Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Oct 03 2024 20:10:37 FOUS30 KWBC 032010 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 410 PM EDT Thu Oct 3 2024 Day 1 Valid 16Z Thu Oct 03 2024 - 12Z Fri Oct 04 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. A continued depiction of locally heavy rainfall exists within this morning CAMs around Southeastern LA into the coastal areas of AL/MS. The threat within the latest hi-res is a bit less ostentatious compared to even the previous forecast outputs correlating to lower probabilities for heavier precip necessary to attain a risk area. Still anticipating some localized totals of 2-4" across the Southeast Parishes with the areas of highest threat for any flash flood concerns still residing within urban corridors like New Orleans, Biloxi, and Mobile. Considering all those locations are running <45% within the 3" precip probability, the threat will remain non-zero, but still falling short of the MRGL risk threshold necessary to implement a low-end risk. A secondary area of note resides over the Tampa metro where locally enhanced rainfall from sea breeze convection will drop a quick 2-4" with locally as much as 5" within some CAMs output. Rainfall rates, both hourly and intra-hour will be the defining point for flash flood concerns over the area and current prospects are borderline for flash flood concerns, but again non-zero in the grand scheme. The nil ERO across the CONUS was maintained, but will still monitor the two areas above for targeted upgrades pending radar evolution. Mesoscale Precip Discussions might be more beneficial in this setup considering the smaller footprint of flash flood potential. Kleebauer Day 2 Valid 12Z Fri Oct 04 2024 - 12Z Sat Oct 05 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. The broad cyclonic regime across the Gulf will continue through the end of the week with a westward expansion of elevated PWATs into portions of coastal TX. Recent trends are for convective development to remain mostly offshore within the best the zone of greatest theta-E, although some inferences of the convective potential are forecast to wander ashore of Deep South TX between CRP and BRO. Best chance for totals >2" are focused along the immediate coast from Kenedy to Cameron counties with South Padre and Brownsville the most common focal points for a heavier rain footprint. The consensus is still for the heaviest rain to remain offshore, but some CAMs try to usher in a few pockets of heavier precip capable of low-end prob flash flooding concerns. This shows up well with the 3-hr FFG exceedance probability on the 12z HREF, but again very low-end threat considering the 5-15% probs positioned over the above area. Probabilities for late in the period are heavily skewed thanks to one CAM member going well above consensus in heavy rain placement, so currently not entertaining that idea as of now unless more guidance tags along. In any case, the threat for flash flooding remains non-zero, but below the MRGL risk threshold. The nil ERO forecast for the CONUS continues.=20 Kleebauer Day 3 Valid 12Z Sat Oct 05 2024 - 12Z Sun Oct 06 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Kleebauer Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!6X2h8PnO_VrYitgkidzloEkmUArbqmNqsKT7SrFxohIs= 7iUsTZD4V3fYc2mRxHTBNcrs1seMMQftrusm-nB0HRYRDbU$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6X2h8PnO_VrYitgkidzloEkmUArbqmNqsKT7SrFxohIs= 7iUsTZD4V3fYc2mRxHTBNcrs1seMMQftrusm-nB0wlQiY-A$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6X2h8PnO_VrYitgkidzloEkmUArbqmNqsKT7SrFxohIs= 7iUsTZD4V3fYc2mRxHTBNcrs1seMMQftrusm-nB0BX3N96Q$=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) .