Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Feb 14 2023 13:00:14 ACUS01 KWNS 141300 SWODY1 SPC AC 141258 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Tue Feb 14 2023 Valid 141300Z - 151200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MAINLY FROM EASTERN KANSAS INTO WESTERN MISSOURI... ....SUMMARY... A few strong to severe thunderstorms are possible, mainly from eastern Kansas into western Missouri this afternoon and early evening. ....Synopsis... Mean troughing and associated cyclonic flow has become established across the western half of the CONUS in mid/upper levels,anchored by two prominent shortwave perturbations: 1. An initially closed cyclone, centered near the western end of the OK Panhandle, with trough south-southwestward across the southern High Plains to far west TX. This feature is expected to eject northeastward, reorient to negative tilt, and remain a closed cyclone through 00Z. By then, the 500-mb low should be near OMA, with trough from eastern SD to northwestern MO to the MO/AR Ozarks. The low will move northeastward to Lake Superior by the end of the period, when it should devolve to an open wave, and become entrained in northern-stream flow ahead of a larger central Canadian trough. 2. A broad area of cyclonic flow and vorticity currently wrapping around a trough over the northwestern CONUS. This feature should amplify and dig south-southeastward to the Great Basin by 00Z, with a 110-130-kt 500-mb speed max on its west side over northern CA. A closed cyclone will develop overnight and pivot toward the Four Corners area, with cyclonic flow extending from northern CA to the southern Plains and the northwestern 1/3-1/2 of MX. At the surface, 11Z analysis showed a 981-mb low over southeastern Co between TAD-LHX, with occluded/warm front northeastward across northwestern KS and central NE, and a Pacific cold front arching over southwestern KS, northwest/west-central TX, to central Coahuila. A trough extended from the warm front to another low over west-central SD. The southern low should move northeastward over western/central KS through the remainder of the morning then weaken, along the trough extending from the northern low. By 00Z, a new low, or consolidation of the earlier ones, should develop over northwestern IA, with Pacific front weakening to its southeast and a trough south-southwestward across eastern portions of KS/OK. By 12Z, the main low should reach Upper MI, with an area of cold frontogenesis southwestward over eastern IA, northwestern MO, southeastern KS, and northern OK. This front should become quasistationary across the northern TX Panhandle and northeastern NM, to another low over southwestern CO related to the upstream mid/upper-level perturbation. ....Lower Missouri Valley region... An ongoing, broad arc of showers and isolated/transient thunderstorms is evident in satellite and radar imagery from central TX across central/eastern OK to central/eastern KS, in a plume of low-level warm advection and isentropic lift to LFC, with modest midlevel lapse rates and elevated buoyancy. This convection should shift eastward into MO, AR, northwestern LA and easternmost areas of TX by early afternoon, subsisting on elevated buoyancy. While isolated strong gusts may penetrate to the surface, any severe potential appears too isolated and conditional for an outlook area. Behind that precip, isolated to scattered, low-topped thunderstorms are expected to form over the KS and southeastern NE portions of the outlook during early-mid afternoon. The newer convection should move rapidly northeastward, while offering an isolated, marginal tornado/hail/severe-gust threat. This activity should form in a zone of short-lived but favorable diurnal heating/destabilization that follows the morning convective plume. Time series of forecast soundings reasonably suggest that the midlevel DCVA plume preceding the trough will cool 500-mb temperatures by 10-15 deg C, as the post-precip surface temperatures warm beneath. The net result should be lapse rates around 8-9 deg C/km in the low/middle levels, atop minimal MLCINH once surface temperatures reach the mid 50s F, with dewpoints in the mid/upper 40s. A narrow plume of MLCAPE in the 300-500 J/kg range should develop, amidst strong midlevel flow supporting 30-40 kt effective-shear magnitudes. Sufficient southerly surface-flow component should remain to contribute to well-curved hodographs, with effective SRH in the 150- 200 J/kg range. This will support potential for a couple supercells, and localized risk of any severe mode. Severe potential should decrease after dark into northeastern MO and southern IA, as the convection encounters progressively weaker boundary-layer instability. ...Edwards/Mosier.. 02/14/2023 $$ = = = 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) .