Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jan 29 2023 19:35:31 FOUS30 KWBC 291935 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 234 PM EST Sun Jan 29 2023 Day 1 Valid 16Z Sun Jan 29 2023 - 12Z Mon Jan 30 2023 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTHEAST AND CENTRAL GULF COAST... Very few notable changes with this morning's forecast update, based on the latest observational/mesoanalysis and guidance QPF trends. A slowly strengthening upper level jet streak will put much of the Slight Risk area in the right entrance region of the jet streak. Small disturbances riding along the jet may locally trigger convection across the Slight Risk area as they race northeastward with the jet. Much of the dynamics for this rainfall event will be in the lower levels of the atmosphere as broad southerly flow covering the whole of the Gulf peaks in intensity as far as the LLJ is concerned over southern LA midday Sunday. The LLJ will reintensify as the convection moves east across the FL Panhandle and southern GA Sunday night, including values as strong as 60 kt over the FL Panhandle, far SE AL and far SW GA. Thus, expect convection to be quite efficient at producing heavy rainfall as it moves eastward Sunday and Sunday night. To be sure, the greatest threat within the Slight Risk area will be across western areas from TX through MS, with slightly lower threats for flash flooding further east. Peak 24hr rainfall between 12Z this morning through 12Z Mon will likely exceed 3 inches in spots from areas along/north of the Upper TX Coast east-northeastward through southern-central portions of LA, southern MS-AL, and southwest GA -- i.e. areas within a more favorable thermodynamic environment with PWs close to 1.75" along with better deep-layer instability (MUCAPEs 500-1000 J/kg). The 12Z 1/29 HREF in fact indicates an expanded area of 60-80+ percent probabilities of >3"/24hr within the Slight Risk, with now a larger area of 40-50+ percent probs of >5"/24hr from around McComb MS wsw to the northern Houston metro area. Hurley/Wegman Day 2 Valid 12Z Mon Jan 30 2023 - 12Z Tue Jan 31 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 3 The Day 3 outlook will be updated by 2030Z. Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!7T1dI0czxbwvJlVgyAVdm55juhvVwhIyzwvDpUp0VVWS= jXifTcYRLPdDZp0u0pOy4MdWSa3x-vR0o0vqq82RKkwYsnk$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7T1dI0czxbwvJlVgyAVdm55juhvVwhIyzwvDpUp0VVWS= jXifTcYRLPdDZp0u0pOy4MdWSa3x-vR0o0vqq82RJwKJoww$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7T1dI0czxbwvJlVgyAVdm55juhvVwhIyzwvDpUp0VVWS= jXifTcYRLPdDZp0u0pOy4MdWSa3x-vR0o0vqq82RP8AfbMk$=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) .