Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Oct 14 2023 06:30:17 FOUS30 KWBC 140630 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 229 AM EDT Sat Oct 14 2023 Day 1 Valid 12Z Sat Oct 14 2023 - 12Z Sun Oct 15 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. ....Eastern Ohio Valley into the Mid Atlantic Region... During the day 1 period (through 12Z Sunday), shortwave energy associated with the Midwest to OH Valley system will become absorbed within the amplifying longwave eastern CONUS trough. At the surface, the guidance shows a Miller Type B scenario as the Ohio Valley low today eventually gives way a developing low off the mid Atlantic coast Sat night. Compared to yesterday and especially Thursday, the deep-layer forcing and (especially) moisture flux/transport aren't nearly as anomalous, which is typical during these transitional Miller B events. Across northern portions of the Mid Atlantic region, DPVA and left-exit region upper jet forcing (100-120kt jet streak at 250 mb) will lead to favorable deep-layer isentropic ascent over-top a more stable, CAD profile in the lower layers. Over these areas expect a steady moderate to occasional heavy rainfall, averaging between 0.75-1.5" in a 24hr period with little variation outside of that range. Over southern portions of the Mid Atlantic, particularly southeast VA and eastern NC, instability profiles may become a bit more favorable later this afternoon into the evening as these areas may briefly sneak into the warm sector. However, given the fast progression of the main synoptic players at that point, expect any uptick in short-term rainfall rates to be short-lived per the simulated reflectivity forecasts from the 00Z CAMs Saturday afternoon and evening. This along with the relatively high FFG and low (<50%) soil moisture percentiles will likely result in a sub-Marginal flash flood risk, even if non-zero in some areas. Hurley Day 2 Valid 12Z Sun Oct 15 2023 - 12Z Mon Oct 16 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 3 Valid 12Z Mon Oct 16 2023 - 12Z Tue Oct 17 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley =20 Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-FhuUBD0uMK89GCUzSWM0zObZmNuG5npvfB8_OQ6a6CO= HoEJ2I3zwwVTBqaWV55XEQj_8q29Onwk9PtBlYlZRsKWqek$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-FhuUBD0uMK89GCUzSWM0zObZmNuG5npvfB8_OQ6a6CO= HoEJ2I3zwwVTBqaWV55XEQj_8q29Onwk9PtBlYlZFteyih8$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-FhuUBD0uMK89GCUzSWM0zObZmNuG5npvfB8_OQ6a6CO= HoEJ2I3zwwVTBqaWV55XEQj_8q29Onwk9PtBlYlZhujyuUA$=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) .