Aggregator

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0129 PM CST Mon Dec 26 2022 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms may occur across parts of northern California and southwest Oregon tonight. ...Discussion... No changes to the ongoing outlook appear to be required. ..Goss.. 12/26/2022 .PREV DISCUSSION... /ISSUED 0942 AM CST Mon Dec 26 2022/ ...Synopsis... An initial shortwave trough is moving inland over northwest WA this morning, while a stronger/upstream trough will approach the northern CA/OR coasts by 27/06-12z. Colder midlevel temperatures and steeper low-midlevel lapse rates will accompany the overnight trough as the primary baroclinic zone moves inland, and a few lightning flashes will become possible in the 06-12z time frame. Though wind profiles will be strong, very weak buoyancy will tend to limit any damaging-wind threat near the coast. Read more

No watches are valid as of Mon Dec 26 19:34:01 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Dec 26 19:34:01 UTC 2022.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1227 PM CST Mon Dec 26 2022 Valid 271200Z - 281200Z An Elevated risk area is introduced for portions of southeast Colorado and far northeast New Mexico where downslope winds are forecast to increase through the day. Latest hi-res ensemble guidance shows reasonably high probabilities for RH reductions into the teens with modest probability for sustained winds exceeding 15 mph in the lee of the Sangre de Cristo Mountains Tuesday afternoon. Frequent gusts between 20-25 mph are probable within the downslope regime and stronger gusts exceeding 35 knots are possible closer to terrain features. Recent fuel analyses indicate ERC values across the region are unseasonably high for late December after 30 days of below-average precipitation (5-10% of 30-day normal per latest AHPS analyses), which should support fire spread. Patchy elevated conditions are possible across eastern NM into the western TX Panhandle, but confidence in this potential is too low for highlights. ..Moore.. 12/26/2022 .PREV DISCUSSION... /ISSUED 1150 PM CST Sun Dec 25 2022/ ...Synopsis... Mid-level winds across the southern Rockies will increase on Tuesday. The surface high pressure will move further to the east and a lee trough will develop in the High Plains. Areas of dry downslope winds are possible, particularly in the lee of the Sangre de Cristo Mountains. These areas have seen a regional minimum in precipitation in the last two weeks. Though cooler temperatures will have mitigated some fuel drying, grasses in some locations could support some fire risk. Currently, the strongest winds are expected to be localized to terrain-favored locations. Highlights for southeast Colorado and northeast New Mexico could be added if confidence increases in stronger winds farther into the High Plains. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CST Mon Dec 26 2022 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not forecast across the contiguous United States on Tuesday. ...Discussion... As a mid-level short-wave trough initially centered over the Southeast shifts toward -- and then off -- the Atlantic Coast through the first half of the period, the upper pattern will deamplify a bit over the U.S. Some minor re-amplification will occur farther west, as short-wave troughing approaches/reaches the West Coast states. Overall, thunder potential will remain quite low to nonexistent across the country. A flash or two could occur near the southern Florida coast during the first half of the period, but expect this potential to remain largely, if not fully, offshore. Meanwhile, a few flashes from very shallow convection may occur across parts of southern Oregon/northern California. Greatest potential appears likely to remain confined to coastal areas, so the 10% thunder line is being trimmed westward this forecast. ..Goss.. 12/26/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0942 AM CST Mon Dec 26 2022 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms may occur across parts of northern California and southwest Oregon tonight, but severe weather is not expected. ...Synopsis... An initial shortwave trough is moving inland over northwest WA this morning, while a stronger/upstream trough will approach the northern CA/OR coasts by 27/06-12z. Colder midlevel temperatures and steeper low-midlevel lapse rates will accompany the overnight trough as the primary baroclinic zone moves inland, and a few lightning flashes will become possible in the 06-12z time frame. Though wind profiles will be strong, very weak buoyancy will tend to limit any damaging-wind threat near the coast. ..Thompson/Lyons.. 12/26/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0907 AM CST Mon Dec 26 2022 Valid 261700Z - 271200Z ...NO CRITICAL AREAS... Fire weather concerns will remain limited for today across the CONUS. Gusty post-frontal winds are expected across the southern Plains this afternoon; however, falling temperatures will modulate diurnal RH reductions and mitigate fire weather concerns. ..Moore.. 12/26/2022 .PREV DISCUSSION... /ISSUED 1150 PM CST Sun Dec 25 2022/ ...Synopsis... A shortwave trough will dig into the Southeast today. Farther west, an upper-level ridge will build across the Great Basin into the Plains. At the surface, a modest reinforcement of cold air is expected east of the Divide. Between cooler temperatures, light winds, and unreceptive fuels, fire weather concerns will be minimal. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0120 PM CST Sun Dec 25 2022 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes made. Please see the previous forecast below for more details. ..Squitieri.. 12/25/2022 .PREV DISCUSSION... /ISSUED 1150 PM CST Sat Dec 24 2022/ ...Synopsis... In the wake of the shortwave trough moving through the central Plains and into the Ohio/Tennessee Valley regions, a modest reinforcement of colder air will occur in the southern Plains on Monday. With high pressure building again much of the central/eastern U.S., cold temperatures and generally light winds will continue to keep fire weather concerns minimal. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Sun Dec 25 19:22:01 UTC 2022.

No Mesoscale Discussions are in effect as of Sun Dec 25 19:22:01 UTC 2022.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0114 PM CST Sun Dec 25 2022 Valid 252000Z - 261200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected through tonight. No changes were made to the outlook as thunderstorms are not expected today. Although a shortwave trough will approach western WA into Monday morning, little if any instability is forecast. ..Jewell.. 12/25/2022 .PREV DISCUSSION... /ISSUED 0949 AM CST Sun Dec 25 2022/ ...Synopsis... The general pattern of a midlevel ridge over the Great Basin and a downstream trough over the eastern CONUS will persist through early Monday, with dry/stable conditions in the low levels. Some precipitation is expected along the Pacific Northwest coast, in advance of a shortwave trough that will approach by early Monday. Some weak buoyancy (rooted in the mid levels) will be possible within the warm advection regime preceding the midlevel trough, but the threat for thunderstorms is expected to remain negligible. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CST Sun Dec 25 2022 Valid 261200Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Sporadic thunderstorms may occur over parts of northern California and southwest Oregon Monday night into Tuesday morning. Severe weather is not expected. ...Synopsis... An upper trough will move from the Plains into the Southeast on Monday, with a cold front and high pressure reinforcing the stable air mass from the Gulf of Mexico to the Atlantic Coast. To the west, the upper ridge will continue to break down over the Pacific Northwest as an intense mid/upper level jet streak noses into northern CA and OR into Tuesday morning. An associated deep surface low is forecast to approach Vancouver Island and the west coast of WA, enhancing surface convergence. QG forcing for ascent will increase Monday night across northern CA and into southwest OR as height falls occur along with low-level warm advection. Here, MUCAPE of 100-300 J/kg may develop behind the initial warm advection precipitation and as the stronger cooling aloft steepens lapse rates, most likely after 09Z. Forecast soundings reveal that some of these storms will be elevated, though SBCAPE will develop near the coast closer to 12Z. Given very strong winds just off the surface, a few strong wind gusts may occur. ..Jewell.. 12/25/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0953 AM CST Sun Dec 25 2022 Valid 251700Z - 261200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track. ..Squitieri.. 12/25/2022 .PREV DISCUSSION... /ISSUED 1149 PM CST Sat Dec 24 2022/ ...Synopsis... The surface high within the Plains will shift into the Southeast today. An upper-level shortwave trough will dig southward into the Northern Plains. A weak surface low in the southern High Plains will develop in response to the shortwave trough. Some cool, dry, down-peninsula flow will occur in Florida behind the cold front. Overall, however, continued cold temperatures and unreceptive fuels will keep fire weather concerns low. