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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0208 AM CST Mon Jan 20 2025 Valid 201200Z - 211200Z ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR THE SAN GABRIEL MOUNTAINS WEST TOWARDS THE SANTA MONICA MOUNTAINS AND SANTA SUSANA MOUNTAINS... INCLUDING THE MALIBU COAST... ...CRITICAL FIRE WEATHER AREA FOR MUCH OF SOUTHERN CALIFORNIA... ...Synopsis... While most of the CONUS is dominated by cold air and high pressure, a strong, positively-tilted mid-level trough will move southward across California, with a highly amplified mid-level Pacific ridge following behind it. As the trough axis reaches southern California Monday afternoon, intensifying surface pressure gradients will result in the development of strong Santa Ana winds. The 00Z HREF guidance and global ensembles continue to forecast strong LAX->DAG pressure gradients ranging from -8 mb to -11 mb, with wind speeds trending upward to 40-45 MPH sustained (gusting 70 - 100 MPH on the mountains, 50 - 80 MPH in the valleys/coastal regions). In addition to the upward trend in wind speed and gust forecasts, relative humidity values have trended significantly drier, with values as low as 2%-5%. These Extremely Critical fire-weather conditions, supporting rapid wildfire onset and spread, will begin Monday afternoon and reach peak intensity Monday evening into Tuesday morning. The area of greatest risk lies from the San Gabriel Mountains westward into the Santa Monica Mountains, the Malibu Coast, and the Santa Susana Mountains. Elsewhere, Critical fire-weather conditions extend southward to the U.S./Mexico border, where strong (and critically dry) offshore winds will persist overnight into Tuesday morning. ..Halbert.. 01/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0040 CONCERNING HEAVY SNOW FOR COASTAL MAINE
Mesoscale Discussion 0040 NWS Storm Prediction Center Norman OK 0923 PM CST Sun Jan 19 2025 Areas affected...Coastal Maine Concerning...Heavy snow Valid 200323Z - 200930Z SUMMARY...Heavy snowfall with rates at or exceeding 1"/hour are expected across coastal Maine through 09Z as a surface cyclone tracks northeastward off the coast of New England. DISCUSSION...As a rapidly deepening surface low tracks northeastward off the coast of New England, strong isentropic ascent and lift in the dendritic growth zone will result in heavy snowfall across portions of coastal Maine. Short-term guidance from the 00Z HREF, along with surface pressure falls in recent observations, have increased confidence that some areas on the coast could meet or exceed 1"/hour snowfall rates. The greatest chance for heavy snowfall rates will be north and east of Rockland, and the combination of strong winds and heavy snowfall rates will result in low visibility conditions (at or below 0.5 mi). These conditions are expected to subside in southern Maine starting around 06Z, and exiting northeast Maine by 08-09Z. ..Halbert.. 01/20/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX... LAT...LON 44217093 44517034 44936946 45416838 45336758 45086701 44776675 44396714 44026793 43726904 43606987 43147044 43007066 43197106 43487131 44027122 44217093 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CST Mon Jan 20 2025 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Wednesday. ...Synopsis... An elongated upper trough will exit the East Coast early in the day, as another positive-tilt trough moves into the central CONUS. This trough will extend roughly from the upper Great Lakes into the southern Plains. Meanwhile, an upper ridge will exist along the West Coast, with additional disturbances diving south into the northern Rockies. At the surface, a stable air mass in terms of convection will exist due to high pressure. A weak surface low may form from the FL Straits toward the Bahamas, avoiding the FL Peninsula where the air mass will remain stable. As such, little to no lightning activity is forecast across the USA on Wednesday due to the stable air mass over land. ..Jewell.. 01/20/2025 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CST Mon Jan 20 2025 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Wednesday. ...Synopsis... An elongated upper trough will exit the East Coast early in the day, as another positive-tilt trough moves into the central CONUS. This trough will extend roughly from the upper Great Lakes into the southern Plains. Meanwhile, an upper ridge will exist along the West Coast, with additional disturbances diving south into the northern Rockies. At the surface, a stable air mass in terms of convection will exist due to high pressure. A weak surface low may form from the FL Straits toward the Bahamas, avoiding the FL Peninsula where the air mass will remain stable. As such, little to no lightning activity is forecast across the USA on Wednesday due to the stable air mass over land. ..Jewell.. 01/20/2025 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CST Mon Jan 20 2025 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Wednesday. ...Synopsis... An elongated upper trough will exit the East Coast early in the day, as another positive-tilt trough moves into the central CONUS. This trough will extend roughly from the upper Great Lakes into the southern Plains. Meanwhile, an upper ridge will exist along the West Coast, with additional disturbances diving south into the northern Rockies. At the surface, a stable air mass in terms of convection will exist due to high pressure. A weak surface low may form from the FL Straits toward the Bahamas, avoiding the FL Peninsula where the air mass will remain stable. As such, little to no lightning activity is forecast across the USA on Wednesday due to the stable air mass over land. ..Jewell.. 01/20/2025 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CST Mon Jan 20 2025 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Wednesday. ...Synopsis... An elongated upper trough will exit the East Coast early in the day, as another positive-tilt trough moves into the central CONUS. This trough will extend roughly from the upper Great Lakes into the southern Plains. Meanwhile, an upper ridge will exist along the West Coast, with additional disturbances diving south into the northern Rockies. At the surface, a stable air mass in terms of convection will exist due to high pressure. A weak surface low may form from the FL Straits toward the Bahamas, avoiding the FL Peninsula where the air mass will remain stable. As such, little to no lightning activity is forecast across the USA on Wednesday due to the stable air mass over land. ..Jewell.. 01/20/2025 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CST Mon Jan 20 2025 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Wednesday. ...Synopsis... An elongated upper trough will exit the East Coast early in the day, as another positive-tilt trough moves into the central CONUS. This trough will extend roughly from the upper Great Lakes into the southern Plains. Meanwhile, an upper ridge will exist along the West Coast, with additional disturbances diving south into the northern Rockies. At the surface, a stable air mass in terms of convection will exist due to high pressure. A weak surface low may form from the FL Straits toward the Bahamas, avoiding the FL Peninsula where the air mass will remain stable. As such, little to no lightning activity is forecast across the USA on Wednesday due to the stable air mass over land. ..Jewell.. 01/20/2025 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CST Mon Jan 20 2025 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Wednesday. ...Synopsis... An elongated upper trough will exit the East Coast early in the day, as another positive-tilt trough moves into the central CONUS. This trough will extend roughly from the upper Great Lakes into the southern Plains. Meanwhile, an upper ridge will exist along the West Coast, with additional disturbances diving south into the northern Rockies. At the surface, a stable air mass in terms of convection will exist due to high pressure. A weak surface low may form from the FL Straits toward the Bahamas, avoiding the FL Peninsula where the air mass will remain stable. As such, little to no lightning activity is forecast across the USA on Wednesday due to the stable air mass over land. ..Jewell.. 01/20/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Sun Jan 19 2025 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Tuesday. ...Synopsis... A large positive-tilt upper trough will stretch from the upper Great Lakes into the southern High Plains Tuesday morning, and will progress toward the East Coast by 12Z Wednesday. Behind this wave, another lobe of vorticity will drop south across the Rockies and toward the Plains late. At the surface, a strong high pressure ridge will extend from the Great Basin all the way to the Mid Atlantic Tuesday morning, with this high consolidating across the eastern states and toward the lower MS Valley overnight. Another area of high pressure will develop southward across the Pacific Northwest and northern Rockies, in association with the second upper wave. While 60s F dewpoints will remain from the FL Straits toward the Bahamas, little destabilization is expected over the mainland. Thunderstorms may occur over parts of the central Gulf of Mexico along the surging cold front, with little impact to land expected. ..Jewell.. 01/20/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Sun Jan 19 2025 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Tuesday. ...Synopsis... A large positive-tilt upper trough will stretch from the upper Great Lakes into the southern High Plains Tuesday morning, and will progress toward the East Coast by 12Z Wednesday. Behind this wave, another lobe of vorticity will drop south across the Rockies and toward the Plains late. At the surface, a strong high pressure ridge will extend from the Great Basin all the way to the Mid Atlantic Tuesday morning, with this high consolidating across the eastern states and toward the lower MS Valley overnight. Another area of high pressure will develop southward across the Pacific Northwest and northern Rockies, in association with the second upper wave. While 60s F dewpoints will remain from the FL Straits toward the Bahamas, little destabilization is expected over the mainland. Thunderstorms may occur over parts of the central Gulf of Mexico along the surging cold front, with little impact to land expected. ..Jewell.. 