Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Nov 15 2024 19:22:36 FOUS30 KWBC 151922 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 222 PM EST Fri Nov 15 2024 Day 1 Valid 16Z Fri Nov 15 2024 - 12Z Sat Nov 16 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Orrison Day 2 Valid 12Z Sat Nov 16 2024 - 12Z Sun Nov 17 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Campbell Day 3 Valid 12Z Sun Nov 17 2024 - 12Z Mon Nov 18 2024 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTHERN PLAINS... 20z Update: Only made minor changes to the inherited Marginal and Slight risk area over TX into OK as the forecast looks on track. Very impressive IVT, PWs and forcing will move across TX/OK by Sunday evening into the overnight hours. This should be enough to overcome the limited forecast instability and result in deep=20 convection and heavy rainfall rates. The latest model consensus is=20 for 2-4" of rain, but would expect isolated swaths as high as 4-6"=20 within this setup. The overall progressive nature of the system and limited instability will cap the upper bound of rainfall=20 totals...but this system is dynamic enough with plentiful moisture=20 to suggest at least localized flash flooding is likely. The Marginal risk over western OR also remains. This risk is pretty borderline, as the AR is only weak to moderate and is fairly progressive. However event total rain of 2-4" (through 12z Mon)=20 and hourly rainfall rates possibly approaching 0.5" within a=20 narrow southward shifting axis suggest that some minor flooding=20 issues could arise along coastal areas/mountains. Chenard ....Previous Discussion... An upper trough traversing through the West this weekend is expected to split which will send energy in the Northern Plains/Upper Midwest along with a strong southern stream cutoff low into the Four Corner that will exit into the Central/Southern Plains for the start of the week. A surface low pressure system will forecast to spin up in the lee of the Rockies and deepen as it tracks from the Plains through the Midwest. Scattered to widespread moderate to heavy rainfall will be supported by this setup across portions of the Southern Rockies and the adjacent Southern/Central Plains. Guidance is suggesting 1 to 2 inches of rain for central and eastern portions of New Mexico, particularly over some of the same areas that had several inches of snow last week. With rain on top of snow expected some locations will have an increased risk for flooding concerns. The Marginal Risk area that was already in effect was expanded westward to now cover central and eastern portions of New Mexico. The highest concentration of rainfall will likely focus across parts of northern Texas/panhandle into western Oklahoma. Consensus suggests areal average of 3 to 4.5 inches with locally higher amounts possible. Therefore, a Slight Risk was introduced with this issuance. Campbell Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_3Qd1HcRt3bYMP67Buz5lfQ8V953VRHxv0rqGxj4qxh3= 0Uh1lDZFUEqIjHDzr99HfF5tuMnxq_e0yUsJVp0hF2Ve3S4$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_3Qd1HcRt3bYMP67Buz5lfQ8V953VRHxv0rqGxj4qxh3= 0Uh1lDZFUEqIjHDzr99HfF5tuMnxq_e0yUsJVp0h6byOL-c$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_3Qd1HcRt3bYMP67Buz5lfQ8V953VRHxv0rqGxj4qxh3= 0Uh1lDZFUEqIjHDzr99HfF5tuMnxq_e0yUsJVp0h5YavseU$=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) .