Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 20 2023 19:47:45 ACUS01 KWNS 201947 SWODY1 SPC AC 201946 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0246 PM CDT Wed Sep 20 2023 Valid 202000Z - 211200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST OKLAHOMA INTO NORTHEAST TEXAS...AND OVER PARTS OF THE NORTHERN GREAT BASIN... ....SUMMARY... Strong storms capable of hail and gusty winds are possible across parts of southeastern Oklahoma and northeast Texas through this evening. Gusty winds may also accompany a few storms over the northern Great Basin. ....OK/TX... A very conditional risk for a strong/severe storm through early evening continues across parts of southeast OK into northeast TX. The Marginal (level 1 of 5) risk area has been trimmed from portions of eastern OK into western AR and far northeast TX. Persistent clouds and showers/thunderstorms have limited heating much of the day. Southwestern portions of the Marginal risk area have largely cleared out this afternoon and allowed temperatures to warm into the upper 70s to mid 80s. However, quite a bit of inhibition remains. Furthermore, HRRR and RRFS guidance shows little convective development this afternoon/evening. Some cumulus development is noted closer to the I-35 corridor amid stronger instability and weaker inhibition. Nebulous large-scale ascent may be insufficient to overcome this inhibition. However, if a storm can develop near the western edge of the Marginal risk and track southeast along residual outflow, a risk for hail and strong gusts could occur for a few hours. ....NV/UT/ID/WY... No changes have been made with the 20z update. See previous discussion below for more details. ...Leitman.. 09/20/2023 ..PREV DISCUSSION... /ISSUED 1109 AM CDT Wed Sep 20 2023/ ....OK/AR/TX/LA... A persistent nocturnal MCS is weakening over western AR, with clearing skies over eastern OK in its wake. Strong heating will help yield a moderately unstable air mass by late afternoon across southeastern OK, where there will be some chance of a thunderstorm or two. Effective shear values of 40-50 knots and steep mid-level lapse rates will support a risk of large hail and damaging winds in any persistent storm that develops. However, weakening large scale support and a residual cap suggest the risk of initiation is rather low in the primary instability region. ....NV/UT/ID/WY... A rather dynamic upper trough is digging quickly southeastward today across the Pacific Northwest region. This will allow large scale ascent to overspread much of the northern Great Basin by this afternoon. A corridor of mid-level moisture ahead of the trough extends from northern NV into northwest WY, and should be favorable for the development of scattered high-based showers and thunderstorms later today. Skies are currently clear in this region, allowing steep low-level lapse rates to develop. As winds aloft strengthen this afternoon, the potential will exist for gusty/damaging wind gusts in a few of the fast-moving storms. $$ = = = 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) .