Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed May 10 2023 06:05:12 ACUS02 KWNS 100605 SWODY2 SPC AC 100603 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0103 AM CDT Wed May 10 2023 Valid 111200Z - 121200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTH DAKOTA TO OKLAHOMA... ....SUMMARY... Strong/severe thunderstorms are forecast Thursday across the central Plains vicinity, where large hail can be expected along with locally damaging winds and possibly a couple of tornadoes. ....Synopsis... An upper low is forecast to move slowly northeastward out of the southern Rockies and into the central High Plains region Thursday. Meanwhile, a weaker/lead disturbance is progged to shift slowly northeastward across the Ozarks/lower Mississippi Valley to the Mid Mississippi/Lower Ohio Valley through the period. Elsewhere, northeasterly flow aloft will persist across New England, while ridging prevails across the West Coast states, and from the Southeast northward into the Midwest. At the surface, a weak low initially anticipated over southeastern Colorado will shift slowly northeastward across western Kansas. A weak/secondary low may evolve during the late afternoon/early evening hours across the southwestern Oklahoma vicinity, near a possible bulge in a dryline that will be mixing eastward across the western half of Texas through the afternoon. Elsewhere across the U.S., surface high pressure will largely prevail. ....Plains states from South Dakota to Oklahoma... A rather complex scenario is forecast to evolve across the Plains states, as an upper low within the base of a negatively tilted trough crossing Intermountain West crosses the central High Plains. Southeasterly low-level winds ahead of the upper low and associated surface cyclone should maintain a seasonably moist airmass, which will destabilize through the afternoon in tandem with diurnal heating. At this time, it appears that convective coverage should gradually increase through the afternoon -- northeast of the low across portions of Nebraska, and southeastward in an arcing band from eastern Colorado into western Kansas. With flow veering from southeasterly to southerly and increasing with height, shear will be sufficient to support organized updrafts, and attendant risk for hail and locally damaging winds, and possibly a tornado. This convection should spread northeastward through the afternoon and evening in tandem with the gradual advance of the parent synoptic system, with severe potential eventually waning later in the evening. A more substantial -- through also likely more isolated -- severe risk may evolve across parts of western Oklahoma, near a potential dryline bulge. While capping should hinder development until late afternoon, developing storms would be evolving within an airmass featuring a moist boundary layer beneath steep lapse rates aloft, and with low-level southeasterly flow veering and increasing to southwesterly at mid levels. As a result, a couple of supercell storms are anticipated, which would be capable of producing very large hail, locally damaging wind gusts, and potentially a couple of tornadoes. This risk would spread northeastward through the evening -- across Oklahoma and into southern Kansas. While questions regarding convective coverage argue against upgrading tornado or hail probabilities at this time, such upgrades could be necessary in future outlooks if this scenario becomes more certain, and particularly if it appears that storm coverage may be slightly greater than currently anticipated. ....Southern Mississippi and vicinity... A cluster of thunderstorms -- which may be ongoing at the start of the period near the Mississippi Delta region -- may persist into the afternoon, as the airmass destabilizes. Several CAMs indicate that upscale growth into the afternoon may occur, with a band of storms spreading eastward across the southern half of Mississippi. Though deep-layer flow is progged to remain rather weak, locally gusty/damaging winds could occur with a few of the stronger updrafts, along with marginal hail potential, within this band of storms through the afternoon hours. ...Goss.. 05/10/2023 $$ = = = 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) .