Severe Storms

No watches are valid as of Fri Mar 4 14:37:01 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Mar 4 14:37:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0659 AM CST Fri Mar 04 2022 Valid 041300Z - 051200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible today across portions of the southwestern U.S. into Colorado. Isolated thunderstorms are also expected late tonight from Nebraska into Iowa and southern Minnesota. ...Southwest States/Four Corners... A lead shortwave trough and related speed max over southern California this morning will eject northeastward and reach the Four Corners area this evening and the central High Plains late tonight. Along and north of this jet, cooling mid-level temperatures and steep lapse rates will contribute to weak buoyancy. This likely will be adequate for isolated semi-dry, high-based convection. While convection may struggle to produce appreciable precipitation, gusty winds could accompany some of this convection, especially during the afternoon across east/southeast Utah into western Colorado. While some stronger thunderstorm-related winds could materialize, the potential for severe-caliber thunderstorm-related gusts is currently expected to remain low. ...Central Plains/Upper Midwest... Late tonight, in tandem with weak height falls, an increasingly strong south-southwesterly low-level jet will develop across the central/southern Plains toward the upper Mississippi Valley. Elevated moisture transport will contribute to thermodynamic profiles that are increasingly conducive for thunderstorms, particularly across eastern Nebraska into Iowa and southern Minnesota (mainly 10 pm CST onward). While a few stronger thunderstorm updraft cores with hail may materialize late tonight, current expectations are for hail magnitudes to remain below severe levels given modest elevated buoyancy and an expected flow weakness in the lower part (650-800mb) of the cloud-bearing layer. ..Guyer/Dean.. 03/04/2022 Read more

No Mesoscale Discussions are in effect as of Thu Mar 3 14:43:01 UTC 2022.

No watches are valid as of Thu Mar 3 14:43:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 AM CST Thu Mar 03 2022 Valid 031300Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are expected across portions of southern California tonight. ...Southern California... Strong mid-level height falls (150m in 12hr) will overspread southern California and the Southwest Deserts tonight in advance of a southern-stream trough that will reach the SoCal coast early Friday morning. Increasing forcing for ascent and steepening low/mid-level lapse rates, along with a steady influx of low-level moisture, will be favorable for isolated thunderstorms tonight, initially offshore but subsequently into the coastal areas of SoCal. A couple hundred J/kg of SBCAPE could support some stronger/sustained low-topped thunderstorms late tonight/early Friday (09z-12z), potentially a few with weak/transient supercell characteristics owing to modest low-level hodograph curvature. Some gustier convectively related winds could materialize, but severe-caliber storms currently seem unlikely. ..Guyer/Leitman.. 03/03/2022 Read more

No Mesoscale Discussions are in effect as of Wed Mar 2 14:44:02 UTC 2022.

No watches are valid as of Wed Mar 2 14:44:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0654 AM CST Wed Mar 02 2022 Valid 021300Z - 031200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not forecast across the United States today or tonight. ...Synopsis/Discussion... The continued prevalence of dry/stable conditions across the Lower 48 will continue to result in an essentially nil thunderstorm potential today and tonight. The only conceivable potential for a lightning flash or two would be across northwest Washington in association with a shortwave trough approaching the British Columbia/Washington coasts. However, current expectations are for the shallow convection-related thermodynamic profiles to remain too marginal for a meaningful chance (10+ percent) and duration/coverage of thunderstorms. ..Guyer/Leitman.. 03/02/2022 Read more

No watches are valid as of Mon Feb 28 14:49:01 UTC 2022.

No Mesoscale Discussions are in effect as of Mon Feb 28 14:49:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Mon Feb 28 2022 Valid 281300Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are expected across parts of northeast Florida and southeast Georgia today. ...Northern Florida/southeast Georgia... A southern-stream shortwave trough will continue east-southeastward over Florida and southern Georgia today, while a cold front will sag southward across the Florida Peninsula. Even to the north of the southward-advancing front with a drying boundary layer, cool mid-level temperatures and modest elevated buoyancy may be sufficient for isolated elevated thunderstorms across northeast Florida and possibly far southeast Georgia. Any such lightning-producing convection should shift offshore early this evening. ..Guyer/Leitman.. 02/28/2022 Read more

No watches are valid as of Fri Feb 25 14:40:02 UTC 2022.

MD 0189 CONCERNING HEAVY SNOW FOR NORTHEAST NY...VT...NH...MA...ME
Mesoscale Discussion 0189 NWS Storm Prediction Center Norman OK 0746 AM CST Fri Feb 25 2022 Areas affected...Northeast NY...VT...NH...MA...ME Concerning...Heavy snow Valid 251346Z - 251745Z SUMMARY...Heavy snowfall will continue to develop east-northeastward through the morning from eastern New York, northern Massachusetts, Vermont into New Hampshire and western/southern Maine. Snowfall rates in excess of 1 in/hr are likely for several hours with brief/locally higher rates possible. DISCUSSION...A low-amplitude shortwave trough over the Lower Great Lakes/southern Ontario at mid-morning will continue steadily east-northeastward, with increasing/eastward-transitioning forcing for ascent influencing eastern New York into New England early today. This is associated with DPVA and strong warm advection, with the latter directly influencing a transitional precipitation type across near-coastal/far southern New England. Aforementioned forcing for ascent coincident with a moderately deep and saturated dendritic growth layer will likely continue to support 1+ in/hr snowfall rates through the morning. With steep mid-level lapse rates noted in upstream observed soundings in proximity to the shortwave trough/dry slot, weak static stability/weak slantwise CAPE may also be an influence for a brief bout of locally higher snowfall rates, before snow/precip rates diminish from west-to-east into this afternoon. ..Guyer.. 02/25/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX...BOX...BTV...ALY... LAT...LON 45047170 45497026 45366869 45046866 44256946 43197066 42517108 42787335 43757449 44467476 45087403 45047170 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0646 AM CST Fri Feb 25 2022 Valid 251300Z - 261200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected across the continental United States today or tonight. ...Synopsis/Discussion... A deamplifying shortwave trough will continue east-northeastward over the Northeast States and New England, with a cold front advancing east-southeastward across the coastal Southeast States. A few lightning flashes have been noted in the predawn hours near/behind this front. However, weakening low-level convergence and increasingly marginal thermodynamic profiles suggest that the potential for thunderstorms into the Carolinas/Mid-Atlantic region will likely remain below 10 percent. Dry/stable conditions will otherwise preclude thunderstorms across the remainder of the CONUS. ..Guyer.. 02/25/2022 Read more

No watches are valid as of Thu Feb 24 14:48:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Thu Feb 24 2022 Valid 241300Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible today and tonight from the western Gulf Coast across the lower/mid Mississippi and Ohio Valley regions. ...Synopsis... Positively tilted, large-scale troughing will persist over the western CONUS, with a series of lower-end synoptic to small shortwave troughs traversing the associated cyclonic flow. The leading perturbation -- evident in moisture-channel imagery from central WY across western CO, AZ and northern Baja -- should eject northeastward to the central Plains and southern High Plains by 00Z. By the end of the period, this feature should reach Lower MI and the OH/IN border area, in substantially deamplified form. An upstream shortwave trough -- now over southeastern BC and WA -- will dig southeastward across the interior Northwest to the northern Great Basin and southern ID today, before merging with an initially separate perturbation now over east-central SK tonight. The resultant trough should be positioned from ND across western WY to central NV by 12Z tomorrow. At the surface, 11Z analysis showed a mostly quasistationary frontal zone from southern NC to a weak, frontal-wave low over eastern TN, southwestward across central AL and southern portions of MS/LA. With the oblique approach of the ejecting western trough, a separate, discrete low should develop along a retreated version of the frontal wave by 00Z, most likely over western/central KY near the Ohio River. By that time, the trailing boundary should extend across western TN, central MS, southwestern LA, and the northwestern Gulf to south of BRO, again becoming a cold front. By 12Z, the low should deepen and move to northwestern PA, with cold front across eastern WV, the Appalachians of VA/NC/GA, eastern/southern AL, to near the Mississippi River mouth, and slightly farther southeastward over the northwestern Gulf than 12 hours prior. ...Southeastern LA to northwestern AL this evening/overnight... Isolated to widely scattered thunderstorms are possible on either side of the front through the period, with postfrontal convection dominant before 00Z, and frontal/warm-sector activity more likely this evening through overnight. The latter may access a favorably moist warm sector, characterized by surface dew points in the mid/upper 60s F. Deep-layer lapse rates will be weak: 1. In the low levels, without the benefit of strong diurnal heating, and 2. In midlevels, with neutral to stable thermal layers (basal EML remnants that remain evident in upstream 12Z LIX/SHV/JAN/LCH/CRP RAOBs) lingering in forecast soundings until very near to after cold-frontal passage. DCVA-related large-scale ascent with the ejecting mid/upper trough will remain well behind the surface front. Still, warm advection may be sufficient to lift/cool the remnant EML base enough to permit deeper convection near the front. This regime is possible amidst 35-45-kt effective-shear magnitudes, and hodograph somewhat enlarged on the eastern rim of a departing LLJ whose axis also should be behind the surface cold front. An isolated, briefly strong thunderstorm may mature before being undercut by the front, while embedded within (and training along the axis of) a southwest/ northeast-aligned convective band. However, given a marginal (at best) kinematic/thermodynamic parameter space expected, and the anafrontal regime, severe potential remains too conditional/ uncertain to reintroduce a risk area at this time. ..Edwards/Gleason.. 02/24/2022 Read more

