Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Oct 13 2025 19:47:04 ACUS01 KWNS 131947 SWODY1 SPC AC 131945 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Mon Oct 13 2025 Valid 132000Z - 141200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS CENTRAL AND SOUTHEAST AZ...AND LATE TONIGHT OVER SOUTH-CENTRAL COASTAL CA... ....SUMMARY... Isolated, marginally severe hail and wind may occur this afternoon and evening over parts of central and southeastern Arizona. Locally damaging winds appear possible late tonight along parts of south-central coastal California. ....20Z Update... ....AZ... Southwesterly flow aloft will persist throughout the afternoon/evening and overnight. This flow, coupled with modest mid-level moisture and buoyancy will promote a continued threat for isolated strong thunderstorms, a few of which may be capable of hail and/or gusty winds. MCD #2144 was recently issued to address this isolated severe potential. ....Coastal Central/Southern CA... The deep upper low currently just off the northern CA coast will continue to progress southward tonight, ending the period just off the central CA coast. A strong mid-level jet max will rotate around this low as it progresses southward, spreading eastward into southern CA late tonight/early tomorrow. A strong frontal band is anticipated along the leading edge of the ascent associated with this speed max. Current guidance places this band near the coast around 05Z/06Z before then moving inland over the next few hours. Thermodynamic profiles indicate predominantly shallow convection within and ahead of this frontal band, although a few lightning flash are possible (most likely within the frontal band itself). Additionally, the combination of modest buoyancy and strong deep-layer vertical shear could result in rotation within any more persistent updrafts, with an attendant threat for damaging gusts and/or a brief tornado. Even so, the modest and shallow buoyancy should keep updrafts transient, and any rotation within those updrafts short lived, keeping the overall severe potential low. ...Mosier.. 10/13/2025 ..PREV DISCUSSION... /ISSUED 1045 AM CDT Mon Oct 13 2025/ ....AZ... An upper low currently centered along the OR coast will dig southward through the forecast period. This will maintain deep southwesterly flow throughout the Southwest US and Great Basin. Considerable mid-level moisture and marginal CAPE values will promote a risk of scattered thunderstorms across these areas through tonight. While an isolated strong storm will be possible over a broad region, parts of the central and southeast AZ appear to have the best combination of daytime heating, orographic ascent, and vertical shear to promote a risk of a few strong/severe storms capable of hail and gusty winds. ....Coastal CA... A strong mid-level jet max will rotate inland tonight into parts of south-central coastal CA, along with an associated surface cold front. Forecast soundings along/ahead of the front show sufficient CAPE and vertical shear for a risk of a few low-topped but strong storms capable of damaging wind gusts or perhaps a tornado. The main concerns will be after midnight. $$ = = = 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) .