SPC Feb 28, 2025 1630 UTC Day 1 Convective Outlook

1 month ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Feb 28 2025 Valid 281630Z - 011200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm are unlikely through tonight. ...Synopsis and Discussion... An upper trough over Ontario and the Upper Midwest is forecast to further amplify today as it eventually encompasses much of the eastern CONUS. With a surface cold front having cleared the Gulf/Atlantic Coasts, dry and/or stable conditions are likely to preclude thunderstorms across the central/eastern CONUS through tonight. Farther west, a closed upper low will approach coastal southern CA through the period. While showers may occur across parts of this region as the upper low approaches, thermodynamic profiles are forecast to remain generally unfavorable for lightning production. ..Gleason/Thornton.. 02/28/2025 Read more

SPC Feb 28, 2025 1300 UTC Day 1 Convective Outlook

1 month ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0620 AM CST Fri Feb 28 2025 Valid 281300Z - 011200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm probabilities are very low Friday. Relatively dry and stable conditions will preclude organized thunderstorm development across the continental US today. ..Hart/Grams.. 02/28/2025 Read more

SPC Feb 28, 2025 1300 UTC Day 1 Convective Outlook

1 month ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0620 AM CST Fri Feb 28 2025 Valid 281300Z - 011200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm probabilities are very low Friday. Relatively dry and stable conditions will preclude organized thunderstorm development across the continental US today. ..Hart/Grams.. 02/28/2025 Read more

SPC Feb 28, 2025 Day 4-8 Severe Weather Outlook

1 month ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CST Fri Feb 28 2025 Valid 031200Z - 081200Z ...DISCUSSION... Medium-range guidance suggests that an initially zonal, intense mid/upper jet across the western into central mid-latitude Pacific may undergo considerable amplification into and through this period. It remains a bit unclear how emerging waves will impact the downstream pattern by the middle to latter portion of next week. However, it still appears that one significant preceding short wave trough, migrating inland of the Pacific coast by early Monday, will progress into and across the southern Rockies, before accelerating east-northeastward through mid week. And guidance remains suggestive that this will be accompanied by strong surface cyclogenesis, perhaps most notably across portions of the east central Great Plains toward the lower Great Lakes region late Tuesday through Tuesday night. This may include an evolving warm sector with intensifying low-level and deep-layer shear (in the presence of southerly to southwesterly flow strengthening to 50-100 kt in the 850 to 500 mb layer), coincident with an influx of moistening and destabilizing boundary-layer air off the northwestern Gulf. Spread typical at this extended time frame (day 5) lingers among the various model output concerning the sub-synoptic, and even synoptic, details across the southeastern Great Plains through Ohio Valley and Southeast, which may considerably impact the severe weather risk area and potential. However, the medium-range guidance depicts an environment at least conditionally supportive of an organized severe weather event, including potential for a few strong tornadoes and damaging straight line winds. It is possible, but perhaps a bit more uncertain, that this could continue across parts of the southern and middle Atlantic Seaboard on Wednesday. Read more

SPC Day 2 Fire Weather Outlook

1 month ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CST Fri Feb 28 2025 Valid 011200Z - 021200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHEAST ARIZONA INTO FAR SOUTHWESTERN NEW MEXICO... ...Synopsis... A pronounced mid-level trough will overspread the Lower Colorado River Basin as a broader upper trough amplifies along the East Coast tomorrow (Saturday). Surface high pressure will dominate much of the CONUS east of the Plains states. A surface low will develop over southern Arizona by tomorrow afternoon, supporting 20+ mph sustained southerly surface winds amid 10-15 percent RH by afternoon peak heating, for several hours. Given the continued curing of fuels, surface meteorological conditions should favor wildfire spread potential, warranting the introduction of Critical highlights this outlook. ..Squitieri.. 02/28/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook

1 month ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0135 AM CST Fri Feb 28 2025 Valid 281200Z - 011200Z ...Synopsis... A mid-level trough will amplify across the eastern half of the CONUS today, encouraging the rapid eastward translation of a broad surface low over the Great Lakes. A large area of strong isallobaric surface flow is expected across the Plains states into portions of the Midwest. By afternoon, sustained westerly surface winds in the 20-30 mph range will overspread much of South Dakota into Nebraska, Iowa, and northern Missouri. Meanwhile, a belt of 15-20 mph sustained southwesterly surface winds are likely across the Texas Panhandle toward eastern Missouri/western Illinois. RH will dip to 20-30 percent across the Southern Plains, with only 30-40 percent RH dips likely across South Dakota into the Midwest. Despite marginal RH, strong surface winds will compensate to support the potential for rapid wildfire spread over portions of the Plains states into the Midwest, where some wildfire activity has already been observed in lieu of stronger surface winds. ..Squitieri.. 02/28/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Feb 28, 2025 0830 UTC Day 3 Severe Thunderstorm Outlook

1 month ago
SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0117 AM CST Fri Feb 28 2025 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Widely scattered, generally weak, thunderstorm activity is possible across parts of central California into the Great Basin, and across parts of the central Great Plains, Sunday through Sunday night. ...Discussion... Split westerlies will remain amplified across the eastern Pacific, and characterized by generally high mean mid-level heights extending inland within a broadly confluent belt across the Rockies and east of the Mississippi Valley by late Sunday night, in the wake of large-scale troughing slowly progressing east of the Atlantic Seaboard. Within this regime, a significant, cold mid/upper trough is forecast to progress inland of the Pacific coast into the Great Basin and Southwest, preceded by a less prominent perturbation crossing the southern Rockies and through the central Great Plains by 12Z Monday. In lower levels, modest surface cyclogenesis appears likely to commence across eastern Wyoming and Colorado into the adjacent high plains. Models indicate that this will be accompanied by strengthening southerly return flow, in the wake of cold/dry surface ridging shifting east of the Mississippi Valley into Atlantic Seaboard. Stronger flow is forecast to develop inland of a gradually modifying boundary-layer over the western Gulf Basin, but modest moistening in lower/mid-levels is still probable across the southern through central Great Plains, beneath (at least initially) relatively warm/dry layers farther aloft. ...Central Great Plains... There remains notable spread concerning the motion of the lead short wave perturbation. However, guidance suggest that associated forcing for ascent and mid-level cooling, coupled with the limited moisture return, probably will contribute to sufficient destabilization to support scattered thunderstorm development late Sunday afternoon through Sunday night. This is likely to be generally rooted above a stable boundary layer. While the environment might become conducive to small hail in stronger cells, the risk for severe weather appears negligible at this time. ...Central California into Great Basin... Beneath stronger mid-level cooling and forcing for ascent overspreading the region, models suggest that destabilization will become sufficient for widely scattered weak thunderstorms Sunday into Sunday night. ..Kerr.. 02/28/2025 Read more

SPC Feb 28, 2025 0700 UTC Day 2 Convective Outlook

1 month ago
SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1100 PM CST Thu Feb 27 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the U.S. Saturday through Saturday night. ...Discussion... Models indicate that an amplified split flow, characterized by generally high mid/upper heights, will be maintained across the eastern Pacific into western North America through this period. Within this regime, it appears that an initially slow moving mid-level low near the southern California/northern Baja coast will accelerate inland across the Southwest Saturday through Saturday night, as a more prominent short wave trough digs toward the northern and central California coast. However, there remains notable spread among the various model output concerning how rapidly the lead perturbation transitions to an open wave, and how soon a closed low develops within the trailing perturbation. Downstream, large-scale mid/upper troughing likely will be maintained across much of eastern North America, reinforced by a number of digging short wave perturbations, as far south as the northeastern Gulf Basin through Florida Peninsula. This is forecast to be accompanied by substantive further lower/mid-tropospheric drying across much of the northern and eastern Gulf Basin. In response to the evolving upstream pattern, a developing southerly return flow may contribute to some lower/mid-tropospheric moistening east of the Texas Big Bend toward deepening surface troughing to the lee of the southern Rockies. However, this is likely to be capped by relatively warm and dry layers farther aloft. Dry and/or stable conditions are expected to generally prevail across much of the remainder of the U.S., as well, with little appreciable risk for thunderstorm development. ...Southern Great Basin/Southwest... There remains sizable spread among the various model output concerning the track of the modest mid-level cold core of the inland advancing lead short wave trough. Given initially dry conditions, and limited moisture return as it progresses inland, latest guidance indicates only very weak destabilization beneath the coldest mid-level temperatures. Based on NAM/RAP forecast soundings, any convection which may become capable of producing lightning probably will need forcing augmented by the higher terrain. While a brief weak thunderstorm or two might not be out of the question across the higher terrain of northwestern Arizona late Saturday afternoon, NCEP SREF and HREF calibrated thunderstorm guidance currently suggest that 10 percent thunderstorm probabilities might be to high. ..Kerr.. 02/28/2025 Read more

SPC Feb 28, 2025 0700 UTC Day 2 Convective Outlook

1 month ago
SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1100 PM CST Thu Feb 27 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across much of the U.S. Saturday through Saturday night. ...Discussion... Models indicate that an amplified split flow, characterized by generally high mid/upper heights, will be maintained across the eastern Pacific into western North America through this period. Within this regime, it appears that an initially slow moving mid-level low near the southern California/northern Baja coast will accelerate inland across the Southwest Saturday through Saturday night, as a more prominent short wave trough digs toward the northern and central California coast. However, there remains notable spread among the various model output concerning how rapidly the lead perturbation transitions to an open wave, and how soon a closed low develops within the trailing perturbation. Downstream, large-scale mid/upper troughing likely will be maintained across much of eastern North America, reinforced by a number of digging short wave perturbations, as far south as the northeastern Gulf Basin through Florida Peninsula. This is forecast to be accompanied by substantive further lower/mid-tropospheric drying across much of the northern and eastern Gulf Basin. In response to the evolving upstream pattern, a developing southerly return flow may contribute to some lower/mid-tropospheric moistening east of the Texas Big Bend toward deepening surface troughing to the lee of the southern Rockies. However, this is likely to be capped by relatively warm and dry layers farther aloft. Dry and/or stable conditions are expected to generally prevail across much of the remainder of the U.S., as well, with little appreciable risk for thunderstorm development. ...Southern Great Basin/Southwest... There remains sizable spread among the various model output concerning the track of the modest mid-level cold core of the inland advancing lead short wave trough. Given initially dry conditions, and limited moisture return as it progresses inland, latest guidance indicates only very weak destabilization beneath the coldest mid-level temperatures. Based on NAM/RAP forecast soundings, any convection which may become capable of producing lightning probably will need forcing augmented by the higher terrain. While a brief weak thunderstorm or two might not be out of the question across the higher terrain of northwestern Arizona late Saturday afternoon, NCEP SREF and HREF calibrated thunderstorm guidance currently suggest that 10 percent thunderstorm probabilities might be to high. ..Kerr.. 02/28/2025 Read more

SPC Feb 28, 2025 0600 UTC Day 1 Convective Outlook

1 month ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Thu Feb 27 2025 Valid 281200Z - 011200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm probabilities are very low Friday. ...Discussion... Large-scale pattern is not expected to favor appreciable moistening/destabilization through 01/12z as a dominant upper trough settles south across the Great Lakes/OH Valley region. This feature will not prove favorable for Gulf moisture to advance inland as west-northwesterly flow should prevail through the period. Farther west across southern CA, a notable upper low is forecast to dig southeast, just off the southern CA Coast, as a strong 500mb speed max translates toward the northern Baja Peninsula. While profiles will cool, and mid-level lapse rates steepen, scant moisture should be noted with this system across inland southern CA. Forecast soundings suggest the most-buoyant parcels will struggle to exhibit enough instability to warrant any meaningful risk for deep convection capable of generating lightning. For these reasons thunderstorms will not be forecast today. ..Darrow/Squitieri.. 02/28/2025 Read more

