Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 22 2023 14:45:58 AWUS01 KWNH 221445 FFGMPD FLZ000-GAZ000-ALZ000-222045- Mesoscale Precipitation Discussion 0322 NWS Weather Prediction Center College Park MD 1045 AM EDT Mon May 22 2023 Areas affected...Southeast AL...Southwest & South-central GA...Northern FL...Eastern FL Panhandle... Concerning...Heavy rainfall...Flash flooding possible Valid 221445Z - 222045Z SUMMARY...High efficiency, slow moving thunderstorms may produced spotty 3-5" in 3 hours posing scattered localized rapid inundation flooding concerns through late morning into the afternoon.=20 DISCUSSION...A deeply moist and locally unstable environment exists along a deep layer stationary boundary from the Sargasso across S GA/N FL. Upper-level left exit ascent pattern exists over the region with modest diffluence providing favorable ascent pattern across the area. An elongated 5H shear axis across central AL to the eastern GA Bight has a stronger impulse sliding through the region providing weak but sufficient DPVA and favorable boundary layer to 700mb confluent flow across GA. As such, convergence in this axis has developed widely scattered stronger thunderstorms, but generally have been slow moving at least initially (1-1.5 hrs). Recent rainfall totals near Cairo as well as earlier convection near Jacksonville produced localized totals up to 3" and 4" respectively in a 1.5-2.5 hour time frame.=20 This pattern is likely continue and expand across the area of concern through the next few hours. Full to filtered insolation in proximity of the confluence boundary with further improved mid to upper level ascent patterns will increase convective coverage and vigor. RAP/HRRR forecasts increase CAPE values to 2500-3000 J/kg along and upstream of the confluence axis. With weak/confluent 850-700mb flow, cell motions will remain below 5-10kts and likely increase forward propagation on slow cold pool generation. VWP and RAP forecast suggest the confluence axis will be shifting westward with time under strengthening/backing low level winds off the Atlantic; combine this with westerly inflow at surface to 700mb will support unobstructed moist and unstable air (2" total PWat) should allow for 2-3"/hr rates and localized 3-4" totals through early afternoon. Some storm scale i.e. outflow boundary and/or frictional convergence near the coast interactions may even allow for longer duration stationary cells capable of 5"+ . As such, spotty highly localized rapid inundation flooding is considered possible,especially in proximity to urban centers and areas saturated over the last week or so that have seen 300-500% of normal (per AHPS) across SE AL/SW GA and the eastern Florida panhandle. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9s8SFwlOQ1c5bBiI_h9o2ALvWgaA_oskcZ62sci1jOvtiAS8tg9uep4Iqi3C8TLqBL1E= lBlQU11-MaZBQ5tSGrhC9NI$ for graphic product... ATTN...WFO...BMX...FFC...JAX...TAE...TBW... ATTN...RFC...SERFC...NWC... LAT...LON 32888525 32588392 32008294 31268228 29838204=20 29178268 29268319 29738371 30008407 30008491=20 31088562 31868596 32458592=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) .