Aggregator

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1012 AM CST Tue Jan 21 2025 Valid 211630Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Synopsis... Expansive high pressure associated with a polar airmass is in place across is in place east of Rockies. This high, which is currently centered over eastern OK/western AR, is expected to shift eastward/northeastward throughout the day, ending the period over the Ohio Valley. Associated cold, dry, and stable conditions will preclude thunderstorm development. A similar environment is anticipated across the western CONUS, with high pressure and associated stability dominating the sensible weather. A deepening surface low will continue to shift eastward across the Gulf of Mexico, with strong warm-air advection throughout its warm sector contributing to a broad precipitation field across the Gulf Coast. A few lightning flashes were observed over Acadia Parish in south-central LA over the past hour, but these flashes were most likely created by the self-initiated upward leader process. Given the continuing windy conditions and potential for mixed-phase hydrometeors at low levels, some additional self-initiated flashes are possible throughout the period. ..Mosier/Thornton.. 01/21/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1012 AM CST Tue Jan 21 2025 Valid 211630Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. ...Synopsis... Expansive high pressure associated with a polar airmass is in place across is in place east of Rockies. This high, which is currently centered over eastern OK/western AR, is expected to shift eastward/northeastward throughout the day, ending the period over the Ohio Valley. Associated cold, dry, and stable conditions will preclude thunderstorm development. A similar environment is anticipated across the western CONUS, with high pressure and associated stability dominating the sensible weather. A deepening surface low will continue to shift eastward across the Gulf of Mexico, with strong warm-air advection throughout its warm sector contributing to a broad precipitation field across the Gulf Coast. A few lightning flashes were observed over Acadia Parish in south-central LA over the past hour, but these flashes were most likely created by the self-initiated upward leader process. Given the continuing windy conditions and potential for mixed-phase hydrometeors at low levels, some additional self-initiated flashes are possible throughout the period. ..Mosier/Thornton.. 01/21/2025 Read more

MD 0047 CONCERNING HEAVY SNOW FOR FAR SOUTHEAST TEXAS INTO SOUTH-CENTRAL LOUISIANA
Mesoscale Discussion 0047 NWS Storm Prediction Center Norman OK 0447 AM CST Tue Jan 21 2025 Areas affected...Far southeast Texas into south-central Louisiana Concerning...Heavy snow Valid 211047Z - 211515Z SUMMARY...Moderate snowfall with embedded heavier bands will become more likely over the next several hours in southern Louisiana. DISCUSSION...The broad upper-level trough across the central/eastern U.S. is in the process of intensifying this morning. As this occurs, the upper-level jet along eastern flank of the trough will also intensify. Increasing mid/upper-level ascent as well as at least weak lower-level frontogenesis (850-700 mb or so) will promote favorable conditions for dendritic growth. Moderate snowfall has already been observed at several stations in southwestern Louisiana over the last hour. With the most favorable synoptic conditions expected to occur around mid/late morning, moderate snowfall should become increasingly prevalent across southern Louisiana in particular. Some banded structures will be possible which could produce heavier snowfall rates (0.5-1 in/hr) at least locally. ..Wendt.. 01/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LIX...LCH... LAT...LON 29749396 29999432 30579416 30979267 31019185 30809148 30689122 29949132 29709181 29669242 29709266 29749396 Read more

MD 0046 CONCERNING WINTER MIXED PRECIPITATION FOR PORTIONS OF THE MIDDLE AND UPPER TEXAS COAST VICINITY
Mesoscale Discussion 0046 NWS Storm Prediction Center Norman OK 0256 AM CST Tue Jan 21 2025 Areas affected...Portions of the Middle and Upper Texas Coast Vicinity Concerning...Winter mixed precipitation Valid 210856Z - 211330Z SUMMARY...A mix of sleet and light freezing rain/drizzle will remain possible through daybreak. A gradual shift to snow (from north to south) will also occur with time. DISCUSSION...A mix of winter precipitation continues within and north the Middle/Upper Texas Coast regions. Based on reported precipitation and model sounding data, a mixture of sleet and lighter freezing rain/drizzle is most likely. Given the presence of steep lapse rates at cloud top (both noted in regional observed soundings and model soundings), some convective elements are possible and would be more efficient sleet producers. With time, additional large-scale ascent will cool the atmospheric column such that precipitation should continue to switch to all snow by daybreak and beyond. Should freezing rain/drizzle linger, this is most likely to be nearer the coast where the cold air may be shallow enough to support it. ..Wendt.. 01/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...HGX...CRP...EWX... LAT...LON 28049692 27649732 27679765 27819799 28169817 29139788 29569711 30089523 30039480 29439466 28049692 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Tue Jan 21 2025 Valid 211300Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. today through tonight. A large surface high dominates the weather across the CONUS today, with cold, dry, and stable conditions preventing thunderstorms. A strengthening surface low off the Gulf coast may provide isolated thunderstorms offshore later today and tonight, but lightning activity is expected to remain well south of the coast. ..Hart/Wendt.. 01/21/2025 Read more