SPC Feb 28, 2025 0600 UTC Day 1 Convective Outlook

1 month ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Thu Feb 27 2025 Valid 281200Z - 011200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm probabilities are very low Friday. ...Discussion... Large-scale pattern is not expected to favor appreciable moistening/destabilization through 01/12z as a dominant upper trough settles south across the Great Lakes/OH Valley region. This feature will not prove favorable for Gulf moisture to advance inland as west-northwesterly flow should prevail through the period. Farther west across southern CA, a notable upper low is forecast to dig southeast, just off the southern CA Coast, as a strong 500mb speed max translates toward the northern Baja Peninsula. While profiles will cool, and mid-level lapse rates steepen, scant moisture should be noted with this system across inland southern CA. Forecast soundings suggest the most-buoyant parcels will struggle to exhibit enough instability to warrant any meaningful risk for deep convection capable of generating lightning. For these reasons thunderstorms will not be forecast today. ..Darrow/Squitieri.. 02/28/2025 Read more

SPC Feb 28, 2025 0100 UTC Day 1 Convective Outlook

1 month ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Thu Feb 27 2025 Valid 280100Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms remain possible this evening, primarily across parts of the Mid/Upper Ohio Valley vicinity. ...01z Update... Strong upper trough is advancing across the OH/TN Valley region early this evening. Strong height falls will spread across the Mid Atlantic/Carolinas as the primary synoptic front shifts off the Atlantic Coast by 06z. Isolated thunderstorms continue ahead of a weaker, secondary surface boundary over the OH Valley, but this activity should gradually wane as the boundary layer cools and low-level lapse rates weaken. While a few storms may briefly produce small hail or gusty winds for the next hour or so, severe threat appears negligible the rest of tonight. ..Darrow.. 02/28/2025 Read more

