Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jul 05 2023 17:29:09 ACUS02 KWNS 051729 SWODY2 SPC AC 051727 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Wed Jul 05 2023 Valid 061200Z - 071200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN COLORADO INTO WESTERN KANSAS AND FAR NORTHWEST OKLAHOMA... ....SUMMARY... Severe storms capable of producing large hail, damaging gusts, and a couple of tornadoes, are forecast from the northern High Plains southeastward to Kansas and Oklahoma. ....Synopsis... Thunderstorms will be ongoing tomorrow (Thursday) morning across parts of the central Plains and are expected to drift into the Lower MS Valley by afternoon, supporting an isolated severe threat. An embedded mid-level impulse will traverse the central Rockies and eject into the central Plains during the afternoon, providing enough deep-layer ascent over a moist, unstable airmass to support severe thunderstorm development (with all hazards possible) across the central High Plains. Organized storm clusters may persist with some severe threat into the central and southern Plains into the evening hours. ....Central High Plains into the central and southern Plains... Guidance consensus depicts considerable cloud cover across the High Plains (especially around the WY/NE border) during the morning/early afternoon hours, suggesting that surface temperatures should only reach the 70s to perhaps 80 F by afternoon peak heating. Despite the modest surface temperatures, upper 50s F surface dewpoints should extend westward to the immediate lee of the central Rockies, with 60+ F dewpoints likely along the NE/CO/KS border and points east. 8+ C/km mid-level lapse rates will overspread this relatively moist low-level airmass, supporting 2000+ J/kg SBCAPE by mid afternoon along the High Plains. Considerable veering and strengthening winds with height will support elongated hodographs with modest low-level curvature, suggesting supercells as the likely initial storm mode. Large hail is the greatest threat with the supercells. The longest-lived supercells may produce instances of 2+ inch hail and/or a tornado. This is especially the case in eastern CO, where a Category 3/Enhanced risk has been introduced. During the evening hours, upscale growth into one or more MCSs is likely, with severe gusts becoming the dominant severe hazard. Latest guidance consensus suggests that a longer-lived MCS may develop across KS and progress to the OK border during the night, where a couple of 65+ kt gusts also cannot be ruled out. ....Southern High Plains... Surface lee troughing across parts of southeast NM, along with strong surface heating of a deep, dry/well-mixed boundary layer, may aid in the initiation of isolated high-based thunderstorms along/ahead of a diffuse dryline by mid to late afternoon. Given some stronger speed shear in the mid-levels (and associated hodograph elongation), a couple of multicellular storm structures may materialize, supporting a couple of severe downbursts given 9+ C/km low-level lapse rates. ....Arklatex into the Lower MS Valley... MCS remnants will slowly drift southeast into the Arklatex region at the start of the period (12Z Thursday morning), posing a limited damaging gust threat. By afternoon though, strong surface heating will promote surface temperatures approaching 90 F in spots, amid 70+ F dewpoints, contributing to 2000-3000 J/kg of tall, thin SBCAPE (given mediocre mid-level lapse rates). Deep-layer shear is also expected to be quite poor, which should limit storm organization. However, convergence along outflow boundaries left behind by preceding convection may serve as the impetus for the initiation of thunderstorm clusters. Water loaded downdrafts associated with these clusters may support brief instances of damaging to potentially severe downburst winds, warranting the introduction of a Category 1/Marginal Risk. ...Squitieri.. 07/05/2023 $$ = = = 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) .