Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Mar 06 2023 12:42:53 ACUS01 KWNS 061242 SWODY1 SPC AC 061241 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0641 AM CST Mon Mar 06 2023 Valid 061300Z - 071200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Isolated thunderstorms will be possible today in parts of the southern Great Lakes region and parts of the West Coast States, but no severe threat is expected. ....Synopsis/Discussion... A relatively flat, pattern with strong westerly flow component is expected over most of the CONUS east of the Rockies, downstream from a large-scale trough near the West Coast. A leading shortwave trough -- apparent in moisture-channel imagery over portions of southwestern MN and SD -- is forecast to move eastward to WI by 00Z. By 12Z, this perturbation should turn southeastward across the northern Mid-Atlantic region, in a regime of confluent flow that trails a cyclone now over the Gulf of St. Lawrence. An associated surface low was drawn at 11Z over northwestern MO, with cold front southwestward to northwestern OK, the TX Panhandle, and northeastern NM, to a low near ALS. A warm front was drawn east-southeastward across central IL, southern IN and northeastern KY, and should move east-northeastward up the Ohio Valley through the day. By 00Z, the low should move eastward to central/east- central OH (roughly between CMH-PIT), with cold front trailing across southern portions of IN/IL/MO and eastern/southern OK, becoming quasistationary over northwest TX to a low in the TAD-LHX vicinity. The eastern low should shift into the Mid-Atlantic and weaken thereafter. An area of precip, with isolated to widely scattered embedded thunderstorms, will be rooted in an elevated layer of weak buoyancy northwest through northeast of the surface low this afternoon and evening. Meanwhile, the primary mid/upper-level low of the western trough will remain just offshore from the Pacific Northwest, but with several shortwave/vorticity maxima traversing the downstream cyclonic flow from northern CA to the north-central Rockies. One of these -- now over the Pacific south of the mid/upper-level low, should move inland around 00Z then eastward across the northern Great Basin overnight. DCVA/cooling aloft will help to maintain steep low/middle-level lapse rates, negligible SBCINH (despite cool surface temperatures), and modest buoyancy through the day. Some veering of flow with height is forecast, but hodographs should remain small due to weakness of boundary-layer wind speeds. Effective-shear magnitudes also will be limited by the shallowness of the buoyancy (100-300 J/kg MLCAPE, with even the equilibrium level positioned below strong mid/upper winds). These progs currently indicate sub-optimal conditions for San Joaquin Valley mini-supercells, though small hail will be possible with the deepest activity. ...Edwards/Leitman.. 03/06/2023 $$ = = = 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) .