Severe Storms

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0347 AM CST Mon Dec 16 2024 Valid 191200Z - 241200Z ...DISCUSSION... Medium range guidance is in fairly good agreement that an amplified but progressive upper level pattern will overspread the CONUS during the Day 4-8 period. A shortwave trough over the northern Plains early on Day 4/Thu will deepen and spread east over the eastern half of the CONUS through Day 6 or 7/Sat or Sun. Meanwhile, an amplified upper ridge will build over the western states and spread east into the Plains during this same time period. Spread among guidance increases around Day 6-8/Sat-Mon, but still indicates that another upper trough will emerge over the Plains and Midwest late in the period. A surface cold front will move south and east into the Gulf of Mexico and offshore the Atlantic coast on Thursday. This will clear out any lingering boundary-layer moisture and persistent offshore trajectories will mostly preclude much thunderstorm potential for most of the forecast period. The exception may be on Day 7-8/Sun-Mon as lee troughing allow for southeasterly flow to return across the western Gulf and TX, bringing modest moisture northward across southern/central TX. Nevertheless, severe-thunderstorm potential appears low throughout the forecast period. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CST Mon Dec 16 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas, as well as across the Florida Peninsula and Georgia coast on Wednesday. Severe thunderstorms are not expected. ...Synopsis... An upper trough will migrate across the eastern half of the CONUS on Wednesday. Boundary-layer moisture will remain modest across the southeast U.S., ahead of a southeast-advancing cold front extending from southern OH southwest to western TN and then central TX Wednesday morning. Isolated showers and thunderstorms are likely to be ongoing along the front at the beginning of the period. This activity will likely be elevated and just to the cool side of the surface front. Instability is expected to be very weak with southeast extent into the TN and Lower MS Valley, and morning thunderstorms will likely diminish in coverage as the front moves southeast. Severe thunderstorms are unlikely given limited instability and modest vertical shear. Additional thunderstorms are expected across the FL Peninsula and perhaps the GA coast. Low-level easterly flow will continue to maintain somewhat richer low-level moisture to the east of a surface inverted trough and in a separate regime from the approaching upper trough and surface front to the west. This will aid in modest destabilization through peak heating. Weak vertical shear will limit storm organization, and severe storms appear unlikely at this time. ..Leitman.. 12/16/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CST Mon Dec 16 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas, as well as across the Florida Peninsula and Georgia coast on Wednesday. Severe thunderstorms are not expected. ...Synopsis... An upper trough will migrate across the eastern half of the CONUS on Wednesday. Boundary-layer moisture will remain modest across the southeast U.S., ahead of a southeast-advancing cold front extending from southern OH southwest to western TN and then central TX Wednesday morning. Isolated showers and thunderstorms are likely to be ongoing along the front at the beginning of the period. This activity will likely be elevated and just to the cool side of the surface front. Instability is expected to be very weak with southeast extent into the TN and Lower MS Valley, and morning thunderstorms will likely diminish in coverage as the front moves southeast. Severe thunderstorms are unlikely given limited instability and modest vertical shear. Additional thunderstorms are expected across the FL Peninsula and perhaps the GA coast. Low-level easterly flow will continue to maintain somewhat richer low-level moisture to the east of a surface inverted trough and in a separate regime from the approaching upper trough and surface front to the west. This will aid in modest destabilization through peak heating. Weak vertical shear will limit storm organization, and severe storms appear unlikely at this time. ..Leitman.. 12/16/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CST Mon Dec 16 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas, as well as across the Florida Peninsula and Georgia coast on Wednesday. Severe thunderstorms are not expected. ...Synopsis... An upper trough will migrate across the eastern half of the CONUS on Wednesday. Boundary-layer moisture will remain modest across the southeast U.S., ahead of a southeast-advancing cold front extending from southern OH southwest to western TN and then central TX Wednesday morning. Isolated showers and thunderstorms are likely to be ongoing along the front at the beginning of the period. This activity will likely be elevated and just to the cool side of the surface front. Instability is expected to be very weak with southeast extent into the TN and Lower MS Valley, and morning thunderstorms will likely diminish in coverage as the front moves southeast. Severe thunderstorms are unlikely given limited instability and modest vertical shear. Additional thunderstorms are expected across the FL Peninsula and perhaps the GA coast. Low-level easterly flow will continue to maintain somewhat richer low-level moisture to the east of a surface inverted trough and in a separate regime from the approaching upper trough and surface front to the west. This will aid in modest destabilization through peak heating. Weak vertical shear will limit storm organization, and severe storms appear unlikely at this time. ..Leitman.. 12/16/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CST Mon Dec 16 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas, as well as across the Florida Peninsula and Georgia coast on Wednesday. Severe thunderstorms are not expected. ...Synopsis... An upper trough will migrate across the eastern half of the CONUS on Wednesday. Boundary-layer moisture will remain modest across the southeast U.S., ahead of a southeast-advancing cold front extending from southern OH southwest to western TN and then central TX Wednesday morning. Isolated showers and thunderstorms are likely to be ongoing along the front at the beginning of the period. This activity will likely be elevated and just to the cool side of the surface front. Instability is expected to be very weak with southeast extent into the TN and Lower MS Valley, and morning thunderstorms will likely diminish in coverage as the front moves southeast. Severe thunderstorms are unlikely given limited instability and modest vertical shear. Additional thunderstorms are expected across the FL Peninsula and perhaps the GA coast. Low-level easterly flow will continue to maintain somewhat richer low-level moisture to the east of a surface inverted trough and in a separate regime from the approaching upper trough and surface front to the west. This will aid in modest destabilization through peak heating. Weak vertical shear will limit storm organization, and severe storms appear unlikely at this time. ..Leitman.. 12/16/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CST Mon Dec 16 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas, as well as across the Florida Peninsula and Georgia coast on Wednesday. Severe thunderstorms are not expected. ...Synopsis... An upper trough will migrate across the eastern half of the CONUS on Wednesday. Boundary-layer moisture will remain modest across the southeast U.S., ahead of a southeast-advancing cold front extending from southern OH southwest to western TN and then central TX Wednesday morning. Isolated showers and thunderstorms are likely to be ongoing along the front at the beginning of the period. This activity will likely be elevated and just to the cool side of the surface front. Instability is expected to be very weak with southeast extent into the TN and Lower MS Valley, and morning thunderstorms will likely diminish in coverage as the front moves southeast. Severe thunderstorms are unlikely given limited instability and modest vertical shear. Additional thunderstorms are expected across the FL Peninsula and perhaps the GA coast. Low-level easterly flow will continue to maintain somewhat richer low-level moisture to the east of a surface inverted trough and in a separate regime from the approaching upper trough and surface front to the west. This will aid in modest destabilization through peak heating. Weak vertical shear will limit storm organization, and severe storms appear unlikely at this time. ..Leitman.. 12/16/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CST Mon Dec 16 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas, as well as across the Florida Peninsula and Georgia coast on Wednesday. Severe thunderstorms are not expected. ...Synopsis... An upper trough will migrate across the eastern half of the CONUS on Wednesday. Boundary-layer moisture will remain modest across the southeast U.S., ahead of a southeast-advancing cold front extending from southern OH southwest to western TN and then central TX Wednesday morning. Isolated showers and thunderstorms are likely to be ongoing along the front at the beginning of the period. This activity will likely be elevated and just to the cool side of the surface front. Instability is expected to be very weak with southeast extent into the TN and Lower MS Valley, and morning thunderstorms will likely diminish in coverage as the front moves southeast. Severe thunderstorms are unlikely given limited instability and modest vertical shear. Additional thunderstorms are expected across the FL Peninsula and perhaps the GA coast. Low-level easterly flow will continue to maintain somewhat richer low-level moisture to the east of a surface inverted trough and in a separate regime from the approaching upper trough and surface front to the west. This will aid in modest destabilization through peak heating. Weak vertical shear will limit storm organization, and severe storms appear unlikely at this time. ..Leitman.. 