Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 10 2023 18:59:30 AWUS01 KWNH 101859 FFGMPD NMZ000-AZZ000-UTZ000-NVZ000-110058- Mesoscale Precipitation Discussion 0902 NWS Weather Prediction Center College Park MD 259 PM EDT Thu Aug 10 2023 Areas affected...Lower CO River Basin Concerning...Heavy rainfall...Flash flooding possible Valid 101858Z - 110058Z Summary...Cumulus and thunderstorms are beginning to deepen across portions of the Lower CO River Basin. Expansion and local backbuilding of thunderstorms over the next several hours could support flash flooding through this evening. Discussion...GOES-16 visible imagery over the last hour highlights increasing vertical depth of cumulus streets and thunderstorms across portions of the Lower CO River Basin. A composite outflow boundary from earlier storms is also noted across portions of Clark county, NV into Mohave county, AZ. This bubbling activity is developing within a regime of strong surface heating near the boundary, with strong Eastern Pacific moisture transport into the region. Diffluent flow aloft is also noted as a pair of circulations approach from Southern CA. The mesoscale environment continues to improve across the CO River Basin for heavy rainfall, as 1.5-1.6" PWATs approach from the south and 2000-2500 J/KG MUCAPE materializes along an east-west axis throughout the afternoon. Owing to the strong moisture transport into the area, forecast soundings across the area show increasing saturation of the vertical profile over the next several hours with expanding warm cloud layers of 2000-3000m. Meanwhile, low-level southerly inflow of 15-20 kts is is around the 850-300 mb mean flow. This suggests locally backbuilding storms are possible into the growing instability pool, especially along low-level outflows from earlier storms and the expanding activity. This scenario is reflected in recent runs of the HRRR, which focus development over the next several hours along the aforementioned boundary and southeast with upwards of 1-1.25"/hour rates. By 0z tonight, localized totals of 1-3 inches are possible where convection can sustain and backbuild. This could easily overwhelm the 1 HR FFGs in the region, which are as low as .5-1"/hr. Thus, the localized flash flooding threat is expected to expand through this afternoon. Asherman ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-21_nGKoNXIGRPUVNL20DpfIpIc9zRMYgdMC9D-w994Df5UhFe-FTHbZLEmzsQTmM0eU= _u2RSQabq2mIu_jvpMf-mI8$ for graphic product... ATTN...WFO...ABQ...FGZ...GJT...LKN...SLC...VEF... ATTN...RFC...CBRFC...CNRFC...NWC... LAT...LON 38821272 36970972 35020881 33800926 33991072=20 35321434 37441665 38781612=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) .