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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Thu Dec 21 2023 Valid 212000Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible today across parts of southern California, southern Arizona and from north Texas into southeast Kansas. Severe thunderstorms are not expected. ...20Z Update... Minor changes have been made to the general thunderstorm area across southern CA based on recent observational and short-term guidance trends. Severe thunderstorms continue to appear unlikely along the southern CA Coast owing to a dearth of boundary-layer instability. ..Gleason.. 12/21/2023 .PREV DISCUSSION... /ISSUED 1024 AM CST Thu Dec 21 2023/ ...Discussion... Low-amplitude flow aloft will prevail across most of the U.S. today, away from a developing closed low over the Canadian Maritimes, and a second low that will remain just off the southern California/Baja coast through the period. Surface high pressure -- and associated cool/stable low-level conditions -- will again encompass much of the country, limiting convective potential over a majority of the CONUS. Two exceptions -- where isolated thunderstorms may occur -- include southern portions of California and Arizona, ahead of the aforementioned offshore upper low, and into portions of the Kansas/Oklahoma/North Texas area, ahead of mid-level short-wave troughing advancing eastward across this area through otherwise weak/westerly flow. In both areas, severe weather is not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Thu Dec 21 2023 Valid 212000Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible today across parts of southern California, southern Arizona and from north Texas into southeast Kansas. Severe thunderstorms are not expected. ...20Z Update... Minor changes have been made to the general thunderstorm area across southern CA based on recent observational and short-term guidance trends. Severe thunderstorms continue to appear unlikely along the southern CA Coast owing to a dearth of boundary-layer instability. ..Gleason.. 12/21/2023 .PREV DISCUSSION... /ISSUED 1024 AM CST Thu Dec 21 2023/ ...Discussion... Low-amplitude flow aloft will prevail across most of the U.S. today, away from a developing closed low over the Canadian Maritimes, and a second low that will remain just off the southern California/Baja coast through the period. Surface high pressure -- and associated cool/stable low-level conditions -- will again encompass much of the country, limiting convective potential over a majority of the CONUS. Two exceptions -- where isolated thunderstorms may occur -- include southern portions of California and Arizona, ahead of the aforementioned offshore upper low, and into portions of the Kansas/Oklahoma/North Texas area, ahead of mid-level short-wave troughing advancing eastward across this area through otherwise weak/westerly flow. In both areas, severe weather is not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Thu Dec 21 2023 Valid 212000Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible today across parts of southern California, southern Arizona and from north Texas into southeast Kansas. Severe thunderstorms are not expected. ...20Z Update... Minor changes have been made to the general thunderstorm area across southern CA based on recent observational and short-term guidance trends. Severe thunderstorms continue to appear unlikely along the southern CA Coast owing to a dearth of boundary-layer instability. ..Gleason.. 12/21/2023 .PREV DISCUSSION... /ISSUED 1024 AM CST Thu Dec 21 2023/ ...Discussion... Low-amplitude flow aloft will prevail across most of the U.S. today, away from a developing closed low over the Canadian Maritimes, and a second low that will remain just off the southern California/Baja coast through the period. Surface high pressure -- and associated cool/stable low-level conditions -- will again encompass much of the country, limiting convective potential over a majority of the CONUS. Two exceptions -- where isolated thunderstorms may occur -- include southern portions of California and Arizona, ahead of the aforementioned offshore upper low, and into portions of the Kansas/Oklahoma/North Texas area, ahead of mid-level short-wave troughing advancing eastward across this area through otherwise weak/westerly flow. In both areas, severe weather is not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Thu Dec 21 2023 Valid 212000Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible today across parts of southern California, southern Arizona and from north Texas into southeast Kansas. Severe thunderstorms are not expected. ...20Z Update... Minor changes have been made to the general thunderstorm area across southern CA based on recent observational and short-term guidance trends. Severe thunderstorms continue to appear unlikely along the southern CA Coast owing to a dearth of boundary-layer instability. ..Gleason.. 12/21/2023 .PREV DISCUSSION... /ISSUED 1024 AM CST Thu Dec 21 2023/ ...Discussion... Low-amplitude flow aloft will prevail across most of the U.S. today, away from a developing closed low over the Canadian Maritimes, and a second low that will remain just off the southern California/Baja coast through the period. Surface high pressure -- and associated cool/stable low-level conditions -- will again encompass much of the country, limiting convective potential over a majority of the CONUS. Two exceptions -- where isolated thunderstorms may occur -- include southern portions of California and Arizona, ahead of the aforementioned offshore upper low, and into portions of the Kansas/Oklahoma/North Texas area, ahead of mid-level short-wave troughing advancing eastward across this area through otherwise weak/westerly flow. In both areas, severe weather is not expected. Read more

The Frederick Water Board voted to allocate $2 million from its reserve fund to purchase more water from the City of Winchester to serve its approximately 16,000 customers. Drought and issues with the new water treatment plant have limited water supplies. The Northern Virginia Daily (Strasburg, Va.), Dec 21, 2023

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0101 PM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... No changes, critical fire-weather conditions appear unlikely over the CONUS Friday. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the Intermountain West, encouraging the continuance of surface lee-troughing and chances for rain over the Mississippi Valley as well as parts of the Southwest. Over the rest of the CONUS, weak surface winds or cool temperatures will mitigate significant wildfire-spread potential. ...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 0101 PM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... No changes, critical fire-weather conditions appear unlikely over the CONUS Friday. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the Intermountain West, encouraging the continuance of surface lee-troughing and chances for rain over the Mississippi Valley as well as parts of the Southwest. Over the rest of the CONUS, weak surface winds or cool temperatures will mitigate significant wildfire-spread potential. ...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 0101 PM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... No changes, critical fire-weather conditions appear unlikely over the CONUS Friday. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the Intermountain West, encouraging the continuance of surface lee-troughing and chances for rain over the Mississippi Valley as well as parts of the Southwest. Over the rest of the CONUS, weak surface winds or cool temperatures will mitigate significant wildfire-spread potential. ...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 0101 PM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... No changes, critical fire-weather conditions appear unlikely over the CONUS Friday. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the Intermountain West, encouraging the continuance of surface lee-troughing and chances for rain over the Mississippi Valley as well as parts of the Southwest. Over the rest of the CONUS, weak surface winds or cool temperatures will mitigate significant wildfire-spread potential. ...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 0101 PM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... No changes, critical fire-weather conditions appear unlikely over the CONUS Friday. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the Intermountain West, encouraging the continuance of surface lee-troughing and chances for rain over the Mississippi Valley as well as parts of the Southwest. Over the rest of the CONUS, weak surface winds or cool temperatures will mitigate significant wildfire-spread potential. ...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 0101 PM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... No changes, critical fire-weather conditions appear unlikely over the CONUS Friday. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the Intermountain West, encouraging the continuance of surface lee-troughing and chances for rain over the Mississippi Valley as well as parts of the Southwest. Over the rest of the CONUS, weak surface winds or cool temperatures will mitigate significant wildfire-spread potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

Those celebrating the New Year festivities with fireworks were urged to be very careful, given the ongoing drought. Big Island Now (Hilo), Dec 21, 2023

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CST Thu Dec 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN ARIZONA AND FAR SOUTHWEST NEW MEXICO... ...SUMMARY... Thunderstorms will be possible Friday from southern California across much of the Southwest. Some hail and strong/gusty winds may occur over parts of southern Arizona and far southwest New Mexico Friday afternoon and evening. ...Southwest... A closed upper low initially centered off the coast of southern CA will move eastward Friday across the northern Baja Peninsula and lower CO River Valley. Large-scale ascent preceding this feature and associated mid-level moisture will support showers and thunderstorms from southern CA into much of the Southwest through the period. Widespread cloudiness and limited low-level moisture should hinder the development of much instability. But modest daytime heating and cooling mid-level temperatures as the upper trough/low advances eastward may aid weak buoyancy across parts of southern AZ and vicinity by Friday afternoon. Assuming this weak instability can develop, strengthening mid-level southwesterly flow ahead of the upper trough/low will support deep-layer shear increasing to 35-50 kt by late Friday afternoon and early evening. Some guidance shows the potential for a supercell or two to track northeastward from northern Mexico across parts of southern AZ and perhaps into far southwest NM. If this occurs, then isolated hail will be possible given cold mid-level temperatures and favorable effective bulk shear. The potential for occasional strong/gusty winds may also exist where the boundary layer can become well mixed as low-level lapse rates steepen and modest diurnal heating occurs. Overall confidence in severe potential across parts of the Southwest Friday remains low, as instability is expected to remain rather weak. ..Gleason.. 12/21/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1041 AM CST Thu Dec 21 2023 Valid 211700Z - 221200Z ...NO CRITICAL AREAS... No changes. Increasing precipitation chances, combined with modest winds and mild temperatures will keep fire-weather concerns minimal. ..Lyons.. 12/21/2023 .PREV DISCUSSION... /ISSUED 0101 AM CST Thu Dec 21 2023/ ...Synopsis... Multiple mid-level troughs will traverse the western and central U.S. today, promoting appreciable precipitation accumulations over California and the Southern Plains. Meanwhile, dry air will linger over the Tennessee Valley into the Southeast. However, surface winds are expected to be weak, limiting significant wildfire-spread potential. Fire-weather conditions should also remain quiescent over the rest of the CONUS as well. ...Please see www.spc.noaa.gov/fire for graphic product... Read more