SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Sun May 04 2025 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NEW MEXICO AND FAR WEST TEXAS... ...SUMMARY... Strong to potentially severe storms are expected across east-central and southeast New Mexico and far west Texas this afternoon and evening, with a threat for large hail, isolated severe wind gusts, and possibly a tornado. Other strong to locally severe storms are possible from Florida northward into the Mid-Atlantic and Allegheny Plateau. ...New Mexico/West Texas... In advance of the upper trough over the Southwest Deserts, increasing height falls and strongly diffluent flow aloft will overspread a modestly moist boundary layer with prevalent 40s to near 50F surface dewpoints. Beneath steep mid-level lapse rates, upwards of 500-1000 J/kg MLCAPE is expected by late afternoon. Scattered thunderstorms are expected across northern into east-central New Mexico, with more isolated storms expected into far southeast New Mexico and west Texas. Wind profiles veering with height and increasing mid-level southwesterly winds will provide sufficient deep-layer shear for storm organization, including the probable development of a few supercells. Large hail and localized severe wind gusts will be possible. In addition, enlarging low-level hodographs and gradually improving low-level moisture could support a tornado or two if any mature supercells can persist through late afternoon into the evening. ...Florida... A cluster of storms across the north-central Peninsula, and to a lesser extent across the south-central Peninsula, may pose a localized severe risk as they continue eastward today. Existing cloud cover may tend to somewhat mute more robust heating, but gradual destabilization should still occur particularly along the east coast, which will also probably influence storm development. Effective shear of 25-30 kt will support potentially organized storms capable of hail and isolated damaging gusts, and some tornado threat may exist particularly in the vicinity of the sea breeze or any other boundaries. ...Allegheny Plateau into the Carolinas... East of the semi-stacked/closed low, cloud breaks and cold temperatures aloft should support modest diurnal destabilization across parts of Ohio and West Virginia into western Pennsylvania. Storm development should be aided one or more low-amplitude vorticity maxima rotating around the midlevel cyclone amidst diffluent flow aloft. Low-level winds are expected to remain rather weak, but modestly veering wind profiles and moderate mid-level flow could support some storm organization, if sufficient buoyancy can be realized. Hail and locally gusty winds could accompany the strongest storms, and a corridor of higher severe probabilities (Slight Risk caliber) may be warranted if a scenario with somewhat greater destabilization appears likely. Farther south into the Carolinas and parts of the Mid-Atlantic region, somewhat stronger diurnal heating is expected, and MLCAPE may increase to near/above 1000 J/kg. However, storm coverage is more uncertain, with a notable mid-level dry slot and only weak to modest large-scale ascent expected with southward extent. Any storms that can mature within this environment could become modestly organized with a threat of isolated hail and damaging gusts. ...Eastern Idaho/southwest Montana... Scattered storm development is expected this afternoon and evening across eastern Idaho into southwest Montana, within an environment characterized by cool temperatures aloft and steep lapse rates. Deep-layer shear will be relatively modest, but a few stronger storms with small hail and gusty winds could occur. Subsequent outlooks will reevaluate the need for a potential introduction of low-end severe probabilities. ..Guyer/Jewell.. 05/04/2025