest RH with the strongest winds, and winds becoming more confined to the terrain where fuels are less receptive should keep the bulk of fire weather concerns localized. ...Southern High Plains... As the surface high shifts east and a weak lee trough develops, some modestly dry and breezy conditions are possible in parts of eastern New Mexico into the Texas Panhandle/South Plains. With both winds and RH being marginal, fire weather concerns that exist should remain rather localized. ..Wendt.. 12/09/2023 ...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 1142 PM CST Fri Dec 08 2023 Valid 101200Z - 111200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level trough will continue through the Southeast before lifting into the Mid-Atlantic on Sunday. The surface high in the West will move into the southern Plains and Gulf of Mexico. A belt of strong mid-level northwesterly winds will remain in the central Rockies. Modest lee troughing may occur in the southern/central High Plains as a result. ...Southern California... Offshore pressure gradients will continue to diminish. The strongest winds will again be early in the day. RH recovery during Saturday night may only be modest. Though some elevated fire weather may occur early in the period, diminishing coverage and intensity of winds, a slight offset of the lowest RH with the strongest winds, and winds becoming more confined to the terrain where fuels are less receptive should keep the bulk of fire weather concerns localized. ...Southern High Plains... As the surface high shifts east and a weak lee trough develops, some modestly dry and breezy conditions are possible in parts of eastern New Mexico into the Texas Panhandle/South Plains. With both winds and RH being marginal, fire weather concerns that exist should remain rather localized. ..Wendt.. 12/09/2023 ...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 1142 PM CST Fri Dec 08 2023 Valid 101200Z - 111200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level trough will continue through the Southeast before lifting into the Mid-Atlantic on Sunday. The surface high in the West will move into the southern Plains and Gulf of Mexico. A belt of strong mid-level northwesterly winds will remain in the central Rockies. Modest lee troughing may occur in the southern/central High Plains as a result. ...Southern California... Offshore pressure gradients will continue to diminish. The strongest winds will again be early in the day. RH recovery during Saturday night may only be modest. Though some elevated fire weather may occur early in the period, diminishing coverage and intensity of winds, a slight offset of the lowest RH with the strongest winds, and winds becoming more confined to the terrain where fuels are less receptive should keep the bulk of fire weather concerns localized. ...Southern High Plains... As the surface high shifts east and a weak lee trough develops, some modestly dry and breezy conditions are possible in parts of eastern New Mexico into the Texas Panhandle/South Plains. With both winds and RH being marginal, fire weather concerns that exist should remain rather localized. ..Wendt.. 12/09/2023 ...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 1142 PM CST Fri Dec 08 2023 Valid 101200Z - 111200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level trough will continue through the Southeast before lifting into the Mid-Atlantic on Sunday. The surface high in the West will move into the southern Plains and Gulf of Mexico. A belt of strong mid-level northwesterly winds will remain in the central Rockies. Modest lee troughing may occur in the southern/central High Plains as a result. ...Southern California... Offshore pressure gradients will continue to diminish. The strongest winds will again be early in the day. RH recovery during Saturday night may only be modest. Though some elevated fire weather may occur early in the period, diminishing coverage and intensity of winds, a slight offset of the lowest RH with the strongest winds, and winds becoming more confined to the terrain where fuels are less receptive should keep the bulk of fire weather concerns localized. ...Southern High Plains... As the surface high shifts east and a weak lee trough develops, some modestly dry and breezy conditions are possible in parts of eastern New Mexico into the Texas Panhandle/South Plains. With both winds and RH being marginal, fire weather concerns that exist should remain rather localized. ..Wendt.. 12/09/2023 ...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 1141 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...Synopsis... An upper-level trough will amplify as it moves into the Southeast today. This will push a cold front through the Plains to near the Appalachians. Surface high pressure will increase within the Great Basin and Four Corners regions. ...Southern California... Offshore winds will likely be maximized early this morning. Winds of 20-25 mph (with higher gusts) will overlap with at least marginally reduced RH. RH values will fall to near 10-15% in some locations by the afternoon. Winds will slowly lose some intensity with time, but should remain 15-20 mph for several hours. Lower elevation fuels will be the primary driver of fire spread. However, these fine fuels are only marginally dry at present. Elevated fire weather concerns are possible where these fuels are driest. ...Texas... Elevated fire weather is possible within part of the Permian Basin into the Edwards Plateau. Post-frontal winds will be 15-20 mph amid 15-20% RH. Locally lower RH could occur where a greater downsloping wind component exists. Fine fuels are marginally dry and will support a low-end threat for a large fire. Cold advection will tend to limit the fire weather threat, particularly farther north, as RH will likely remain above critical thresholds in those areas. ..Wendt.. 12/09/2023 ...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 1141 PM CST Fri Dec 08 2023 Valid 091200Z - 101200Z ...Synopsis... An upper-level trough will amplify as it moves into the Southeast today. This will push a cold front through the Plains to near the Appalachians. Surface high pressure will increase within the Great Basin and Four Corners regions. ...Southern California... Offshore winds will likely be maximized early this morning. Winds of 20-25 mph (with higher gusts) will overlap with at least marginally reduced RH. RH values will fall to near 10-15% in some locations by the afternoon. Winds will slowly lose some intensity with time, but should remain 15-20 mph for several hours. Lower elevation fuels will be the primary driver of fire spread. However, these fine fuels are only marginally dry at present. Elevated fire weather concerns are possible where these fuels are driest. ...Texas... Elevated fire weather is possible within part of the Permian Basin into the Edwards Plateau. Post-frontal winds will be 15-20 mph amid 15-20% RH. Locally lower RH could occur where a greater downsloping wind component exists. Fine fuels are marginally dry and will support a low-end threat for a large fire. Cold advection will tend to limit the fire weather threat, particularly farther north, as RH will likely remain above critical thresholds in those areas. ..Wendt.. 12/09/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more