Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Sep 03 2024 08:03:50 FOUS30 KWBC 030803 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 403 AM EDT Tue Sep 3 2024 Day 1 Valid 12Z Tue Sep 03 2024 - 12Z Wed Sep 04 2024 .....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF CENTRAL TEXAS AND THE MIDDLE TEXAS COAST.. ....Texas... The mid-level vort is expected to exit the region although=20 precipitable water values will remain high. Flooding issues will be possible in the area with a widespread 1 to 1.5 inches forecast=20 with locally higher amounts. A Slight Risk remains in effect for=20 central portions of the state although it was expanded y 1 tier of counties to the south to reflect the latest trends in the guidance. A slow moving tropical low will continue to bring periods of heavy rain in the form of slow- moving showers and thunderstorms from=20 the Gulf into the adjacent Texas Coast. Most areas will not see=20 steady rain the entire time, but very localized areas of training=20 storms resulting in flash flooding. The heaviest rains in the=20 state are expected to be along the Gulf Coast from Galveston south=20 and west through Corpus Christi. Locally heavy rains to 2 inches=20 per hour will be possible. ....Mississippi and Alabama Gulf Coast... The Marginal Risk was maintained for the potential of slow moving=20 and training storms to the east of the low along a stalling front=20 into coastal Mississippi and Alabama. The abundance of atmospheric moisture and instability, as well as, the slow-moving nature of=20 the synoptic systems increases confidence that an isolated flash=20 flood or two could develop along this stretch of coast.=20 ....Idaho/Montana... There is potential for isolated to scattered heavy rainfall as an advancing shortwave encounters an anomalously moist airmass. PW=20 values rising to near 1 inch will support storms capable of heavy=20 rain that may produce isolated flash flooding should the storms=20 impact particularly flood sensitive or more urban areas. Campbell Day 2 Valid 12Z Wed Sep 04 2024 - 12Z Thu Sep 05 2024 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE MISSISSIPPI DELTA REGION AND ADJACENT GULF COAST... ....Gulf Coast and Lower Mississippi Valley... The surface front will continue to be draped west to east across=20 the South, albeit further south than previous forecast cycles. This frontal boundary will provide focus for showers and thunderstorms to spread across the entire Gulf Coast from south Texas all the=20 way to the Florida Peninsula on Wednesday. Most of the guidance=20 shows 1 to 3 inches will concentrate over this part of the region=20 thus increasing the risk for excessive rainfall and local flooding=20 potential.=20 There is the potential for a few locations for local=20 maximums to exceed 6 inches near northern Louisiana/Arkansas.=20 Onshore flow across southeast Louisiana and southern Mississippi=20 could yield 1 to 4 inches as well. The focus for the heaviest rains will be in the central Gulf Coast from Louisiana east through the=20 Florida Panhandle. Locally heavy rains are likely, especially from=20 New Orleans east through Pensacola, where a higher-end Slight is in place. With increasing amounts of rain forecast in and around New=20 Orleans, continued increases in rainfall there may require an=20 eventual targeted Moderate Risk should trends continue. Given the trends, the back edge of the Marginal Risk was trimmed eastward toward the Texas coast in addition to reducing the northern boundary by 1 tier of counties across Alabama and Mississippi. =20=20 Campbell/Wegman Day 3 Valid 12Z Thu Sep 05 2024 - 12Z Fri Sep 06 2024 ....THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ALONG THE CENTRAL GULF COAST... ....Gulf Coast and Lower Mississippi Valley... The area of precipitation mentioned for the Day 2 period will=20 shift eastward across the central Gulf Coast with the heaviest QPF still focusing across portions of southeast Louisiana, southern Alabama, southern Mississippi and clipping western portions of the Florida panhandle. Again, there was a notable southern shift in=20 placement within a majority of the guidance from previous cycles.coastlineThe inherited Marginal Risk areas was removed=20 from southern Tennessee and northern portions of Alabama,=20 Mississippi and northwest Georgia while trimmed eastward across=20 central Louisiana. The Slight Risk spans along the Gulf Coast from=20 west-central Louisiana to eastern Choctawhatchee Bay Florida. Campbell Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9s2-VScCoqLSMI2wz5QVxm-OHmaFhCYLTKT--tyqHjTZ= CPZB0744EUIrhwtsTvm7Gbv-nKrTbbmW0F0ObGHevcpwRuE$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9s2-VScCoqLSMI2wz5QVxm-OHmaFhCYLTKT--tyqHjTZ= CPZB0744EUIrhwtsTvm7Gbv-nKrTbbmW0F0ObGHeBqeqrgY$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9s2-VScCoqLSMI2wz5QVxm-OHmaFhCYLTKT--tyqHjTZ= CPZB0744EUIrhwtsTvm7Gbv-nKrTbbmW0F0ObGHen_BYb6o$=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) .