01/20/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Sun Jan 19 2025 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Tuesday. ...Synopsis... A large positive-tilt upper trough will stretch from the upper Great Lakes into the southern High Plains Tuesday morning, and will progress toward the East Coast by 12Z Wednesday. Behind this wave, another lobe of vorticity will drop south across the Rockies and toward the Plains late. At the surface, a strong high pressure ridge will extend from the Great Basin all the way to the Mid Atlantic Tuesday morning, with this high consolidating across the eastern states and toward the lower MS Valley overnight. Another area of high pressure will develop southward across the Pacific Northwest and northern Rockies, in association with the second upper wave. While 60s F dewpoints will remain from the FL Straits toward the Bahamas, little destabilization is expected over the mainland. Thunderstorms may occur over parts of the central Gulf of Mexico along the surging cold front, with little impact to land expected. ..Jewell.. 01/20/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Sun Jan 19 2025 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Tuesday. ...Synopsis... A large positive-tilt upper trough will stretch from the upper Great Lakes into the southern High Plains Tuesday morning, and will progress toward the East Coast by 12Z Wednesday. Behind this wave, another lobe of vorticity will drop south across the Rockies and toward the Plains late. At the surface, a strong high pressure ridge will extend from the Great Basin all the way to the Mid Atlantic Tuesday morning, with this high consolidating across the eastern states and toward the lower MS Valley overnight. Another area of high pressure will develop southward across the Pacific Northwest and northern Rockies, in association with the second upper wave. While 60s F dewpoints will remain from the FL Straits toward the Bahamas, little destabilization is expected over the mainland. Thunderstorms may occur over parts of the central Gulf of Mexico along the surging cold front, with little impact to land expected. ..Jewell.. 01/20/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Sun Jan 19 2025 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Tuesday. ...Synopsis... A large positive-tilt upper trough will stretch from the upper Great Lakes into the southern High Plains Tuesday morning, and will progress toward the East Coast by 12Z Wednesday. Behind this wave, another lobe of vorticity will drop south across the Rockies and toward the Plains late. At the surface, a strong high pressure ridge will extend from the Great Basin all the way to the Mid Atlantic Tuesday morning, with this high consolidating across the eastern states and toward the lower MS Valley overnight. Another area of high pressure will develop southward across the Pacific Northwest and northern Rockies, in association with the second upper wave. While 60s F dewpoints will remain from the FL Straits toward the Bahamas, little destabilization is expected over the mainland. Thunderstorms may occur over parts of the central Gulf of Mexico along the surging cold front, with little impact to land expected. ..Jewell.. 01/20/2025 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1149 PM CST Sun Jan 19 2025 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast on Tuesday. ...Synopsis... A large positive-tilt upper trough will stretch from the upper Great Lakes into the southern High Plains Tuesday morning, and will progress toward the East Coast by 12Z Wednesday. Behind this wave, another lobe of vorticity will drop south across the Rockies and toward the Plains late. At the surface, a strong high pressure ridge will extend from the Great Basin all the way to the Mid Atlantic Tuesday morning, with this high consolidating across the eastern states and toward the lower MS Valley overnight. Another area of high pressure will develop southward across the Pacific Northwest and northern Rockies, in association with the second upper wave. While 60s F dewpoints will remain from the FL Straits toward the Bahamas, little destabilization is expected over the mainland. Thunderstorms may occur over parts of the central Gulf of Mexico along the surging cold front, with little impact to land expected. ..Jewell.. 