Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 19 2024 04:50:13 ACUS02 KWNS 190450 SWODY2 SPC AC 190448 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1148 PM CDT Mon Mar 18 2024 Valid 201200Z - 211200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON AND EVENING ACROSS PARTS OF THE TEXAS PANHANDLE AND ADJACENT WESTERN OKLAHOMA...AND WEDNESDAY NIGHT NEAR AND SOUTH OF THE TEXAS HILL COUNTRY INTO MIDDLE TEXAS COASTAL PLAIN... ....SUMMARY... One or two clusters of thunderstorms could develop across parts of the southern Great Plains late Wednesday afternoon through Wednesday night. Some of this activity may pose at least some risk for severe hail and wind. ....Synopsis... Models continue to indicate that a less amplified, but still broadly confluent, split flow will evolve east of the Rockies into the western Atlantic through this period. Within one branch, consolidating short wave perturbations emanating from the higher latitudes likely will continue digging to the southeast of the lower Great Lakes region, before turning eastward across the remainder of the Northeast late Wednesday through Wednesday night. This may be accompanied by renewed surface cyclogenesis across portions of northern New England into the Canadian Maritimes, trailed by a reinforcing cold intrusion surging southeastward across much of the northern and middle Atlantic Seaboard, and more slowly southward across the lower Ohio into Tennessee Valleys, Ozark Plateau and central Great Plains through 12Z Thursday. Within a lower-latitude branch, the remnants of a perturbation emerging from the Southwest may slowly progress east of the Southern Rockies in the form of generally weak positively tilted troughing, but with perhaps a couple of still notable embedded smaller-scale impulses. One of these, possibly still a fairly well-defined mid-level cyclonic vorticity center, may progress east-southeastward across the Texas Panhandle into western Oklahoma late Wednesday through Wednesday night. A trailing perturbation may accelerate through stronger flow across the Southwestern international border area toward the Texas Big Bend, preceded by a more subtle impulse emanating from the subtropical eastern Pacific, which may reach Texas coastal areas by 12Z Thursday. There is considerable spread evident in the model output concerning these developments, but models continue to indicate little in the way of substantive surface cyclogenesis, within broad surface troughing across the southern Great Plains. And low-level moisture return off a modifying Gulf boundary layer likely will be limited in the wake of a prior intrusion of cool/dry air through much of the northern Gulf Basin. Better low-level moistening may remain confined to the lower Rio Grande Valley and portions of the Texas coastal plain, beneath warm and capping elevated mixed-layer air. ....Texas Panhandle Vicinity... To the east of a weak surface low, surface dew points may only reach the mid 40s to around 50F by late Wednesday afternoon. But it still appears that daytime heating will contribute to a modestly deep, well-mixed boundary layer, supportive of CAPE on the order of 500 J/kg, as relatively cold mid-level air (-20 to -22C around 500 mb) overspreads the region with the approaching cyclonic vorticity center. Although lower/mid-tropospheric wind fields and shear may only become modest, at best, this environment could still support strong convection posing a risk for small to marginally severe hail and a few strong gusts, before convection becomes more widespread while spreading east-southeastward Wednesday evening. ....Southern Texas... A warm elevated mixed layer will likely contribute to strong inhibition through much of the period, but models suggest that a return of mid 60s F surface dew points by late Wednesday night may contribute to mixed-layer CAPE up to around 1000 J/kg. Considerable uncertainty still exists concerning forcing for ascent to overcome the inhibition, but at least some model output suggests that a subtropical perturbation could support the initiation of storms by late Wednesday night, if not earlier. If this occurs, strong deep-layer shear will provide potential for the evolution of supercells posing a risk for large hail and locally strong wind gusts. ...Kerr.. 03/19/2024 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .