Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 30 2023 08:30:04 FOUS30 KWBC 300829 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 429 AM EDT Sat Sep 30 2023 Day 1 Valid 12Z Sat Sep 30 2023 - 12Z Sun Oct 01 2023 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE GREAT BASIN, NEW MEXICO AND FAR WEST TEXAS, UPPER MIDWEST, AND FLORIDA... ....Great Basin/Nevada... A deep upper-trough will transport a plume of moisture (1-2 PWAT stndv) into the West today. A cold front associated with a deepening low pressure system will act as a focus for convection over the Great Basin, in particular. There's been some consolidation and better agreement between the hi-res and global guidance with respect to the location of the axis of heaviest precipitation. Some parts of central Nevada, southeastern Oregon and southwestern Idaho could see rainfall rates around 0.25"/hr with isolated higher amounts. Ample forcing over elevated terrain could lead to more efficient/enhanced rain rates. Between 1-3" of rainfall is expected through tonight. ....New Mexico/west Texas... Convection supported by a deep upper trough to the West and leading shortwave energy will support another localized flash flood threat over parts of eastern New Mexico and into west Texas. Decent instability (1000J/kg+), modest moisture flux and a favorable low level jet may produce bursts of heavy rainfall over our marginal risk area. Urban areas and dry washes are most vulnerable of flash flooding. ....Upper Midwest... An embedded shortwave within an omega ridge will continue driving convection through this afternoon. The heaviest rainfall may already be occurring over parts of eastern Minnesota and northwestern Wisconsin. That being said, impressive forcing, instability (1000J/Kg+) and moisture (2-3 PWAT stndv) could still generate excessive rainfall leading to isolated instances of flash flooding. ....Florida... A slow moving shortwave trough will allow for the continuation of scattered to isolated thunderstorms across the central/southern peninsula today. Some cells may produce localized heavy rainfall within the marginal risk area. Antecedent conditions will also contribute to the sensitivity to any isolated heavy rainfall threats. Kebede 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!6Fcoh5HwMRqgpijEbwy5wnZSxrMneDaj5cWSFF8Fdo4V= eduFQ_ZAPZu4owKqo43eX6gDlu-PmZ-xjztUsjqCRp_qvAU$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6Fcoh5HwMRqgpijEbwy5wnZSxrMneDaj5cWSFF8Fdo4V= eduFQ_ZAPZu4owKqo43eX6gDlu-PmZ-xjztUsjqCbgPoHvw$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6Fcoh5HwMRqgpijEbwy5wnZSxrMneDaj5cWSFF8Fdo4V= eduFQ_ZAPZu4owKqo43eX6gDlu-PmZ-xjztUsjqCq-TpaQ0$=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) .