Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 30 2023 19:57:23 ACUS01 KWNS 301957 SWODY1 SPC AC 301955 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sat Sep 30 2023 Valid 302000Z - 011200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHWEST THIS AFTERNOON AND EVENING.... ....SUMMARY... Isolated severe wind gusts will be possible across parts of the Southwest, mainly from late afternoon into this evening. Storms have started to form over the mountains from central New Mexico to south-central Colorado. Expect an increase in coverage and intensity of these storms through the afternoon with a threat for isolated large hail and severe wind gusts. Instability remains quite weak across the Great Basin this afternoon. Weak instability has developed across southern Nevada, beneath the cooling temperatures aloft. However, extensive cloud cover across this area has limited surface heating and any greater instability. Farther south and east, heating is occurring across southern Utah and northern Arizona. However, this region is very dry with dewpoints in the 20s. Nonetheless, there may be adequate heating for a line of thunderstorms to develop from southwest Utah into northwest Arizona and vicinity later this afternoon. ...Bentley.. 09/30/2023 ..PREV DISCUSSION... /ISSUED 1117 AM CDT Sat Sep 30 2023/ ....Central/eastern NM to southeast CO... Low to mid-level moisture will gradually increase across most of NM into southeast CO, to the east of an amplified upper trough shifting east from CA to NV. In the wake of weakening morning convection across eastern NM, robust boundary-layer heating will yield a modestly unstable air mass by late afternoon with MLCAPE largely peaking around 1000 J/kg. Scattered late afternoon thunderstorms are expected to develop off the higher terrain of central to eastern NM into southern CO. Amid the peripheral influence of strengthening mid to upper flow associated with the CA/NV trough, modest-moving multicell clusters should evolve and offer a threat for sporadic severe wind gusts centered on 4 to 8 PM MDT. ....Southern Great Basin... Ahead of the aforementioned upper trough, a low-level baroclinic zone will strengthen somewhat as it shifts east this afternoon into tonight. The paucity of low to mid-level moisture within the warm sector ahead of this zone should delay convective initiation until at least early evening and likely confined to the Lower CO Valley vicinity. A slow-moving band of thunderstorms may evolve across northwest AZ to southwest UT along the edge of surface-based instability. Strong low to mid-level flow should compensate for the meager buoyancy and support a threat for sporadic severe wind gusts. Additional convection should form farther west over the Mojave Desert and spread north-northeast into western UT during the evening as mid-level cooling spreads east, but also coinciding with boundary-layer cooling. Localized strong to severe wind gusts and small hail will be possible with this activity before subsiding later tonight. $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .