Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 12 2023 21:02:27 AWUS01 KWNH 122102 FFGMPD OKZ000-KSZ000-NEZ000-COZ000-NMZ000-WYZ000-130301- Mesoscale Precipitation Discussion 0473 NWS Weather Prediction Center College Park MD 501 PM EDT Mon Jun 12 2023 Areas affected...HIgh Plains from Wyoming through northern New Mexico Concerning...Heavy rainfall...Flash flooding likely Valid 122101Z - 130301Z Summary...Thunderstorms expanding across the High Plains will continue this evening. Rain rates will likely exceed 2"/hr at times. Some of these storms may organize into an MCS across CO/KS, while others remain disorganized and slow moving. Any of these heavy rain rates atop saturated soils will result in additional instances of flash flooding. Discussion...The regional radar mosaic across Colorado this afternoon shows widespread showers and thunderstorms from the Cheyenne Ridge southward through the Raton Mesa. Rainfall has been impressive this afternoon already, with some mesonet sites reporting more than 4 inches of rain, and flash flooding is occurring. This convection is being fueled by persistent southeast inflow driving PWs to around 0.8 inches on GPS measurements, around the 90th percentile for the date, with concurrent MUCAPE of 1000-2000 J/kg producing extremely favorable thermodynamics. Into this environment, ascent is impressive through height falls/PVA downstream of a strong shortwave/vort max lifting across eastern CO aligned with low-level convergence on a surface trough and 20-40 kts of 0-6km bulk shear, highest in southeast CO. Recent radar estimates from KFTG WSR-88D of rain-rates have exceeded 1.5"/hr. The evolution through the next few hours is somewhat uncertain due to variations in the high-res simulated reflectivity, but there may be two distinct convective modes driving the the flash flood risk. The first is across eastern CO where an MCS is currently developing noted by an expanding line of thunderstorms downstream of some mesoscale cyclonic turning indicative of an MCV. With continued high instability and moisture being drawn from the east, it is possible this will congeal into a forward propagating MCS as it interacts with up to 40 kts of bulk shear. While this would likely result in faster storm motions noted by Corfidi vectors reaching 25 kts, that will occur in tandem with even higher rain rates which the HRRR sub-hourly fields indicate could produce 0.75-1"/15 min. This suggests that despite the fast motion, this heavy rain could accumulate to more than 3 inches in some areas, resulting in flash flooding, especially where it falls atop soils saturated from 200-600% of normal 14-day rainfall. Both north and south of this probable MCS, more discrete cells, possibly supercells across NM and more typical pulse cells into northern CO/WY, are expected. These will also have intense rain rates, possibly exceeding 2"/hr according to HREF probabilities, and maybe even slightly greater in any supercells. While storm motions over NM will be progressive to the east, across northern CO and into WY, 0-6km mean winds are only 5-10 kts, suggesting slow storms with repeating rounds possible. These slow moving cells should additionally result in instances of flash flooding, especially if they occur over any burns scars or more sensitive soils before waning with exhausting instability tonight. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-gNpUGKFYS5whFW8_4paU355f6H3F5W6KgEcv-1GJ0GqRR91skUuY3sZB25d7QzTNxmR= IiRrKWuOIAhVnUmaz76QsTk$ for graphic product... ATTN...WFO...ABQ...AMA...BOU...CYS...DDC...GLD...LBF...PUB... ATTN...RFC...ABRFC...MBRFC...NWC... LAT...LON 41780556 41720468 41480388 41040294 40790246=20 40490207 39820159 39060111 38180129 37270191=20 36910242 36700366 36650414 36630452 36920464=20 37590464 38360445 38960430 39670412 40270445=20 40910523 41260573=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) .