Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 08 2023 17:26:46 ACUS02 KWNS 081726 SWODY2 SPC AC 081725 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Fri Sep 08 2023 Valid 091200Z - 101200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN INTERMOUNTAIN REGION INTO THE CENTRAL AND SOUTHERN PLAINS...AND OVER THE EASTERN U.S. ALONG AND EAST OF THE APPALACHIANS... ....SUMMARY... Isolated strong to severe thunderstorms are possible on Saturday from the northern High Plains into the central Plains, and south to Texas, and over much of the East along and east of the Appalachians. ....Northern Intermountain region into the central and southern Plains... A cold front is forecast to continue shifting southward across the southern Plains Saturday, while a second/reinforcing front shifts southward across the northern and into the central Plains today. This will occur as cyclonic mid-level disturbances continue to rotate southeastward around the northern and eastern fringe of the upper ridge centered over the Southwest. Boundary-layer heating/airmass destabilization will occur during the afternoon, from the northern High Plains into the central Plains ahead of the northern cold front, and southward across Texas -- particularly near and south of the initial front that should arc northwestward into the High Plains during the afternoon. These two boundaries should help focus convective development/evolution. Afternoon storms are expected to develop from southern Montana and Wyoming into Nebraska, shifting southeastward/southward with time within a kinematic environment featuring moderate mid-level southwesterly flow atop low-level southerlies. Meanwhile, storms are forecast to develop from the central and southern High Plains into central Texas, along the southern-most front, with southeastward propagation expected. In both of these regions, upscale growth of storms into clusters/mesoscale convective systems is expected, though honing in on these clusters remains difficult at this time. While these concentrations of storms could yield locally greater severe-weather coverage, and potentially higher probabilities in future outlooks, will limit outlook upgrades at this time to substantial expansion of the MRGL risk area. ....Eastern States... Multiple disturbances/vorticity maxima aloft are forecast to shift north-northeastward across the eastern U.S., ahead of the main trough that will remain aligned from the Great Lakes to the eastern Gulf of Mexico through the period. A moist low-level airmass in the vicinity of a very weak/remnant north-south surface baroclinic zone will once again heat and destabilize through the day, fueling scattered to numerous showers and thunderstorms from New England to Florida, and west to the western slopes of the Appalachians. With lower and middle tropospheric southerly flow generally in the 15 to 25 kt range expected across this region, multicell organization/clustering is expected locally, with damaging wind gusts and marginally severe hail expected with occasionally stronger storms. Risk will diminish gradually through late evening, in tandem with nocturnal cooling effects. ...Goss.. 09/08/2023 $$ = = = 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) .