Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 04 2023 08:21:32 FOUS30 KWBC 040821 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 420 AM EDT Wed Oct 04 2023 Day 1 Valid 12Z Wed Oct 04 2023 - 12Z Thu Oct 05 2023 ....THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE SOUTHERN PLAINS... ....Southern Plains... Training bands of convection are expected to impact a north-south axis from the Texas Gulf Coast up through the ArkLaTex beginning this morning before a squall line, emanating over northern Texas and Oklahoma pushes through the region this evening. Rain rates at around 0.5"/hr aren't expected to be too high from this early round of storms, but the training aspect should still be able to cause some flash flooding concerns this morning and afternoon. A complex of thunderstorms, initiated ahead of a cold front, which is supported by a deep upper level trough centered over southern Canada, are expected to congeal into a squall line with 1-2" (locally higher) rain rates. There will be ample upper level forcing with strong 250mb jet and substantial divergence streaking across Oklahoma and northern Texas this afternoon and evening. Several of the CAMs including the HRRR suggest outflow boundaries propagating from the squall line, surface boundary draped across the Red River and Lower Mississippi Valley, and other preceding convective cells could support another axis of training convection around the eastern portions of the Red River this afternoon and evening. These higher rain rates combined with training could overcome some of the dry soils present in much of the Slight Risk area. The Moderate Risk area was extended back into the Dallas/Fort Worth metro area to account for the vulnerability of the urban environment to the high rain rates associated with this afternoon and evening's storms. ....Texas coast... Moist southerly flow from the Gulf will interact with a shallow coastal front and generate rounds of training thunderstorms beginning this morning. Substantial instability (~1000J/Kg) and high PWATs (2-2.5") will be present as well. The 00z HREF 40km neighborhood probabilities of 24hr QPF exceeding 5 inches is between 20-60% for much of the central Texas coast from Houston to Corpus Christi. Recent heavy rainfall over this area made extending the slight risk into this area an easy call especially given the potential for training over Houston's metro area. 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!6eBBStzhcRH28e5jk5TB3VxwIMUits5bbUUIo79ZLFUx= Hze1xTyNkuUxA0q42qsR8pZPc4yaw2VwglxGxEgcbb4KNAA$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6eBBStzhcRH28e5jk5TB3VxwIMUits5bbUUIo79ZLFUx= Hze1xTyNkuUxA0q42qsR8pZPc4yaw2VwglxGxEgcIqHdXv4$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6eBBStzhcRH28e5jk5TB3VxwIMUits5bbUUIo79ZLFUx= Hze1xTyNkuUxA0q42qsR8pZPc4yaw2VwglxGxEgci5O1zmk$=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) .