Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Sep 07 2023 05:57:08 ACUS01 KWNS 070557 SWODY1 SPC AC 070555 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 07 2023 Valid 071200Z - 081200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE MID ATLANTIC AND NORTHEAST... ....SUMMARY... Potential for locally damaging wind gusts and marginal hail will be possible across the Northeast, and southwestward into the Southeast. Gusty winds and hail may also occur locally over parts of the central and southern Plains and Arklatex area. ....Synopsis... An upper high will remain situated over NM, with ridge extending northward into the northern High Plains. Modest northwest flow will stretch from the central Plains to the northern Gulf Coast, with various embedded disturbances. To the east, height falls will occur over the northeastern states as a weak midlevel wave moves east across the Great Lakes. Along the western periphery of the western Atlantic ridge, enhanced midlevel southerly flow over 35 kt will be possible from VA into VT. At the surface, a trough will develop from VA into eastern PA and NY by late afternoon, with a cold front farther west from western NY toward Lake Ontario by 00Z. A surface trough will also develop from the TX Panhandle northward across western NE/SD/ND, with high pressure from Ontario southward into the lower MO Valley. Robust low-level moisture will exist across the Mid Atlantic and northeast, aiding instability during the day ahead of the upper trough. A plume of relatively moist air will also exist from the northern Gulf Coast curling northwestward toward southern OK, beneath the enhanced northwesterlies aloft. ....Northern VA into western New England... Substantial surface heating is likely this afternoon from NC/VA northward into New England, coincident with a moist air mass containing surface dewpoints in the upper 60s F. Despite the weak upper ridge to the east, 500 mb temperatures will average near -8C, resulting in 1500-2000 J/kg MUCAPE. Shear is not forecast to be very strong, given the midlevel disturbance arriving late. However, scattered storms are likely to develop in the uncapped air mass from the southern Appalachians northward into PA and NY by early afternoon, spreading northeastward into VT through 00Z. Cluster of storms may propagate northeastward during the late afternoon, producing areas of damaging gusts. Despite the weak shear, cooling profiles aloft will favor isolated marginal hail with the strongest storms. Additional isolated wind damage cannot be ruled with storms across the Carolinas and into GA as well, given favorably steep low-level lapse rates and at least 1500 J/kg MLCAPE. ....OK into LA... A narrow plume of 1500-2000 J/kg MUCAPE is forecast to develop from LA into parts of OK during the day, with effective shear averaging 25-30 kt. Storms are most likely during the afternoon over LA, but isolated activity could develop farther northwest near the southern edge of the moist plume where temperatures will be hot. The deeply mixed boundary layer along with marginal shear may aid a few strong to locally severe gusts or even hail. Another area of isolated storms may develop near the TX Panhandle/OK border, with similar potential. ....Central and eastern NE... Boundary-layer mixing as well as moisture advection will be enhanced by 15-20 kt southerly winds during the day, with primarily elevated instability developing. The glancing influence of an embedded shortwave trough moving out of WY late in the day and into the evening may yield isolated storms capable of marginal hail. ...Jewell/Wendt.. 09/07/2023 $$ = = = 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) .