Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Dec 25 2023 23:38:33 AWUS01 KWNH 252337 FFGMPD NCZ000-SCZ000-GAZ000-TNZ000-260600- Mesoscale Precipitation Discussion 1220 NWS Weather Prediction Center College Park MD 637 PM EST Mon Dec 25 2023 Areas affected...northeastern Georgia, portions of western North Carolina and western South Carolina Concerning...Heavy rainfall...Flash flooding possible Valid 260000Z - 260600Z Summary...A persistent regime for moderate to heavy rainfall should remain in place through at least 06Z, with rain rates of 0.25-0.5 inch/hr persisting throughout that time. The persistence of these rain rates should gradually result in an increasing flash flood threat. Discussion...Areas of moderate to heavy rainfall have persisted over the discussion area for the past 6 to 10 hours. Rainfall totals during this timeframe have ranged from 1-2.5 inches, with highest amounts generally located from White County, GA northeastward through Asheville, NC. Meanwhile, strong (40-kt) southeasterly low-level flow continues to impinge orthogonally on the southern Appalachians while maintaining moist advection into the region. Orographic lift and ascent associated with geopotential height falls approaching the region has continued to support areas of rainfall and 0.25-0.4 inch/hr rates over the past hour - generally concentrated where heavier rainfall totals have already occurred. Furthermore, satellite imagery and objective analyses indicate deepening convection across northern Georgia likely in response to cooling aloft and related destabilization.=20 These showers are expected to migrate northeastward toward the discussion area in concert with continued orographic lift, perhaps supporting a brief bump in hourly rain rates at times between now and 06Z. FFG thresholds were fairly high across the region (exceeding 2 inches/3 hours across most of the discussion area). The persistent rainfall and wetting soils suggest that these FFGs will fall through the night, and runoff potential will increase. This, combined with potential for a bump in rain rates, suggests that flood/flash flood potential will gradually increase over time.=20 This risk is likely to last through 06Z or so, with the threat thereafter likely reduced due to weakening low-level flow/orographic lift in tandem with a northeastward shift of the 850mb jet away from the discussion area. 1.5-3.5 inch rainfall totals are possible across the discussion area through 06Z. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6KrwG86D3tMxqy5qX1z68hrMF4fiHkDQgyuVDPDha0f9x3OGsTuSxu4kNpiA1lt5-2jF= YQons09eP7CXh5dYNVoHZuQ$ for graphic product... ATTN...WFO...FFC...GSP...MRX...RNK... ATTN...RFC...LMRFC...OHRFC...SERFC...NWC... LAT...LON 36208188 36208121 35578100 34628172 33908291=20 33918390 34318423 34978406 35348357 35958250=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .