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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Thu Dec 21 2023 Valid 211630Z - 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. ...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. ..Goss/Thornton.. 12/21/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Thu Dec 21 2023 Valid 211630Z - 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. ...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. ..Goss/Thornton.. 12/21/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Thu Dec 21 2023 Valid 211300Z - 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. ...DISCUSSION... An eastern Pacific upper-level low, to the southwest of California, will move eastward today towards the northwestern coast of Baja California. Isolated thunderstorms, aided by large-scale ascent and steep mid-level lapse rates, will be possible across parts of southern California, along the northern periphery of the system. Further east into the southern and central Plains, a shortwave trough will move eastward through the region. Moisture advection will take place ahead of the shortwave trough across the southern Plains, as a surface low deepens in the northwestern Texas Panhandle. As weak instability develops near the moist axis, isolated thunderstorms will be possible late this afternoon from north Texas into southeast Kansas. No severe threat is expected across the continental United States today or tonight. ..Broyles/Thompson.. 12/21/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Thu Dec 21 2023 Valid 211300Z - 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. ...DISCUSSION... An eastern Pacific upper-level low, to the southwest of California, will move eastward today towards the northwestern coast of Baja California. Isolated thunderstorms, aided by large-scale ascent and steep mid-level lapse rates, will be possible across parts of southern California, along the northern periphery of the system. Further east into the southern and central Plains, a shortwave trough will move eastward through the region. Moisture advection will take place ahead of the shortwave trough across the southern Plains, as a surface low deepens in the northwestern Texas Panhandle. As weak instability develops near the moist axis, isolated thunderstorms will be possible late this afternoon from north Texas into southeast Kansas. No severe threat is expected across the continental United States today or tonight. ..Broyles/Thompson.. 12/21/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Thu Dec 21 2023 Valid 211300Z - 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. ...DISCUSSION... An eastern Pacific upper-level low, to the southwest of California, will move eastward today towards the northwestern coast of Baja California. Isolated thunderstorms, aided by large-scale ascent and steep mid-level lapse rates, will be possible across parts of southern California, along the northern periphery of the system. Further east into the southern and central Plains, a shortwave trough will move eastward through the region. Moisture advection will take place ahead of the shortwave trough across the southern Plains, as a surface low deepens in the northwestern Texas Panhandle. As weak instability develops near the moist axis, isolated thunderstorms will be possible late this afternoon from north Texas into southeast Kansas. No severe threat is expected across the continental United States today or tonight. ..Broyles/Thompson.. 12/21/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Thu Dec 21 2023 Valid 211300Z - 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. ...DISCUSSION... An eastern Pacific upper-level low, to the southwest of California, will move eastward today towards the northwestern coast of Baja California. Isolated thunderstorms, aided by large-scale ascent and steep mid-level lapse rates, will be possible across parts of southern California, along the northern periphery of the system. Further east into the southern and central Plains, a shortwave trough will move eastward through the region. Moisture advection will take place ahead of the shortwave trough across the southern Plains, as a surface low deepens in the northwestern Texas Panhandle. As weak instability develops near the moist axis, isolated thunderstorms will be possible late this afternoon from north Texas into southeast Kansas. No severe threat is expected across the continental United States today or tonight. ..Broyles/Thompson.. 12/21/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Thu Dec 21 2023 Valid 211300Z - 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. ...DISCUSSION... An eastern Pacific upper-level low, to the southwest of California, will move eastward today towards the northwestern coast of Baja California. Isolated thunderstorms, aided by large-scale ascent and steep mid-level lapse rates, will be possible across parts of southern California, along the northern periphery of the system. Further east into the southern and central Plains, a shortwave trough will move eastward through the region. Moisture advection will take place ahead of the shortwave trough across the southern Plains, as a surface low deepens in the northwestern Texas Panhandle. As weak instability develops near the moist axis, isolated thunderstorms will be possible late this afternoon from north Texas into southeast Kansas. No severe threat is expected across the continental United States today or tonight. ..Broyles/Thompson.. 12/21/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Thu Dec 21 2023 Valid 211300Z - 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. ...DISCUSSION... An eastern Pacific upper-level low, to the southwest of California, will move eastward today towards the northwestern coast of Baja California. Isolated thunderstorms, aided by large-scale ascent and steep mid-level lapse rates, will be possible across parts of southern California, along the northern periphery of the system. Further east into the southern and central Plains, a shortwave trough will move eastward through the region. Moisture advection will take place ahead of the shortwave trough across the southern Plains, as a surface low deepens in the northwestern Texas Panhandle. As weak instability develops near the moist axis, isolated thunderstorms will be possible late this afternoon from north Texas into southeast Kansas. No severe threat is expected across the continental United States today or tonight. ..Broyles/Thompson.. 12/21/2023 Read more

MD 2338 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN CA COAST
Mesoscale Discussion 2338 NWS Storm Prediction Center Norman OK 0356 AM CST Thu Dec 21 2023 Areas affected...Southern CA coast Concerning...Severe potential...Watch unlikely Valid 210956Z - 211130Z Probability of Watch Issuance...5 percent SUMMARY...Isolated, weakly rotating storms possible, but the severe threat remains low. DISCUSSION...Low-topped convection continues to move onshore across Ventura County within a baroclinic band east of the closed low near 33 N and 126 W. Surface observations and modified RAP model soundings suggest weak surface-based CAPE (near 500 J/kg) extends just inland from the coast, with buoyancy quickly diminishing inland as a result of some offshore component to the near-surface flow. The VWP from KVTX has shown some backing and increase in flow in the lowest 1 km AGL in the past 30-60 minutes, with a resultant increase in hodograph curvature/SRH. Thus, some potential for weakly rotating storms will continue for the next few hours near and just off coast. Given the marginal nature of the buoyancy and its limited inland extent, the potential for a brief tornado and/or damaging gust still appears fairly low. ..Thompson/Broyles.. 12/21/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOX... LAT...LON 33651912 33981950 34411966 34471940 34471923 34241852 33941824 33501837 33461846 33521877 33651912 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Thu Dec 21 2023 Valid 241200Z - 291200Z ...DISCUSSION... Upper troughing is expected to extend from the High Plains into central Mexico early D4/Sunday morning. A series of shortwave troughs are expected to progress through this trough as it gradually shifts eastward. The lead shortwave in this series is expected to move across the Southeast on D5/Monday. Modest moisture will be in place and some isolated thunderstorms are possible over the Southeast as this shortwave moves through. Most of the stronger mid-level flow will lag to the west of this wave, but some overlap between the modest buoyancy and shear could support a low-coverage severe potential. By D6/Tuesday, the evolution of these shortwaves will likely have resulted in the development of a mature mid-latitude cyclone centered over the Lower MO Valley/Mid MS Valley vicinity. As this system matures, an attendant cold front is expected to push eastward across the TN Valley and Southeast on D5/Monday and D6/Tuesday. Buoyancy will likely be limited ahead of this front, but some isolated thunderstorms are still possible, particularly across the Southeast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Thu Dec 21 2023 Valid 241200Z - 291200Z ...DISCUSSION... Upper troughing is expected to extend from the High Plains into central Mexico early D4/Sunday morning. A series of shortwave troughs are expected to progress through this trough as it gradually shifts eastward. The lead shortwave in this series is expected to move across the Southeast on D5/Monday. Modest moisture will be in place and some isolated thunderstorms are possible over the Southeast as this shortwave moves through. Most of the stronger mid-level flow will lag to the west of this wave, but some overlap between the modest buoyancy and shear could support a low-coverage severe potential. By D6/Tuesday, the evolution of these shortwaves will likely have resulted in the development of a mature mid-latitude cyclone centered over the Lower MO Valley/Mid MS Valley vicinity. As this system matures, an attendant cold front is expected to push eastward across the TN Valley and Southeast on D5/Monday and D6/Tuesday. Buoyancy will likely be limited ahead of this front, but some isolated thunderstorms are still possible, particularly across the Southeast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Thu Dec 21 2023 Valid 241200Z - 291200Z ...DISCUSSION... Upper troughing is expected to extend from the High Plains into central Mexico early D4/Sunday morning. A series of shortwave troughs are expected to progress through this trough as it gradually shifts eastward. The lead shortwave in this series is expected to move across the Southeast on D5/Monday. Modest moisture will be in place and some isolated thunderstorms are possible over the Southeast as this shortwave moves through. Most of the stronger mid-level flow will lag to the west of this wave, but some overlap between the modest buoyancy and shear could support a low-coverage severe potential. By D6/Tuesday, the evolution of these shortwaves will likely have resulted in the development of a mature mid-latitude cyclone centered over the Lower MO Valley/Mid MS Valley vicinity. As this system matures, an attendant cold front is expected to push eastward across the TN Valley and Southeast on D5/Monday and D6/Tuesday. Buoyancy will likely be limited ahead of this front, but some isolated thunderstorms are still possible, particularly across the Southeast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Thu Dec 21 2023 Valid 241200Z - 291200Z ...DISCUSSION... Upper troughing is expected to extend from the High Plains into central Mexico early D4/Sunday morning. A series of shortwave troughs are expected to progress through this trough as it gradually shifts eastward. The lead shortwave in this series is expected to move across the Southeast on D5/Monday. Modest moisture will be in place and some isolated thunderstorms are possible over the Southeast as this shortwave moves through. Most of the stronger mid-level flow will lag to the west of this wave, but some overlap between the modest buoyancy and shear could support a low-coverage severe potential. By D6/Tuesday, the evolution of these shortwaves will likely have resulted in the development of a mature mid-latitude cyclone centered over the Lower MO Valley/Mid MS Valley vicinity. As this system matures, an attendant cold front is expected to push eastward across the TN Valley and Southeast on D5/Monday and D6/Tuesday. Buoyancy will likely be limited ahead of this front, but some isolated thunderstorms are still possible, particularly across the Southeast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Thu Dec 21 2023 Valid 241200Z - 291200Z ...DISCUSSION... Upper troughing is expected to extend from the High Plains into central Mexico early D4/Sunday morning. A series of shortwave troughs are expected to progress through this trough as it gradually shifts eastward. The lead shortwave in this series is expected to move across the Southeast on D5/Monday. Modest moisture will be in place and some isolated thunderstorms are possible over the Southeast as this shortwave moves through. Most of the stronger mid-level flow will lag to the west of this wave, but some overlap between the modest buoyancy and shear could support a low-coverage severe potential. By D6/Tuesday, the evolution of these shortwaves will likely have resulted in the development of a mature mid-latitude cyclone centered over the Lower MO Valley/Mid MS Valley vicinity. As this system matures, an attendant cold front is expected to push eastward across the TN Valley and Southeast on D5/Monday and D6/Tuesday. Buoyancy will likely be limited ahead of this front, but some isolated thunderstorms are still possible, particularly across the Southeast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Thu Dec 21 2023 Valid 241200Z - 291200Z ...DISCUSSION... Upper troughing is expected to extend from the High Plains into central Mexico early D4/Sunday morning. A series of shortwave troughs are expected to progress through this trough as it gradually shifts eastward. The lead shortwave in this series is expected to move across the Southeast on D5/Monday. Modest moisture will be in place and some isolated thunderstorms are possible over the Southeast as this shortwave moves through. Most of the stronger mid-level flow will lag to the west of this wave, but some overlap between the modest buoyancy and shear could support a low-coverage severe potential. By D6/Tuesday, the evolution of these shortwaves will likely have resulted in the development of a mature mid-latitude cyclone centered over the Lower MO Valley/Mid MS Valley vicinity. As this system matures, an attendant cold front is expected to push eastward across the TN Valley and Southeast on D5/Monday and D6/Tuesday. Buoyancy will likely be limited ahead of this front, but some isolated thunderstorms are still possible, particularly across the Southeast. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CST Thu Dec 21 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected from the Southeast into the central and southern Plains on Saturday. Severe thunderstorms are not currently anticipated. ...Synopsis... An upper low is forecast to begin the period over eastern AZ before devolving further into an open wave while continuing northeastward over the remainder of the Southwest and into the southern/central High Plains. Another shortwave trough is expected to follow quickly in the wake of the lead wave, progressing southeastward across the Great Basin and into the Four Corner. This overall evolution will result in a persistence of upper troughing over the Rockies and High Plains, with southwesterly flow aloft being maintained across the southern Plains. Showers and isolated thunderstorms will likely be ongoing near and ahead of the southern-stream upper low, from eastern AZ across NM and into far west TX. Additional showers and thunderstorms are expected to develop during the afternoon across the southern High Plains as the low moves northeastward. Cool surface temperatures and modest low-level moisture will temper buoyancy, but enhanced mid-level flow will contribute to enough shear for storm organization. As a result, any more robust, sustained updrafts may be able to produce hail. However, the current expectation is for the limited buoyancy to keep the severe potential too isolated to introduce any severe probabilities. Showers and thunderstorm will continue to expand eastward into more of the southern Plains during the evening and overnight, but limited buoyancy and shear should limit the severe potential with this activity as well. ..Mosier.. 12/21/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CST Thu Dec 21 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected from the Southeast into the central and southern Plains on Saturday. Severe thunderstorms are not currently anticipated. ...Synopsis... An upper low is forecast to begin the period over eastern AZ before devolving further into an open wave while continuing northeastward over the remainder of the Southwest and into the southern/central High Plains. Another shortwave trough is expected to follow quickly in the wake of the lead wave, progressing southeastward across the Great Basin and into the Four Corner. This overall evolution will result in a persistence of upper troughing over the Rockies and High Plains, with southwesterly flow aloft being maintained across the southern Plains. Showers and isolated thunderstorms will likely be ongoing near and ahead of the southern-stream upper low, from eastern AZ across NM and into far west TX. Additional showers and thunderstorms are expected to develop during the afternoon across the southern High Plains as the low moves northeastward. Cool surface temperatures and modest low-level moisture will temper buoyancy, but enhanced mid-level flow will contribute to enough shear for storm organization. As a result, any more robust, sustained updrafts may be able to produce hail. However, the current expectation is for the limited buoyancy to keep the severe potential too isolated to introduce any severe probabilities. Showers and thunderstorm will continue to expand eastward into more of the southern Plains during the evening and overnight, but limited buoyancy and shear should limit the severe potential with this activity as well. ..Mosier.. 