Aggregator

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

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

MD 0039 CONCERNING HEAVY SNOW FOR PORTIONS OF THE MID-ATLANTIC AND NORTHEAST
Mesoscale Discussion 0039 NWS Storm Prediction Center Norman OK 0334 PM CST Sun Jan 19 2025 Areas affected...Portions of the Mid-Atlantic and Northeast Concerning...Heavy snow Valid 192134Z - 200100Z SUMMARY...Heavy snowfall will continue to shift northeastward this evening across portions of the Mid-Atlantic and Northeast with rates of >=1" per hour possible. DISCUSSION...The latest water vapor imagery indicates that the mid/upper-level speed max is exiting the coast. As a result, the surface low is deepening off of Delmarva and is forecast to continue strengthening offshore and move quickly to the northeast. Low-level frontogenesis will continue to support upward vertical motion and precipitation banding. Precipitation type is more uncertain near the coast where strong low-level warm air advection will act to offset cooling by evaporation and melting over the next few hours. Thus, the corridor with the highest confidence of 1"+ snowfall rates over the next few hours has been highlighted. ..Jirak/Mosier.. 01/19/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...OKX...ALY...PHI...BGM... LAT...LON 41857286 41487335 41127372 40807419 40527458 40357527 40617574 41167540 41777467 42177422 42537378 42897315 43077272 43187218 42867184 42477217 42307238 41857286 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sun Jan 19 2025 Valid 200100Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for additional thunderstorm development across the southern Florida Peninsula and Keys appears negligible through the remainder of tonight. ...01z Update... The cold front is still in the process of advancing across the southern Florida Peninsula. However, stronger low-level convergence is now generally focused near and offshore of coastal areas to the south through east of the Palm Beach vicinity, and probabilities for additional thunderstorm development are becoming increasingly negligible beneath lingering warm and dry layers aloft. Based on latest observational data, the risk for thunderstorms will generally remain focused well offshore of the Atlantic coast, and south of the Florida Keys, through the remainder of tonight. ..Kerr.. 01/20/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sun Jan 19 2025 Valid 200100Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for additional thunderstorm development across the southern Florida Peninsula and Keys appears negligible through the remainder of tonight. ...01z Update... The cold front is still in the process of advancing across the southern Florida Peninsula. However, stronger low-level convergence is now generally focused near and offshore of coastal areas to the south through east of the Palm Beach vicinity, and probabilities for additional thunderstorm development are becoming increasingly negligible beneath lingering warm and dry layers aloft. Based on latest observational data, the risk for thunderstorms will generally remain focused well offshore of the Atlantic coast, and south of the Florida Keys, through the remainder of tonight. ..Kerr.. 01/20/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sun Jan 19 2025 Valid 200100Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for additional thunderstorm development across the southern Florida Peninsula and Keys appears negligible through the remainder of tonight. ...01z Update... The cold front is still in the process of advancing across the southern Florida Peninsula. However, stronger low-level convergence is now generally focused near and offshore of coastal areas to the south through east of the Palm Beach vicinity, and probabilities for additional thunderstorm development are becoming increasingly negligible beneath lingering warm and dry layers aloft. Based on latest observational data, the risk for thunderstorms will generally remain focused well offshore of the Atlantic coast, and south of the Florida Keys, through the remainder of tonight. ..Kerr.. 01/20/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sun Jan 19 2025 Valid 200100Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for additional thunderstorm development across the southern Florida Peninsula and Keys appears negligible through the remainder of tonight. ...01z Update... The cold front is still in the process of advancing across the southern Florida Peninsula. However, stronger low-level convergence is now generally focused near and offshore of coastal areas to the south through east of the Palm Beach vicinity, and probabilities for additional thunderstorm development are becoming increasingly negligible beneath lingering warm and dry layers aloft. Based on latest observational data, the risk for thunderstorms will generally remain focused well offshore of the Atlantic coast, and south of the Florida Keys, through the remainder of tonight. ..Kerr.. 01/20/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sun Jan 19 2025 Valid 200100Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for additional thunderstorm development across the southern Florida Peninsula and Keys appears negligible through the remainder of tonight. ...01z Update... The cold front is still in the process of advancing across the southern Florida Peninsula. However, stronger low-level convergence is now generally focused near and offshore of coastal areas to the south through east of the Palm Beach vicinity, and probabilities for additional thunderstorm development are becoming increasingly negligible beneath lingering warm and dry layers aloft. Based on latest observational data, the risk for thunderstorms will generally remain focused well offshore of the Atlantic coast, and south of the Florida Keys, through the remainder of tonight. ..Kerr.. 01/20/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sun Jan 19 2025 Valid 200100Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for additional thunderstorm development across the southern Florida Peninsula and Keys appears negligible through the remainder of tonight. ...01z Update... The cold front is still in the process of advancing across the southern Florida Peninsula. However, stronger low-level convergence is now generally focused near and offshore of coastal areas to the south through east of the Palm Beach vicinity, and probabilities for additional thunderstorm development are becoming increasingly negligible beneath lingering warm and dry layers aloft. Based on latest observational data, the risk for thunderstorms will generally remain focused well offshore of the Atlantic coast, and south of the Florida Keys, through the remainder of tonight. ..Kerr.. 01/20/2025 Read more

No watches are valid as of Sun Jan 19 22:31:02 UTC 2025.

