Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 19 2024 20:14:36 FOUS30 KWBC 192014 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 414 PM EDT Tue Mar 19 2024 Day 1 Valid 01Z Wed Mar 20 2024 - 12Z Wed Mar 20 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent.=20 Oravec Day 2 Valid 12Z Wed Mar 20 2024 - 12Z Thu Mar 21 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent.=20 Otto Day 3 Valid 12Z Thu Mar 21 2024 - 12Z Fri Mar 22 2024 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF=20 THE WESTERN AND CENTRAL GULF COAST... A 500 mb southern stream trough is forecast to track eastward from the southern High Plains Thursday morning to the west-central Gulf Coast by Friday morning. The advancing of this feature will allow=20 a northward returning warm front in the western Gulf to lift into=20 southeastern texas during they day on Thursday. A weak low along=20 the front is forecast to hover near or just south of the Gulf Coast into Thursday night but some models (12Z GFS) are showing a=20 convective low along the frontal boundary which races eastward=20 across the open Gulf Waters Thursday evening/night. Instability and hence the heaviest potential for flash flooding intense rainfall=20 rates is likely to remain within about ~100 miles of the coast with strong convection developing ahead of the upper trough within=20 divergent and diffluent flow aloft, with possible repeating cells=20 and training from west to east or west-southwest to east-northeast=20 within the plume of instability forecast to reach into the=20 1000-2000 J/kg range along the Coastal Plain.=20 Instability farther north is a bit questionable as some model differences remain, most notably with the 12Z NAM which depicts a stronger and farther north closed low at 500 mb compared to the remaining model consensus. The 12Z NAM was given little weight with its farther north solution and heavier rainfall well north of the Gulf Coast into Texarkana and northern Louisiana. Given some of the convective uncertainties, there could be more significant changes to the Marginal Risk, currently drawn across=20 the middle/upper Texas coast into southwestern Louisiana, with future updates.=20 Otto Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8C1xyAvkFBVpo42Ryawg4odDfwUHcqmnv7jPTpy3x0j0= 6NKJrcq_5VA2XorUNmNGH_WAfaNClMMFlrl52udmv1wryHk$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8C1xyAvkFBVpo42Ryawg4odDfwUHcqmnv7jPTpy3x0j0= 6NKJrcq_5VA2XorUNmNGH_WAfaNClMMFlrl52udmkFZsXbQ$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8C1xyAvkFBVpo42Ryawg4odDfwUHcqmnv7jPTpy3x0j0= 6NKJrcq_5VA2XorUNmNGH_WAfaNClMMFlrl52udmXU07rks$=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) .