Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Oct 04 2024 15:45:18 FOUS30 KWBC 041545 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 1145 AM EDT Fri Oct 4 2024 Day 1 Valid 16Z Fri Oct 04 2024 - 12Z Sat Oct 05 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Coastal trough with an embedded surface low will settle just off the TX coast with prevailing northeast flow centered from CRP down to BRO. This will aid in advection of elevated moisture with PWATs jumping >2" by this afternoon leading to a bit more environment moisture to work with for locally heavy rain opportunities. There's still a sharp gradient within the theta-E alignment with the best instability axis located directly along the coast and out into the neighboring Gulf. The setup is borderline conducive for heavier totals, but mainly confined to that immediate coastal plain where the convective pattern is likely to settle. Considering the very high FFG's located within the zone of interest, the main threat will be relegated to the urban zones like Brownsville to perhaps Harlingen, but even that far inland might be a stretch. The current probabilities are inflated due to two CAMs members already insinuating a heavy rain footprint overhead with more to come. The radar is not in agreement and the 12z HRRR has the best handle amongst the CAMs this morning, and that signal is fairly meager for a flash flood threat. Will continue with the non-zero wording, but will remain very localized for flash flood concerns, if any occur, and not within the 5% threshold necessary for a risk area addition. A nil ERO will be maintained across the CONUS as a result.=20 Kleebauer Day 2 Valid 12Z Sat Oct 05 2024 - 12Z Sun Oct 06 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Wegman Day 3 Valid 12Z Sun Oct 06 2024 - 12Z Mon Oct 07 2024 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR SOUTHWEST FLORIDA AND THE LOWER KEYS... A tropical wave or weak and slow-moving disturbance over the Gulf will drift east into the Florida Peninsula Sunday. Multiple inches of rain are expected through the day from Tampa south into the Keys. The heaviest rain is expected Sunday afternoon and evening, where added instability from diurnal heating will locally increase rainfall rates. The slow-moving nature of any storms will be the greatest contributor to flash flooding. FFGs have recovered since Helene last week, so despite the forecast of 2-4 inches of rain broadly over the Florida Gulf coast, only isolated flash flooding is expected at this point. Wegman Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5Ax5DE-vHid5Hk8b7Wj-AAoSXoLzQvkMNltlhqcio5tu= pGiS94I7Gv5vfvWkuQdzjZvUV5x2r-iM29cs1GK3RwMsLLM$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5Ax5DE-vHid5Hk8b7Wj-AAoSXoLzQvkMNltlhqcio5tu= pGiS94I7Gv5vfvWkuQdzjZvUV5x2r-iM29cs1GK3rM4qmYY$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5Ax5DE-vHid5Hk8b7Wj-AAoSXoLzQvkMNltlhqcio5tu= pGiS94I7Gv5vfvWkuQdzjZvUV5x2r-iM29cs1GK3Qg_N66Y$=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .