Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Aug 30 2023 09:11:49 AWUS01 KWNH 300911 FFGMPD FLZ000-GAZ000-301510- Mesoscale Precipitation Discussion 1009 NWS Weather Prediction Center College Park MD 511 AM EDT Wed Aug 30 2023 Areas affected...Portions of the FL Panhandle....Big Bend of FL...Southern GA Concerning...Heavy rainfall...Flash flooding likely Valid 300910Z - 301510Z SUMMARY...Extremely dangerous Hurricane Idalia approaching the Big Bend of FL. Landfall to occur in a few hours. Very heavy rainfall arriving with the core of Idalia will likely lead to numerous instances of flash flooding, some of which may be significant, going through the morning hours. DISCUSSION...GOES-E IR satellite imagery shows Hurricane Idalia quickly approaching the Big Bend of FL as the storm advances steadily across the northeast Gulf of Mexico. As of 5AM EDT, the eye of Idalia was centered at 29.1N 84.1W, or about 60 miles west of Cedar Key, FL and the storm was moving north-northeast at 18 mph. Heavy rainfall associated with Idalia's Central Dense Overcast (CDO) is overspreading eastern portions of the FL Panhandle and the FL Big Bend region, with locally strong outer rainbands around Idalia's eastern semicircle impacting the central and northern portions of the FL Peninsula. Some of the rainfall rates within these outer rainbands have been as high as 1.5 to 2 inches/hour. The rainfall rates offshore with Idalia's CDO including its eyewall have been steadily increasing, and over the last few hours, the northern and western eyewall of Idalia has become quite intense looking on radar as the hurricane continues to intensify, and the rates within the eyewall are likely reaching 3 to 4 inches/hour. These heavier rainfall rates associated with Idalia's eyewall will begin arriving by 12Z (8AM EDT) as the storm prepares for landfall and then begins moving inland. By 15Z (11AM EDT), the storm should begin turning northeast while crossing into far southern GA as it comes under influence of an upper trough moving into the Northeast U.S. Strengthening right-entrance region upper-jet dynamics and increasing larger scale baroclinic forcing will allow the heavier rains with Idalia to become increasingly concentrated around the north side of the circulation later this morning. Eventually drier air should begin to undercut the southern and eastern flanks of the storm. The 00Z HREF guidance shows very high probabilities (60% to 80%) of 2+ inch/hour rates along and just to the left of Idalia's track, with 3+ inch/hour rates (20% to 50%) showing up as well. Expect areas near Tallahassee and east down toward Perry to get into some of these extreme rainfall rates, with the axis then extending north toward Moultrie and Valdosta in southwest GA by mid to late morning. Expect some additional rainfall totals for the time frame going through 15Z (11AM EDT) to reach 3 to 6 inches with isolated heavier amounts up to 8 inches. Numerous instances of flash flooding, some of which may be significant, are expected as a result this morning. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-Z58AD8teAKrPKofvOLTE-LXYFUrOX-5AQF_wvpV_SK2mgk94PiRPiixC2GZOAIJ0C3z= Ye1l668wAQPQ4q3s_HvpsUk$ for graphic product... ATTN...WFO...FFC...JAX...MLB...TAE...TBW... ATTN...RFC...SERFC...NWC... LAT...LON 31888264 31608188 31288160 30658160 29978178=20 29398185 28848189 28128221 28158278 28668287=20 29068303 29588344 29848414 29638478 29978518=20 30798492 31468428 31828348=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) .