Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 26 2025 19:34:34 ACUS01 KWNS 261934 SWODY1 SPC AC 261933 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0233 PM CDT Fri Sep 26 2025 Valid 262000Z - 271200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING FROM CENTRAL INTO SOUTHEAST ARIZONA... ....SUMMARY... Occasional large hail (1-2 inches in diameter) and outflow gusts of 60-70 mph will be possible through this evening from central into southeast Arizona. ....Central/southeast AZ through this evening... A closed mid-upper low now over southeast CA will move little through Saturday morning, and the left-exit region of an embedded jet core will focus over central/southeast AZ through this evening. Surface heating in cloud breaks is boosting temperatures into the mid 80s to lower 90s where dewpoints are in the low-mid 60s, which is contributing to moderate buoyancy (MLCAPE of 1500-2000 J/kg). New storms will continue to develop through the afternoon along the southern and western flanks of the ongoing convection from the Mogollon Rim into southeast AZ. Sufficiently long hodographs/deep-layer shear and the moderate buoyancy will support a mix of clusters and supercells capable of producing occasional large hail (1-2 inches in diameter) and outflow gusts of 60-70 mph. Favorable storm interactions could produce a brief tornado, though this threat will remain highly localized. ....Southeast Atlantic coast this afternoon... Thunderstorm development is underway from north FL across southeast GA into the Carolinas, downstream from a weak midlevel trough over TN/AL. A westerly component to the near-surface winds suggests the sea breeze will remain close to the coast through the afternoon and will serve to focus additional thunderstorm development. However, regional 18z soundings revealed poor midlevel lapse rates and (at best) modest midlevel shear, which suggest that the threat for wind damage remains too low to introduce severe wind probabilities. ...Thompson.. 09/26/2025 ..PREV DISCUSSION... /ISSUED 1121 AM CDT Fri Sep 26 2025/ ....Southwest... A well-defined upper low continues to progress slowly eastward across southern CA. Given its displacement well south of the primary westerlies along the US/Canada border, only limited eastward progression of this low is anticipated, with some potential it stalls in over the Lower CO River Valley vicinity. Ample moisture remains in place ahead of this upper low, and the resulting combination of persistent large-scale ascent associated with the low and this moisture will result in scattered to numerous thunderstorms across much of the southern Great Basin and Southwest. Buoyancy will be limited throughout much of this region, tempering the overall updraft strength and storm severity. The only exception is from central into southeast AZ and far southwest NM where greater low-level moisture exists south of a warm front that extends northwestward across the region to a surface low over the Lower CO Valley. Additional thunderstorm development is anticipated in this vicinity of this front this afternoon, where the greater low-level moisture (i.e. low 60s dewpoints) will contribute to afternoon MLCAPE around 1500 to 2000 J/kg. Moderate low to mid-level southwesterlies will help increase deep-layer shear values, particularly along the warm front where surface southeasterlies are possible. These environmental conditions support the potential for rotating storms capable of producing large hail. Steep low-level lapse rates throughout the warm sector suggest the potential for damaging gusts exists as well. A low-probability tornado threat may materialize along the warm front, with the magnitude of the threat dependent on the strength of the surface southeasterlies. ....Elsewhere... Broad upper troughing extending from the Northeast through the Lower MS Valley will contribute to scattered thunderstorms across much of the Southeast and Mid-Atlantic. Limited buoyancy should temper the overall storm intensity, although a strong storm or two is possible within the moist environment over the Carolinas. A few thunderstorms are also possible across northern MN as a cold front moves through the region overnight. $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .