Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 29 2023 08:13:58 FOUS30 KWBC 290813 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 413 AM EDT Sat Jul 29 2023 Day 1 Valid 12Z Sat Jul 29 2023 - 12Z Sun Jul 30 2023 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE NORTHEAST AND THE CENTRAL APPALACHIANS/OHIO VALLEY... ....Northeast and Mid-Atlantic... A well-defined shortwave associated with ongoing convection over the Great Lakes region is forecast to move east of the lower Lakes, with storms reintensifying as the wave interacts with deepening moisture and increasing instability supported by daytime heating and amplifying southwesterly flow. Recent runs of the RAP show PWs increasing to at or above 2 inches within an area of strong ascent afforded in part by favorable upper forcing. Ahead of the system, a downstream wave now moving across Pennsylvania may bring some scattered showers and storms to parts of southern New England later this morning. This will likely be followed by more organized strong storms, with intense rainfall rates likely, and training possible from eastern New York and Pennsylvania to southern and central New England during the afternoon into the evening hours. The Slight Risk area reflects where the HREF guidance centers its heaviest amounts from the Catskills eastward into southern and central New England, with significant probabilities for amounts exceeding 3 inches.=20 Some locally heavy amounts are possible farther south as well as storms are expected to develop along the trailing cold front as it presses south through Mid-Atlantic this afternoon and evening. ....Central Appalachians to the central Plains... A Slight Risk area was maintained across portions of the central Appalachians and extended west into portions of the Ohio Valley.=20 Storms developing along the previously noted cold front may create at least isolated flash flood concerns, especially across areas in West Virginia and eastern to central Kentucky that have recently been impacted by heavier rains and where FFGs are relatively low.=20 Some of the CAMs show a fairly good signal for slow-moving/training storms, especially from central Kentucky into the Appalachians, increasing the threat for heavy amounts and flash flooding concerns.=20 Meanwhile, convection developing over the central Plains may intensify and spread southeast across the mid Mississippi and into the lower Ohio Valley later today. While these storms are expected to be generally progressive, some locally heavy amounts producing isolated flash flooding cannot be ruled out.=20=20 ....South Carolina... An area of low pressure will continue drifting slowly northward, producing additional showers and thunderstorms along the South Carolina Coast. Ample moisture and instability will continue to support a localized flash flood threat across this region before the wave begins to turn to the east early Sunday ahead of the amplifying trough to the north. ....Eastern and south-central Colorado and the Sangre de Cristo Mountains of New Mexico... Easterly low level inflow is expected to contribute to an increase in moisture and the development of showers and thunderstorms over the mountains. Weak flow aloft is expected to increase the potential for slow-moving storms, which may result in locally heavy amounts with isolated flash flooding concerns. ....Southeastern Arizona/Southwestern New Mexico... Deepening moisture ahead of an inverted upper trough tracking west across northern Mexico is forecast to help support increasing coverage of showers and thunderstorms across the region. Models shows PWs returning to 1-1.5 standard deviations above normal across portions of the region, raising the threat for showers and thunderstorms with locally heavy amounts and isolated runoff concerns. Pereira 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!7IzCtGsBTLBxCx9Y0M-N71NkZ7d-pCYmb3TwBqacqgMv= Zh2SVNZkGY9nShkCxjmdyzF7OKH5lDkgCY4o-8y-kUNMJsM$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!7IzCtGsBTLBxCx9Y0M-N71NkZ7d-pCYmb3TwBqacqgMv= Zh2SVNZkGY9nShkCxjmdyzF7OKH5lDkgCY4o-8y-gEcpa-4$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!7IzCtGsBTLBxCx9Y0M-N71NkZ7d-pCYmb3TwBqacqgMv= Zh2SVNZkGY9nShkCxjmdyzF7OKH5lDkgCY4o-8y-Uq5OjIE$=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) .