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0949 AM CST Sun Dec 25 2022 Valid 251630Z - 261200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected through tonight. ...Synopsis... The general pattern of a midlevel ridge over the Great Basin and a downstream trough over the eastern CONUS will persist through early Monday, with dry/stable conditions in the low levels. Some precipitation is expected along the Pacific Northwest coast, in advance of a shortwave trough that will approach by early Monday. Some weak buoyancy (rooted in the mid levels) will be possible within the warm advection regime preceding the midlevel trough, but the threat for thunderstorms is expected to remain negligible. ..Thompson/Lyons.. 12/25/2022 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0130 PM CST Sat Dec 24 2022 Valid 251200Z - 261200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/24/2022 .PREV DISCUSSION... /ISSUED 1142 PM CST Fri Dec 23 2022/ ...Synopsis... High pressure will generally remain in place in the West and parts of the Plains on Sunday. The main high pressure center east of the Rockies will likely shift more into the Southeast. Some moderation of the cold temperatures in the southern Plains is also expected. Nonetheless, poor fuel receptiveness to fire and otherwise poor overlap of dry/windy conditions will continue to limit fire concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Sat Dec 24 19:33:01 UTC 2022.

No Mesoscale Discussions are in effect as of Sat Dec 24 19:33:01 UTC 2022.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0106 PM CST Sat Dec 24 2022 Valid 242000Z - 251200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little if any thunderstorms are expected through tonight. An isolated flash cannot be ruled out over parts of Oregon. No changes were made from the previous outlook. Weak elevated MUCAPE around 100-200 J/kg may develop toward 00Z over parts of southwest Oregon with warm advection near 850 mb south of the main upper trough. However, overall coverage of thunderstorms is expected to remain below the 10% threshold. ..Jewell.. 12/24/2022 .PREV DISCUSSION... /ISSUED 1018 AM CST Sat Dec 24 2022/ ...Synopsis... A cold, continental air mass dominates the majority of the CONUS, in the wake of a deep cyclone now over western QC. A midlevel shortwave trough will crest the ridge along the Pacific coast while moving over WA later today. Very weak midlevel buoyancy will accompany the warm advection regime today near the WA/OR coast, and some shallow/post-frontal buoyancy is expected by this evening. In both cases, the threat for thunderstorms over land is too low to warrant the addition of an outlook area. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1032 AM CST Sat Dec 24 2022 Valid 251200Z - 261200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are unlikely over the contiguous United States on Sunday. ...Synopsis... An upper low will remain over eastern Canada on Sunday with an upper ridge over the West. In between, another shortwave trough will amplify as a wave dives southeastward across the Plains and toward the MS Valley. This will maintain a relatively stable surface pattern with offshore winds over the Gulf of Mexico and East Coast due to high pressure. Over the Pacific Northwest, heights will lower as a shortwave trough approaches the coast, but the deeper temperature gradient aloft will remain well offshore through Monday morning. As such, instability is not forecast to favor thunderstorms over land. Elsewhere, lake-effect snow will likely impact parts of northern NY, and a lightning flash cannot be ruled out near Lake Ontario. However, coverage of lightning is forecast to remain below the outlook threshold of 10%. ..Jewell.. 12/24/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1018 AM CST Sat Dec 24 2022 Valid 241630Z - 251200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected through tonight. ...Synopsis... A cold, continental air mass dominates the majority of the CONUS, in the wake of a deep cyclone now over western QC. A midlevel shortwave trough will crest the ridge along the Pacific coast while moving over WA later today. Very weak midlevel buoyancy will accompany the warm advection regime today near the WA/OR coast, and some shallow/post-frontal buoyancy is expected by this evening. In both cases, the threat for thunderstorms over land is too low to warrant the addition of an outlook area. ..Thompson/Lyons.. 12/24/2022 Read more