Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Aug 07 2023 05:49:18 ACUS02 KWNS 070549 SWODY2 SPC AC 070547 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Mon Aug 07 2023 Valid 081200Z - 091200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL PLAINS...AND FROM SOUTHERN ALABAMA TO COASTAL GEORGIA... ....SUMMARY... Severe thunderstorms are expected across portions of the central Plains Tuesday afternoon into Tuesday night. Damaging gusts and large to very large hail will be possible. Severe thunderstorms also are possible Tuesday afternoon across parts of central/southern Alabama/Georgia, posing mainly a damaging wind risk. Other more isolated strong to severe storms are expected across parts of southern New England where strong gusts and a tornado are possible. ....Synopsis... An active pattern with several shortwave impulses migrating through moderate west/northwesterly flow is expected from the central Plains into the Southeast on Tuesday. A mid/upper shortwave trough will also shift east over the Northeast. At the surface, low pressure near Lake Ontario will shift northeast along the St. Lawrence Valley. A cold front attendant to the low will develop eastward across southern New England through the day and offshore the northeast Atlantic coast during the evening/overnight. The southern extent of the front will stall over South Carolina. Southerly low-level flow will maintain a very moist airmass from the central Plains into the Southeast. ....Southeast... Residual outflow from convection in the Day 1 period may reside from northern MS into central AL/GA. This will result in differential heating ahead of convection expected to be ongoing across eastern OK/AR Tuesday morning in response to a vorticity maximum migrating through northwesterly flow aloft. As this convectively enhanced vorticity max and related MCV shifts east by early afternoon, thunderstorm are expected to increase rapidly from MS into central/southern AL. Given 30-40 kt midlevel westerly flow in the vicinity of a west to east oriented surface boundary, an organized cluster/MCS is forecast to spread east across central/southern AL/GA. Strong instability, steep low-level lapse rates and high PW values will support damaging gust potential as convection spreads east toward the GA coast by late afternoon/early evening. ....Central Plains... A midlevel shortwave trough is forecast to spread from the Great Basin to the central Rockies on Tuesday. Southeasterly low-level flow will maintain 60s F dewpoints across parts of NE into KS and northeast CO. Steep midlevel lapse rates near 8 C/km atop the moist boundary-layer will support MLCAPE around 2000-3000 J/kg. Meanwhile, effective shear magnitudes greater than 40 kt will support initial supercells. Elongated hodographs/favorable vertical shear, coupled with steep midlevel lapse rates, suggest large to very large hail will be possible. A modest southerly low-level jet is expected to develop during the evening/overnight and convection may grow upscale into a severe MCS as storms shift east/southeast from the High Plains into central NE/northern KS. Vertically veering wind profiles will result in favorably curved low-level hodographs in the vicinity of a surface trough across northeast CO into southwest NE, and a tornado is possible in this corridor from late afternoon/evening. Timing of convection is a little uncertain as the main upper wave is expected to eject a bit late, with larger-scale ascent overspreading the region during the evening/overnight. However, isolated storms will likely develop by late afternoon in low-level upslope flow and strong diurnal heating of the moist airmass. ....Northeast... Storms will likely be ongoing Tuesday morning in a warm advection band ahead of the surface cold front. Backed low-level winds and juxtaposition to the surface low will result in 0-1 km SRH greater than 250 s2/m2. While instability will be on the weak side, surface dewpoints in the upper 60s to low 70s and favorable shear could support a tornado or two. Isolated strong gusts are also possible with warm advection storms, and with any convection that may develop during the afternoon along the eastward-advancing cold front. ...Leitman.. 08/07/2023 $$ = = = 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) .