Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jan 17 2023 08:06:50 FOUS30 KWBC 170806 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 305 AM EST Tue Jan 17 2023 Day 1 Valid 12Z Tue Jan 17 2023 - 12Z Wed Jan 18 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent Oravec Day 2 Valid 12Z Wed Jan 18 2023 - 12Z Thu Jan 19 2023 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE LOWER ARKANSAS, LOWER MISSISSIPPI, LOWER TENNESSEE AND LOWER TO MIDDLE OHIO RIVER VALLEYS... PW values expected to rise to 2 to 3 standard deviations above the mean from eastern portions of the Southern Plains, northeastward into the Lower Arkansas, Lower Mississippi, Lower Tennessee and Lower to Middle Ohio River Valleys as low level flow strengthens off the western Gulf in response to strong height falls pushing into the Central to Southern Plains day 2. Strong frontal convergence along the cold front pushing eastward from eastern sections of the Southern Plains toward the Lower Mississippi Valley Thursday will support enhancing convection in the above mentioned axis of anomalous PW values beginning Thursday morning.=20 There may be a period of training of cells parallel to this front from northern Louisiana, northeastward through eastern Arkansas, western Tennessee and western Kentucky. Hourly rainfall rates of 1"+ possible in area of training. The frontal/pre-frontal convective line should become more progressive Thursday evening/Thursday night into early Friday as it pushes eastward from the Lower Mississippi Valley and into portions of the central Gulf coastal region, lessening the threat of training and heavy rainfall amounts. The slight risk was confined to the regions where training may occur during the first half of the day 2 period and matches the model consensus max qpf axes. The strengthening south southwesterly flow ahead of the strong eastward moving height falls will also support strengthening isentropic lift along and north of the west to east oriented warm front forecast to stretch south of the Ohio River day 2. The slight risk was maintained along and north of this front along and south of the Lower to Middle Ohio River where there may also be a period of training of cells in a southwest to northeasterly direction Thursday afternoon into Thursday night. With respect to changes from the previous outlook for this period, no significant changes made to the slight risk area, while the eastern portion of the marginal risk area across Mississippi and Alabama was trimmed westward between 80 and 160 miles. Oravec 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!9IwBguBuxc6qjEgExPD_a5FWdWCfAN2DkoFzno_ziLy0= QCYxq1c9tzi2lq2Nj1xYjD3wR6jCPM4ffxBSwLOfb368ua4$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9IwBguBuxc6qjEgExPD_a5FWdWCfAN2DkoFzno_ziLy0= QCYxq1c9tzi2lq2Nj1xYjD3wR6jCPM4ffxBSwLOfKDBpKYQ$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9IwBguBuxc6qjEgExPD_a5FWdWCfAN2DkoFzno_ziLy0= QCYxq1c9tzi2lq2Nj1xYjD3wR6jCPM4ffxBSwLOf4QeXeMA$=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) .