Aggregator

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0151 AM CST Fri Dec 13 2024 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is expected to remain limited on Sunday. ...Synopsis... An upper trough will migrate east from the Rockies into the Plains on Sunday. As this occurs, a surface low will track across the northern Plains. Meanwhile, a cold front will develop southeast across much of the northern/central Plains through the day. The front will continue southeast through the nighttime hours, becoming positioned from near Lake Michigan southwestward toward the Red River by Monday morning. Southerly low-level flow ahead of the front will allow 60s F dewpoints to spread north across east TX into southeast OK, and eastward across AR/LA. While vertically veering wind profiles typically would support some potential for organized convection, thermodynamics are expected to remain rather poor due to low-level inhibition and weak lapse rates. Furthermore, stronger height falls are not expected across the region until late in the period, further suppressing deep convective potential through much of the forecast period. While isolated elevated convection is possible in the low-level warm advection regime, severe potential appears limited. ..Leitman.. 12/13/2024 Read more

Corpus Christi was presently in Stage 2 drought restrictions and is expected to enter Stage 3 restrictions in August when Lake Corpus Christi and Choke Canyon combined storage are expected to drop below 20%. Corpus Christi entered Stage 1 restrictions in June 2022 and moved to Stage 2 in March 2024. Corpus Christi Caller Times (Texas), June 11, 2024 Stage 2 drought restrictions took effect in Corpus Christi on March 12, nearly two years after Stage 1 drought restrictions began. The combined capacity of Lake Corpus Christi and Choke Canyon Reservoir have dropped below 30%, which is the trigger for the next stage. On Monday, March 11, the combined capacity was 29.4%, according to the city manager. Stage 1 drought restrictions began in June 2022. Corpus Christi Caller Times (Texas) March 12, 2024

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1154 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central/South-Central States... An upper cyclone and attendant trough will lift east/northeast from the central/southern Plains toward the Great Lakes on Saturday. Only a weak reflection of this upper system is expected at the surface, where a low over eastern KS during the morning hours will generally weaken as it lifts northeast into the Upper Midwest. Southerly low-level flow will transport 60s F surface dewpoints into the TX coast and east TX and the Sabine Valley vicinity through evening. Isolated thunderstorms will be possible in this low-level warm advection regime ahead of the upper trough and weakening surface low from east TX/LA into the Lower and Mid-MS Valley. A strong storm or two may be possible across southeast TX into LA where deeper boundary-layer moisture and modest surface-based destabilization will overlap with weak vertical shear. However, large-scale ascent will remain weak as large-scale ascent remains displaced to the north. Additionally, low and midlevel lapse rates will remain poor. Overall severe potential is expected to remain negligible, and thunderstorm activity across the region should diminish during the evening hours. ...Pacific Coast States... Persistent onshore flow is forecast through the evening hours as an upper trough located offshore the Pacific coast Saturday morning moves inland toward the Rockies by Sunday morning. Isolated thunderstorms are expected, especially during the 12-18z time frame when large-scale ascent will be maximized amid steepening midlevel lapse rates. A strong southwesterly low-level jet will overspread portions of central CA during the morning to midday time period, resulting in some hodograph curvature. However, cool surface temperatures and very modest instability (generally less than 200 J/kg MLCAPE) will likely limit surface-based convection. ..Leitman.. 12/13/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1154 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central/South-Central States... An upper cyclone and attendant trough will lift east/northeast from the central/southern Plains toward the Great Lakes on Saturday. Only a weak reflection of this upper system is expected at the surface, where a low over eastern KS during the morning hours will generally weaken as it lifts northeast into the Upper Midwest. Southerly low-level flow will transport 60s F surface dewpoints into the TX coast and east TX and the Sabine Valley vicinity through evening. Isolated thunderstorms will be possible in this low-level warm advection regime ahead of the upper trough and weakening surface low from east TX/LA into the Lower and Mid-MS Valley. A strong storm or two may be possible across southeast TX into LA where deeper boundary-layer moisture and modest surface-based destabilization will overlap with weak vertical shear. However, large-scale ascent will remain weak as large-scale ascent remains displaced to the north. Additionally, low and midlevel lapse rates will remain poor. Overall severe potential is expected to remain negligible, and thunderstorm activity across the region should diminish during the evening hours. ...Pacific Coast States... Persistent onshore flow is forecast through the evening hours as an upper trough located offshore the Pacific coast Saturday morning moves inland toward the Rockies by Sunday morning. Isolated thunderstorms are expected, especially during the 12-18z time frame when large-scale ascent will be maximized amid steepening midlevel lapse rates. A strong southwesterly low-level jet will overspread portions of central CA during the morning to midday time period, resulting in some hodograph curvature. However, cool surface temperatures and very modest instability (generally less than 200 J/kg MLCAPE) will likely limit surface-based convection. ..Leitman.. 12/13/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1154 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central/South-Central States... An upper cyclone and attendant trough will lift east/northeast from the central/southern Plains toward the Great Lakes on Saturday. Only a weak reflection of this upper system is expected at the surface, where a low over eastern KS during the morning hours will generally weaken as it lifts northeast into the Upper Midwest. Southerly low-level flow will transport 60s F surface dewpoints into the TX coast and east TX and the Sabine Valley vicinity through evening. Isolated thunderstorms will be possible in this low-level warm advection regime ahead of the upper trough and weakening surface low from east TX/LA into the Lower and Mid-MS Valley. A strong storm or two may be possible across southeast TX into LA where deeper boundary-layer moisture and modest surface-based destabilization will overlap with weak vertical shear. However, large-scale ascent will remain weak as large-scale ascent remains displaced to the north. Additionally, low and midlevel lapse rates will remain poor. Overall severe potential is expected to remain negligible, and thunderstorm activity across the region should diminish during the evening hours. ...Pacific Coast States... Persistent onshore flow is forecast through the evening hours as an upper trough located offshore the Pacific coast Saturday morning moves inland toward the Rockies by Sunday morning. Isolated thunderstorms are expected, especially during the 12-18z time frame when large-scale ascent will be maximized amid steepening midlevel lapse rates. A strong southwesterly low-level jet will overspread portions of central CA during the morning to midday time period, resulting in some hodograph curvature. However, cool surface temperatures and very modest instability (generally less than 200 J/kg MLCAPE) will likely limit surface-based convection. ..Leitman.. 12/13/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1154 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central/South-Central States... An upper cyclone and attendant trough will lift east/northeast from the central/southern Plains toward the Great Lakes on Saturday. Only a weak reflection of this upper system is expected at the surface, where a low over eastern KS during the morning hours will generally weaken as it lifts northeast into the Upper Midwest. Southerly low-level flow will transport 60s F surface dewpoints into the TX coast and east TX and the Sabine Valley vicinity through evening. Isolated thunderstorms will be possible in this low-level warm advection regime ahead of the upper trough and weakening surface low from east TX/LA into the Lower and Mid-MS Valley. A strong storm or two may be possible across southeast TX into LA where deeper boundary-layer moisture and modest surface-based destabilization will overlap with weak vertical shear. However, large-scale ascent will remain weak as large-scale ascent remains displaced to the north. Additionally, low and midlevel lapse rates will remain poor. Overall severe potential is expected to remain negligible, and thunderstorm activity across the region should diminish during the evening hours. ...Pacific Coast States... Persistent onshore flow is forecast through the evening hours as an upper trough located offshore the Pacific coast Saturday morning moves inland toward the Rockies by Sunday morning. Isolated thunderstorms are expected, especially during the 12-18z time frame when large-scale ascent will be maximized amid steepening midlevel lapse rates. A strong southwesterly low-level jet will overspread portions of central CA during the morning to midday time period, resulting in some hodograph curvature. However, cool surface temperatures and very modest instability (generally less than 200 J/kg MLCAPE) will likely limit surface-based convection. ..Leitman.. 12/13/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected. ...Central US... Significant low-latitude energy currently extends across the southwestern US, with a split-flow regime noted at 500mb. Late-evening satellite imagery depicts a low-amplitude short-wave trough ejecting northeast across northern Mexico, but a much stronger feature approaching the Four Corners. This lead short wave will encourage modified boundary-layer moisture to begin advancing north across TX into the southern Plains early in the period. LLJ is forecast to increase Friday night across eastern OK into the lower MO Valley, as strong height falls spread into the central Plains. Latest model guidance suggests gradual air mass destabilization will occur within the warm-advection regime. Forecast soundings suggest scattered convection should develop during the overnight hours when elevated parcels become uninhibited by steepening lapse rates, and weaker inhibition. Current thinking is this activity should prove too weak to warrant any meaningful risk for severe hail. ...Northern California... Short-wave ridging will dominate CA early in the period, then substantial height falls will spread east ahead of a strong short-wave trough. While this feature will not advance inland until later in the day2 period, high-level diffluent flow will support frontal convection. Although the majority of convection should be focused along the boundary offshore, latest guidance suggests the wind shift will approach the northern CA coast by 12z. Forecast soundings exhibit weak, elevated MUCAPE ahead of the boundary, and around 100 J/kg SBCAPE near the actual cold front as profiles cool. A few flashes of lightning may be noted with the stronger updrafts. ..Darrow/Lyons.. 12/13/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected. ...Central US... Significant low-latitude energy currently extends across the southwestern US, with a split-flow regime noted at 500mb. Late-evening satellite imagery depicts a low-amplitude short-wave trough ejecting northeast across northern Mexico, but a much stronger feature approaching the Four Corners. This lead short wave will encourage modified boundary-layer moisture to begin advancing north across TX into the southern Plains early in the period. LLJ is forecast to increase Friday night across eastern OK into the lower MO Valley, as strong height falls spread into the central Plains. Latest model guidance suggests gradual air mass destabilization will occur within the warm-advection regime. Forecast soundings suggest scattered convection should develop during the overnight hours when elevated parcels become uninhibited by steepening lapse rates, and weaker inhibition. Current thinking is this activity should prove too weak to warrant any meaningful risk for severe hail. ...Northern California... Short-wave ridging will dominate CA early in the period, then substantial height falls will spread east ahead of a strong short-wave trough. While this feature will not advance inland until later in the day2 period, high-level diffluent flow will support frontal convection. Although the majority of convection should be focused along the boundary offshore, latest guidance suggests the wind shift will approach the northern CA coast by 12z. Forecast soundings exhibit weak, elevated MUCAPE ahead of the boundary, and around 100 J/kg SBCAPE near the actual cold front as profiles cool. A few flashes of lightning may be noted with the stronger updrafts. ..Darrow/Lyons.. 12/13/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected. ...Central US... Significant low-latitude energy currently extends across the southwestern US, with a split-flow regime noted at 500mb. Late-evening satellite imagery depicts a low-amplitude short-wave trough ejecting northeast across northern Mexico, but a much stronger feature approaching the Four Corners. This lead short wave will encourage modified boundary-layer moisture to begin advancing north across TX into the southern Plains early in the period. LLJ is forecast to increase Friday night across eastern OK into the lower MO Valley, as strong height falls spread into the central Plains. Latest model guidance suggests gradual air mass destabilization will occur within the warm-advection regime. Forecast soundings suggest scattered convection should develop during the overnight hours when elevated parcels become uninhibited by steepening lapse rates, and weaker inhibition. Current thinking is this activity should prove too weak to warrant any meaningful risk for severe hail. ...Northern California... Short-wave ridging will dominate CA early in the period, then substantial height falls will spread east ahead of a strong short-wave trough. While this feature will not advance inland until later in the day2 period, high-level diffluent flow will support frontal convection. Although the majority of convection should be focused along the boundary offshore, latest guidance suggests the wind shift will approach the northern CA coast by 12z. Forecast soundings exhibit weak, elevated MUCAPE ahead of the boundary, and around 100 J/kg SBCAPE near the actual cold front as profiles cool. A few flashes of lightning may be noted with the stronger updrafts. ..Darrow/Lyons.. 12/13/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected. ...Central US... Significant low-latitude energy currently extends across the southwestern US, with a split-flow regime noted at 500mb. Late-evening satellite imagery depicts a low-amplitude short-wave trough ejecting northeast across northern Mexico, but a much stronger feature approaching the Four Corners. This lead short wave will encourage modified boundary-layer moisture to begin advancing north across TX into the southern Plains early in the period. LLJ is forecast to increase Friday night across eastern OK into the lower MO Valley, as strong height falls spread into the central Plains. Latest model guidance suggests gradual air mass destabilization will occur within the warm-advection regime. Forecast soundings suggest scattered convection should develop during the overnight hours when elevated parcels become uninhibited by steepening lapse rates, and weaker inhibition. Current thinking is this activity should prove too weak to warrant any meaningful risk for severe hail. ...Northern California... Short-wave ridging will dominate CA early in the period, then substantial height falls will spread east ahead of a strong short-wave trough. While this feature will not advance inland until later in the day2 period, high-level diffluent flow will support frontal convection. Although the majority of convection should be focused along the boundary offshore, latest guidance suggests the wind shift will approach the northern CA coast by 12z. Forecast soundings exhibit weak, elevated MUCAPE ahead of the boundary, and around 100 J/kg SBCAPE near the actual cold front as profiles cool. A few flashes of lightning may be noted with the stronger updrafts. ..Darrow/Lyons.. 12/13/2024 Read more

