Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Nov 29 2023 15:44:37 FOUS30 KWBC 291544 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 1044 AM EST Wed Nov 29 2023 Day 1 Valid 16Z Wed Nov 29 2023 - 12Z Thu Nov 30 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Campbell/Kleebauer Day 2 Valid 12Z Thu Nov 30 2023 - 12Z Fri Dec 01 2023 ....THERE IS A MARGINAL RISK AREA FROM THE CENTRAL GULF COAST TO THE MID-MISSISSIPPI/OHIO RIVER VALLEY... Surface low over the plains will evolve with a developing cold front pushing eastward within the time frame. The latest guidance continues to show a swath of QPF of 1 to 3 inches lifting from the Gulf Coast to the Ohio River Valley. Moisture return from the Gulf will have the PW values upwards of 2 to 2.5 standard deviations above normal over a large portion of the Lower and Middle Mississippi Valley. One this deep moisture plume meets the greatest instability hourly rates will likely max out near 2 inches/hour, leading to local maximums near 4 or more inches during this period across Louisiana and the immediate vicinity. The Marginal Risk that was already in effect from the Central Gulf to southwest Indiana remains in effect. Minor adjustments were made along the eastern boundary to trim it back to the west reflecting the latest model trends and WPC forecast. Campbell Day 3 Valid 12Z Fri Dec 01 2023 - 12Z Sat Dec 02 2023 ....THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE CENTRAL/EASTERN GULF COAST AND THE SOUTHEAST... The low pressure system will continue to advance east during this period with its warm front lifting trough the Deep South and Southeast. Convection is expected to be the most concentrated near the Gulf Coast and tracking northeast into southern Alabama and Georgia ahead of the warm front. With anomalous moisture continuing to feed northward into this boundary, enhanced rainfall can be expected. Most of the guidance has 1 to 2+ inches spreading from south-central Louisiana into central Georgia/northern Florida. There is suggestions that a narrow axis of 3 to 4 inches could setup within this flow but the exact location remains uncertain. It could span from far southwest Alabama to southwest Georgia per a couple of solutions, or further south across the Florida panhandle and inland. A Marginal Risk area was maintained from the previous Day 4 period as it reflected the part of the country were localized flash flooding problems could arise. Campbell Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9cM3_S_CrT_ZD3fAjarVm2nm7bfAwjzhSlL5o83pqG3p= -J3nYfelQU8SAeJUHx7ALH2EUgx6x_BgLCG37PmRVbQBZDo$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9cM3_S_CrT_ZD3fAjarVm2nm7bfAwjzhSlL5o83pqG3p= -J3nYfelQU8SAeJUHx7ALH2EUgx6x_BgLCG37PmRtjLCL-Y$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9cM3_S_CrT_ZD3fAjarVm2nm7bfAwjzhSlL5o83pqG3p= -J3nYfelQU8SAeJUHx7ALH2EUgx6x_BgLCG37PmRNYRHvk0$=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) .