MD 0039 CONCERNING HEAVY SNOW FOR PORTIONS OF THE MID-ATLANTIC AND NORTHEAST
Mesoscale Discussion 0039 NWS Storm Prediction Center Norman OK 0334 PM CST Sun Jan 19 2025 Areas affected...Portions of the Mid-Atlantic and Northeast Concerning...Heavy snow Valid 192134Z - 200100Z SUMMARY...Heavy snowfall will continue to shift northeastward this evening across portions of the Mid-Atlantic and Northeast with rates of >=1" per hour possible. DISCUSSION...The latest water vapor imagery indicates that the mid/upper-level speed max is exiting the coast. As a result, the surface low is deepening off of Delmarva and is forecast to continue strengthening offshore and move quickly to the northeast. Low-level frontogenesis will continue to support upward vertical motion and precipitation banding. Precipitation type is more uncertain near the coast where strong low-level warm air advection will act to offset cooling by evaporation and melting over the next few hours. Thus, the corridor with the highest confidence of 1"+ snowfall rates over the next few hours has been highlighted. ..Jirak/Mosier.. 01/19/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...OKX...ALY...PHI...BGM... LAT...LON 41857286 41487335 41127372 40807419 40527458 40357527 40617574 41167540 41777467 42177422 42537378 42897315 43077272 43187218 42867184 42477217 42307238 41857286 Read more

MD 0038 CONCERNING HEAVY SNOW FOR PORTIONS OF MID-ATLANTIC STATES
Mesoscale Discussion 0038 NWS Storm Prediction Center Norman OK 1200 PM CST Sun Jan 19 2025 Areas affected...Portions of Mid-Atlantic States Concerning...Heavy snow Valid 191800Z - 192230Z SUMMARY...Snowfall will continue to increase from southwest to northeast across portions of West Virginia, Maryland, and Pennsylvania this afternoon with rates exceeding 1" per hour. DISCUSSION...An upper-level trough and associated speed max rotating around a low near Hudson Bay are moving toward the East Coast this afternoon. In response at the surface, a low over North Carolina is forecast to deepen and shift northeastward through the afternoon. To the north to northwest of the surface low, low-level frontogenesis will promote upward vertical motion and precipitation banding. Given these favorable factors and cold vertical profiles, snowfall rates of >=1" per hour are likely this afternoon with higher rates possible in banded structures. ..Jirak/Mosier.. 01/19/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...CTP...LWX...RNK...PBZ...RLX... LAT...LON 39687582 39517657 39347767 39067877 38717917 38377961 38078019 38018068 38168091 38788077 39448031 40117977 40437925 40867841 40947721 40887643 40637544 40257509 39927529 39687582 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0355 PM CST Sun Jan 19 2025 Valid 211200Z - 271200Z ...Southern California - Day 3/Tuesday... Critical to extremely critical fire-weather conditions will be ongoing across southern CA at the start of the Day 3/Tuesday period, as the offshore pressure gradient will be at peak magnitudes (LAX-DAG gradient around -8 to -10 mb). This gradient, coupled with continued upper-level support through at least 15Z, will result in very strong/gusty northeasterly surface winds and single-digit RH across much of southern CA. The strongest winds should remain focused over the wind-prone Santa Ana corridor of northern/western Los Angeles County into eastern Ventura County -- where the greatest risk of Extremely Critical conditions will persist through at least 15Z. Thereafter, the positive-tilt shortwave trough and strong winds aloft that were providing upper-level support for the strong Santa Ana event on Day 3/Tuesday will continue east-southeastward into the central CONUS. However, strong surface high pressure will persist across the Intermountain West, favoring continued dry offshore flow across southern CA on Day 4/Wednesday through Day 5/Thursday. Current indications are that the offshore pressure gradient will yield elevated to locally critical fire-weather conditions both days/mornings, though the lack of upper-level support limits confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. ..Weinman.. 01/19/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0355 PM CST Sun Jan 19 2025 Valid 211200Z - 271200Z ...Southern California - Day 3/Tuesday... Critical to extremely critical fire-weather conditions will be ongoing across southern CA at the start of the Day 3/Tuesday period, as the offshore pressure gradient will be at peak magnitudes (LAX-DAG gradient around -8 to -10 mb). This gradient, coupled with continued upper-level support through at least 15Z, will result in very strong/gusty northeasterly surface winds and single-digit RH across much of southern CA. The strongest winds should remain focused over the wind-prone Santa Ana corridor of northern/western Los Angeles County into eastern Ventura County -- where the greatest risk of Extremely Critical conditions will persist through at least 15Z. Thereafter, the positive-tilt shortwave trough and strong winds aloft that were providing upper-level support for the strong Santa Ana event on Day 3/Tuesday will continue east-southeastward into the central CONUS. However, strong surface high pressure will persist across the Intermountain West, favoring continued dry offshore flow across southern CA on Day 4/Wednesday through Day 5/Thursday. Current indications are that the offshore pressure gradient will yield elevated to locally critical fire-weather conditions both days/mornings, though the lack of upper-level support limits confidence in any more than locally critical conditions -- precluding 70-percent probabilities at this time. ..Weinman.. 01/19/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more