Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0634 AM CST Tue Feb 15 2022 Valid 151300Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms may occur late this afternoon into early tonight from parts of central Nevada toward the Coastal Range in southern California. ...Synopsis... A deep midlevel trough will progress southeastward over CA/NV and will reach the lower CO River valley by Wednesday morning. Cold midlevel temperatures and associated steep lapse rates will support the potential for low-topped convection and isolated lightning flashes both from east of the southern Sierra Nevada into northwest AZ this afternoon into early tonight, and across southern CA. Otherwise, air mass modification and the early stages of return flow are underway across the Gulf basin and FL Straits. However, the degree of moistening inland will be insufficient for deep convection until later in the D2 period across the southern Plains and south FL. ..Thompson.. 02/15/2022 Read more

No Mesoscale Discussions are in effect as of Mon Feb 14 14:50:01 UTC 2022.

No watches are valid as of Mon Feb 14 14:50:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0627 AM CST Mon Feb 14 2022 Valid 141300Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms possible across the Pacific Northwest region later today into tonight. ...Synopsis... A midlevel shortwave trough just west of Vancouver Island this morning will dig south-southeastward over OR to northeastern CA/northern NV by Tuesday morning. Steepening low-midlevel lapse rates with the approach of the midlevel cold pool (colder than -30 C at 500 mb) will support weak buoyancy and the potential for isolated lightning flashes with low-topped convection in the zone of ascent immediately preceding the midlevel trough. Otherwise, the CONUS will be dominated by cool and/or dry air in the low levels, which will preclude thunderstorms. ..Thompson.. 02/14/2022 Read more

No watches are valid as of Thu Feb 10 17:47:02 UTC 2022.

No Mesoscale Discussions are in effect as of Thu Feb 10 17:47:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1108 AM CST Thu Feb 10 2022 Valid 111200Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Aside from a small portion of Deep South Texas, the risk for thunderstorms appears low across much of the contiguous United States on Friday. ...Synopsis and Discussion... Mean upper troughing will remain prominent over much of the central and eastern states as multiple shorter wavelength impulses move across these regions. At the surface, a low initially over the Great Lakes will develop northeastward into Quebec through the day, while an attendant cold front sweeps south-southeastward across much of the Plains and MS Valley. Ahead of this front, modest low-level moisture should return northward across parts of Deep South TX into the northern Gulf of Mexico and south FL. Mid-level lapse rates are forecast to gradually steepen across Deep South TX through the period, which combined with the increasing low-level moisture should foster the development of weak MUCAPE, particularly Friday night. Although large-scale ascent will likely remain nebulous on the southern periphery of the large-scale upper trough, isolated thunderstorms appear possible Friday into Friday night across portions of Deep South TX as elevated instability gradually increases. ..Gleason.. 02/10/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1039 AM CST Thu Feb 10 2022 Valid 101700Z - 111200Z ...NO CRITICAL AREAS... The previous forecast remains on track, and no changes were made with this update. Despite minimum afternoon RH remaining in the 25 to 35 percent range across parts of KS and NE, breezy/gusty west-southwesterly winds could support localized/brief elevated fire-weather conditions today. However, these conditions appear too marginal and localized to introduce an Elevated area at this time. ..Weinman.. 02/10/2022 .PREV DISCUSSION... /ISSUED 0147 AM CST Thu Feb 10 2022/ ...Synopsis... Broad cyclonic flow aloft will overspread the CONUS as a surface cyclone approaches the Great Lakes and a cold front moves southeast across the northern Plains. Relatively cooler temperatures and resultant higher RH in proximity to the cold front should limit wildfire spread potential across the central/northern Plains. Drier surface air is expected across the southern High Plains, but the lack of an appreciable surface wind field should also limit wildfire spread concerns here as well. Dry offshore flow is expected to continue across southern California, with Elevated to occasionally Critical meteorological surface conditions likely. Nonetheless, fuels are poorly receptive to fire spread on a widespread basis, with no fire weather highlights introduced. ...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 1030 AM CST Thu Feb 10 2022 Valid 101630Z - 111200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected across the contiguous United States through tonight. ...Synopsis/Discussion... A highly amplified large-scale pattern with longwave troughing east of the Rockies, in conjunction with limited moisture and continental trajectories, will result in negligible thunderstorm potential across the CONUS today and tonight. Some shallow convection is expected this afternoon and early evening across eastern New York into New England near an eastward-moving front. However, it is generally not expected to reach sufficient depth/favorable temperatures for lightning generation. ..Guyer.. 02/10/2022 Read more

No Mesoscale Discussions are in effect as of Wed Feb 9 17:16:01 UTC 2022.