MD 2265 CONCERNING HEAVY SNOW FOR PORTIONS OF WESTERN NY STATE AND LAKE ERIE COAST
Mesoscale Discussion 2265 NWS Storm Prediction Center Norman OK 0752 PM CST Thu Dec 12 2024 Areas affected...portions of western NY State and Lake Erie Coast Concerning...Heavy snow Valid 130152Z - 130545Z SUMMARY...Heavy lake-effect snow is likely to continue for a few more hours across parts of western NY downstream from lake Erie. The heaviest snow rates ~ 2-3 in/hr are expected before 4z before the band begins to weaken and shift south. DISCUSSION...As of 0145Z, composite radar imagery shows a well-developed band of heavy lake-effect snow ongoing across portions of western NY downstream from Lake Erie. After slight weakening earlier this afternoon, a notable uptick in reflectivity and band organization has been noted this evening. The axis of heaviest snow has shifted north with rates of 1-3 in/hr moving into the southern suburbs of BUF. This should continue for a a few more hours this evening as flow in the lowest 2-3 km remains west/southwesterly as observed from the 00Z KBUF RAOB. Peak snowfall rates of 2-3 in/hr are likely in the next 1-2 hours while low-level flow is best aligned with the lake fetch and remains fairly strong. Snowfall rates will begin to decrease later this evening and overnight as the stronger westerly flow weakens with the departing upper cyclone over the Canadian Maritimes. As this occurs, low-level winds are also expected to veer to northwesterly, supporting a southward shift in the band as it weakens. While lake-effect snow showers are likely to continue through the overnight, snowfall rates should decrease below 1 in/hr after 6-8z. ..Lyons.. 12/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF... LAT...LON 42887906 42977873 42967841 42857834 42767830 42457896 42347938 42327960 42327968 42657953 42887906 Read more

MD 2264 CONCERNING HEAVY SNOW FOR COASTAL LAKE ONTARIO INTO TUG HILL VICINITY OF NORTH CENTRAL NEW YORK STATE
Mesoscale Discussion 2264 NWS Storm Prediction Center Norman OK 0725 PM CST Thu Dec 12 2024 Areas affected...coastal Lake Ontario into Tug Hill vicinity of north central New York state Concerning...Heavy snow Valid 130125Z - 130530Z SUMMARY...An ongoing band of snow is forecast to shift or redevelop northward across portions of the Tug Hill, toward the Watertown vicinity, during the next few hours. As this occurs, it appears that peak snow rates will intensify, perhaps locally as high as 3-4 inches per hour by 10 PM to Midnight EST. DISCUSSION...Although heights are now rising, as stronger height falls begin to shift northeast of the Canadian Maritimes, deep mid-level troughing lingers across the Great Lakes region through much of the Northeast. In response to the progression of smaller-scale perturbations within this regime, including one notable impulse digging east-southeast of the upper Great Lakes, low/mid-level wind fields are in the process of backing across the lower Great Lakes region. Gradually, it appears this will include the eastern Lake Ontario into Tug Hill vicinity, where mean winds in the lowest 2-3 km AGL are forecast to transition from west-southwesterly to a more prominent southwesterly component through 03-05Z. It appears that this will coincide with strengthening large-scale ascent aided by at least a subtly moistening upslope component across the Tug Hill vicinity, near/southeast of Watertown. In the presence of subfreezing and saturating lower/mid-tropospheric thermodynamic profiles, forecast soundings indicate that this lift may become maximized for several hours within a layer near/above 850 mb, where temperatures are around -15 C and the environment is most conducive to dendritic ice crystal growth. Based on various model output, it appears that this will promote heavy snow rates in excess of 1 inch per, with guidance from the Rapid Refresh suggesting localized peak rates as high as 3-4 inches per hour. ..Kerr.. 12/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF... LAT...LON 43987612 44007559 43807540 43727581 43767603 43847621 43987612 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0628 PM CST Thu Dec 12 2024 Valid 130100Z - 131200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The probability of lightning is low across the CONUS tonight. ...01z Update... Seasonally cold upper trough will shift east across the Great Lakes into the northeastern US later tonight. Steep low-level lapse rates will continue to support shallow convection across the bigger/warmer bodies of water, especially downstream of Lake Ontario and Lake Erie. While a flash of lightning can not be ruled out with this activity, the prospect for thunderstorms is very low across most of the CONUS. ..Darrow.. 12/13/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0628 PM CST Thu Dec 12 2024 Valid 130100Z - 131200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The probability of lightning is low across the CONUS tonight. ...01z Update... Seasonally cold upper trough will shift east across the Great Lakes into the northeastern US later tonight. Steep low-level lapse rates will continue to support shallow convection across the bigger/warmer bodies of water, especially downstream of Lake Ontario and Lake Erie. While a flash of lightning can not be ruled out with this activity, the prospect for thunderstorms is very low across most of the CONUS. ..Darrow.. 12/13/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0628 PM CST Thu Dec 12 2024 Valid 130100Z - 131200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The probability of lightning is low across the CONUS tonight. ...01z Update... Seasonally cold upper trough will shift east across the Great Lakes into the northeastern US later tonight. Steep low-level lapse rates will continue to support shallow convection across the bigger/warmer bodies of water, especially downstream of Lake Ontario and Lake Erie. While a flash of lightning can not be ruled out with this activity, the prospect for thunderstorms is very low across most of the CONUS. ..Darrow.. 12/13/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0628 PM CST Thu Dec 12 2024 Valid 130100Z - 131200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The probability of lightning is low across the CONUS tonight. ...01z Update... Seasonally cold upper trough will shift east across the Great Lakes into the northeastern US later tonight. Steep low-level lapse rates will continue to support shallow convection across the bigger/warmer bodies of water, especially downstream of Lake Ontario and Lake Erie. While a flash of lightning can not be ruled out with this activity, the prospect for thunderstorms is very low across most of the CONUS. ..Darrow.. 12/13/2024 Read more

No watches are valid as of Thu Dec 12 22:16:02 UTC 2024.

No Mesoscale Discussions are in effect as of Thu Dec 12 22:16:02 UTC 2024.

Customers in Lancaster were still urged to voluntarily conserve water as the Conestoga River remained low. The water bureau initially asked the public to conserve water on November 4. WGAL (Lancaster, Pa.), Dec 12, 2024

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0328 PM CST Thu Dec 12 2024 Valid 141200Z - 201200Z A progressive pattern brings several storms across the CONUS with potential for cool temperatures and widespread precipitation. This will keep fire concerns low across much of the CONUS. Periods of dry/windy conditions are expected across the High/Southern Plains, however, fuels do not appear supportive of large-fire potential at this time. A few periods of Elevated conditions may be warranted where freeze cured grasses may carry some potential for increased fire activity. ERC forecasts do indicate fuels will dry, particularly across western Texas into eastern New Mexico, but largely remain below Critical thresholds. ..Thornton.. 12/12/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more