Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 24 2023 08:11:39 FOUS30 KWBC 240811 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 411 AM EDT Thu Aug 24 2023 Day 1 Valid 12Z Thu Aug 24 2023 - 12Z Fri Aug 25 2023 ....A SLIGHT RISK OF EXCESSIVE RAINFALL IS IN EFFECT FOR PORTIONS OF THE SOUTHWEST AND NORTHEAST/OHIO VALLEY.. ....Lower Great Lakes and upper Ohio Valley to the Northeast... Northwesterly flow around the broad anti-cyclonic ridge axis over the central US will remain steady with prevailing steering pattern focused from the western Great Lakes down through Lower MI into northeast OH into PA. Environment across the aforementioned area will be ripe with PWAT anomalies 1-3 standard deviations above normal and SBCAPE on the order of 3500-4500 J/kg allowing for sufficient buoyancy into the afternoon and evening hrs with expected initiation upstream over Central MI, pressing east and southeast along the general steering flow. 00z HREF mean 24 hr qpf signals a widespread area of heavy precip with 1HR HREF probs indicating a heightened risk of 1+" per hour rainfall rates with anything that does develop, as well as precip totals on the order of 1-2+" through the period. Convection will eventually grow upscale across northwest PA and northeast OH with forward propagation into PA and the southwest portion of NY state. There is some discrepancy in short range guidance on where the eventual complex will motion, but ensemble mean QPF orientation and general steering pattern would lend a greater signal for any complex to be positioned over the south shore of Erie down to northern WV on the southern extent and all points east thru PA. Given the antecedent conditions in place across northeast OH from this evening's convection and guidance pinning more convective precip for later today, have extended the SLGT further to the west across northern OH as the pattern favors another chance for flooding over areas that were impacting this past evening, especially towards Cleveland and surrounding suburbs. ....Southwest US... Remnants from Harold will continue to maneuver around the western flank of the broad ridge axis centered over the plains. Enhanced low-mid level moisture flux stemming from the storm's remnants and seasonal monsoonal pattern will spread northward into the Four Corners with increased ascent focused near the mid-level vorticity maxima associated with what's left of the disturbance. Given the topographic elements and lower 1 HR FFG from all the recent rainfall, a SLGT risk continues across southern UT and western CO. =20 Kleebauer Day 2 The Day 2 outlook will be updated by 0830Z. Day 3 The Day 3 outlook will be updated by 0830Z. Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9kQjAObJG5S3DmC6yGDdwVLcn9wnA4nO1Dk-2c9zHQMa= FjqqyiOV56KJlP6gRaeWxR9LM5Ae9-mYNOthMnVUQkpUxeA$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9kQjAObJG5S3DmC6yGDdwVLcn9wnA4nO1Dk-2c9zHQMa= FjqqyiOV56KJlP6gRaeWxR9LM5Ae9-mYNOthMnVU3MMQVP8$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9kQjAObJG5S3DmC6yGDdwVLcn9wnA4nO1Dk-2c9zHQMa= FjqqyiOV56KJlP6gRaeWxR9LM5Ae9-mYNOthMnVU127Ec5k$=20 $$ =3D =3D =3D 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) .