No watches are valid as of Wed Feb 9 17:16:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CST Wed Feb 09 2022 Valid 101200Z - 111200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast across the contiguous United States on Thursday. ...Synopsis and Discussion... Large-scale upper troughing will be maintained over much of the central/eastern CONUS on Thursday, with multiple shorter wavelength impulses moving generally eastward across this region. Due to a prior frontal passage and surface high pressure remaining centered over the Southeast and northern Gulf of Mexico, low-level moisture is expected to remain quite meager over land. This will limit instability and the potential for thunderstorms across the CONUS on Thursday. ..Gleason.. 02/09/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1030 AM CST Wed Feb 09 2022 Valid 091630Z - 101200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected across the U.S. through tonight. ...Synopsis/Discussion... An amplified large-scale pattern will persist with the continuance of mean longwave troughing east of the Rockies. The CONUS-wide prevalence of cool/stable conditions will likely preclude thunderstorm development. That said, a few thunderstorms will remain a possibility offshore near a front near/just east of the Florida Keys and south Florida. Elsewhere, across the Ohio Valley, while low/mid-level lapse rates will be rather steep (> 7 C/km) with daytime heating/mixing, low-level moisture will be quite limited within the continental polar air mass. The scenario should be insufficient for deep convection/lightning this afternoon/early evening across northern Kentucky and southern Ohio and vicinity. ..Guyer.. 02/09/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0958 AM CST Wed Feb 09 2022 Valid 091700Z - 101200Z An Elevated area was added for parts of the northeastern TX Panhandle, western and north-central OK, and south-central KS. Here, clear skies and downslope flow should favor deep boundary-layer mixing and RH reductions into the middle/upper teens to lower/middle 20s by this afternoon (based on modified AMA/DDC/OUN/LMN 12Z soundings). While a weak pressure gradient should generally limit sustained winds to around 10-15 mph across this area, a belt of fast flow aloft should favor frequent wind gusts of 20-25 mph as the boundary layer deepens to around 2-3 km. In addition, fuels are favorable for the development and spread of wildfires over the area, with ERCs in the 70th-80th percentile (aided by ongoing drought and a lack of substantial precipitation). Elsewhere, the previous forecast remains valid, with localized elevated conditions possible over north-central KS and the TX South Plains (see below). ..Weinman.. 02/09/2022 .PREV DISCUSSION... /ISSUED 0140 AM CST Wed Feb 09 2022/ ...Synopsis... Broad mid-level troughing will dominate the upper pattern across the central and eastern U.S. today as surface high pressure persists across the inter-mountain West. This high pressure will spill into the Plains states, fostering weak, dry northerly surface flow. Dry offshore flow will also persist across California. In the Plains states, fuels are very receptive to fire spread across most locales. However, Elevated conditions are expected to remain localized given the lack of a widespread, stronger surface wind field. The best chance for any Elevated conditions would be across the central Plains, where surface winds may exceed 15 mph and briefly coincide with minimum RH around 20-25 percent by afternoon peak heating. While winds will be weaker across western Texas, RH may drop into the 10-15 percent range, supporting localized wildfire-spread potential wherever gusty winds may occur. Elevated to Critical meteorological surface conditions are expected to accompany the offshore flow across southern California through the day tomorrow. However, high fuel moisture will limit widespread significant wildfire-spread potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Feb 8 13:18:01 UTC 2022.

No Mesoscale Discussions are in effect as of Tue Feb 8 13:18:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0646 AM CST Tue Feb 08 2022 Valid 081300Z - 091200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast across the contiguous Unites States today. ...Southeast FL/Keys through tonight... A southern stream shortwave trough will move across the Gulf of Mexico to north FL overnight, while a quasi-stationary front persists just off the southeast FL coast and near/just south of the Keys. The stronger/deeper buoyancy will remain confined to the southeast Gulf of Mexico, and the threat for thunderstorms should remain a little west of the Keys. Shallow convection will also occur near or just off the southeast FL coast, but buoyancy profiles appear to be too shallow/warm to support any appreciable threat for lightning. ..Thompson.. 02/08/2022 Read more

No watches are valid as of Fri Feb 4 15:23:01 UTC 2022.

