Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Oct 10 2024 00:26:01 FOUS30 KWBC 100025 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 825 PM EDT Wed Oct 9 2024 Day 1 Valid 01Z Thu Oct 10 2024 - 12Z Thu Oct 10 2024 ....THERE IS A HIGH RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF CENTRAL FLORIDA... ....WIDESPREAD AND NUMEROUS INSTANCES OF FLASH FLOODING ARE EXPECTED WITH LIFE-THREATENING AND CATASTROPHIC FLASH FLOODING PROBABLE... ....01Z Excessive Rainfall Discussion Update...=20 With Milton's eyewall getting close to the FL west coast near Sarasota-Venice, the latest observational trends and recent guidance (especially HRRR and HREF CAMs) show the heaviest rainfall axis on the north side of Milton's track. Therefore with this update we trimmed the outlooks on the southern periphery=20 (especially the High and Moderate), while also extending the High- Moderate-Slight areas a little farther north along the east coast.=20=20 Given the estimated rainfall that has fallen thus far (using MRMS QPE), along with the expected additional rain between 00Z Thu-00Z Fri, we now expect 10-14 inches across much of the High Risk area, with localized totals around 18 inches.=20 Hurley Day 2 Valid 12Z Thu Oct 10 2024 - 12Z Fri Oct 11 2024 ....THERE IS A HIGH RISK OF EXCESSIVE RAINFALL FOR THE ORLANDO METRO AND PORTIONS OF THE FIRST AND SPACE COASTS... ....WIDESPREAD AND NUMEROUS INSTANCES OF FLASH FLOODING WITH LIFE- THREATENING AND CATASTROPHIC FLASH FLOODING WILL LIKELY BE ONGOING THURSDAY MORNING... 2030Z UTC Excessive Rainfall Discussion Update... Maintained the High Risk for a portion of the central Florida peninsula as rainfall associated with Milton should still be falling as the Day 2 period begins at 12Z. There was a shift towards a faster solution in the morning guidance...so trimmed a bit of the areal coverage of various outlook categories. There were few other changes needed. Bann 0830 UTC Excessive Rainfall Discussion... A High Risk area was introduced with this update in coordination with MLB/Melbourne, FL forecast office. Almost no changes were made to the other ERO risk areas. Unfortunately, guidance continues to very gradually slow the forward speed of Milton as it completes its track across the Florida Peninsula and exits out into the Atlantic on Thursday. As a result there was a small increase in the forecast rainfall after 12Z/8am Thursday from Orlando east up I-4 to the Atlantic coast. The introduction of the High Risk for this area was much more the result of expected continued catastrophic impacts from widespread power outages and around a foot of storm total rain which will continue into Thursday morning and perhaps a portion of Thursday afternoon. Along the immediate coast, onshore flow at the time of high tide may also hamper any drainage into the ocean by the local streams, creeks, and rivers. Overall, with 3-5 inches of rain expected after 8am Thursday in the High Risk area, which will be on top of previous rainfall and likely the heaviest intensity of the entire storm, it's likely the widespread impacts indicative of a High risk will continue into the day Thursday. The rain will quickly end from west to east Thursday morning for west Florida and Thursday afternoon for east Florida. Thus, all of the ERO risk areas are likely to be downgraded long before the 12Z Friday end of the period. Since there remains some uncertainty, especially around Tampa, as to what the nature of any lingering rainfall will look like, the area remains in a Marginal Risk. Wegman Day 3 Valid 12Z Fri Oct 11 2024 - 12Z Sat Oct 12 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Bann Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!77AWnWWUHjZ-M6NNX8OFXQc1Mj15f-utixIiKADQ0TO1= g1LjNRz3u0N41q-NJnP7YMjMPe_2etKf4o--VoaPmYfx_5k$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!77AWnWWUHjZ-M6NNX8OFXQc1Mj15f-utixIiKADQ0TO1= g1LjNRz3u0N41q-NJnP7YMjMPe_2etKf4o--VoaP4aJ90fc$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!77AWnWWUHjZ-M6NNX8OFXQc1Mj15f-utixIiKADQ0TO1= g1LjNRz3u0N41q-NJnP7YMjMPe_2etKf4o--VoaPyNZ1V2o$=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) .