Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 07 2024 05:45:07 ACUS01 KWNS 070545 SWODY1 SPC AC 070543 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1143 PM CST Wed Mar 06 2024 Valid 071200Z - 081200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE EASTERN TEXAS PANHANDLE AND NORTHWESTERN OKLAHOMA INTO SOUTHERN KANSAS...AND ACROSS PARTS OF WEST CENTRAL INTO NORTH CENTRAL TEXAS... ....SUMMARY... A few thunderstorms may pose primarily a risk for severe hail and locally strong wind gusts across parts of the southern Great Plains this afternoon into tonight. ....Synopsis... Flow across the mid-latitude Pacific is becoming more amplified and, later today through tonight, models indicate this will include building mid/upper ridging spreading inland across the Pacific coast. Preceding this ridge, while one short wave trough digs near/west of the Sierra Nevada, toward the Southwestern international border, a downstream perturbation is forecast to accelerate east-northeastward out of the Southwest, into the southern Great Plains by early Friday. In the wake of a vigorous short wave trough slowly accelerating from southern Manitoba toward the southern Hudson/James Bay vicinity, a significant cold intrusion is already underway to the lee of the northern Rockies. As this air continues to nose southward through the high plains, modestly deep surface troughing will precede it across the southern Great Plains through lower Missouri Valley, but guidance suggests little in the way of embedded surface cyclogenesis through this period. One evolving wave along a developing frontal zone may shift from the Texas Panhandle/northwestern Oklahoma vicinity into the lower Missouri Valley late this afternoon through tonight. A narrow plume of better low-level moisture return may be ongoing across the lower Rio Grande Valley into the San Angelo/Abilene vicinity by 12Z this morning, before more substantive low-level moisture return commences across the western Gulf/northwestern Gulf coast and coastal plain toward the southeastern Great Plains/lower Mississippi Valley. Much of the this, however, may take place beneath relative warm layers in the lower/mid-tropospheric and layers further aloft, beneath low-amplitude subtropical ridging. ....Southern Great Plains... Considerable thunderstorm development may be ongoing by 12Z this morning, in response to ascent supported by lower/mid-tropospheric warm advection, beneath difluent high level flow, from parts of west central/northwest Texas into Kansas, Missouri and Arkansas. Steeper mid/upper level lapse rates supportive of somewhat better potential for severe hail in widely scattered stronger storms probably will be initially focused from the Kansas/Oklahoma border vicinity toward the Ozark Plateau. However, as convection across this region becomes more widespread and spreads northeastward, the initial risk for severe hail is expected to wane. There is considerable model output indicating that a more prominent cluster of convection may evolve through late morning into afternoon across parts of west central through north central Texas, perhaps aided by weak perturbation associated with the subtropical jet. This may include a gradually intensifying line, supported by better near-surface moist inflow along the leading (southern and eastern) edge of associated convective outflow, which may eventually pose at least some risk for severe hail and wind. However, this potential may be limited by generally weak lapse rates, particularly as it continues eastward through the day. While convective development to the south may impede better low-level moisture return, a narrow corridor of stronger pre-frontal daytime heating across the Texas Panhandle toward the Wichita, KS vicinity will provide at least one focus for stronger late afternoon into evening thunderstorm development. Beneath the leading edge of stronger mid/upper cooling associated with the troughing emerging from the Southwest, steepening lapse rates will contribute to an environment conducive to potential for at least severe hail, in the presence of sufficient shear for supercells. In the wake of early day convection, an appreciable increase in potential for strong/severe thunderstorm development will await mid-level forcing for ascent and cooling aloft associated with the primary short wave perturbation emerging from the Southwest. This may not reach the Edwards Plateau vicinity until mid/late evening, before spreading toward the Interstate 35 corridor of central into northern Texas overnight. But it appears that boundary-layer based instability will probably become supportive of supercells, beneath 60-70+ kt southwesterly mid-level flow. Low-level hodographs may not become particularly large, but some risk for a tornado and locally damaging wind gusts may accompany stronger cells, in addition to severe hail. ...Kerr/Weinman.. 03/07/2024 $$ = = = 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) .