Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Mar 01 2025 19:04:16 FOUS30 KWBC 011903 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 203 PM EST Sat Mar 1 2025 Day 1 Valid 16Z Sat Mar 01 2025 - 12Z Sun Mar 02 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Cook/Roth Day 2 Valid 12Z Sun Mar 02 2025 - 12Z Mon Mar 03 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Chenard Day 3 Valid 12Z Mon Mar 03 2025 - 12Z Tue Mar 04 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. 19z Update: At the moment leaning towards the guidance that produces more widespread convection by late Monday night over central and eastern OK. Our areal averaged QPF has increased into the 0.5"-1" range, but would expect totals to locally exceed 2".=20 Still think convection will be progressive enough to limit the=20 flash flood risk, especially given the drier antecedent conditions=20 over the area. Thus will continue to hold off any risk area,=20 although a localized urban flash flood threat can not be ruled out, and still possible a Marginal risk is eventually needed. Chenard ....Previous Discussion... ....Southeast Oklahoma... A cold low progresses from the Great Basin into the High Plains of CO by Tuesday morning. This leads to the formation of a CO cyclone late Monday which advances eastward across southwest KS. Warm air advection ahead of the cyclone is expected to advect 500-1000 J/kg of MU CAPE and precipitable water values of 1.25"+ by Tuesday morning into southeast OK. Inflow at 850 hPa accelerates past 50 kts. Since the airmass in the wake of its cold front is more dry than cold, instability lurks in its "cold sector" as well. NAM parameters suggest organized convection should occur either in the form/mode of supercells or a squall line -- assuming convection is around for 4+ hours and can form a cold pool to force forward propagation -- somewhere near southeast OK. For the moment, only the 00z Canadian Regional model brings rainfall amounts over 1.5" (local spots of 3-4" near the Red River Valley of the South). The region has been dry over the past week, allowing much of the ArkLaTex and southeast OK (outside of the Ouachita mountains) to not be particularly sensitive to heavy rainfall should the 00z Canadian verify. While the risk of excessive rainfall is non- zero, believe it still remains under the 5 percent threshold for the time being. Roth Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-2OMb1qEOJrV1GG0fXpp7zNZIyvxls2G9JV3wBuqBdTI= pDPGnCI3PKyJxhXlfMdGZLgk-mGsKfHmAgO1GLlNlvUHX10$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-2OMb1qEOJrV1GG0fXpp7zNZIyvxls2G9JV3wBuqBdTI= pDPGnCI3PKyJxhXlfMdGZLgk-mGsKfHmAgO1GLlNmxPfMbc$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-2OMb1qEOJrV1GG0fXpp7zNZIyvxls2G9JV3wBuqBdTI= pDPGnCI3PKyJxhXlfMdGZLgk-mGsKfHmAgO1GLlNc11w_pQ$=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) .