Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 25 2023 08:01:06 FOUS30 KWBC 250801 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Wed Oct 25 2023 Day 1 Valid 12Z Wed Oct 25 2023 - 12Z Thu Oct 26 2023 ....THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE SOUTHERN PLAINS... ....Central Texas into south central Oklahoma... The strong height falls moving across northern Mexico Tuesday into early Wednesday will be ejecting northeastward into the Southern Plains day 1, continuing the multi day heavy rain event for portions of the Southern Plains. No significant changes expected to the axis of above average PW values across the Southern to Central Plains into the Lower MO Valley for the upcoming day 1 period with anomalies remaining 2 to 3+ standard deviations above the mean across these regions. This and the overall strong upper dynamics associated with the northeastward ejecting closed low will support the likelihood for additional widespread heavy rains from the Big Bend, northeastward into Northwest TX, much of OK, save for the Panhandle and southeast OK and into southeast Kansas. While the latest hi res guidance is verifying slow with the current area of organized convection pushing into West Texas early this morning, there is good agreement that this area will continue to push eastward and support additional heavy rains. The previous outlook was upgraded, adding a moderate risk across large portions of Central to Northwest TX into far south central OK. The moderate risk corresponds well with where the latest HREF neighborhood probabilities are high for 2 and 3"+ amounts, 40-80%, and 20-50% for 5"+ totals and also high for the HREF EAS probabilities for 1 and 2"+ amounts. Much of the moderate risk area also corresponds to where there is overlap of heavy precip over the past 24 hours and the expected day 1 heavy qpf axis. The day 1 slight area continues to match fairly well with CSU first guess fields, although having a slightly different orientation to the axis to match the latest day 1 qpf. ....Upper Mississippi Valley... Latest surface analysis continues to show a well defined frontal boundary stretching from southeast MN, east northeastward into central WI and the central to eastern U.P. of MI. This boundary has been a focus for active area of heavy rains pushing parallel, along and to the north of the this front. Model consensus is for additional rains to develop along and to the north of this front late Wednesday afternoon/evening as low level west southwesterly to southwesterly flow strengthens again into the front. This will favor the potential for another round of convection to move parallel to the boundary early Thursday and possibly across areas that received heavy amounts over the past 24 hours. There is expected to be some overlap across southern MN to west central WI=20 with past 24 hours heavy rains and additional rains late day 1.=20 At the moment, we kept the risk level at marginal given latest model qpfs and HREF neighborhood probabilities that are less than 20% for 1"+ amounts in an hour across the overlap areas.=20 Oravec 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!5V37iMRjcfXOl4bvCTy2_1QKjZDKdoZh_EDnNxVGheTt= Oki4SJXqmdsP_U1OVtdWAsEKaKKL26bgkD6YF4qLlfsn4Bs$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5V37iMRjcfXOl4bvCTy2_1QKjZDKdoZh_EDnNxVGheTt= Oki4SJXqmdsP_U1OVtdWAsEKaKKL26bgkD6YF4qLceDmZUc$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5V37iMRjcfXOl4bvCTy2_1QKjZDKdoZh_EDnNxVGheTt= Oki4SJXqmdsP_U1OVtdWAsEKaKKL26bgkD6YF4qLQUhfrs4$=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) .