12/21/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CST Thu Dec 21 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected from the Southeast into the central and southern Plains on Saturday. Severe thunderstorms are not currently anticipated. ...Synopsis... An upper low is forecast to begin the period over eastern AZ before devolving further into an open wave while continuing northeastward over the remainder of the Southwest and into the southern/central High Plains. Another shortwave trough is expected to follow quickly in the wake of the lead wave, progressing southeastward across the Great Basin and into the Four Corner. This overall evolution will result in a persistence of upper troughing over the Rockies and High Plains, with southwesterly flow aloft being maintained across the southern Plains. Showers and isolated thunderstorms will likely be ongoing near and ahead of the southern-stream upper low, from eastern AZ across NM and into far west TX. Additional showers and thunderstorms are expected to develop during the afternoon across the southern High Plains as the low moves northeastward. Cool surface temperatures and modest low-level moisture will temper buoyancy, but enhanced mid-level flow will contribute to enough shear for storm organization. As a result, any more robust, sustained updrafts may be able to produce hail. However, the current expectation is for the limited buoyancy to keep the severe potential too isolated to introduce any severe probabilities. Showers and thunderstorm will continue to expand eastward into more of the southern Plains during the evening and overnight, but limited buoyancy and shear should limit the severe potential with this activity as well. ..Mosier.. 12/21/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CST Thu Dec 21 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected from the Southeast into the central and southern Plains on Saturday. Severe thunderstorms are not currently anticipated. ...Synopsis... An upper low is forecast to begin the period over eastern AZ before devolving further into an open wave while continuing northeastward over the remainder of the Southwest and into the southern/central High Plains. Another shortwave trough is expected to follow quickly in the wake of the lead wave, progressing southeastward across the Great Basin and into the Four Corner. This overall evolution will result in a persistence of upper troughing over the Rockies and High Plains, with southwesterly flow aloft being maintained across the southern Plains. Showers and isolated thunderstorms will likely be ongoing near and ahead of the southern-stream upper low, from eastern AZ across NM and into far west TX. Additional showers and thunderstorms are expected to develop during the afternoon across the southern High Plains as the low moves northeastward. Cool surface temperatures and modest low-level moisture will temper buoyancy, but enhanced mid-level flow will contribute to enough shear for storm organization. As a result, any more robust, sustained updrafts may be able to produce hail. However, the current expectation is for the limited buoyancy to keep the severe potential too isolated to introduce any severe probabilities. Showers and thunderstorm will continue to expand eastward into more of the southern Plains during the evening and overnight, but limited buoyancy and shear should limit the severe potential with this activity as well. ..Mosier.. 12/21/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CST Thu Dec 21 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected from the Southeast into the central and southern Plains on Saturday. Severe thunderstorms are not currently anticipated. ...Synopsis... An upper low is forecast to begin the period over eastern AZ before devolving further into an open wave while continuing northeastward over the remainder of the Southwest and into the southern/central High Plains. Another shortwave trough is expected to follow quickly in the wake of the lead wave, progressing southeastward across the Great Basin and into the Four Corner. This overall evolution will result in a persistence of upper troughing over the Rockies and High Plains, with southwesterly flow aloft being maintained across the southern Plains. Showers and isolated thunderstorms will likely be ongoing near and ahead of the southern-stream upper low, from eastern AZ across NM and into far west TX. Additional showers and thunderstorms are expected to develop during the afternoon across the southern High Plains as the low moves northeastward. Cool surface temperatures and modest low-level moisture will temper buoyancy, but enhanced mid-level flow will contribute to enough shear for storm organization. As a result, any more robust, sustained updrafts may be able to produce hail. However, the current expectation is for the limited buoyancy to keep the severe potential too isolated to introduce any severe probabilities. Showers and thunderstorm will continue to expand eastward into more of the southern Plains during the evening and overnight, but limited buoyancy and shear should limit the severe potential with this activity as well. ..Mosier.. 12/21/2023 Read more