Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 26 2025 19:18:52 AWUS01 KWNH 261918 FFGMPD NMZ000-AZZ000-UTZ000-NVZ000-270100- Mesoscale Precipitation Discussion 1009 NWS Weather Prediction Center College Park MD 318 PM EDT Tue Aug 26 2025 Areas affected...Northern Arizona...Southern Utah...Extreme West-northwestern New Mexico... Concerning...Heavy rainfall...Flash flooding possible Valid 261920Z - 270100Z SUMMARY...Deep layer moist, confluent flow, and moderately unstable environment to support some repeating/training convective elements across dry/hard soils with localized 1-2" totals and possible flash flooding conditions through the evening hours. DISCUSSION...GOES WV mosaic depicts a well defined broad diffluent area across much of the northern Great Basin into the Rockies of WY/ID with core of weakly negatively tilted mid-level vorticity center in central NV angling into NW AZ. A convectively enhanced smaller scale shortwave is exiting southwest UT into central UT, lifting northward. The combination of the stronger height-falls has left the upstream areas within the southeast quadrant with above normal moisture flux out of the Sonoran Desert and across the San Francisco Plateau and across UT. Total PWat values of 1-1.25" have expanded up through the valleys of Eastern and western UT and across N AZ mainly driven in the lowest layers with Tds as high as the low 60s at KPGA and CNY, similar to those more common along the Colorado River into SW UT (near KSGU) with all locations in the area of concern well above normal into the mid to upper 50s. In the wake of the height-falls and best divergence aloft, fairly clear skies have provided solid insolation to allow for increased surface heating and unstable environments support MUCAPEs of 1000 to 1500 J/kg (greater along the AZ/NM boarder) within the increasingly confluent streamwise flow. Convergence along the Mogollon Rim and Mountain/Valley circulations have seen numerous convective development areas across NW AZ, along the Mogollon Rim and into the enhanced unstable area along the AZ/NM border along and downstream of the San Francisco and Gallo Ranges. Given the flux convergence rates of 1-1.5"/hr are possible, though deep layer flow is stronger further south in the wake of the exiting waves, limiting duration. However, north-south confluence axes are likely to develop and will grant the best potential of 1-2" totals due to short-term (1-2 hour) training or repeating through 3-5 hour periods. Hard/limited soil conditions with these rates suggest localized incidents of flash flooding are possible through the evening.=20=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9hvKjIqfQ5nKLHMM2GpDRcLe5fNZJXYKSTRn-7OlVa4uX6aZ8D_bjfzdnRXR_C6F9poF= eAcnYrJLblRrXfkLhVKi3aY$ for graphic product... ATTN...WFO...ABQ...FGZ...GJT...SLC...VEF... ATTN...RFC...FWR...STR...NWC... LAT...LON 39080961 38600910 37050919 36420886 35990853=20 35650797 34400788 33900843 33821029 34121183=20 34271291 34901362 35671395 36881404 37931390=20 38321304 38791089=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .