Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Dec 24 2024 14:04:58 AWUS01 KWNH 241404 FFGMPD ARZ000-TXZ000-OKZ000-241930- Mesoscale Precipitation Discussion 1185 NWS Weather Prediction Center College Park MD 904 AM EST Tue Dec 24 2024 Areas affected...North/Northeast Texas...Portions of SE OK & SW AR... Concerning...Heavy rainfall...Flash flooding possible Valid 241405Z - 241930Z SUMMARY...Increasing convective activity with potential of 1.5"+/hr rates with back-building and short-term training potential may exceed FFG, especially near urban centers resulting in possible localized flash flooding. DISCUSSION...GOES-E 10.3um loop shows convection breaking out along the frontal zone across North Texas into the Red River Valley with steady increasing lightning detection within most active cores, particularly along the upstream edge. Surface analysis denotes a weak surface low near F02 with stationary front meandering through the Red River with northern stream cold front slowly dropping southwest across eastern portions of the Big Country back through the Concho Valley; south of which, returning Gulf moisture is starting to encroach with reinforcing shot of enhanced theta-E with mid 60s Tds in the southern Triangle lifting north as well. CIRA LPW shows a slug of detached mid-level moisture from the Pacific stream pooled along the frontal boundary in association with a weak shortwave over northeast OK. GOES-E WV suite also denotes, core of northern stream upstream larger scale wave is starting to dig across the Central High Plains; effectively strengthening the low level flow to further enhanced deep moisture convergence over the midday into afternoon hours.=20 This has resulted in a 500-1000mb thickness ridge over E TX that is supporting a veered propagation vector field that will align with deeper layer steering for at least a few hours across the Big Country into Northeast Texas providing a solid potential for 1) training of convection but 2) increasing upstream moisture convergence and steepening lapse rates (with modest mid-level drying from the southwest) to support increasing instability and convergence for development/backbuilding.=20 In the short-term, the cells are converting modest instability with MLCAPE increasing to about 500-1000 J/kg along the upwind edge with downstream cells likely becoming a bit more elevated with MUCAPE pool of 500 J/kg to maintain more scattered/isolated cells into SW AR with time. Solid deep layer convergence and total PWats of 1.25" (though bulk of .75"+ at sfc/850mb layer) will allow for some intense rainfall production. RADAR estimates of 1.5"/hr have already be observed with potential for additional capacity if the training/repeating corridor saturates through depth. A balance of unidirectional SSW steering and some outflow/cold pool propagation southeastward may reduce ideal training setup given weaker instability totals, but risk of 2-3" totals in 2-3 hours may result in localized flash flooding. This only increases in proximity to DFW urban corridor, where risk goes up and may be the only location that these totals may overcome the higher FFG given drier 30-50% soil saturation environment along and east of I-35...though saturation increases toward the Texarkana region, hence the inclusion of the area at this time. As such, a incident or two of flash flooding is considered possible in the near-term.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_0Q92CWVPg1fjm9lGxImqhznbTs7LPIRekyUZg4JCUizngcJcy2cG-pCf62ScdIFVIjE= ApfoMoqXUQ4VO-_ZsLljK8Q$ for graphic product... ATTN...WFO...FWD...LZK...OUN...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...WGRFC...NWC... LAT...LON 34729428 34249336 33499368 32819472 32049641=20 31759835 32379852 33159788 33879686 34449568=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) .