Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Feb 12 2023 17:20:04 ACUS02 KWNS 121719 SWODY2 SPC AC 121718 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1118 AM CST Sun Feb 12 2023 Valid 131200Z - 141200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. Monday through Monday night. ....Synopsis... Models indicate that mid-level ridging centered over the southern mid-latitude eastern Pacific may become a bit more suppressed during this period, as short waves begin to a amplify within a prominent belt of westerlies on its northern periphery. Near the leading edge of this regime, it appears that digging larger-scale mid-level troughing will evolve across the Pacific Northwest through northern Great Basin vicinity, as a couple of smaller-scale perturbations progress inland downstream of building mid-level ridging near 140W. As this occurs, a significant mid-level low, initially migrating northeastward near the western Sonora/Arizona border, is forecast to accelerate across the southern Rockies into the southern Great Plains by late Monday night. Downstream, a preceding mid-level low emerging from the Southwest likely will accelerate east-northeastward, away from the Mid Atlantic coast, ahead of another short wave trough digging east-southeast of the Upper Great Lakes region. In response to these developments, a cold front, trailing the surface cyclone accompanying the lead mid-level low, is expected to stall and weaken across the Bahamas/Caribbean/into western Gulf of Mexico vicinity. And the center of cold surface ridging likely will shift from the northern Gulf coast vicinity into the Southeast, while surface troughing deepens to the lee of the Rockies. A moistening boundary layer over the western Gulf of Mexico will begin to advect northward on a developing southerly return flow. However, in the wake of the recent cold intrusion, boundary-layer moisture characterized by surface dew points in excess of 55 F may not reach areas north of Deep South Texas until Monday night, and it appears that this will be mostly beneath warm, dry and capping lower/mid tropospheric layers. ....Pacific Coast into Great Plains... Weak destabilization beneath mid-level cold pools, including 500 mb temperatures near or below -30C, may contribute to scattered convective development which may become capable of producing lighting across parts of the Pacific Northwest, and the Southwestern Deserts into the southern Rockies Monday into Monday night. East of the Rockies, it appears that warm, dry lower/mid tropospheric layers will largely inhibit thunderstorm development in association with the boundary-layer moistening accompanying the Gulf return flow. Based on NAM and Rapid Refresh forecast soundings, the extent to which moistening (of lower latitude eastern Pacific origins) aloft can contribute to destabilization supportive of convection capable of producing lightning also remains rather unclear. At this point, forecast soundings which might become marginally conducive to scattered weak thunderstorm development seem mostly confined to portions of the Texas South Plains and Big Country, near the leading edge of the stronger mid-level forcing for ascent and cooling associated with the low emerging from the Southwest. ...Kerr.. 02/12/2023 $$ = = = 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) .