MD 0045 CONCERNING HEAVY SNOW FOR PORTIONS OF FAR WESTERN NEW YORK
Mesoscale Discussion 0045 NWS Storm Prediction Center Norman OK 1030 PM CST Mon Jan 20 2025 Areas affected...portions of far western New York Concerning...Heavy snow Valid 210430Z - 211030Z SUMMARY...At least 2-3 inch/hour snowfall rates should continue past sunrise with an intense lake-effect snow band. DISCUSSION...MRMS mosaic and KTYX radar imagery show an intense, steady-state lake-effect snow band persisting across Jefferson and Lewis Counties in far western NY. This snow-band is benefiting from an optimal fetch of moisture off of Lake Ontario, where 8+ C/km 0-3 km lapse rates are in place. As such, convective snowfall within this lake-effect band should persist past sunrise, as shown by the latest high-resolution guidance consensus. Furthermore, given the convective nature of the band, and degree of saturation in the dendritic growth zone, snowfall rates at least in the 2-3 inch/hour range are expected through the remainder of tonight. ..Squitieri.. 01/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF... LAT...LON 43977634 44027567 43947519 43697514 43547540 43587581 43617612 43647630 43977634 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0302 AM CST Tue Jan 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... An amplified and progressive upper trough will move quickly from the MS Valley to the East Coast on Friday/D4, with zonal flow developing behind this system. High pressure will follow, maintaining dry offshore winds across the Southeast. Models remain in relatively good agreement with the large-scale pattern through the weekend, depicting a positive-tilt upper trough over the southwestern states. A broad fetch of west/southwest flow aloft is forecast to extend across the southern Plains and into much of the East, with the deep upper low over eastern Canada. Sufficient instability is forecast to develop across parts of southern and eastern TX into the lower MS Valley Saturday/D5 Night into Sunday/D6. Given the antecedent cool air at the surface, substantial clouds and precipitation appear likely, reducing overall destabilization and severe potential. Models diverge around Monday/D7, with uncertainly regarding whether another wave will develop into the northern Plains and Great Lakes as disturbances rotate around the large-scale low. To the west, the trough/low over the Southwest may eventually eject east, but timing for this is uncertain as well with low predictability at this time frame. In any case, severe potential is forecast to be low through the period. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0302 AM CST Tue Jan 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... An amplified and progressive upper trough will move quickly from the MS Valley to the East Coast on Friday/D4, with zonal flow developing behind this system. High pressure will follow, maintaining dry offshore winds across the Southeast. Models remain in relatively good agreement with the large-scale pattern through the weekend, depicting a positive-tilt upper trough over the southwestern states. A broad fetch of west/southwest flow aloft is forecast to extend across the southern Plains and into much of the East, with the deep upper low over eastern Canada. Sufficient instability is forecast to develop across parts of southern and eastern TX into the lower MS Valley Saturday/D5 Night into Sunday/D6. Given the antecedent cool air at the surface, substantial clouds and precipitation appear likely, reducing overall destabilization and severe potential. Models diverge around Monday/D7, with uncertainly regarding whether another wave will develop into the northern Plains and Great Lakes as disturbances rotate around the large-scale low. To the west, the trough/low over the Southwest may eventually eject east, but timing for this is uncertain as well with low predictability at this time frame. In any case, severe potential is forecast to be low through the period. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0302 AM CST Tue Jan 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... An amplified and progressive upper trough will move quickly from the MS Valley to the East Coast on Friday/D4, with zonal flow developing behind this system. High pressure will follow, maintaining dry offshore winds across the Southeast. Models remain in relatively good agreement with the large-scale pattern through the weekend, depicting a positive-tilt upper trough over the southwestern states. A broad fetch of west/southwest flow aloft is forecast to extend across the southern Plains and into much of the East, with the deep upper low over eastern Canada. Sufficient instability is forecast to develop across parts of southern and eastern TX into the lower MS Valley Saturday/D5 Night into Sunday/D6. Given the antecedent cool air at the surface, substantial clouds and precipitation appear likely, reducing overall destabilization and severe potential. Models diverge around Monday/D7, with uncertainly regarding whether another wave will develop into the northern Plains and Great Lakes as disturbances rotate around the large-scale low. To the west, the trough/low over the Southwest may eventually eject east, but timing for this is uncertain as well with low predictability at this time frame. In any case, severe potential is forecast to be low through the period. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0302 AM CST Tue Jan 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... An amplified and progressive upper trough will move quickly from the MS Valley to the East Coast on Friday/D4, with zonal flow developing behind this system. High pressure will follow, maintaining dry offshore winds across the Southeast. Models remain in relatively good agreement with the large-scale pattern through the weekend, depicting a positive-tilt upper trough over the southwestern states. A broad fetch of west/southwest flow aloft is forecast to extend across the southern Plains and into much of the East, with the deep upper low over eastern Canada. Sufficient instability is forecast to develop across parts of southern and eastern TX into the lower MS Valley Saturday/D5 Night into Sunday/D6. Given the antecedent cool air at the surface, substantial clouds and precipitation appear likely, reducing overall destabilization and severe potential. Models diverge around Monday/D7, with uncertainly regarding whether another wave will develop into the northern Plains and Great Lakes as disturbances rotate around the large-scale low. To the west, the trough/low over the Southwest may eventually eject east, but timing for this is uncertain as well with low predictability at this time frame. In any case, severe potential is forecast to be low through the period. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0302 AM CST Tue Jan 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... An amplified and progressive upper trough will move quickly from the MS Valley to the East Coast on Friday/D4, with zonal flow developing behind this system. High pressure will follow, maintaining dry offshore winds across the Southeast. Models remain in relatively good agreement with the large-scale pattern through the weekend, depicting a positive-tilt upper trough over the southwestern states. A broad fetch of west/southwest flow aloft is forecast to extend across the southern Plains and into much of the East, with the deep upper low over eastern Canada. Sufficient instability is forecast to develop across parts of southern and eastern TX into the lower MS Valley Saturday/D5 Night into Sunday/D6. Given the antecedent cool air at the surface, substantial clouds and precipitation appear likely, reducing overall destabilization and severe potential. Models diverge around Monday/D7, with uncertainly regarding whether another wave will develop into the northern Plains and Great Lakes as disturbances rotate around the large-scale low. To the west, the trough/low over the Southwest may eventually eject east, but timing for this is uncertain as well with low predictability at this time frame. In any case, severe potential is forecast to be low through the period. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0302 AM CST Tue Jan 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... An amplified and progressive upper trough will move quickly from the MS Valley to the East Coast on Friday/D4, with zonal flow developing behind this system. High pressure will follow, maintaining dry offshore winds across the Southeast. Models remain in relatively good agreement with the large-scale pattern through the weekend, depicting a positive-tilt upper trough over the southwestern states. A broad fetch of west/southwest flow aloft is forecast to extend across the southern Plains and into much of the East, with the deep upper low over eastern Canada. Sufficient instability is forecast to develop across parts of southern and eastern TX into the lower MS Valley Saturday/D5 Night into Sunday/D6. Given the antecedent cool air at the surface, substantial clouds and precipitation appear likely, reducing overall destabilization and severe potential. Models diverge around Monday/D7, with uncertainly regarding whether another wave will develop into the northern Plains and Great Lakes as disturbances rotate around the large-scale low. To the west, the trough/low over the Southwest may eventually eject east, but timing for this is uncertain as well with low predictability at this time frame. In any case, severe potential is forecast to be low through the period. Read more