12/16/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...Synopsis... Quasi zonal mid-level flow is expected to quickly amplify as ridging develops over the Western US D2/Tues. In the wake of a cold front moving across the central US the day prior, surface high pressure will quickly build over the Great Basin. The high pressure will allow for moderate offshore winds and elevated to near-critical fire-weather concerns over portions of southern CA. ...Southern California... As high pressure intensifies behind the cold front across the Great Basin and interior West, moderate offshore flow is expected to develop D2/Tues into D3/Wed. Santa Ana winds of 15-25 mph will overlap with low RH values of 10-20% across parts of Los Angeles and Ventura counties for several hours. Elevated to near-critical fire-weather conditions appear likely amid dry fuels across portions of southern CA, particularly overnight D2/Tues into D3/Wed. Some uncertainty remains regarding the strength of the winds and minimum RH values in the absence of stronger upper-level support. The best overlap of strong winds and low RH is expected late D2/Tues into early D3/Wed morning. However, if winds trend stronger and earlier as some guidance suggests, critical highlights may be needed sooner. ..Lyons.. 12/16/2024 ...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 0150 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...Synopsis... Quasi zonal mid-level flow is expected to quickly amplify as ridging develops over the Western US D2/Tues. In the wake of a cold front moving across the central US the day prior, surface high pressure will quickly build over the Great Basin. The high pressure will allow for moderate offshore winds and elevated to near-critical fire-weather concerns over portions of southern CA. ...Southern California... As high pressure intensifies behind the cold front across the Great Basin and interior West, moderate offshore flow is expected to develop D2/Tues into D3/Wed. Santa Ana winds of 15-25 mph will overlap with low RH values of 10-20% across parts of Los Angeles and Ventura counties for several hours. Elevated to near-critical fire-weather conditions appear likely amid dry fuels across portions of southern CA, particularly overnight D2/Tues into D3/Wed. Some uncertainty remains regarding the strength of the winds and minimum RH values in the absence of stronger upper-level support. The best overlap of strong winds and low RH is expected late D2/Tues into early D3/Wed morning. However, if winds trend stronger and earlier as some guidance suggests, critical highlights may be needed sooner. ..Lyons.. 12/16/2024 ...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 0150 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...Synopsis... Quasi zonal mid-level flow is expected to quickly amplify as ridging develops over the Western US D2/Tues. In the wake of a cold front moving across the central US the day prior, surface high pressure will quickly build over the Great Basin. The high pressure will allow for moderate offshore winds and elevated to near-critical fire-weather concerns over portions of southern CA. ...Southern California... As high pressure intensifies behind the cold front across the Great Basin and interior West, moderate offshore flow is expected to develop D2/Tues into D3/Wed. Santa Ana winds of 15-25 mph will overlap with low RH values of 10-20% across parts of Los Angeles and Ventura counties for several hours. Elevated to near-critical fire-weather conditions appear likely amid dry fuels across portions of southern CA, particularly overnight D2/Tues into D3/Wed. Some uncertainty remains regarding the strength of the winds and minimum RH values in the absence of stronger upper-level support. The best overlap of strong winds and low RH is expected late D2/Tues into early D3/Wed morning. However, if winds trend stronger and earlier as some guidance suggests, critical highlights may be needed sooner. ..Lyons.. 12/16/2024 ...