Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Apr 15 2023 08:16:53 FOUS30 KWBC 150816 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 416 AM EDT Sat Apr 15 2023 Day 1 Valid 01Z Sat Apr 15 2023 - 12Z Sat Apr 15 2023 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE CENTRAL GULF COAST... ....Central Gulf Coast... A strong shortwave trough currently streaming through the southern Texas early this morning is expected to fire up a round of convection that tracks generally along the Gulf Coast from southeast Texas through southern Mississippi and the northwest Florida Panhandle beginning later this morning. The environment is expected to be characterized by anomalous PWs, reaching 1.5-1.75" particularly from southeast Louisiana through southern Mississippi and the northwest Florida Panhandle. Combined with an axis of higher instability, intense rain rates approaching 1-2"/hr will be common as the line moves through. There is some potential for training or backbuilding with some components of the embedded line segments oriented more parallel to the mean flow. The 00Z HREF probabilities show potential for localized 2-3" totals, which may impact the urban and more vulnerable areas of New Orleans to Mobile. Some recent heavier rainfall events have primed the soils, with the 0-40 cm layer soil moisture percentiles running above 70-80 percent, contributing to the flash flood potential. ....Mid-MS Valley to Upper Midwest... Shortwave energy coming out of the central Rockies today will help deepen an area of low pressure over the Plains that then tracks toward northern Illinois by early Sunday morning. The air mass along/ahead of the advancing frontal boundary will be characterized by modest moisture (PWs > 1") and with peak heating today, a line of showers and thunderstorms is expected across portions of southern Iowa through Missouri into Arkansas. Here, isolated instances of flash flooding will be possible due to intense rain rates of 1" to locally 2" in an hour. Further north, as the low lifts toward northern Illinois, a steady/prolonged rain is expected from portions of eastern Iowa into Wisconsin. A few rounds of moderate to locally heavy rainfall will be possible. For areas further north into Wisconsin and the U.P. of Michigan, ongoing snowmelt flooding could induce additional flooding more easily. 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!6ErjI9DM7gCcKEIRpn8Gow96Qkv6fG2Q73pMrCCn8HWg= ushUaMT3dpxR2Bcn8SgcJ4MGFAhhY2probsqcDEtsnaA1Hw$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!6ErjI9DM7gCcKEIRpn8Gow96Qkv6fG2Q73pMrCCn8HWg= ushUaMT3dpxR2Bcn8SgcJ4MGFAhhY2probsqcDEtgLCj2ZY$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!6ErjI9DM7gCcKEIRpn8Gow96Qkv6fG2Q73pMrCCn8HWg= ushUaMT3dpxR2Bcn8SgcJ4MGFAhhY2probsqcDEtl_U40qI$=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) .