01/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1101 PM CST Sun Jan 19 2025 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Discussion... A significant short wave perturbation is forecast to continue progressing through the crest of blocking larger-scale mid-level ridging centered over the northeastern Pacific, eventually digging across the Canadian Rockies and adjacent Pacific Northwest by late tonight. Downstream, short wave ridging likely will overspread the Canadian Prairies, northern U.S. Rockies and Great Basin, in the wake of digging short wave troughing across the northern Great Plains through upper Mississippi Valley/Great Lakes region and across the Southwest/southern Rockies and adjacent international border vicinity. Farther east, it appears that strong, confluent southwesterly mid/upper flow will be maintained between a prominent ridge centered over the subtropical western Atlantic and a broad, cold cyclonic circulation centered east-northeast of Hudson Bay. Beneath this regime, surface troughing likely will develop and deepen across the Canadian Prairies into the lee of the northern U.S. Rockies. Otherwise, though its center is forecast to shift from the lee of the northern through southern Rockies, expansive cold surface ridging will generally be maintained across much of the interior U.S, with another high center building across the Allegheny Mountains/Mid Atlantic vicinity. The frontal zone demarcating the leading edge of this cold intrusion probably will begin to stall and weaken east/southeast of the Florida Peninsula into the southeastern Gulf of Mexico, well in the wake of a rapidly deepening cyclone migrating across and northeast of the Canadian Maritimes. ...Texas coastal areas... Models do indicate that weak troughing will form on the southern flank of the cold surface ridge, from the southwestern toward northwestern Gulf of Mexico today through tonight. Any associated boundary-layer destabilization likely will remain focused well offshore of the lower Texas coast. However, elevated moisture return may contribute to weak CAPE rooted around the 700 mb level as far north as the upper Texas coast by 12Z Tuesday. RAP and NAM forecast soundings suggest that it might not be out of the question that convection, supported by ascent associated with lower/mid-tropospheric warm advection, might become capable of producing some lightning. But, due to lingering uncertainties, thunderstorm probabilities will be maintained at less than 10 percent, at least for now. ..Kerr.. 01/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1101 PM CST Sun Jan 19 2025 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Discussion... A significant short wave perturbation is forecast to continue progressing through the crest of blocking larger-scale mid-level ridging centered over the northeastern Pacific, eventually digging across the Canadian Rockies and adjacent Pacific Northwest by late tonight. Downstream, short wave ridging likely will overspread the Canadian Prairies, northern U.S. Rockies and Great Basin, in the wake of digging short wave troughing across the northern Great Plains through upper Mississippi Valley/Great Lakes region and across the Southwest/southern Rockies and adjacent international border vicinity. Farther east, it appears that strong, confluent southwesterly mid/upper flow will be maintained between a prominent ridge centered over the subtropical western Atlantic and a broad, cold cyclonic circulation centered east-northeast of Hudson Bay. Beneath this regime, surface troughing likely will develop and deepen across the Canadian Prairies into the lee of the northern U.S. Rockies. Otherwise, though its center is forecast to shift from the lee of the northern through southern Rockies, expansive cold surface ridging will generally be maintained across much of the interior U.S, with another high center building across the Allegheny Mountains/Mid Atlantic vicinity. The frontal zone demarcating the leading edge of this cold intrusion probably will begin to stall and weaken east/southeast of the Florida Peninsula into the southeastern Gulf of Mexico, well in the wake of a rapidly deepening cyclone migrating across and northeast of the Canadian Maritimes. ...Texas coastal areas... Models do indicate that weak troughing will form on the southern flank of the cold surface ridge, from the southwestern toward northwestern Gulf of Mexico today through tonight. Any associated boundary-layer destabilization likely will remain focused well offshore of the lower Texas coast. However, elevated moisture return may contribute to weak CAPE rooted around the 700 mb level as far north as the upper Texas coast by 12Z Tuesday. RAP and NAM forecast soundings suggest that it might not be out of the question that convection, supported by ascent associated with lower/mid-tropospheric warm advection, might become capable of producing some lightning. But, due to lingering uncertainties, thunderstorm probabilities will be maintained at less than 10 percent, at least for now. ..Kerr.. 01/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1101 PM CST Sun Jan 19 2025 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Discussion... A