Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 05 2025 05:50:00 ACUS01 KWNS 050549 SWODY1 SPC AC 050548 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Mon May 05 2025 Valid 051200Z - 061200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR SOUTHEAST NEW MEXICO INTO SOUTHWEST TEXAS... ....SUMMARY... Severe thunderstorms are expected from the southern High Plains into parts of central Texas this afternoon and evening. Scattered large to very large hail and severe winds are the primary threats, though a couple of tornadoes also are possible. Additional strong to severe storms are possible along the eastern Florida coast and from eastern North Carolina into the central Appalachians and upper Ohio River Valley. ....Synopsis... An omega blocking pattern continues to develop over the CONUS per recent water-vapor imagery and 00 UTC upper-air analysis, with two meandering upper lows over the Ohio River Valley and Southwest respectively. Northward moisture advection and ascent on the eastern periphery of both upper lows will promote another day of scattered thunderstorms (including strong to severe storms) across the central Appalachians/Mid-Atlantic and southern High Plains into the Intermountain West. ....Southern High Plains... Upper-level diffluence over the southern High Plains will continue to promote gradual surface pressure falls and a southeasterly return flow regime across far eastern NM and western TX through much of the day. Although moisture return will initially be somewhat modest, persistent broad-scale ascent over the region will result in cooling temperatures aloft/steepening mid-level lapse rates that should compensate for the poor moisture quality. Thunderstorm development is expected initially within a warm advection regime across south-central TX by early afternoon with additional storm development by late afternoon across the Permian basin in closer proximity to a deepening lee trough/sharpening dryline. Across both regions, deep-layer wind shear on the order of 50 knots should promote supercells with an attendant threat for large hail. Across south-central TX, higher-quality moisture and stronger veering in the lowest 1-2 km AGL may support a tornado threat. By early evening, a shortwave trough embedded within the mean flow (observable in water-vapor imagery off the southern CA coast as of 06 UTC) is forecast to overspread southwest TX. Stronger surface pressure falls associated with this shortwave will induce strengthening low-level winds, which will not only enlarge low-level hodographs, but will augment moisture return into the region. Ascent within the strengthening warm advection regime should result in scattered supercell development between 00-06 UTC across the southern Permian Basin and adjacent areas of southeast NM. Given the increasingly favorable convective environment, a few long-lived supercells appear possible and will be capable of producing large to very large (2+ inch) hail and perhaps a couple of tornadoes. Upscale growth into one or more clusters appears likely heading into the overnight hours as lift spreads northeast into northwest and central TX. There remains some uncertainty among guidance regarding the development of a more organized MCS into TX through early Tuesday morning, but cells developing within the warm advection regime ahead of the upper wave may be capable of severe hail/wind. ....Central Appalachians and Mid-Atlantic... Recent surface observations reveal a residual front/marine boundary draped from eastern VA into the eastern Carolinas. East of this boundary, richer low-level moisture in the form of low to mid-60s dewpoints is noted extending northward into southeast PA. Aloft, an embedded shortwave orbiting around the primary upper low is noted over the mid-MS River Valley in recent water-vapor imagery. This feature is expected to pivot into the Mid-Atlantic and central Appalachians through the afternoon/evening and will be favorably timed with the diurnal heating cycle. The combination of cold temperatures aloft in proximity to the upper low and rich low-level moisture will limit capping and promote thunderstorm initiation along the boundary by early afternoon from the DelMarVa region into NC. Further to the northwest, lift ahead of the embedded shortwave combined with cold mid-level temperatures should promote thunderstorm development across WV and OH by late afternoon. Across both regions, 1000-1500 J/kg MLCAPE and elongated, nearly straight hodographs should promote organized cells capable of large hail and damaging winds. Similar thermodynamic and kinematic environments were observed yesterday across the region, and yielded isolated to scattered strong to severe thunderstorms, including a couple of supercells. ....Eastern Florida Coast... Regional 00 UTC soundings sampled somewhat steep mid-level lapse rates atop a seasonally moist boundary layer (characterized by upper 60s to low 70s dewpoints) with limited inhibition. Heating of this air mass should eliminate any residual capping by late morning and early afternoon as temperatures climb into the 80s. Convective initiation will become more probable by mid/late afternoon as confluence along sea-breeze boundaries increases. Isolated to scattered thunderstorms are expected, and 30-40 knot mid-level flow should promote a few organized cells capable of producing large hail and damaging gusts. ...Moore.. 05/05/2025 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .