Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 22 2023 08:13:25 FOUS30 KWBC 220813 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 412 AM EDT Mon May 22 2023 Day 1 Valid 12Z Mon May 22 2023 - 12Z Tue May 23 2023 ....THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE CENTRAL/SOUTHERN PLAINS AND FOR PORTIONS OF THE SOUTHEAST... ....Southern to Central Plains... Scattered dry-line induced showers and thunderstorms are expected later today across portions of the Texas Panhandle into south-central Kansas, aided by a weak mid/upper level shortwave tracking through the region and a modest low-level jet. The 00Z HREF shows scattered signals for 1-2" hourly totals, particularly the TX/OK Panhandle region where the various hi-res models show potential for 2-4" totals through the 24-hr period. This additional rainfall today is expected to fall on increasingly wet soils due to the recent rainfall over the last several days (7-day departures are as high as 400-600 percent of normal in places). As a result, isolated to scattered instances of flash flooding will be possible. ....Southeast... Widespread to numerous showers and thunderstorms are expected to develop along a residual stationary boundary draped across the region. Meanwhile, the mid/upper levels feature weak shortwave energy that is expected to slide eastward from the ArkLaTex region to southern Georgia today. Moist easterly flow has allowed anomalous moisture to pool along the surface boundary and precipitable water values are forecast to remain at or above 1.5" across the risk area, approaching 1.75" locally. These values are near 1.5 to 2.0 standard deviations above normal. With maximum daytime heating producing ample instability, deep convection firing up along the frontal boundary and other residual boundaries should lead to loosely organized convective clusters capable of producing intense rainfall rates. The 00Z HREF neighborhood probabilities indicate potential for 1-2" hourly totals with localized 2"+ hourly totals, most likely across southern Georgia southward into the Florida peninsula. This is where the HREF probabilities also suggest around 30-40% chances for 24-hr totals ending 12Z Tuesday of 4-5". These types of rain rates and totals may lead to isolated to scattered instances of flash flooding, particularly over the more urban and susceptible locations. Taylor 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!_e8qkiw6KPpoz6t8QUQZOHSILJ23j_nzURTqFxgKjYmj= 1ZuTWw6jyRe6_llmq-2J0uELY-tH0ZCpE7jkFFTAw77Sc5M$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_e8qkiw6KPpoz6t8QUQZOHSILJ23j_nzURTqFxgKjYmj= 1ZuTWw6jyRe6_llmq-2J0uELY-tH0ZCpE7jkFFTAVhvTFRA$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_e8qkiw6KPpoz6t8QUQZOHSILJ23j_nzURTqFxgKjYmj= 1ZuTWw6jyRe6_llmq-2J0uELY-tH0ZCpE7jkFFTAPlHkOLk$=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) .