Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Sep 26 2024 08:07:19 AWUS01 KWNH 260807 FFGMPD FLZ000-261405- Mesoscale Precipitation Discussion 1063 NWS Weather Prediction Center College Park MD 406 AM EDT Thu Sep 26 2024 Areas affected...Apalachicola region of FL Panhandle Concerning...Heavy rainfall...Flash flooding likely Valid 260805Z - 261405Z SUMMARY...As bands of heavy rain located north of Hurricane Helene approach the eastern FL Panhandle, renewed areas of flash flooding are expected toward 12Z. An additional 2-4 inches is expected through 14Z. DISCUSSION...Hurricane Helene was located about 375 miles SSW of Apalachicola, FL according to the 06Z position by NHC, moving north around 8 kt, though an increase in forward speed is expected late this morning. While this position is still well south of the FL Panhandle, 0745Z radar imagery showed axes and spiral bands of heavy rain located in the eastern Gulf of Mexico, grazing the western FL Peninsula and Gulf/Franklin counties of the Panhandle. GOES East water vapor and infrared satellite imagery showed healthy outflow in the northern semicircle of Helene's circulation and enhanced divergence aloft was present along the FL Panhandle due to the presence of a potent upper level jet max centered over the upper TN/OH Valleys. An increasing frequency of bands of heavy rain are expected to impact the FL Panhandle over the next 3-6 hours as Helene continues to advance north. While rain bands oriented generally west to east should push north without too much in the way of training concerns, rain bands that are aligned more with the mean steering flow from SSE to NNW will be favored for training. Even short term training could still allow for a quick 1-2 inches of rain in as little as 15-30 minutes due to the tropical environment in place. It is expected that steady rain will continue throughout the remainder of the morning, but with bursts of heavy rain occurring at times and with an increased frequency through 14Z along with an additional 2-4 inches. Given multi-sensor MRMS estimates of 5 to 10 inches of rain over the past 24 hours from near Apalachicola to Lake Talquin, soil saturation will more easily support runoff from additional heavy rain. Since instability of 500 to 1000+ J/kg is forecast to remain along and offshore of the coast, higher rainfall rates may be limited to coastal sections of the east-central Peninsula, but longer duration/lower intensity rainfall could still have flood impacts farther north. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-uwol5Mp4pDUbDRleBlBuMxXeJNIQI5JtTkfRh_K1Dxz8zgZPVJCvYHKNRwPdm0KYkO7= wfWPNkuiQ1hSdoFhn3ZNCz8$ for graphic product... ATTN...WFO...TAE... ATTN...RFC...SERFC...NWC... LAT...LON 30508455 30298420 29738424 29508479 29468531=20 29588552 29758563 30098552 30318536 30458492=20 =20=20=20=20=20=20=20=20=20=20=20=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) .