Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Nov 23 2025 20:00:22 FOUS30 KWBC 232000 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 300 PM EST Sun Nov 23 2025 Day 1 Valid 16Z Sun Nov 23 2025 - 12Z Mon Nov 24 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF CENTRAL AND NORTHERN TEXAS INTO PORTIONS OF SOUTHERN OKLAHOMA... ....16z Update... No major changes for the update, maintaining an inherited SLGT Risk and adjusting the contours a bit (mainly shrinking the northern extent) based on the latest 12z CAMs. Highest confidence for SLGT impacts exists across the northern TX Hill Country into the the Big Country, where FFGs (1-3 hr) are as low as 1.5-2.0". Convection is expected to proliferate rather late in the period, around and after 06z for the bulk of heavy precipitation in the main area of concern (including San Angelo). Farther northeast in the SLGT, both rates and resulting totals look lower with less confidence overall. That said, still maintained the SLGT for areas with FFGs (3-6 hour) of 2.5-3.0" given moderate to high (40-60%) 40-km HREF 2" exceedance probs and low (up to 15%) 3" exceedance probs. Outside the SLGT risk, also expanded the MRGL southeast to the coast in the vicinity of Corpus Christi, due to both observational trends this morning and resulting trends in the hi-res CAMs suggesting low-end potential for 3-5" exceedance (though FFGs are much higher). Churchill ....Previous Discussion... Showers and thunderstorms will be firing up ahead of and along the east-west stationary/warm frontal boundary draped across southern Texas and again with the approach of the cold front from western Texas by late afternoon/evening. Parts of the Dallas/Fort Worth metro could realize rain accumulations of at least 3 inches, however much of the Consensus keeps the majority of the higher QPF focused north of the Hill Country and for less populated locations. While this less populated region of Central/ Northwest Texas within the south-central portion of the Slight Risk has indications of 5"+ potential (per 40-km HREF 5" exceedance probs of ~15%), this signal is being driven seemingly entirely by one member (the FV3, which is generally one of the less reliable members) with the bulk of the CAM guidance in good agreement indicating 2-4" totals. The bulk of the expected QPF will occur in the last 6 hour segment of the period, this may or may not play a limiting factor in the need of a local Moderate Risk. Campbell Day 2 Valid 12Z Mon Nov 24 2025 - 12Z Tue Nov 25 2025 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR MUCH OF NORTH TEXAS AND CENTRAL AND SOUTHERN ARKANSAS INTO ADJACENT=20 PORTIONS OF SOUTHEASTERN OKLAHOMA, NORTHERN LOUISIANA, AND=20 NORTHWEST MISSISSIPPI... ....20z Update... Organized convection will be ongoing across North Texas and into southeastern Oklahoma and the Ark-La-Tex region Mon AM, moving=20 east across Arkansas and into the Mid-South during the day. The=20 best potential for heavy rainfall will center around North Texas=20 initially before spreading eastward. Guidance has consolidated on a more southern solution relative to prior days, and this includes=20 the latest 12z hi-res model suite (which now extends through the=20 full period). The rather broad Slight Risk is now relatively low=20 confidence, given expected localized totals of around 3-4" being=20 near or just above FFGs across northern portions of the SLGT and at or below FFGs across southern portions of the SLGT (though still=20 maintained at SLGT here given the highest potential for localized=20 5" exist to the south where instability is greatest...despite these probabilities being less than 20% per 12z HREF exceedance probs).=20 Churchill/Campbell Day 3 Valid 12Z Tue Nov 25 2025 - 12Z Wed Nov 26 2025 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20 THE SOUTHEAST, TENNESSEE VALLEY, AND SOUTHERN APPALACHIANS... ....20z Update... Little change to the inherited outlook, as guidance remains in relatively good agreement concerning localized totals as high as 2-3". Should these occur over a short enough period (or exceed 3"+ in areas farther south) than isolated instances of flash flooding are possible.=20 Churchill ....Previous Discussion... The low pressure system is expected to continue advancing eastward then will track northeast while weakening on Tuesday. This will shift the focus of convection to south-central/Southeast during this period. A Marginal Risk for excessive rainfall was maintained from the previous Day 4 outlook. Areal averages of 1 to 3 inches will be common. Campbell Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_LnRLRkxBdMHOgqordKjwzEZI9F4dI-GejIW2KmsbS0-= APX0Sws5B-PBoQTRd64pa0Wr_ii4ur0hEXOKoWvd9lDt2lo$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_LnRLRkxBdMHOgqordKjwzEZI9F4dI-GejIW2KmsbS0-= APX0Sws5B-PBoQTRd64pa0Wr_ii4ur0hEXOKoWvdNwwR-44$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_LnRLRkxBdMHOgqordKjwzEZI9F4dI-GejIW2KmsbS0-= APX0Sws5B-PBoQTRd64pa0Wr_ii4ur0hEXOKoWvd7-m0x-c$=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .