Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Sun Dec 04 2022 Valid 041700Z - 051200Z ...NO CRITICAL AREAS... No changes are need to the current D1 Fire Outlook. See previous discussion below. ..Thornton.. 12/04/2022 .PREV DISCUSSION... /ISSUED 0101 AM CST Sun Dec 04 2022/ ...Synopsis... Fire weather concerns will remain limited across the CONUS today. Latest analyses indicate that the driest fuels remain across the central High Plains of eastern CO, western KS, and southwest NE. While persistent zonal flow over the central Rockies will maintain weak lee troughing across this region today, a combination of gradual height rises and displacement from stronger mid/upper flow to the north will limit the surface mass response and overall wind magnitudes. RH values may fall into the 20-30% range this afternoon, but fire weather concerns will be limited to locations that see occasional gusts between 15-20 mph (most probable across central NE). Recent ensemble guidance shows low probability for widespread fire weather concerns, further precluding the need for highlights. ...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 1010 AM CST Sun Dec 04 2022 Valid 041630Z - 051200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... A mid/upper-level low west of the OR/CA border area will drift towards the coast through early Monday. Bands of ascent associated with embedded perturbations along with moderately steep lower-level lapse rates and weak buoyancy will support potential for isolated thunderstorms from the northern CA coast into the Sacramento Valley through tonight. Small hail is possible in low-topped convection along the immediate coast where buoyancy should be relatively greater, but the bulk of strong mid/upper speed shear will exist above the buoyancy profile owing to a pronounced inversion between 500-350 mb. Weak elevated convection will remain possible across southeast AZ and far southwest NM, within a persistent subtropical moisture plume. Scant buoyancy might support sporadic lightning flashes. ..Grams/Squitieri.. 12/04/2022 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1242 PM CST Sat Dec 03 2022 Valid 041200Z - 051200Z ...NO CRITICAL AREAS... No changes are needed to the D2 Fire Outlook. See previous discussion below. ..Thornton.. 12/03/2022 .PREV DISCUSSION... /ISSUED 0150 AM CST Sat Dec 03 2022/ ...Synopsis... Fire weather concerns will remain limited for Sunday across much of the CONUS. Broad, low-amplitude ridging is expected across the central U.S. on Sunday, which will maintain largely zonal flow across the Rockies and weak lee troughing over the High Plains. A surface low deepening over the Canadian Prairies ahead of an upper disturbance will result in 15-20 mph gradient winds across the northern and central Plains. An antecedent dry air mass in place across eastern CO/western KS will likely see another day of RH reductions into the 25-35% range; however, winds across this region are expected to remain near or below 15 mph. A small area of overlapping dry air/breezy conditions is possible across west/southwest NE that may allow for brief/localized elevated conditions, but this potential appears too limited for highlights based on latest ensemble guidance. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No Mesoscale Discussions are in effect as of Sat Dec 3 18:44:01 UTC 2022.