MD 0182 CONCERNING FREEZING RAIN FOR PORTIONS OF CENTRAL/NORTHEAST TX INTO EASTERN OK AND MUCH OF CENTRAL/NORTHERN AR
Mesoscale Discussion 0182 NWS Storm Prediction Center Norman OK 0416 AM CST Thu Feb 24 2022 Areas affected...Portions of central/northeast TX into eastern OK and much of central/northern AR Concerning...Freezing rain Valid 241016Z - 241615Z SUMMARY...Another round of freezing rain will develop across central/northeast Texas and spread northeastward this morning. Freezing-rain rates around 0.05 inch per 3 hours may occur, with locally higher rates possible. DISCUSSION...Recent radar imagery across central into northeast TX shows a gradual filling of light reflectivities, with multiple recent reports of light freezing drizzle and freezing rain. A synoptic-scale upper trough over the Rockies and Southwest will continue to eject northeastward, while a low-amplitude shortwave trough over northern Mexico moves northeastward over TX this morning. Modest ascent associated with this latter feature, and warm advection attendant to a 30-40-kt southwesterly low-level jet, will likely aid in a gradual increase of precipitation coverage across central/northeast TX over the next few hours. 10Z surface observations indicate the sub-freezing temperatures are present where most of this light precipitation is falling. With a substantial low-level warm nose also over this region per latest mesoanalysis estimates and NAM/RAP forecast soundings, freezing rain is expected to be the dominant precipitation type. As the showery precipitation gradually expands in coverage/intensity and develops northeastward, freezing-rain rates around 0.05 inch per 3 hours may occur. This swath of generally light freezing rain is expected to overspread parts of eastern OK and much of central/northern AR through 16Z (10 AM CST), where surface temperatures remain below freezing. Locally higher rates will be possible within the heavier precipitation cores. Some elevated convection may be capable of producing isolated lighting flashes, as about 250-500 J/kg of MUCAPE exists over much of this region. ..Gleason.. 02/24/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SHV...TSA...FWD...OUN... LAT...LON 30949778 31689829 32009834 33269751 34439652 35589537 36079413 36289309 36429189 36429127 36029106 35489111 34949164 34369265 34299333 34049438 33689473 32799516 31809585 31139680 30949778 Read more

No watches are valid as of Wed Feb 23 14:48:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0644 AM CST Wed Feb 23 2022 Valid 231300Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today or tonight. ...Synopsis/Discussion... In mid/upper levels, deep troughing predominates over the western CONUS, with intermittently closed cyclonic flow centered over NV. The synoptic trough will lose some amplitude through the period, but remain strong and well-defined, as it moves eastward to a position at 12Z tomorrow from eastern WY to central CO, the Four Corners area, and southwestern AZ/northern Baja. Marginal low/middle-level moisture, favorable large-scale DCVA/lift, related steep midlevel lapse rates, and resulting weak buoyancy will promote isolated thunderstorm potential in a corridor of cyclonic flow from southern CA to the Four Corners. Downstream southwesterly flow will prevail over the central CONUS, gradually becoming westerly with eastward extent into the Atlantic Coast States. A weak/embedded shortwave trough -- initially located over parts of northeast TX to southeastern NM and far west TX -- will eject northeastward rapidly, reaching parts of KY by 00Z, and NJ by 12Z in a much-weakened condition. Until then, associated low-level warm/moist advection to its east and south -- elevated atop an intense post-frontal cold/stable layer where north of the frontal zone described below -- will support sporadic thunder. This will include bouts of lightning accompanying sleet and freezing rain from an ongoing/expanding episode over north-central/northwest TX and southern OK, across more of OK/AR through afternoon. Forecast soundings suggest 200-700 J/kg MUCAPE may develop over the cold- frontal layer, and isolated subsevere hail may occur in the most intense cores already yielding sleet and freezing rain. At the surface, a cold front was drawn at 11Z from the Adirondacks across central PA, southwestern VA, eastern TN, northwestern AL, southwestern MS, to near GLS and LRD, across northern Coahuila and northeastern Chihuahua, to central/north-central NM. By 00Z, this boundary should extend from the Delmarva Peninsula to central/ southwestern GA, southern portions of AL/MS/LA, and just offshore from most of the TX Coast, to near BRO. By 12Z, the front should move little from LA southwestward while retreating inland across central and perhaps northern parts of MS/AL/GA. ..Edwards/Gleason.. 02/23/2022 Read more