MD 0130 CONCERNING WINTER MIXED PRECIPITATION FOR PARTS OF FAR NORTHEASTERN PA...NORTHERN NJ...SOUTHERN NY...AND NEW ENGLAND
Mesoscale Discussion 0130 NWS Storm Prediction Center Norman OK 0920 AM CST Fri Feb 04 2022 Areas affected...Parts of far northeastern PA...northern NJ...southern NY...and New England Concerning...Winter mixed precipitation Valid 041520Z - 042115Z SUMMARY...A mix of sleet and freezing rain should continue through much of the day where surface temperatures fall below freezing. Freezing rain rates around 0.05 inch per 3 hours appear possible. DISCUSSION...A broad swath of precipitation is ongoing this morning from the northern Mid-Atlantic into New England associated with large-scale lift preceding an upper trough over the Upper Midwest/Great Lakes. Latest surface analysis also shows a front extending from VA/MD northeastward to southern NY and coastal southern New England. The 12Z observed sounding from ALB showed a +2.7C warm nose centered around 825 mb and a deep sub-freezing layer from that level to the surface. This is supporting melting and then complete refreezing of hydrometeors aloft. Multiple sleet observations have been reported in a narrow corridor as a result, generally extending from parts of northeastern PA to eastern NY and southern NH. Latest RAP forecast soundings farther south into northern NJ, southern NY, and MA show a more pronounced warm nose. Indeed, mostly freezing rain is occurring across these areas where surface temperatures have fallen below freezing behind the front. Current expectations are for the front to continue advancing slowly southward through the day, with air temperatures gradually decreasing as well. This process should support a gradual transition from rain to freezing rain this morning and afternoon from parts of northeastern PA into northern NJ, southern NY, CT, RI, and much of MA. This includes the NYC metro area. Similarly, freezing rain that is ongoing farther north should gradually transition to sleet and perhaps even some snow as the warm nose aloft is slowly eroded with the approach of the upper trough. Given current radar reflectivity trends, freezing rain rates around 0.05 inch per 3 hours appear plausible, with locally higher accretion rates to about 0.10 inch per hour possible. ..Gleason.. 02/04/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...OKX...ALY...PHI...BGM... LAT...LON 40597385 40597426 40797556 40937571 41607520 42247463 42827388 43217150 43117062 42557046 41597070 41367175 41207310 40597385 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0656 AM CST Fri Feb 04 2022 Valid 041300Z - 051200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe-thunderstorm potential appears minimal today over the conterminous U.S. ...Synopsis... The mid/upper-level pattern will trend toward eastern troughing again through the period, as two primary shortwave perturbations phase: 1. A northern-stream trough now over MN and the eastern Dakotas, forecast to dig southeastward to the central Appalachians and amplify by 12Z tomorrow. 2. A southern-stream trough evident in moisture-channel imagery from central KS across the TX Panhandle, south-central NM and southeastern AZ. This feature will maintain substantially positive tilt as it shifts eastward to GA, central AL, southern MS, and southwestern LA by the end of the period. A surface cold front -- analyzed at 11Z across northern VA, western NC, western GA, and the western FL Panhandle -- will move eastward to southeastward, offshore from New England by 00Z. At that time, the front should extend from the Hampton Roads region across the eastern Carolinas to near coastal GA, and over extreme northern peninsular FL. By 12Z, the front will have cleared all the Atlantic Coast except central FL, extending from there southwestward over the south-central Gulf. ...Coastal NC to northeastern FL... Widely scattered to scattered non-severe thunderstorms have been common just ahead of the front through the preceding overnight hours, over parts of GA, AL and the FL Panhandle. This convection should persist through the afternoon with minor intensification possible, until the front passes offshore from GA and the Carolinas. Isolated gusts approaching severe limits cannot be ruled out; however, the severe threat appears too weak to maintain an unconditional outlook over coastal GA. With large-scale ascent lagging the front and prefrontal convective band, temperatures aloft and related weak mid/upper-level lapse rates should not change much above the front at any given latitude. A pronounced stable layer in midlevels (500-600 mb) -- observed in 12Z TLH/CHS soundings, is forecast to remain along/ahead of the convective band through the afternoon. With northward extent, already modest low-level destabilization will weaken, and prefrontal surface winds should veer gradually with time, shrinking hodographs. A corridor of 200-700 J/kg MLCAPE is expected, amidst 20-30-kt effective-shear magnitudes and around 35-45-kt cloud-layer shear. ..Edwards/Goss.. 02/04/2022 Read more