Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Oct 06 2023 12:46:28 ACUS01 KWNS 061246 SWODY1 SPC AC 061245 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Fri Oct 06 2023 Valid 061300Z - 071200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Severe thunderstorms are not expected over the contiguous U.S. ....Synopsis/Discussion... In mid/upper levels, height falls are expected over most of the CONUS east of the Mississippi Valley, as a major synoptic- to large-scale trough both amplifies and shifts slightly eastward. As this occurs, the southern part of a strongly curved upper jet rounding the base of the midlatitude trough will blend with the largely zonal subtropical jet over central/eastern Gulf Coast States, during the latter half of the period. Contributing to this process will be a strong shortwave trough, initially embedded in larger-scale cyclonic flow and extending from northwestern WI across southern MN to southern SD. By 00Z, This perturbation will pivot to a position near an axis from APN-LAF-STL-JEF. By 12Z, it should reach southern ON, western PA and northern KY. Associated strong midlevel DCVA/cooling will bring -26 to -29 deg C 500-mb temperatures over warm waters of Lake Michigan this afternoon/evening, contributing to steep lapse rates within a favorably moist low/middle-level airmass behind the leading surface cold front, and 100-400 J/kg MLCAPE extending into icing layers suitable for lightning. Associated thunder potential should persist eastward over adjoining parts of the Lower Peninsula, weakening with eastward extent into central Lower MI. Small hail (perhaps locally abundant amounts of it) may occur in the most vigorous cells, but severe potential appears too low for an outlook area. At 11Z, a cold front was analyzed from southern Lake Huron to near a FDY-CVG-JAN-LCH-CRP line and into northern Coahuila. As this boundary moves slowly eastward and southward through the period, it will be reinforced by secondary front(s) and areas of low-level cold advection. By 00Z, the main front should reach Lake Ontario, western PA, eastern parts of KY/TN/AL, to the north-central/west-central Gulf. By 12Z tomorrow, the front should proceed to eastern parts of NY and NC, to northern FL and the central/southwestern Gulf. Isolated convection within a plume of precip east of the front -- over the northern/inland Mid-Atlantic and NY -- may briefly deepen enough for bursts of lightning. Marginal thunder potential also may exist with low-CAPE, orographically aided convection over a small part of southeastern AZ. Meager lapse rates and lack of favorable shear in all these areas should mitigate organized severe potential. ...Edwards/Dean.. 10/06/2023 $$ = = = 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) .