Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri May 19 2023 12:55:16 ACUS01 KWNS 191255 SWODY1 SPC AC 191253 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Fri May 19 2023 Valid 191300Z - 201200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR CENTRAL TX INTO EASTERN OK/WESTERN AR... ....SUMMARY... Strong/locally severe storms are expected this afternoon and evening from parts of the southern Plains eastward into parts of Arkansas. ....Eastern OK/western AR into central TX this afternoon/evening... Within a generally weak flow regime between a northern stream shortwave trough over MN and subtropical ridging over northern Mexico, a couple of MCVs are moving eastward over OK/southern KS this morning. The primary MCV will likely persist through the day across north central/northeast OK, while a surface cold front (in the wake of the MN shortwave trough) will move southeastward into the I-44 corridor across OK and northwest TX by late afternoon. Weakening outflow could persist through the day across OK into central TX, with storm development possible along the lingering outflow as well as the cold front. Lingering clouds add some uncertainty to the degree of surface heating today in OK, with stronger surface heating and more cloud breaks likely with southward extent into TX. As a result, the steeper low-midlevel lapse rates are expected across TX, where afternoon temperatures near 90 F and boundary-layer dewpoints at least in the mid 60s will contribute to MLCAPE in excess of 3000 J/kg. Vertical shear across TX will be in the range supporting multicell clusters and some transient supercells, capable of producing large hail and occasional damaging outflow gusts. Lapse rates and surface heating will be weaker into eastern OK, but vertical shear will be a little stronger along the south flank of the primary MCV. Thus, there will be some potential for a supercell or two across east central OK this afternoon, given sufficient surface heating in cloud breaks. Storms will persist into this evening and at least early tonight, developing southward toward the Hill Country in TX, and east-southeastward into western AR. The hail/wind threat will slowly diminish by 03-06z as the low levels stabilize and convective inhibition increases. ....North central OR this afternoon/evening... Modest low-midlevel moisture will persist in a south-southwesterly flow regime again today across OR/WA. Forcing for ascent appears to be nebulous, so terrain circulations will be the primary driver of thunderstorm development this afternoon near the crest of the Cascades. Vertical shear will be rather weak, but multicell clusters could produce isolated strong outflow gusts and small hail later this afternoon from crest of the Cascades into north central OR. The severe threat is low with these storms, but there is still some potential for a Marginal risk area in later updates. ...West central AZ this evening... Lingering low-level moisture, surface heating in cloud breaks, and midlevel flow from the northeast at 15-20 kt will allow convection over the Mogollon Rim to spread southwestward into the lower deserts over west central AZ. Inverted-V profiles, DCAPE of 750-1000 J/kg, and MLCAPE of 500-1000 J/kg will support some potential for strong outflow gusts with a cluster of storms this evening. The severe threat is on the lower margins for any probabilities, and this area will continue to be re-evaluated today. ...Thompson/Broyles.. 05/19/2023 $$ = = = 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) .