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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1022 AM CST Fri Dec 22 2023 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS PARTS OF SOUTHEAST CALIFORNIA AND SOUTHERN ARIZONA... ...SUMMARY... Isolated large hail and strong-severe gusts are possible from midday into evening across parts of southern Arizona and vicinity. ...Southwest US... Morning water vapor loop shows a compact upper-low off the coast to the southwest of San Diego, CA. A 70+ knot mid-level jet max is rotating around the base of the low, and will overspread northwest Mexico and into southern AZ tonight. Widespread clouds and scattered precipitation will limit heating/destabilization in most parts of AZ today. However, visible imagery shows broken cloud cover over southern CA just ahead of the upper low. Steep mid-level lapse rates and cold temperatures aloft may result in sufficient CAPE for a few robust updrafts this afternoon. CAM guidance suggests the main area of concern is along and east of the Colorado River valley. A few storms may produce hail and gusty wind in this region this afternoon. Other strong storms may form in the low-level warm-advection zone and beneath the strong winds aloft across southeast AZ after dark. This area will see very little daytime heating or destabilization, but stronger vertical shear profiles and sufficient CAPE could encourage an organized storm or two capable of gusty winds. ..Hart/Wendt.. 12/22/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 1023 AM CST Fri Dec 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... The forecast remains on track. For details, see the previous discussion below. ..Weinman.. 12/22/2023 .PREV DISCUSSION... /ISSUED 1157 PM CST Thu Dec 21 2023/ ...Synopsis... Fuels remain mostly moist across the CONUS. In addition, cool and/or dry conditions will prevail today across most of the CONUS. Therefore, fire-weather concerns remain minimal. Wetting rain and mountain snow is expected across Arizona today which will further delay any fire-weather concerns across the region despite ongoing long-term drought conditions. ...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 0653 AM CST Fri Dec 22 2023 Valid 221300Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA... ...SUMMARY... Isolated large hail and strong-severe gusts are possible from midday into evening across parts of southern Arizona. ...Synopsis... A closed, mid/upper-level cyclone was apparent in moisture-channel imagery offshore from southern CA and northern Baja -- centered about 200-225 nm west-southwest of SAN. Separately, a strong, northern-stream shortwave trough was evident just offshore from the Pacific Northwest. The northern-stream trough will move inland by around 18Z today, then reach the northern Rockies by the end of the period. It will be increasingly phased with the increasingly progressive, southern-stream cyclone/trough, whose circulation center should cross northernmost Baja around 00Z, then shift northeastward toward the Grand Canyon/FLG region by 12Z tomorrow. ...Southern AZ... Isolated severe hail and/or gusts are possible today over portions of southern AZ. Ahead of the mid/upper cyclone, a baroclinic-leaf pattern apparent in satellite imagery -- with precip and embedded thunderstorms that should remain elevated and nonsevere for several more hours -- will continue to spread eastward to northeastward over the region through the day. Meanwhile, at the surface, and in low levels, warm advection and moisture transport are forecast to increase today over much of the Desert Southwest, beneath a zone of strong difluence aloft preceding the mid upper-level cyclone. So will large-scale DCVA-related lift closer to the cold-core region. predominantly separate areas of strong/isolated severe-thunderstorm potential will develop in each regime from midday into early evening, but with some spatial overlap in the outlook area due to the progressive nature of the system as a whole. Diurnal destabilization should be gradual, given the presence of cloud cover to limit the pace and strength of diabatic surface heating. However, in combination with boundary-layer theta-e advection and cooling aloft, low/middle-level lapse rates should steepen, with that and increasing low-level moisture contributing to lessening MLCINH through the afternoon. Activity developing in MX, or near the international border, near or off the southern rim of the early cloud/precip shield, will move into an increasingly buoyant environment, with each regime yielding peak MLCAPE in the 300-800 J/kg range. Strengthening deep shear should aid in storm organization, though potentially messy mode and lack of greater instability may be counterbalancing factors. Forecast soundings suggest strong deep/speed shear, with long but not especially large hodographs by the time surface-based effective-inflow parcels are common. 45-55-kt effective-shear magnitudes are expected area-wide. Decreasing instability should diminish severe potential with time overnight. ..Edwards/Broyles.. 12/22/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Fri Dec 22 2023 Valid 221300Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA... ...SUMMARY... Isolated large hail and strong-severe gusts are possible from midday into evening across parts of southern Arizona. ...Synopsis... A closed, mid/upper-level cyclone was apparent in moisture-channel imagery offshore from southern CA and northern Baja -- centered about 200-225 nm west-southwest of SAN. Separately, a strong, northern-stream shortwave trough was evident just offshore from the Pacific Northwest. The northern-stream trough will move inland by around 18Z today, then reach the northern Rockies by the end of the period. It will be increasingly phased with the increasingly progressive, southern-stream cyclone/trough, whose circulation center should cross northernmost Baja around 00Z, then shift northeastward toward the Grand Canyon/FLG region by 12Z tomorrow. ...Southern AZ... Isolated severe hail and/or gusts are possible today over portions of southern AZ. Ahead of the mid/upper cyclone, a baroclinic-leaf pattern apparent in satellite imagery -- with precip and embedded thunderstorms that should remain elevated and nonsevere for several more hours -- will continue to spread eastward to northeastward over the region through the day. Meanwhile, at the surface, and in low levels, warm advection and moisture transport are forecast to increase today over much of the Desert Southwest, beneath a zone of strong difluence aloft preceding the mid upper-level cyclone. So will large-scale DCVA-related lift closer to the cold-core region. predominantly separate areas of strong/isolated severe-thunderstorm potential will develop in each regime from midday into early evening, but with some spatial overlap in the outlook area due to the progressive nature of the system as a whole. Diurnal destabilization should be gradual, given the presence of cloud cover to limit the pace and strength of diabatic surface heating. However, in combination with boundary-layer theta-e advection and cooling aloft, low/middle-level lapse rates should steepen, with that and increasing low-level moisture contributing to lessening MLCINH through the afternoon. Activity developing in MX, or near the international border, near or off the southern rim of the early cloud/precip shield, will move into an increasingly buoyant environment, with each regime yielding peak MLCAPE in the 300-800 J/kg range. Strengthening deep shear should aid in storm organization, though potentially messy mode and lack of greater instability may be counterbalancing factors. Forecast soundings suggest strong deep/speed shear, with long but not especially large hodographs by the time surface-based effective-inflow parcels are common. 45-55-kt effective-shear magnitudes are expected area-wide. Decreasing instability should diminish severe potential with time overnight. ..Edwards/Broyles.. 12/22/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Fri Dec 22 2023 Valid 221300Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA... ...SUMMARY... Isolated large hail and strong-severe gusts are possible from midday into evening across parts of southern Arizona. ...Synopsis... A closed, mid/upper-level cyclone was apparent in moisture-channel imagery offshore from southern CA and northern Baja -- centered about 200-225 nm west-southwest of SAN. Separately, a strong, northern-stream shortwave trough was evident just offshore from the Pacific Northwest. The northern-stream trough will move inland by around 18Z today, then reach the northern Rockies by the end of the period. It will be increasingly phased with the increasingly progressive, southern-stream cyclone/trough, whose circulation center should cross northernmost Baja around 00Z, then shift northeastward toward the Grand Canyon/FLG region by 12Z tomorrow. ...Southern AZ... Isolated severe hail and/or gusts are possible today over portions of southern AZ. Ahead of the mid/upper cyclone, a baroclinic-leaf pattern apparent in satellite imagery -- with precip and embedded thunderstorms that should remain elevated and nonsevere for several more hours -- will continue to spread eastward to northeastward over the region through the day. Meanwhile, at the surface, and in low levels, warm advection and moisture transport are forecast to increase today over much of the Desert Southwest, beneath a zone of strong difluence aloft preceding the mid upper-level cyclone. So will large-scale DCVA-related lift closer to the cold-core region. predominantly separate areas of strong/isolated severe-thunderstorm potential will develop in each regime from midday into early evening, but with some spatial overlap in the outlook area due to the progressive nature of the system as a whole. Diurnal destabilization should be gradual, given the presence of cloud cover to limit the pace and strength of diabatic surface heating. However, in combination with boundary-layer theta-e advection and cooling aloft, low/middle-level lapse rates should steepen, with that and increasing low-level moisture contributing to lessening MLCINH through the afternoon. Activity developing in MX, or near the international border, near or off the southern rim of the early cloud/precip shield, will move into an increasingly buoyant environment, with each regime yielding peak MLCAPE in the 300-800 J/kg range. Strengthening deep shear should aid in storm organization, though potentially messy mode and lack of greater instability may be counterbalancing factors. Forecast soundings suggest strong deep/speed shear, with long but not especially large hodographs by the time surface-based effective-inflow parcels are common. 45-55-kt effective-shear magnitudes are expected area-wide. Decreasing instability should diminish severe potential with time overnight. ..Edwards/Broyles.. 12/22/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Fri Dec 22 2023 Valid 221300Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA... ...SUMMARY... Isolated large hail and strong-severe gusts are possible from midday into evening across parts of southern Arizona. ...Synopsis... A closed, mid/upper-level cyclone was apparent in moisture-channel imagery offshore from southern CA and northern Baja -- centered about 200-225 nm west-southwest of SAN. Separately, a strong, northern-stream shortwave trough was evident just offshore from the Pacific Northwest. The northern-stream trough will move inland by around 18Z today, then reach the northern Rockies by the end of the period. It will be increasingly phased with the increasingly progressive, southern-stream cyclone/trough, whose circulation center should cross northernmost Baja around 00Z, then shift northeastward toward the Grand Canyon/FLG region by 12Z tomorrow. ...Southern AZ... Isolated severe hail and/or gusts are possible today over portions of southern AZ. Ahead of the mid/upper cyclone, a baroclinic-leaf pattern apparent in satellite imagery -- with precip and embedded thunderstorms that should remain elevated and nonsevere for several more hours -- will continue to spread eastward to northeastward over the region through the day. Meanwhile, at the surface, and in low levels, warm advection and moisture transport are forecast to increase today over much of the Desert Southwest, beneath a zone of strong difluence aloft preceding the mid upper-level cyclone. So will large-scale DCVA-related lift closer to the cold-core region. predominantly separate areas of strong/isolated severe-thunderstorm potential will develop in each regime from midday into early evening, but with some spatial overlap in the outlook area due to the progressive nature of the system as a whole. Diurnal destabilization should be gradual, given the presence of cloud cover to limit the pace and strength of diabatic surface heating. However, in combination with boundary-layer theta-e advection and cooling aloft, low/middle-level lapse rates should steepen, with that and increasing low-level moisture contributing to lessening MLCINH through the afternoon. Activity developing in MX, or near the international border, near or off the southern rim of the early cloud/precip shield, will move into an increasingly buoyant environment, with each regime yielding peak MLCAPE in the 300-800 J/kg range. Strengthening deep shear should aid in storm organization, though potentially messy mode and lack of greater instability may be counterbalancing factors. Forecast soundings suggest strong deep/speed shear, with long but not especially large hodographs by the time surface-based effective-inflow parcels are common. 45-55-kt effective-shear magnitudes are expected area-wide. Decreasing instability should diminish severe potential with time overnight. ..Edwards/Broyles.. 12/22/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0251 AM CST Fri Dec 22 2023 Valid 251200Z - 301200Z ...DISCUSSION... Medium-range forecast guidance is in fairly good agreement for much of the Day 4-8 period. General consensus is that a closed upper low will develop over the Midwest and gradually shift east/northeast toward the Great Lakes with time. Large-scale upper troughing will persist east of the Mississippi River through Day 8/Fri. At the same time, an upper ridge will develop and shift east across the western half of the CONUS. At the surface, low pressure and attendant cold front will develop east in tandem with the upper low/trough over the Midwest and eastern states. Thunderstorms will be possible across the Southeast Days 4-5/Mon-Tue ahead of the front, but weak large-scale ascent and poor thermodynamics will likely preclude severe potential. In the wake of the cold front, high pressure over the Rockies and Plains will lead to stable conditions. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0251 AM CST Fri Dec 22 2023 Valid 251200Z - 301200Z ...DISCUSSION... Medium-range forecast guidance is in fairly good agreement for much of the Day 4-8 period. General consensus is that a closed upper low will develop over the Midwest and gradually shift east/northeast toward the Great Lakes with time. Large-scale upper troughing will persist east of the Mississippi River through Day 8/Fri. At the same time, an upper ridge will develop and shift east across the western half of the CONUS. At the surface, low pressure and attendant cold front will develop east in tandem with the upper low/trough over the Midwest and eastern states. Thunderstorms will be possible across the Southeast Days 4-5/Mon-Tue ahead of the front, but weak large-scale ascent and poor thermodynamics will likely preclude severe potential. In the wake of the cold front, high pressure over the Rockies and Plains will lead to stable conditions. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0251 AM CST Fri Dec 22 2023 Valid 251200Z - 301200Z ...DISCUSSION... Medium-range forecast guidance is in fairly good agreement for much of the Day 4-8 period. General consensus is that a closed upper low will develop over the Midwest and gradually shift east/northeast toward the Great Lakes with time. Large-scale upper troughing will persist east of the Mississippi River through Day 8/Fri. At the same time, an upper ridge will develop and shift east across the western half of the CONUS. At the surface, low pressure and attendant cold front will develop east in tandem with the upper low/trough over the Midwest and eastern states. Thunderstorms will be possible across the Southeast Days 4-5/Mon-Tue ahead of the front, but weak large-scale ascent and poor thermodynamics will likely preclude severe potential. In the wake of the cold front, high pressure over the Rockies and Plains will lead to stable conditions. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0251 AM CST Fri Dec 22 2023 Valid 251200Z - 301200Z ...DISCUSSION... Medium-range forecast guidance is in fairly good agreement for much of the Day 4-8 period. General consensus is that a closed upper low will develop over the Midwest and gradually shift east/northeast toward the Great Lakes with time. Large-scale upper troughing will persist east of the Mississippi River through Day 8/Fri. At the same time, an upper ridge will develop and shift east across the western half of the CONUS. At the surface, low pressure and attendant cold front will develop east in tandem with the upper low/trough over the Midwest and eastern states. Thunderstorms will be possible across the Southeast Days 4-5/Mon-Tue ahead of the front, but weak large-scale ascent and poor thermodynamics will likely preclude severe potential. In the wake of the cold front, high pressure over the Rockies and Plains will lead to stable conditions. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Fri Dec 22 2023 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential appears low on Sunday. ...Southern Plains to Lower MS Valley... An upper trough will pivot east across the southern Plains toward the Ozarks and Lower MS Valley on Sunday. At the surface, a cold front will develop southeast across the central and southern Plains during the afternoon/evening, with a Pacific front shifting east across central TX early in the day ahead of the synoptic front. A line and/or clusters of thunderstorms will likely be ongoing Sunday morning across parts of Oklahoma into northern/central TX ahead of these surface boundaries. Some uncertainty in the eastward extent of the Pacific front over central TX exists Sunday morning. Instability will be generally weak, limited by surface dewpoints in the 50s to low 60s across central TX. However, vertically veering low-level wind profiles with result in somewhat enlarged and curved hodographs in the 0-3 km layer. A 30-40 kt southerly low-level jet the first few hours of the period will also contribute to 0-1 km SRH around 100-200 m2/s2. This could conditionally support a low-end tornado risk. However, forecast guidance varies considerably in the quality of low-level thermodynamics. Given this uncertainty in the mesoscale environment, coupled with the climatologically unfavorable time of day (approx. 12-15z), low severe probabilities will not be introduced across parts of central TX at this time. Thunderstorm activity will spread east over the ArkLaTex through the day and toward the Lower MS Valley during the evening/overnight hours. While better low-level moisture will be present across these areas ahead of the eastward-advancing cold front, poor lapse rates and weak instability will limit severe potential. ..Leitman.. 12/22/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Fri Dec 22 2023 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential appears low on Sunday. ...Southern Plains to Lower MS Valley... An upper trough will pivot east across the southern Plains toward the Ozarks and Lower MS Valley on Sunday. At the surface, a cold front will develop southeast across the central and southern Plains during the afternoon/evening, with a Pacific front shifting east across central TX early in the day ahead of the synoptic front. A line and/or clusters of thunderstorms will likely be ongoing Sunday morning across parts of Oklahoma into northern/central TX ahead of these surface boundaries. Some uncertainty in the eastward extent of the Pacific front over central TX exists Sunday morning. Instability will be generally weak, limited by surface dewpoints in the 50s to low 60s across central TX. However, vertically veering low-level wind profiles with result in somewhat enlarged and curved hodographs in the 0-3 km layer. A 30-40 kt southerly low-level jet the first few hours of the period will also contribute to 0-1 km SRH around 100-200 m2/s2. This could conditionally support a low-end tornado risk. However, forecast guidance varies considerably in the quality of low-level thermodynamics. Given this uncertainty in the mesoscale environment, coupled with the climatologically unfavorable time of day (approx. 12-15z), low severe probabilities will not be introduced across parts of central TX at this time. Thunderstorm activity will spread east over the ArkLaTex through the day and toward the Lower MS Valley during the evening/overnight hours. While better low-level moisture will be present across these areas ahead of the eastward-advancing cold front, poor lapse rates and weak instability will limit severe potential. ..Leitman.. 12/22/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Fri Dec 22 2023 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential appears low on Sunday. ...Southern Plains to Lower MS Valley... An upper trough will pivot east across the southern Plains toward the Ozarks and Lower MS Valley on Sunday. At the surface, a cold front will develop southeast across the central and southern Plains during the afternoon/evening, with a Pacific front shifting east across central TX early in the day ahead of the synoptic front. A line and/or clusters of thunderstorms will likely be ongoing Sunday morning across parts of Oklahoma into northern/central TX ahead of these surface boundaries. Some uncertainty in the eastward extent of the Pacific front over central TX exists Sunday morning. Instability will be generally weak, limited by surface dewpoints in the 50s to low 60s across central TX. However, vertically veering low-level wind profiles with result in somewhat enlarged and curved hodographs in the 0-3 km layer. A 30-40 kt southerly low-level jet the first few hours of the period will also contribute to 0-1 km SRH around 100-200 m2/s2. This could conditionally support a low-end tornado risk. However, forecast guidance varies considerably in the quality of low-level thermodynamics. Given this uncertainty in the mesoscale environment, coupled with the climatologically unfavorable time of day (approx. 12-15z), low severe probabilities will not be introduced across parts of central TX at this time. Thunderstorm activity will spread east over the ArkLaTex through the day and toward the Lower MS Valley during the evening/overnight hours. While better low-level moisture will be present across these areas ahead of the eastward-advancing cold front, poor lapse rates and weak instability will limit severe potential. ..Leitman.. 12/22/2023 Read more