Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Feb 09 2025 08:09:49 FOUS30 KWBC 090808 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 308 AM EST Sun Feb 9 2025 Day 1 Valid 12Z Sun Feb 09 2025 - 12Z Mon Feb 10 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 2 Valid 12Z Mon Feb 10 2025 - 12Z Tue Feb 11 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 3 Valid 12Z Tue Feb 11 2025 - 12Z Wed Feb 12 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF=20 THE MID-SOUTH AND LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY... ....ArkLaTex-ArkLaMis into the Mid-South and Tennessee Valley... Strong NW-SE upper level jet streak will dive southeast into CA late on Day 3 (Tue night) -- on the western periphery of the=20 longwave trough towards the base. As this occurs, the broad western U.S. trough will amplify, thereby enhancing the deep-layer ascent and southwesterly flow/moisture transport within a maturing Warm=20 Conveyor Belt (WCB) downstream across the Mid South-Lower MS Valley and TN Valley. 850-700 mb moisture flux anomalies increase to 2-3=20 standard deviations above normal Tue-Tue night, while TPW values=20 climb to 1.5-1.75" (around +2 standard deviation above normal). The strengthening dynamical and thermodynamical support will make for=20 efficient rainfall rates despite the lack of deep-layer=20 instability. Much of the guidance, non-CAM at this point being a=20 Day 3 forecast, depicts a widespread swath of 1.5-2.5" of rain=20 within the outlook areas, with more stripes of >3" within the=20 Slight Risk area. Storm motions nearly parallel to the WSW-ENE=20 oriented surface boundary will boost the potential for training,=20 and even though currently the non-CAM guidance is advertising=20 meager deep-layer elevated instability (MUCAPEs generally 250-500=20 J/Kg), believe these values will be amplified somewhat as the event gets within the high-res CAM windows, again given the dynamic and=20 thermodynamic response to the broad-scale upper trough amplification. 2.00"+/3hr rainfall rates are anticipated where the cells do=20 train, again most likely within the Slight Risk area, which could=20 lead to localized-scattered instances of flash flooding. Hurley Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5Vg4A5CEf6psiSAC9G2KkH2dCUUIUt74Lx2o6Gu-_gFT= 5FYYMghMM50QheMWdZwGzVyZwJuFHFX4IYkhnjc8E8Qd8wY$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5Vg4A5CEf6psiSAC9G2KkH2dCUUIUt74Lx2o6Gu-_gFT= 5FYYMghMM50QheMWdZwGzVyZwJuFHFX4IYkhnjc8OA08Q_w$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5Vg4A5CEf6psiSAC9G2KkH2dCUUIUt74Lx2o6Gu-_gFT= 5FYYMghMM50QheMWdZwGzVyZwJuFHFX4IYkhnjc8daFfYqg$=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) .