Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 28 2024 07:58:40 FOUS30 KWBC 280758 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 358 AM EDT Sat Sep 28 2024 Day 1 Valid 12Z Sat Sep 28 2024 - 12Z Sun Sep 29 2024 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE OHIO AND TENNESSEE VALLEYS AS WELL AS FOR CENTRAL FLORIDA... ....Ohio/Tennessee Valleys... The combined upper low and remnant circulation of what is left of Helene is expected to slow/stall over the Ohio and Tennessee=20 Valleys. With very little if any instability to work with the bulk of rain today will likely be stratiform with hourly rates around=20=20 0.5 inch/hour or lower. At best there may be some isolated flash=20 flooding, therefore maintained the broad Marginal Risk that is in place over the region. ....Florida... A trailing cold front across the Florida peninsula will be present during this period along with abundant instability and moisture=20 within proximity to this feature. The development of strong thunderstorms can be expected, especially on the western side of the peninsula. Recent heavy rain has increased soil sensitivity for much of the area therefore maintained a Marginal Risk for excessive rainfall for the western and central peninsula. Campbell Day 2 Valid 12Z Sun Sep 29 2024 - 12Z Mon Sep 30 2024 ....THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-ATLANTIC/APPALACHIANS AS WELL AS THE NORTHERN FLORIDA=20 PENINSULA... ....Mid-Atlantic/Central Appalachians... During this period the remnant low of Helene will get picked up by the upper level jet and track eastward into the Mid-Atlantic and=20 Central/Northern Appalachians. There will be an increase in available instability which may lead to localized enhanced rainfall rates for portions of the Shenandoah Valley and west to the=20 Allegheny Front in Maryland, West Virginia, and Virginia; which may result in isolated to widely scattered instances of flash=20 flooding. The level of threat continues to be handled well with the Marginal Risk that is currently in effect. There may be a need for a Slight Risk with future updates depending on model trends and observations. ....Florida... Convection will continue to fire up in proximity to a stalled frontal boundary draped across northern/central Florida. Storm motion may be fast-moving with some tracking over areas hard-hit=20 by Helene, but because progressive nature of the convection a=20 Marginal Risk remains appropriate for this period. Campbell Day 3 Valid 12Z Mon Sep 30 2024 - 12Z Tue Oct 01 2024 ....THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-ATLANTIC/CENTRAL APPALACHIANS... The lingering upper low over the East and accompanying moisture=20 from Helene will continue to produce some showers and thunderstorms over portions of the Appalachians and Mid-Atlantic into Monday. Heavy intensity and accumulations are not expected to be widespread or heavy, however the recent wet period keeps an elevated threat for excessive rainfall and isolated flooding concerns. A Marginal remains in effect from south-central Virginia to central=20 Pennsylvania. Campbell Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4BZDEm9SSzIaUODyoVMGaS8P9vft4xyhnqQ2tQr2S_M4= rdTNm5W63W7UH5Q-0okj7KwzN4VNW4-e9H4GQsL2VBhlFK4$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4BZDEm9SSzIaUODyoVMGaS8P9vft4xyhnqQ2tQr2S_M4= rdTNm5W63W7UH5Q-0okj7KwzN4VNW4-e9H4GQsL2E795Ym4$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4BZDEm9SSzIaUODyoVMGaS8P9vft4xyhnqQ2tQr2S_M4= rdTNm5W63W7UH5Q-0okj7KwzN4VNW4-e9H4GQsL2GjUlIno$=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) .