Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 16 2023 06:55:01 AWUS01 KWNH 160654 FFGMPD TXZ000-NMZ000-161230- Mesoscale Precipitation Discussion 1076 NWS Weather Prediction Center College Park MD 254 AM EDT Sat Sep 16 2023 Areas affected...Southern High Plains of NM through the Permian Basin of TX Concerning...Heavy rainfall...Flash flooding possible Valid 160653Z - 161230Z Summary...Showers and thunderstorms developing along a cold front will organize into clusters and drop slowly southeast through the morning. Rainfall rates of 2"/hr or more are likely, which through training could produce 2-3" of rain with locally higher amounts. Flash flooding is possible. Discussion...The regional radar mosaic tonight shows an expanding cluster of showers and thunderstorms from the high plains of eastern NM eastward through the Rolling Plains of Texas. This convection is expanding along a southward advancing cold front analyzed by WPC draped from near the Sandia Manzano mountains northeast through central Oklahoma. As this front digs southward, it is encountering robust thermodynamics characterized by MUCAPE of 1000-1500 J/kg and PWs of 1.1 to 1.3 inches, around the 90th percentile according to the SPC sounding climatology. Forcing for ascent is being enhanced by the RRQ of a strengthening jet streak moving over the Southern Plains and along the nose of a modest 15kt LLJ emerging from the Rio Grand Valley/Gulf of Mexico. Thunderstorms in this environment are producing radar-estimated rain rates of 1.5-2"/hr. During the next few hours, this front will continue to sag southward into the favorable thermodynamics. At the same time, the upper jet streak centered near OK/AR will intensify to 70-90 kts, placing more impressive diffluence across TX, in conjunction with the LLJ veering more to the south and accelerating to 20-25 kts. This should result in an expansion of convective coverage along the front which is reflected by high-res simulated reflectivity, with intensification also expected noted by HREF rain-rate probabilities reaching 15-20% for 2"/hr and HRRR 15-min rainfall exhibiting pockets of 0.75-1" (brief 3-4"/hr rates). Although mean 0-6km winds and layer Corfidi vectors are progged to remain progressive to the east, the persistent LLJ impinging into the front should drive some regeneration along the convergence axis back into higher instability over NM. This will likely enhance the training threat from west to east despite the southward frontal progression, and both the HREF and RRFS TL ensembles indicate a 30-40% chance for more than 3" of rain in some areas, with locally higher amounts approaching 5" possible. Rainfall during the past 7 days has been generally 300-600% of normal according to AHPS, with further soil saturation occurring from 24-hr MRMS measured rainfall of 1-3". This has compromised FFG to as low as 1.5"/3hrs in some areas, for which the HREF indicates has a 30-50% chance of being exceeded. This indicates that where any enhanced training along this front can occur overnight, instances of flash flooding could result. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7m7dVakmnI9jxWtZ4IaU80rEx8Typ1EhE8k3Q7ObPJ6FAGQHvQUZDPV_UMnjy0WeaTrg= 4dP7hXM-lFkEcJPF6c_kuvQ$ for graphic product... ATTN...WFO...ABQ...LUB...MAF...OUN...SJT... ATTN...RFC...ABRFC...WGRFC...NWC... LAT...LON 34460287 34460206 34270073 33670003 32629976=20 32199985 31769996 31450042 31420109 31560211=20 31840305 32180377 32800461 33220498 33710497=20 34220438=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) .