Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Dec 07 2022 08:29:09 FOUS30 KWBC 070829 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 328 AM EST Wed Dec 07 2022 Day 1 Valid 12Z Wed Dec 07 2022 - 12Z Thu Dec 08 2022 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF THE SOUTHERN PLAINS EAST TO THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS... ....North Texas and Eastern Oklahoma eastward into the western Tennessee Valley... Models still suggest the potential for locally heavy to excessive rainfall from parts of North TX into central-eastern Oklahoma and across portions of the Lower MS Valley and TN Valley, though the signal for anything other than an isolated (marginal) threat has diminished considerably over the past couple of model cycles. Aloft, a southern stream trough pivots across the Southwest U.S. on Wednesday and across the High Plains Wednesday night. This initial shortwave will be moving rather swiftly, given the increased confluence (de-amplification of the shortwave with time) by late Wednesday night. Given the flattening wave and more west-east oriented front, the the degree and depth of south-southwest low-mid layer flow will be somewhat restricted (warm conveyor belt or WCB more compact). Moreover, limited deep-layer instability (MUCAPEs 500-1000 J/Kg early dropping below 500 J/Kg later this afternoon and overnight) will also limit the short-term rainfall rates. So despite a relatively quick bout of robust low-mid layer moisture transport, with PW values topping out between 1.5-1.7", the lack of instability along with progressive nature of the favorable forcing (forward-propagating Corfidi or MBE vectors) will lead to a more limited (isolated) flash flood threat. In addition, per the latest NASA SPoRT analysis, 0-100cm soil moisture percentiles are running between 10-30% of normal across much of the outlook area. As a result, the Slight Risk area that was present in yesterday's Day 2 ERO has been dropped to a Marginal. Hurley Day 2 Valid 12Z Thu Dec 08 2022 - 12Z Fri Dec 09 2022 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley 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!4fiT3c-9PoMUTb8DZJz1y7aJ7GFFKrmfxhHWrTiNsw5V= 4jkDFhDOHibbkY0M7SRrAuXcLVpbz79wg4cUOTuAcxBRkQo$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4fiT3c-9PoMUTb8DZJz1y7aJ7GFFKrmfxhHWrTiNsw5V= 4jkDFhDOHibbkY0M7SRrAuXcLVpbz79wg4cUOTuA1BQMYtg$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4fiT3c-9PoMUTb8DZJz1y7aJ7GFFKrmfxhHWrTiNsw5V= 4jkDFhDOHibbkY0M7SRrAuXcLVpbz79wg4cUOTuAPVACdBw$=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) .