Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Nov 04 2022 19:37:25 ACUS01 KWNS 041937 SWODY1 SPC AC 041936 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0236 PM CDT Fri Nov 04 2022 Valid 042000Z - 051200Z ....THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PARTS OF NORTHEAST TX...SOUTHEAST OK...SOUTHWEST AR...AND NORTHWEST LA... ....SUMMARY... A threat for tornadoes, severe gusts and large hail exists today and tonight over parts of central, north and east Texas, southeastern Oklahoma, southern/western Arkansas, and northern Louisiana. ....20Z Update... ....OK/TX/AR/LA... Recent surface analysis placed a low near BVO (in northeast OK) with a cold front extending southwestward across central OK to another low southwest of SPS (in northwest TX). A dryline extends south-southward from this second low through the Edwards Plateau. Upper 60s/low 70s dewpoints precede this front from southeast OK southward into the TX Hill Country. Recent 18Z FWD sounding shows the capping in place at 12Z has eroded amid a moistening boundary layer and modest 700-mb cooling. Low- to mid-level flow has also strengthened during this period, increasing to near 60 kt around 850-mb. This is in line with previous forecast reasoning, with the warm-sector becoming very kinematically supportive of supercells capable of tornadoes. Thus far, modest thermodynamics appear to be the limiting factor. However, large-scale forcing for ascent will continue to increase while low-level moisture advection persists. Additional storm development now appears underway across central TX as well as west of the Metroplex. The overall forecast remains the same. An initially discrete mode is expected throughout the warm sector where very favorable low-level and deep-layer shear profiles support updraft rotation and tornadoes (including strong tornadoes). A transition to a more linear mode is then expected as the front continues eastward, with the potential for widespread damaging winds across northeast TX, southeast OK, and southwest AR. ....Southern WI/Northern IL... A few instances of strong gusts and/or isolated hail are possible within the fast-moving thunderstorms over the region. See recently issued MCD #1918 for details on this area. ...Mosier.. 11/04/2022 ..PREV DISCUSSION... /ISSUED 1121 AM CDT Fri Nov 04 2022/ ....OK/TX/AR/LA... Morning water vapor imagery shows a large upper trough moving across NM, with an 80-90 knot mid level jet rotating eastward into west TX. At the surface, a cold front is sagging southward across western OK with strong southerly low-level winds aiding moistening in the warm sector over central/east TX/OK. Widespread low clouds will hinder daytime heating/destabilization over much of the warm sector today. However, dewpoints in the mid 60s to lower 70s will yield afternoon MLCAPE values of 1000-2000 J/kg ahead of the cold front. Present indications are that the mid level capping inversion shown on the 12z FWD raob is weakening rapidly, with a nearly saturated boundary-layer and little convective inhibition expected throughout the afternoon. Persistent large-scale forcing ahead of the approaching trough will lead to scattered fast-moving thunderstorm development in the warm sector before 19z. Forecast soundings show very favorable low-level and deep-layer shear profiles for updraft rotation and tornadoes (including strong tornadoes). The main forecast question is whether activity will become widespread early, rapidly weakening the available instability. Even if this occurs, a transition to bowing structures seems likely with the potential for widespread damaging winds. For these reasons, have upgraded to MDT risk for parts of the Arklatex region. Storms will persist well into the night, tracking across much of LA/AR and into western MS. ....IA/IL/WI... A surface cold front currently extends from southern WI into eastern IA and northern MO. A few strong and fast-moving thunderstorms are affecting areas along/ahead of this front. Given the strong winds aloft and sufficient CAPE, isolated strong/damaging wind gusts could occur with this activity. $$ = = = 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) .