Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Oct 03 2023 12:37:38 ACUS01 KWNS 031237 SWODY1 SPC AC 031236 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0736 AM CDT Tue Oct 03 2023 Valid 031300Z - 041200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY TONIGHT FROM WESTERN/CENTRAL KS INTO SOUTH CENTRAL NE... ....SUMMARY... Isolated very large hail, occasional severe gusts and a few tornadoes will be possible this afternoon through early tonight across parts of the Great Plains. ....Synopsis... A surface cyclone in ND will develop northeastward today toward southeast SK/western ON as an associated/lead shortwave trough ejects northeastward over the northern Plains. A trailing shortwave trough near the Four Corners will progress east-northeastward over the central Plains later this afternoon through early tonight, with weak lee cyclogenesis is expected near the CO/KS border today. A surface cold front will move eastward/southeastward across the Dakotas, western NE and northeast CO this afternoon, in the wake of the ND cyclone (and north of the weak lee cyclone). South of the weak lee cyclone, a dryline will mix eastward into southwest KS and the western TX Panhandle by mid afternoon. The front and the dryline will help focus severe thunderstorm development, primarily this afternoon/evening from NE/KS into west TX. ....Central/southern Plains through tonight... A narrow corridor of low-mid 60s boundary-layer dewpoints will spread northward today to the east of a sharpening dryline, and in the wake of scattered morning convection that is ongoing from western KS to the TX South Plains. Surface heating along the moist axis, beneath midlevel lapse rates greater than 7 C/km, will result in afternoon MLCAPE values of 1500-2500 J/kg with weakening convective inhibition. Initial severe storm development may occur by about 20z across KS/NE, with subsequent expansion of the storms northeastward across NE toward southeast SD, with more scattered development southward along the dryline toward TX. Long hodographs (effective bulk shear ranging from 45 kt across west TX to 65 kt closer to the KS/NE border) with the moderate buoyancy will favor supercells initially, with the potential to produce isolated very large hail up to 2.5 inches in diameter. Some upscale growth into line segments is anticipated from northern KS into NE as storms align along the cold front. The tornado threat will be modulated by rather modest hodograph curvature/SRH through much of the afternoon where the more discrete supercells are expected, and any evening increase in low-level shear will be somewhat countered by the tendency for more linear convective modes with northward extent. Farther south into west TX, weaker forcing for ascent suggests that storm coverage will be widely scattered along the dryline. Still, there will be sufficient vertical shear/buoyancy for splitting supercells capable of producing large hail/isolated wind damage late this afternoon through late evening. ...Thompson.. 10/03/2023 $$ = = = 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) .