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 0150 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...Synopsis... Quasi zonal mid-level flow is expected to quickly amplify as ridging develops over the Western US D2/Tues. In the wake of a cold front moving across the central US the day prior, surface high pressure will quickly build over the Great Basin. The high pressure will allow for moderate offshore winds and elevated to near-critical fire-weather concerns over portions of southern CA. ...Southern California... As high pressure intensifies behind the cold front across the Great Basin and interior West, moderate offshore flow is expected to develop D2/Tues into D3/Wed. Santa Ana winds of 15-25 mph will overlap with low RH values of 10-20% across parts of Los Angeles and Ventura counties for several hours. Elevated to near-critical fire-weather conditions appear likely amid dry fuels across portions of southern CA, particularly overnight D2/Tues into D3/Wed. Some uncertainty remains regarding the strength of the winds and minimum RH values in the absence of stronger upper-level support. The best overlap of strong winds and low RH is expected late D2/Tues into early D3/Wed morning. However, if winds trend stronger and earlier as some guidance suggests, critical highlights may be needed sooner. ..Lyons.. 12/16/2024 ...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 0150 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...Synopsis... Quasi zonal mid-level flow is expected to quickly amplify as ridging develops over the Western US D2/Tues. In the wake of a cold front moving across the central US the day prior, surface high pressure will quickly build over the Great Basin. The high pressure will allow for moderate offshore winds and elevated to near-critical fire-weather concerns over portions of southern CA. ...Southern California... As high pressure intensifies behind the cold front across the Great Basin and interior West, moderate offshore flow is expected to develop D2/Tues into D3/Wed. Santa Ana winds of 15-25 mph will overlap with low RH values of 10-20% across parts of Los Angeles and Ventura counties for several hours. Elevated to near-critical fire-weather conditions appear likely amid dry fuels across portions of southern CA, particularly overnight D2/Tues into D3/Wed. Some uncertainty remains regarding the strength of the winds and minimum RH values in the absence of stronger upper-level support. The best overlap of strong winds and low RH is expected late D2/Tues into early D3/Wed morning. However, if winds trend stronger and earlier as some guidance suggests, critical highlights may be needed sooner. ..Lyons.. 12/16/2024 ...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 0150 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...Synopsis... Quasi zonal mid-level flow is expected to quickly amplify as ridging develops over the Western US D2/Tues. In the wake of a cold front moving across the central US the day prior, surface high pressure will quickly build over the Great Basin. The high pressure will allow for moderate offshore winds and elevated to near-critical fire-weather concerns over portions of southern CA. ...Southern California... As high pressure intensifies behind the cold front across the Great Basin and interior West, moderate offshore flow is expected to develop D2/Tues into D3/Wed. Santa Ana winds of 15-25 mph will overlap with low RH values of 10-20% across parts of Los Angeles and Ventura counties for several hours. Elevated to near-critical fire-weather conditions appear likely amid dry fuels across portions of southern CA, particularly overnight D2/Tues into D3/Wed. Some uncertainty remains regarding the strength of the winds and minimum RH values in the absence of stronger upper-level support. The best overlap of strong winds and low RH is expected late D2/Tues into early D3/Wed morning. However, if winds trend stronger and earlier as some guidance suggests, critical highlights may be needed sooner. ..Lyons.. 12/16/2024 ...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 0147 AM CST Mon Dec 16 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Fire-weather concerns across the CONUS are minimal. A cold front trailing a strong low in southern Canada will cross the central US, allowing a much cooler air mass to settle over the western US and Rockies. Despite strong mid-level flow supporting downslope winds, poor overlap of strong winds and low humidity is expected outside of brief gusty offshore winds in southern CA. Otherwise, precipitation ahead of the front and from the prior day will augment fuels such that little or no fire-weather risk is expected. ..Lyons.. 12/16/2024 ...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 0147 AM CST Mon Dec 16 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Fire-weather concerns across the CONUS are minimal. A cold front trailing a strong low in southern Canada will cross the central US, allowing a much cooler air mass to settle over the western US and Rockies. Despite strong mid-level flow supporting downslope winds, poor overlap of strong winds and low humidity is expected outside of brief gusty offshore winds in southern CA. Otherwise, precipitation ahead of the front and from the prior day will augment fuels such that little or no fire-weather risk is expected. ..Lyons.. 12/16/2024 ...