SPC MD 120

1 month ago
MD 0120 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF INDIANA AND OHIO...AND FAR NORTHERN KENTUCKY
Mesoscale Discussion 0120 NWS Storm Prediction Center Norman OK 0319 PM CST Thu Feb 27 2025 Areas affected...parts of Indiana and Ohio...and far northern Kentucky Concerning...Severe potential...Watch unlikely Valid 272119Z - 272345Z Probability of Watch Issuance...5 percent SUMMARY...Damaging gusts and perhaps a couple marginally-severe hailstones are possible this afternoon across parts of Ohio, eastern Indiana, and far northern Kentucky. A watch is not anticipated. DISCUSSION...A 500 mb trough axis is situated over portions of the Ohio Valley this afternoon with very cold temperatures aloft (approximately -30 C at 500 mb per RAP analyses). This is atop a post-frontal air mass with surface dewpoints generally in the upper 30s F, resulting in MLCAPE values of 300-400 J/kg with steep lapse rates. Convective temperature has been reached in portions of southwest Ohio, where low-topped convection has been ongoing, and additional low-topped convection is developing along a weak cold front across portions of northern Indiana and northwest Ohio. Given the steep lapse rates, low freezing level, straight hodograph, and the fact that most or all of the buoyancy is above the freezing level, a few marginally-severe hailstones may occur. The primary limiting factors for severe hail is expected to be the low-topped nature of the convection and slightly marginal deep-layer shear. Additionally, flow in the boundary layer is not overly strong, with 850 mb winds of approximately 30 kts, but convection may mix that down to the surface and provide some enhancement to produce a few damaging gusts. The convection, and therefore the severe threat, is expected to wane later in the afternoon and evening as storms move to the east and east-southeast with the loss of diurnal heating. ..Supinie/Gleason.. 02/27/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PBZ...RLX...CLE...ILN...IWX...IND... LAT...LON 39168552 39928598 40938617 41238537 41478430 41178300 40718205 40258168 39778163 39458178 39008204 38748242 38568349 38618437 38708486 39168552 Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0343 PM CST Thu Feb 27 2025 Valid 011200Z - 071200Z Critical fire weather conditions are expected this weekend and into early next week across portions of the southern High Plains. Long-range guidance continues to show very good agreement in the evolution of the upper-level regime through the extended period as a series of shortwave troughs migrate across the Southwest into the southern Plains and OH Valley beginning this weekend and into the middle of the upcoming work week. Persistent dry conditions across AZ, NM, and much of OK/TX has resulted in an expanding swath of receptive fuels with most locations now reporting ERCs near or above the 80th percentile and 10-hour fuel moisture below 10%. This fuel environment will support fire spread as surface winds increase with the passage of these upper disturbances. ...D3/Sat to D4/Sun - Southwest/Southern High Plains... The first of two waves is currently off the CA coast and is expected to move into the lower CO River Valley over the next 72 hours. As this occurs, surface pressure falls across the Four Corners region will promote a widespread swath of 15-25 mph winds from southeast AZ into NM. Elevated fire weather conditions are likely as RH values fall into the teens/low 20s, and critical conditions are possible along the AZ/NM border based on windier/drier ensemble solutions. A stronger wind signal is noted across the southern High Plains on D4/Sunday as a lee cyclone deepens across the region. Post-dryline winds will likely exceed 20 mph, though the coverage of the wind swath remains uncertain due to spread in the exact location of the surface low in deterministic/ensemble guidance. Additionally, some solutions hint at scattered showers across the TX Panhandle into western OK. A 70% risk area has been introduced to southeast NM/west TX where confidence in critical conditions is highest, but critical conditions are possible across the TX Panhandle if the low develops on the northern end of the ensemble envelope across southeast CO/southwest KS and precipitation amounts are minimal. ...D5/Mon to D6/Tue - Southwest and Southern High Plains... A repeat of the Sat/Sun sequence is expected on Mon/Tue as a second, more amplified, upper trough translates across the Southwest and southern High Plains. The stronger kinematic fields associated with the second wave will likely result in a more robust low-level mass response as a surface low develops late Monday into Tuesday over the High Plains. While critical wind speeds are possible both days, both GEFS and ECENS guidance depicts the strongest signal on D6/Tuesday across southeast NM into southwest TX. Some solutions, including the 12z ECMWF, which typically has a weak wind bias, show the potential for a swath of 30 mph winds under the mid-level jet. While exact details remain uncertain at this range, the overall signal has been consistent enough through multiple model runs to support 70% risk probabilities. ..Moore.. 02/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Feb 27, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Thu Feb 27 2025 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Isolated to scattered thunderstorms are possible today across parts of the Mid/Upper Ohio Valley, and Carolinas into central Georgia. Occasional strong to damaging winds may occur this afternoon and early evening across portions of the Upper Ohio Valley vicinity. ...20Z Update... The forecast remains on track, and very minimal changes were made with this update. Isolated to widely scattered low-topped thunderstorms are developing within a weak low-level convergence zone across southwestern Ohio and southeastern Indiana this afternoon, with additional development northward along the surface trough in northern Indiana. This activity will continue tracking/developing east-southeastward into this evening, and any small clusters that evolve will be capable of producing strong to locally damaging wind gusts and small hail. For additional information, see the previous discussion below. ..Weinman.. 02/27/2025 .PREV DISCUSSION... /ISSUED 1028 AM CST Thu Feb 27 2025/ ...Upper Ohio Valley... Very cold mid-level temperatures (around -30 C at 500 mb) will overspread OH and vicinity this afternoon, as the primary upper trough pivots eastward over the Great Lakes and OH Valley. The airmass across this region is behind the main cold front, and low-level moisture will admittedly remain quite limited (surface dewpoints generally in the 30s to low 40s). Even so, the combination of modest daytime heating, coupled with cooling temperatures aloft and steepening low/mid-level lapse rates, should allow for weak MLCAPE to develop across parts of the Upper OH Valley through late this afternoon. Low/mid-level winds are not forecast to be overly strong through much of the day, but some increase in westerly boundary-layer flow is anticipated this afternoon. Current expectations are for at least isolated thunderstorms to develop this afternoon and early evening as large-scale ascent associated with the upper trough overspreads this region, and as a weak secondary surface trough/wind shift moves southeastward. Given the steepened lapse rate environment, some of this convection may be capable of producing occasional strong to damaging winds and small hail. Accordingly, a Marginal Risk has been added across parts of OH, northeast KY, and WV, where the greatest concentration of thunderstorms with some wind threat is anticipated. ...Georgia into the Carolinas... Modest instability should develop later today across parts of central GA into the Carolinas ahead of a cold front amid increasing mid-level moisture and diurnal heating. This should support a chance for isolated thunderstorms to develop across these areas as the cold front continues east-southeastward. While small hail and gusty winds may occur with the more robust thunderstorms, the mainly anafrontal and elevated convective structure will likely limit the overall severe potential. Read more

