Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Apr 29 2023 08:33:20 FOUS30 KWBC 290833 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 432 AM EDT Sat Apr 29 2023 Day 1 Valid 12Z Sat Apr 29 2023 - 12Z Sun Apr 30 2023 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR THE FLORIDA PANHANDLE INTO SOUTHERN GEORGIA... ....Southeastern US... No significant changes were made to the Day 1 ERO area. It's very worth noting the latest runs have backed off significantly on the total expected rainfall in the Slight Risk area, favoring most of the convection remaining south of the area into the Gulf. However, there remains several models that at least depict strong storms locally producing multiple inches of rain in a short time as the main round of convection moves through around mid-afternoon and a second separate and weaker round of mostly showers moves through around midnight. There is still some potential for training convection, but that chance is fairly low. Due to recent rainfall, especially over the Florida Panhandle, the soils remain nearly saturated over most of the Slight Risk area, and thus any rain that falls today is likely to quickly run off into the local watersheds. The Slight Risk area therefore remains, but it's certainly a lower confidence and therefore lower end Slight Risk, that with model trends, could be downgraded later today as the convective forecast by then will be a now-cast for many areas. Elsewhere across east central MS and west central AL, a strong and developing upper level wave will race across the area today. Given some modest instability to 500 J/kg and PWAT around 1.25 inches, think the added forcing will be more effective at adding to the strength of the storms expected to traverse that area this evening. Soil moisture is a little bit drier in that area compared to the surrounding area, and the modest instability may be enough to prevent anything more than isolated flash flooding. Thus, that area in particular is in a higher-end Marginal. ....Southern New England, New York City Metro Area, Long Island, and the Hudson Valley... Convective rainfall has already begun across the Marginal Risk area for CT and points south and west. Rainfall rates as of the time of this writing are approaching 1 inch per hour. In more sensitive areas of urbanized northern NJ and NYC, these rates may be enough to cause localized flooding in poor drainage areas, so southwestern portions of the Marginal Risk are already seeing the rain that may cause flash flooding, and the focus for the Day 1 ERO is for the morning hours. Meanwhile further northeast across MA and RI the threat will be more for later this morning into tonight. Some backbuilding along the back edge of the precipitation is likely across southern New England, so the potential for higher rainfall totals will be there. Wegman 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!8zsuqV8Xw5TieoRe6mHlerk-zBhEB4tWvq-3l7SMwO3V= KA31heUEMuEn8WFNzNu4bQE1wUSpTyEY-SPFNPAolHzNffY$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8zsuqV8Xw5TieoRe6mHlerk-zBhEB4tWvq-3l7SMwO3V= KA31heUEMuEn8WFNzNu4bQE1wUSpTyEY-SPFNPAoabzQm-w$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8zsuqV8Xw5TieoRe6mHlerk-zBhEB4tWvq-3l7SMwO3V= KA31heUEMuEn8WFNzNu4bQE1wUSpTyEY-SPFNPAopy5iZmQ$=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) .