No watches are valid as of Sat Dec 3 18:44:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Sat Dec 03 2022 Valid 041200Z - 051200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few lightning flashes may still occur near coastal northern California/southern Oregon, and possibly across parts of the Desert Southwest on Sunday. ...Synopsis... Cool, dry, and stable low-level air, overspread by relatively zonal flow aloft, should limit buoyancy, deep-layer ascent, and associated thunderstorm potential across much of the CONUS tomorrow/Sunday. One exception may be the immediate inland portions of the West Coast, where a mid-level trough and associated surface low will promote enough lift and buoyancy (albeit scant) to support occasional lightning flashes throughout the day. Though ascent will be weak, a couple of lightning flashes may also occur across southern portions of AZ and NM, where low 50s F surface dewpoints will support marginal buoyancy. ..Squitieri.. 12/03/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1017 AM CST Sat Dec 03 2022 Valid 031700Z - 041200Z ...NO CRITICAL AREAS... No changes are needed to the current D1 Fire Outlook. See previous discussion below. ..Thornton.. 12/03/2022 .PREV DISCUSSION... /ISSUED 1249 AM CST Sat Dec 03 2022/ ...Synopsis... The potential for critical fire weather conditions will remain low for today, though regional concerns are possible across parts of western Kansas this afternoon. Early-morning surface observations show building high pressure across the central Plains in the wake of a surging cold front. This surface high is expected to migrate east/southeast through the afternoon with a southerly flow regime becoming established on its western periphery over the High Plains. Despite cold temperatures, the dry continental air mass, coupled with no appreciable moisture return, will support RH in the 25-35% range across western KS. Gradient winds at 15-20 mph may occasionally gust to 25-30 mph. Although antecedent drought conditions across KS will support fire spread, elevated fire weather conditions are expected to remain patchy and localized in nature to where RH can approach 20% and coincide with gusty winds. Confidence in a more widespread threat is limited by increasing cloud cover during peak daytime heating, which should limit RH reductions and boundary-layer mixing. ...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 0937 AM CST Sat Dec 03 2022 Valid 031630Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...Discussion... A shortwave trough over the Lower Great Lakes will quickly move east across the Saint Lawrence Valley. An attendant surface cold front will push east across the Northeast and off the New England coast this evening, with its trailing portion lagging southwestward in the Southeast. Low-level moisture will remain greater over the central Gulf Coast, but forcing for ascent will continue to weaken along the slowly advancing portion of the front. Very poor 700-500 mb lapse rates of 4.5-5 C/km evident in 12Z JAN and BMX soundings suggest lingering convection in the interior Deep South will struggle to adequately deepen for charge separation. Farther northeast over the Carolinas vicinity, elevated buoyancy appears to be quite minimal and potential for sporadic flashes within warm advection-driven convection should diminish by mid-afternoon. In the West, isolated thunderstorms may persist into the afternoon with highly elevated convection across southern AZ where scant buoyancy has developed within a modest warm/moist advection regime, downstream of a lower-latitude shortwave trough in the eastern Pacific. Farther north, a more prominent upper low off the OR coast will slowly edge towards the coast through early Sunday. Adequate mid-level cooling might support low-topped thunderstorms overnight along the northern CA coast. ..Grams/Kerr.. 12/03/2022 Read more

No watches are valid as of Fri Dec 2 17:46:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Dec 2 17:46:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Fri Dec 02 2022 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Synopsis... A strong mid/upper-level shortwave trough initially over the Great Lakes is forecast to move quickly eastward toward New England through the day, as a cold front sweeps through New England, the Ohio Valley, and Southeast/southern Plains. To the west, a deep-layer cyclone is forecast to gradually move eastward and approach the southern OR/northern CA coasts by the end of the period. Weak buoyancy will support showers with some embedded lightning potential across parts of the Southeast into the southern/central Appalachians. A few lightning flashes may also be possible late in the period near the northern CA coast, as the deep-layer cyclone approaches the region. ...Parts of New England... Increasing low-level moisture, frontal convergence, and strong low-level flow may result in the development of gusty low-topped showers along the front across parts of New England Saturday afternoon. With buoyancy currently expected to remain negligible across the region, the potential for convectively enhanced severe gusts is too uncertain at this time for wind probabilities. ..Dean.. 12/02/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1039 AM CST Fri Dec 02 2022 Valid 021700Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR CENTRAL HIGH PLAINS... No changes were made to the current outlook. Latest surface observations within the Critical risk area across southeastern Colorado show winds gusting 50+ mph with relative humidity dropping around 20-25 percent. Further downslope warming and drying will continue through the afternoon ahead of the cold frontal passage. See previous discussion for more details. ..Thornton.. 12/02/2022 .PREV DISCUSSION... /ISSUED 0102 AM CST Fri Dec 02 2022/ ...Synopsis... Critical fire weather conditions are expected today across portions of the central High Plains. Early-morning surface observations show robust troughing in the lee of the central to northern Rockies ahead of a progressive upper-level wave. A surface cyclone consolidating across the northern High Plains will shift east through the day with a trailing cold front surging south/southeast in its wake. Strong winds ahead of and behind this front will support fire weather concerns across eastern CO and much of western KS. ...Central High Plains... Strong downslope flow is already evident in the lee of the CO Rockies where RH is falling into the 20-30% range. This dry air mass will spread east into eastern CO and western KS by early afternoon behind the surface trough. Continued downslope warming, coupled with clearing skies, will allow temperatures to warm into the low 70s with RH values falling into the 15-25% range. Sustained gradient winds at 20-25 mph will see frequent gusts to 30-40 mph amid deep boundary-layer mixing. The greatest fire weather concern will likely emerge across portions of west-central KS where critical wind/RH will overlap with the greatest 14 and 30-day rainfall deficits. The cold front will most likely move into northwest KS by late afternoon, bringing a shift to northwesterly winds gusting to 40-50 mph. While RH is expected to quickly recover behind the front, the strong post-frontal winds may support spread of any ongoing fires. ...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 1021 AM CST Fri Dec 02 2022 Valid 021630Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis... A potent mid-level shortwave trough over the Eastern Great Basin/central Rockies will rapidly move east and reach the Great Lakes/OH Valley by early Saturday morning. An elongated area of surface low pressure from the central High Plains to the Upper Midwest will consolidate as the cyclone develops northeast into Ontario by early tonight. A cold front will sweep southeast across much of the central U.S. through daybreak Saturday. A corridor of strong moisture transport atop a seasonably cool continental airmass centered over the TN Valley, will contribute to weak buoyancy and the development of scattered showers and a few thunderstorms. ..Smith/Squitieri.. 12/02/2022 Read more

No watches are valid as of Thu Dec 1 17:56:02 UTC 2022.

