Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Dec 28 2024 04:12:43 AWUS01 KWNH 280412 FFGMPD FLZ000-ALZ000-MSZ000-281010- Mesoscale Precipitation Discussion 1199 NWS Weather Prediction Center College Park MD 1111 PM EST Fri Dec 27 2024 Areas affected...Southern MS...Southwest AL...Far Western FL Panhandle Concerning...Heavy rainfall...Flash flooding likely Valid 280410Z - 281010Z SUMMARY...Extremely heavy rainfall associated with training showers and thunderstorms is expected over the next several hours just north of the Gulf Coast involving portions of southern MS, southwest AL and the far western FL Panhandle. Flash flooding is already occurring locally and is expected to continue overnight, including growing concerns for major urban flash flooding. DISCUSSION...The latest GOES-E IR satellite imagery in conjunction with dual pol radar shows a corridor of extremely heavy shower and thunderstorm activity impacting portions of Harrison and Jackson Counties in southern MS, along with Mobile and Baldwin Counties in southwest AL. The convection over the last hour has been growing further in organization with cooling convective tops (as low as -65C) and the activity showing well-defined cell-training and backbuilding characteristics. This convection is being driving by moist, convergent and unstable low-level flow advancing north in close proximity to a warm front. This coupled with a focused axis of moisture convergence and divergent flow aloft is likely to foster a continuation of locally concentrated and slow-moving showers and thunderstorms with cell-training concerns going well into the overnight hours. MLCAPE values of near 1000 to 1500 J/kg have been pooling across the central Gulf Coast region, and the 00Z RAOB from LIX along with the latest CIRA-ALPW imagery shows a rather deep column of moisture in place with PWs of 1.5 to 1.7 inches. This coupled with as much as 30 to 40 kts of effective bulk shear, and the proximity of the warm front should favor organized convection capable of producing rainfall rates as high as 2 to 3 inches/hour with the strongest cells. A look at the 00Z HREF guidance suggests additional rainfall totals going through dawn may reach as high as 4 to 8 inches, and some localized totals approaching 10+ inches cannot be ruled out given the enhanced backbuilding and cell-training concerns. Flash flooding is already occurring, and there will be major urban flash flooding concerns overnight along areas close to I-10. Areas near and just to the north of a line from Biloxi, MS to Mobile, AL and potentially edging east into the far western FL Panhandle north of Pensacola will need to be very closely monitored overnight for a threat for locally significant flash flooding. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-Qif0ATdGfBHQYG_-1XDQqcfOslfa8rthM-HBDYZchRAaFAnAyLl9bPt88Te02ozUMxq= 1vdC7YvcR7BpPAdFtrREfTo$ for graphic product... ATTN...WFO...LIX...MOB... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 31348709 31028674 30638688 30358737 30258835=20 30378905 30668907 30958868 31278787=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) .