Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Nov 20 2022 19:47:00 ACUS01 KWNS 201946 SWODY1 SPC AC 201945 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0145 PM CST Sun Nov 20 2022 Valid 202000Z - 211200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Severe thunderstorms are not expected through tonight. ....20Z Update... No changes have been made to the prior outlook. ...Gleason.. 11/20/2022 ..PREV DISCUSSION... /ISSUED 1020 AM CST Sun Nov 20 2022/ ....Synopsis/Discussion... In mid/upper levels, mean troughing will be maintained over eastern Canada through the period. However, the strong subsidiary trough -- now apparent in moisture-channel imagery from near James Bay across parts of the Mid-Atlantic region -- will move eastward through New England around 00Z and Atlantic Canada thereafter. This process will shift low-level winds unfavorably for lake-effect bands over the lower Great Lakes, foster dry advection in the boundary layer, and lower effective tropopause levels. Those, in turn, will lessen lightning potential through the afternoon. A positively tilted, southern-stream shortwave trough was evident from northwestern OK across the TX Panhandle, central NM, southeastern AZ, and the northern Gulf of California. The trough should pivot eastward through the period -- with faster translation of its middle/southern parts, while retaining positive tilt. By 12Z, the trough should extend across central OK, northwest TX, extreme southeastern NM, far west TX, and central Sonora. To its southeast over south TX, a broad plume of elevated low-level warm advection and moisture advection/transport will persist, supporting increasing convective potential (including isolated to widely scattered thunderstorms) overnight into early morning. At the surface, 15Z analysis showed a quasistationary front across Great Abaco, Bahamas, southwestward over the Gulf Stream to very near Elliott Key and Key Largo FL, then across the Straits just south of the Lower/Middle Keys. Minor oscillations in frontal position are possible through the period, but it generally should remain quasistationary. Most associated convection has remained (and should continue to be) just below ideal icing layers for lightning, based on modified MFL/EYW RAOBs and radar cross-sections. Still, isolated lightning has been observed sporadically south of the Lower Keys, and weak storm-scale rotation has been noted in cells over the Straits, east of both Key Largo and Miami-Dade County. This may prompt occasional deepening of updrafts briefly favorable for lightning. Activity should remain too weak for a severe threat. $$ = = = 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) .