MD 1994 CONCERNING HEAVY SNOW FOR NORTHERN SIERRA NEVADA
Mesoscale Discussion 1994 NWS Storm Prediction Center Norman OK 1154 AM CST Thu Dec 01 2022 Areas affected...northern Sierra Nevada Concerning...Heavy snow Valid 011754Z - 012200Z SUMMARY...Heavy snow is likely to continue through this afternoon along the western slopes of the Sierra Nevada, to the west and southwest of Lake Tahoe, with rates perhaps peaking on the order of 2-3+ inches per hour during the 1-4 PM PST time frame. DISCUSSION...In advance of a significant short wave trough still digging near the northern Pacific coast, a surface cold front is already in the process of advancing southward across northern into central California. This includes the northern Sierra Nevada, with a continued gradual progress across the higher terrain to the west and southwest of Lake Tahoe during the next several hours. As lower-levels gradually cool in the wake of the cold front, models indicate that strong warm advection will be maintained aloft (around/above the 700 mb level) into the 21-00Z time frame along/west of the Sierra Nevada, before the upstream mid-level troughing turns inland of the Pacific coast. The latest Rapid Refresh suggests that heaviest snow rates will be maintained in a corridor along the higher terrain to the west and southwest of Lake Tahoe, and may intensify further late this afternoon as lift in the dendritic growth layer maximizes. As low-levels cool, forecast soundings suggest that snow levels may lower toward and below 3000 ft. ..Kerr.. 12/01/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...REV...STO... LAT...LON 39982148 40012074 39082025 38632031 38622070 39052096 39392122 39982148 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CST Thu Dec 01 2022 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Friday. ...Synopsis... A mid/upper-level trough is forecast to move from the central/northern Rockies across the Great Plains during the day on Friday, and into parts of the Midwest/Great Lakes by early Saturday morning. In conjunction with this trough, a surface cyclone is forecast to deepen over the upper MS Valley and then move northeastward into northern Ontario, as an attendant cold front moves through the central/northern Plains and Midwest. Surface-based buoyancy is expected to remain negligible across the CONUS, which should help to limit any threat of severe thunderstorms. A rather strong southwesterly low-level jet will support stronger moisture return above the surface into parts of the lower/mid MS Valley and OH Valley. This will result in the development of modest elevated buoyancy, and may support the potential for sporadic lightning flashes as precipitation expands through the afternoon/evening within a low-level warm advection regime. ..Dean.. 12/01/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1042 AM CST Thu Dec 01 2022 Valid 011700Z - 021200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 12/01/2022 .PREV DISCUSSION... /ISSUED 0131 AM CST Thu Dec 01 2022/ ...Synopsis... Falling heights and increasing mid-level flow will lead to lee cyclogenesis across eastern Colorado today. Strengthening surface winds will develop across portions of the central Plains. However, these winds of 15 to 20 mph will likely occur with relative humidity in the 25 to 30 percent range. Therefore, borderline relative humidity amid only moderately dry fuels precludes the need for an Elevated fire weather delineation. However, these dry and breezy conditions will help cure fuels for stronger winds on Friday. ...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 1027 AM CST Thu Dec 01 2022 Valid 011630Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis... Water-vapor imagery early today shows a mid-level trough moving ashore the West Coast with quasi-zonal flow downstream over the central U.S. The mid-level trough over the West will move east into the northern Rockies/Great Basin by early morning Friday. A few thunderstorms are possible from near the mouth of the Columbia River southward into far northern parts of coastal CA, due in part to -35 deg C 500 mb temperatures and scant buoyancy. Elsewhere, a few thunderstorms may develop and perhaps move ashore in parts of South FL and the upper Keys this afternoon. ..Smith.. 12/01/2022 Read more

No watches are valid as of Wed Nov 30 17:58:02 UTC 2022.

No Mesoscale Discussions are in effect as of Wed Nov 30 17:58:02 UTC 2022.