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 0147 AM CST Mon Dec 16 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Fire-weather concerns across the CONUS are minimal. A cold front trailing a strong low in southern Canada will cross the central US, allowing a much cooler air mass to settle over the western US and Rockies. Despite strong mid-level flow supporting downslope winds, poor overlap of strong winds and low humidity is expected outside of brief gusty offshore winds in southern CA. Otherwise, precipitation ahead of the front and from the prior day will augment fuels such that little or no fire-weather risk is expected. ..Lyons.. 12/16/2024 ...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 0147 AM CST Mon Dec 16 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Fire-weather concerns across the CONUS are minimal. A cold front trailing a strong low in southern Canada will cross the central US, allowing a much cooler air mass to settle over the western US and Rockies. Despite strong mid-level flow supporting downslope winds, poor overlap of strong winds and low humidity is expected outside of brief gusty offshore winds in southern CA. Otherwise, precipitation ahead of the front and from the prior day will augment fuels such that little or no fire-weather risk is expected. ..Lyons.. 12/16/2024 ...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 0147 AM CST Mon Dec 16 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Fire-weather concerns across the CONUS are minimal. A cold front trailing a strong low in southern Canada will cross the central US, allowing a much cooler air mass to settle over the western US and Rockies. Despite strong mid-level flow supporting downslope winds, poor overlap of strong winds and low humidity is expected outside of brief gusty offshore winds in southern CA. Otherwise, precipitation ahead of the front and from the prior day will augment fuels such that little or no fire-weather risk is expected. ..Lyons.. 12/16/2024 ...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 0147 AM CST Mon Dec 16 2024 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Synopsis... Fire-weather concerns across the CONUS are minimal. A cold front trailing a strong low in southern Canada will cross the central US, allowing a much cooler air mass to settle over the western US and Rockies. Despite strong mid-level flow supporting downslope winds, poor overlap of strong winds and low humidity is expected outside of brief gusty offshore winds in southern CA. Otherwise, precipitation ahead of the front and from the prior day will augment fuels such that little or no fire-weather risk is expected. ..Lyons.. 12/16/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected from the southern Plains to the Lower Ohio and Tennessee Valley vicinities and across Florida on Tuesday. Severe-thunderstorm chances are low at this time. ...Eastern OK/ArkLaTex/Ozarks Vicinity... An upper trough will deepen as it moves across the Plains to the MS Valley vicinity on Tuesday. A 500 mb jet max around 50-70 kt will become oriented from eastern OK into the Ohio Valley/lower Great Lakes area after 06z, and stronger height falls are not expected to overspread the region until the nighttime hours. At the surface, 50s to low/mid 60s F dewpoints are expected across south/east TX into the Mid-South vicinity. A strong cold front will track southeast across KS/OK during the evening, and by 06z be positioned from northern AR into southeast OK and north-central TX. This boundary will become a focus for increasing isentropic ascent and isolated to scattered thunderstorms during the overnight/early Wednesday period. Neutral height tendencies will likely suppress convection during the day across much of the area. As convection develops along the advancing cold front overnight, uncertainty remains regarding any surface-based instability overlapping with stronger vertical shear (which decreases rapidly with southward extent). Forecast soundings vary across forecast guidance, but at least weak elevated instability is expected driven by cooling aloft. Stronger elevated cores could produce small hail, given forecast lapse rates around 6.8-7 C/km amid 30+ kt effective shear magnitudes (especially from southeast OK into AR). Overall, severe potential appears quite conditional for the last 3-6 hours of the forecast period. Will hold off on including low-end hail probabilities, though a Marginal (level 1 of 5) risk may be needed in later outlooks depending on forecast trends. ...FL Peninsula... Isolated thunderstorms are expected on Tuesday as a moist airmass and at least weak instability overspread the region. Onshore, easterly low-level flow will provide convergence along an inverted surface trough. Given sufficient destabilization, this will support development of thunderstorms moving onshore through evening. Weak 0-6 km bulk shear (less than 20 kt) will preclude organized convection, and severe storms are not expected. ..Leitman.. 12/16/2024 Read more