Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Oct 20 2024 04:12:03 AWUS01 KWNH 200411 FFGMPD TXZ000-NMZ000-201010- Mesoscale Precipitation Discussion 1107 NWS Weather Prediction Center College Park MD 1210 AM EDT Sun Oct 20 2024 Areas affected...Eastern NM Concerning...Heavy rainfall...Flash flooding likely Valid 200410Z - 201010Z SUMMARY...Heavy showers and thunderstorms are expected to continue to impact portions of eastern NM overnight. Additional areas of flash flooding are likely. DISCUSSION...The latest GOES-E IR satellite imagery shows a very divergent flow regime aloft over eastern NM with an expansive canopy of persistent cold convective tops associated with an elongated band of heavy showers and thunderstorms. All of this is occurring downstream of a rather strong upper-level low that is nearly stationary over central AZ. MLCAPE values over eastern AZ remain on the order of 500 to 1000 J/kg out ahead of a quasi-stationary front, but the front is helping to focus a strong north/south axis moisture convergence which is being facilitated by a southeast low-level jet of 40 to 50 kts that is persisting across the southern High Plains. This enhanced moisture convergence/transport working in tandem with the available instability and deep layer ascent downwind of the upper low has resulted in some very well-organized convection including a few occasional supercell structures this evening that have been resulting in locally extreme rainfall rates. In fact, Roswell, NM (KROW) picked up 0.73" of rain in just a 7-minute period between 0148Z and 0155Z. The persistence of this extreme rainfall rate led to Roswell seeing 2.70" of rain in one hour from 0151Z to 0251Z. This has led to locally catastrophic flash flooding impacts, with a Flash Flood Emergency for the city of Roswell. The instability trends over eastern NM are somewhat negative with 3-hour differentials in the MLCAPE of -200 to -400 J/kg. This suggests that the rainfall rates will likely tend to come down a bit in the hours ahead, however, the persistence of deep layer ascent/upper-level jet forcing and the low-level jet yielding enhanced moisture flux convergence should tend to compensate and help keep rainfall rates still capable of reaching 1.5" to 2.0"/hour with the stronger cells. Some gradual eastward advance of the overall convective rainfall axis is expected overnight, but some additional rainfall amounts of 3 to 4 inches will be possible locally where any of these cells continue to train or backbuild over the same area. As a result, additional areas of flash flooding will be likely. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6Erj1W2ZbGyiBF-FSnt-SrG-9xoMutAVM4HNJIbSKgsAMN7kdXXu-NmMmIk8dTvWHuXU= eb0UGL4mjNc6pCwboFNLaog$ for graphic product... ATTN...WFO...ABQ...AMA...EPZ...LUB...MAF... ATTN...RFC...ABRFC...WGRFC...NWC... LAT...LON 36490328 36060290 35190289 34000322 33170377=20 32780425 32640496 33090539 33520542 34670525=20 35840496 36450415=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) .