Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Dec 12 2023 19:47:19 FOUS30 KWBC 121947 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 246 PM EST Tue Dec 12 2023 Day 1 Valid 16Z Tue Dec 12 2023 - 12Z Wed Dec 13 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Campbell Day 2 Valid 12Z Wed Dec 13 2023 - 12Z Thu Dec 14 2023 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF SOUTHEAST FLORIDA... 21Z update... WPC increased the QPF amounts across south Florida, with nearly 2 inches forecast across portions of southern Miami-Dade County. This equated to about a 0.50 to 1 inch bump from the 12Z forecast. The Marginal Risk area was nudged west/south to account for this higher QPF and to include portions of the Upper Keys as they will likely have periods of moderate to heavy rainfall as well during this period. Campbell Models continue to indicate a period of convective development across the southeastern tip of the FL Peninsula in conjunction with a weak mid-level impulse moving up from the Western Caribbean in tandem with a stationary boundary over the FL Straits moving back north in time for Wednesday afternoon/evening. There is some suggestion of a little less vigor in the convective potential just due to the changes within the mid-level energy advection and the northern extent of greater theta-E's in association with the increased low-level moisture flux along our frontal boundary. The latest HREF isn't super enthused with the potential, but there's still some hints of isolated heavy thunderstorms possible within the frictional convergence field established near the SE FL coast as energy moves overhead with peak diurnal destabilization. The most aggressive models are actually showing localized 3-5" maximums within a short window late-Wednesday afternoon into the early evening before giving way to some passing showers and isolated thunder for the remainder of the period. Considering the environmental parameters shifting towards a favorable convective pattern within a significant moisture flux, opted to maintain the previous MRGL, but did tighten the bounds on the northern end as the best potential is focusing between Fort Lauderdale down to Miami/Homestead. Kleebauer 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!4Kl4stq2U8HoEjYArFIAXoHrA7n3qSNnjuCSuEOwL1ui= pKdfe5FMlhsNML6Y16FFlyHvVw8AYDl11wuELQpDk81oCd4$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4Kl4stq2U8HoEjYArFIAXoHrA7n3qSNnjuCSuEOwL1ui= pKdfe5FMlhsNML6Y16FFlyHvVw8AYDl11wuELQpD6WDUb0o$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4Kl4stq2U8HoEjYArFIAXoHrA7n3qSNnjuCSuEOwL1ui= pKdfe5FMlhsNML6Y16FFlyHvVw8AYDl11wuELQpDZEE2ad4$=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) .