significant short wave perturbation is forecast to continue progressing through the crest of blocking larger-scale mid-level ridging centered over the northeastern Pacific, eventually digging across the Canadian Rockies and adjacent Pacific Northwest by late tonight. Downstream, short wave ridging likely will overspread the Canadian Prairies, northern U.S. Rockies and Great Basin, in the wake of digging short wave troughing across the northern Great Plains through upper Mississippi Valley/Great Lakes region and across the Southwest/southern Rockies and adjacent international border vicinity. Farther east, it appears that strong, confluent southwesterly mid/upper flow will be maintained between a prominent ridge centered over the subtropical western Atlantic and a broad, cold cyclonic circulation centered east-northeast of Hudson Bay. Beneath this regime, surface troughing likely will develop and deepen across the Canadian Prairies into the lee of the northern U.S. Rockies. Otherwise, though its center is forecast to shift from the lee of the northern through southern Rockies, expansive cold surface ridging will generally be maintained across much of the interior U.S, with another high center building across the Allegheny Mountains/Mid Atlantic vicinity. The frontal zone demarcating the leading edge of this cold intrusion probably will begin to stall and weaken east/southeast of the Florida Peninsula into the southeastern Gulf of Mexico, well in the wake of a rapidly deepening cyclone migrating across and northeast of the Canadian Maritimes. ...Texas coastal areas... Models do indicate that weak troughing will form on the southern flank of the cold surface ridge, from the southwestern toward northwestern Gulf of Mexico today through tonight. Any associated boundary-layer destabilization likely will remain focused well offshore of the lower Texas coast. However, elevated moisture return may contribute to weak CAPE rooted around the 700 mb level as far north as the upper Texas coast by 12Z Tuesday. RAP and NAM forecast soundings suggest that it might not be out of the question that convection, supported by ascent associated with lower/mid-tropospheric warm advection, might become capable of producing some lightning. But, due to lingering uncertainties, thunderstorm probabilities will be maintained at less than 10 percent, at least for now. ..Kerr.. 01/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1101 PM CST Sun Jan 19 2025 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Discussion... A significant short wave perturbation is forecast to continue progressing through the crest of blocking larger-scale mid-level ridging centered over the northeastern Pacific, eventually digging across the Canadian Rockies and adjacent Pacific Northwest by late tonight. Downstream, short wave ridging likely will overspread the Canadian Prairies, northern U.S. Rockies and Great Basin, in the wake of digging short wave troughing across the northern Great Plains through upper Mississippi Valley/Great Lakes region and across the Southwest/southern Rockies and adjacent international border vicinity. Farther east, it appears that strong, confluent southwesterly mid/upper flow will be maintained between a prominent ridge centered over the subtropical western Atlantic and a broad, cold cyclonic circulation centered east-northeast of Hudson Bay. Beneath this regime, surface troughing likely will develop and deepen across the Canadian Prairies into the lee of the northern U.S. Rockies. Otherwise, though its center is forecast to shift from the lee of the northern through southern Rockies, expansive cold surface ridging will generally be maintained across much of the interior U.S, with another high center building across the Allegheny Mountains/Mid Atlantic vicinity. The frontal zone demarcating the leading edge of this cold intrusion probably will begin to stall and weaken east/southeast of the Florida Peninsula into the southeastern Gulf of Mexico, well in the wake of a rapidly deepening cyclone migrating across and northeast of the Canadian Maritimes. ...Texas coastal areas... Models do indicate that weak troughing will form on the southern flank of the cold surface ridge, from the southwestern toward northwestern Gulf of Mexico today through tonight. Any associated boundary-layer destabilization likely will remain focused well offshore of the lower Texas coast. However, elevated moisture return may contribute to weak CAPE rooted around the 700 mb level as far north as the upper Texas coast by 12Z Tuesday. RAP and NAM forecast soundings suggest that it might not be out of the question that convection, supported by ascent associated with lower/mid-tropospheric warm advection, might become capable of producing some lightning. But, due to lingering uncertainties, thunderstorm probabilities will be maintained at less than 10 percent, at least for now. ..Kerr.. 01/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1101 PM CST Sun Jan 19 2025 