Subj : DAY1SVR: Day 1 Convective To : All From : Mike Powell Date : Sat Feb 17 2024 09:05:00 ACUS01 KWNS 171251 SWODY1 SPC AC 171249 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Sat Feb 17 2024 Valid 171300Z - 181200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Severe thunderstorms are not forecast across the continental U.S. through tonight. ....Synopsis/Discussion... Mid/upper-level mean troughing will persist over eastern North America and the northeastern Pacific, with ridging across western portions of the CONUS and Canada. A vast cyclonic gyre anchors the Pacific mean trough. A notable shortwave perturbation -- evident in the broader cyclone's southeastern quadrant west of CA, near 135W -- will eject northeastward today, reaching the northwestern CA coastline around 06Z. Associated midlevel DCVA and steepening of low/middle-level lapse rates, will support weak buoyancy atop a cool, moist marine layer. Associated potential for widely scattered to scattered showers and isolated thunder will approach the coast during mid/late afternoon and persist until the trough passes late this evening. East of the ridge, another shortwave trough was evident in moisture- channel imagery across portions of CO/UT. This feature will shift southeastward to the Mid-South, Arklatex and North TX by the end of the period, causing height falls over the lower Mississippi Valley and western Gulf Coast regions. In response to these developments, a southern-stream trough now over west-central/north-central MX will move eastward across the western/northern parts of the MX Gulf Coast to the western Gulf. Several lesser vorticity lobes/shortwaves will travel downstream to FL, perhaps cooling initially unfavorably warm midlevel temperatures enough to contribute to isolated thunder potential within an extensive precip plume. The convection should be mainly along and north of a slow-moving cold front now located over central FL. Weak lows may traverse the front in association with the perturbations aloft, but the most prominent surface low preceding the main Mexican trough should remain west of the peninsula through the period. The front should move slowly southward, reaching south FL by 12Z tomorrow. Weak instability (especially in midlevels) and disorganized convective modes should preclude both a severe threat and more than isolated thunderstorms. ...Edwards/Mosier.. 02/17/2024 $$ --- SBBSecho 3.14-Linux * Origin: ILink: CCO - capitolcityonline.net (454:3/105) .