SPC Feb 27, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Thu Feb 27 2025 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY... ...SUMMARY... Isolated to scattered thunderstorms are possible today across parts of the Mid/Upper Ohio Valley, and Carolinas into central Georgia. Occasional strong to damaging winds may occur this afternoon and early evening across portions of the Upper Ohio Valley vicinity. ...20Z Update... The forecast remains on track, and very minimal changes were made with this update. Isolated to widely scattered low-topped thunderstorms are developing within a weak low-level convergence zone across southwestern Ohio and southeastern Indiana this afternoon, with additional development northward along the surface trough in northern Indiana. This activity will continue tracking/developing east-southeastward into this evening, and any small clusters that evolve will be capable of producing strong to locally damaging wind gusts and small hail. For additional information, see the previous discussion below. ..Weinman.. 02/27/2025 .PREV DISCUSSION... /ISSUED 1028 AM CST Thu Feb 27 2025/ ...Upper Ohio Valley... Very cold mid-level temperatures (around -30 C at 500 mb) will overspread OH and vicinity this afternoon, as the primary upper trough pivots eastward over the Great Lakes and OH Valley. The airmass across this region is behind the main cold front, and low-level moisture will admittedly remain quite limited (surface dewpoints generally in the 30s to low 40s). Even so, the combination of modest daytime heating, coupled with cooling temperatures aloft and steepening low/mid-level lapse rates, should allow for weak MLCAPE to develop across parts of the Upper OH Valley through late this afternoon. Low/mid-level winds are not forecast to be overly strong through much of the day, but some increase in westerly boundary-layer flow is anticipated this afternoon. Current expectations are for at least isolated thunderstorms to develop this afternoon and early evening as large-scale ascent associated with the upper trough overspreads this region, and as a weak secondary surface trough/wind shift moves southeastward. Given the steepened lapse rate environment, some of this convection may be capable of producing occasional strong to damaging winds and small hail. Accordingly, a Marginal Risk has been added across parts of OH, northeast KY, and WV, where the greatest concentration of thunderstorms with some wind threat is anticipated. ...Georgia into the Carolinas... Modest instability should develop later today across parts of central GA into the Carolinas ahead of a cold front amid increasing mid-level moisture and diurnal heating. This should support a chance for isolated thunderstorms to develop across these areas as the cold front continues east-southeastward. While small hail and gusty winds may occur with the more robust thunderstorms, the mainly anafrontal and elevated convective structure will likely limit the overall severe potential. Read more

SPC Feb 27, 2025 1930 UTC Day 3 Severe Thunderstorm Outlook

1 month ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Feb 27 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is anticipated for Saturday. A flash or two cannot be ruled out over northern Arizona and vicinity. ...Synopsis and Discussion... An upper low will move east from southern CA into AZ during the day, beneath a large-scale ridge over the Pacific Northwest and northern Rockies. Strong cooling aloft combined with daytime heating may yield weak instability supporting isolated, weak diurnal convection from southern NV across northern AZ and toward the Four Corners area. Elsewhere, a large-scale upper trough will remain over the East, with cool/stable air due to high pressure and offshore flow from the Gulf to the East Coast. An amplified upper trough will approach the West Coast Saturday night, with little instability forecast. ..Jewell.. 02/27/2025 Read more

SPC Feb 27, 2025 1930 UTC Day 3 Severe Thunderstorm Outlook

1 month ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Feb 27 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is anticipated for Saturday. A flash or two cannot be ruled out over northern Arizona and vicinity. ...Synopsis and Discussion... An upper low will move east from southern CA into AZ during the day, beneath a large-scale ridge over the Pacific Northwest and northern Rockies. Strong cooling aloft combined with daytime heating may yield weak instability supporting isolated, weak diurnal convection from southern NV across northern AZ and toward the Four Corners area. Elsewhere, a large-scale upper trough will remain over the East, with cool/stable air due to high pressure and offshore flow from the Gulf to the East Coast. An amplified upper trough will approach the West Coast Saturday night, with little instability forecast. ..Jewell.. 02/27/2025 Read more
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