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Discussion... A significant short wave perturbation is forecast to continue progressing through the crest of blocking larger-scale mid-level ridging centered over the northeastern Pacific, eventually digging across the Canadian Rockies and adjacent Pacific Northwest by late tonight. Downstream, short wave ridging likely will overspread the Canadian Prairies, northern U.S. Rockies and Great Basin, in the wake of digging short wave troughing across the northern Great Plains through upper Mississippi Valley/Great Lakes region and across the Southwest/southern Rockies and adjacent international border vicinity. Farther east, it appears that strong, confluent southwesterly mid/upper flow will be maintained between a prominent ridge centered over the subtropical western Atlantic and a broad, cold cyclonic circulation centered east-northeast of Hudson Bay. Beneath this regime, surface troughing likely will develop and deepen across the Canadian Prairies into the lee of the northern U.S. Rockies. Otherwise, though its center is forecast to shift from the lee of the northern through southern Rockies, expansive cold surface ridging will generally be maintained across much of the interior U.S, with another high center building across the Allegheny Mountains/Mid Atlantic vicinity. The frontal zone demarcating the leading edge of this cold intrusion probably will begin to stall and weaken east/southeast of the Florida Peninsula into the southeastern Gulf of Mexico, well in the wake of a rapidly deepening cyclone migrating across and northeast of the Canadian Maritimes. ...Texas coastal areas... Models do indicate that weak troughing will form on the southern flank of the cold surface ridge, from the southwestern toward northwestern Gulf of Mexico today through tonight. Any associated boundary-layer destabilization likely will remain focused well offshore of the lower Texas coast. However, elevated moisture return may contribute to weak CAPE rooted around the 700 mb level as far north as the upper Texas coast by 12Z Tuesday. RAP and NAM forecast soundings suggest that it might not be out of the question that convection, supported by ascent associated with lower/mid-tropospheric warm advection, might become capable of producing some lightning. But, due to lingering uncertainties, thunderstorm probabilities will be maintained at less than 10 percent, at least for now. ..Kerr.. 01/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1101 PM CST Sun Jan 19 2025 Valid 201200Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Discussion... A significant short wave perturbation is forecast to continue progressing through the crest of blocking larger-scale mid-level ridging centered over the northeastern Pacific, eventually digging across the Canadian Rockies and adjacent Pacific Northwest by late tonight. Downstream, short wave ridging likely will overspread the Canadian Prairies, northern U.S. Rockies and Great Basin, in the wake of digging short wave troughing across the northern Great Plains through upper Mississippi Valley/Great Lakes region and across the Southwest/southern Rockies and adjacent international border vicinity. Farther east, it appears that strong, confluent southwesterly mid/upper flow will be maintained between a prominent ridge centered over the subtropical western Atlantic and a broad, cold cyclonic circulation centered east-northeast of Hudson Bay. Beneath this regime, surface troughing likely will develop and deepen across the Canadian Prairies into the lee of the northern U.S. Rockies. Otherwise, though its center is forecast to shift from the lee of the northern through southern Rockies, expansive cold surface ridging will generally be maintained across much of the interior U.S, with another high center building across the Allegheny Mountains/Mid Atlantic vicinity. The frontal zone demarcating the leading edge of this cold intrusion probably will begin to stall and weaken east/southeast of the Florida Peninsula into the southeastern Gulf of Mexico, well in the wake of a rapidly deepening cyclone migrating across and northeast of the Canadian Maritimes. ...Texas coastal areas... Models do indicate that weak troughing will form on the southern flank of the cold surface ridge, from the southwestern toward northwestern Gulf of Mexico today through tonight. Any associated boundary-layer destabilization likely will remain focused well offshore of the lower Texas coast. However, elevated moisture return may contribute to weak CAPE rooted around the 700 mb level as far north as the upper Texas coast by 12Z Tuesday. RAP and NAM forecast soundings suggest that it might not be out of the question that convection, supported by ascent associated with lower/mid-tropospheric warm advection, might become capable of producing some lightning. But, due to lingering uncertainties, thunderstorm probabilities will be maintained at less than 10 percent, at least for now. ..Kerr.. 01/20/2025 Read more