Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Apr 14 2023 12:31:50 ACUS01 KWNS 141231 SWODY1 SPC AC 141230 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0730 AM CDT Fri Apr 14 2023 Valid 141300Z - 151200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO EARLY TONIGHT FROM NORTHWEST OK ACROSS KS TO SOUTHEAST NE... ....SUMMARY... Severe thunderstorms capable of producing large hail and damaging winds are most likely from late afternoon through evening from central Kansas into southeast Nebraska. ....Central Plains through tonight... Downstream from a midlevel trough over the Rockies/Great Basin, a lee cyclone will move south-southeastward across western KS today, as cool air surges southward across the central High Plains. Farther east and south, low-level moisture return is underway from TX to OK/KS, though boundary-layer moisture depth/magnitude is somewhat modest by mid April standards. The low-level moistening is occurring beneath a plume of steep midlevel lapse rates (8-9 C/km), and will result in a corridor of 2000-3000 J/kg MLCAPE by late afternoon (along and west of the I-35 corridor). The majority of observations and forecast scenarios suggest that the boundary layer will remain capped from roughly I-20 in the Big Country to roughly I-40 in western OK. There is some small concern for storm development in OK near or just south of I-40 this afternoon. Forecast soundings suggest the boundary layer should remain capped, and that any convection would be rooted within the elevated mixed layer - possibly associated with weak ascent and midlevel moistening preceding a subtle/lead shortwave trough now over west central TX (this is the likely source of the convective signal shown in NAM forecasts with the BMJ convective scheme). Otherwise, the more probable scenario for storm development will be by this evening along the cold front in KS, and perhaps a little to the south along the dryline into northwest OK. High-based thunderstorm clusters can be expected with modest low-level moisture and deep-layer vertical shear that is marginal for supercells. Severe outflow winds of 60-75 mph will be possible given the steep lapse rate profiles and DCAPE near or greater than 1000 J/kg. Any supercell-like structures will have the potential to produce isolated very large hail of 2 to 2.5 inches in diameter. Storm clusters will spread east-northeastward and slowly weaken by about 06z. ....Carolinas/southern VA this afternoon/evening... The closed midlevel low now over northern AL will gradually evolve into more of an open wave while ejecting northeastward toward the Mid-Atlantic tonight. Low-level moisture (dewpoints in the 60s) will spread northward today across NC toward southern VA, with surface heating expected in cloud breaks between the eastern NC convection this morning and the thicker clouds over GA. Midlevel lapse rates and vertical shear will remain modest (< 7 C/km and near 30 kt effective bulk shear), but MLCAPE could approach 1000 J/kg. The net result will be scattered storm cells/clusters capable of producing isolated wind damage and marginally severe hail for a few hours later this afternoon/evening. ...Thompson/Gleason.. 04/14/2023 $$ = = = 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) .