Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jun 03 2025 01:04:08 AWUS01 KWNH 030102 FFGMPD AZZ000-NVZ000-030600- Mesoscale Precipitation Discussion 0347 NWS Weather Prediction Center College Park MD 902 PM EDT Mon Jun 02 2025 Areas affected...Southern NV...Northwest AZ... Concerning...Heavy rainfall...Flash flooding possible Valid 030100Z - 030600Z SUMMARY...Clusters of thunderstorms starting to orient favorably for some repeating and potential for localized totals over 1" in short duration. Given hard ground conditions, incident(s) of flash flooding are considered possible. DISCUSSION...RAP analysis shows clusters of thunderstorms that developed along a fairly solid stationary front further north across eastern NV into central UT have developed potent enough cold pools/outflow boundaries. These boundaries along with forward propagation into a pool of deeper moisture and conditionally unstable environment into the Colorado River Valley have resulted in expanding and intensifying convective activity.=20 GOES-W Visible imagery shows increasingly numerous overshooting tops entering Clark county, NV through Mohave county in NW AZ.=20 Here MLCAPEs of 750-1000 J/kg remain in the fading solar input with low to mid 50s Tds across much of the lower Valley floors.=20 Trapped 700mb moisture within western mid-level trof has relatively high 80% RH and total PWat values to 1.25" where terrain is lower. While there will remain sub-cloud evaporative loss, rates of 1"/hr are probable; though with forward/southward speed totals of .5" seem more common with the cores of the downdrafts. Hard ground conditions will allow for heavy runoff and minor flooding concerns; however, convective latent heat feed-back has helped to develop a solid 850-700mb circulation in proximity to the sagged western portion of the front in northern Lincoln county. Low level wind is starting to respond and strengthen from 10kts toward 15-20kts with increased cyclonic curvature. As as result, flanking line convection into southern Nye county is orienting more NW to SE, parallel to the steering flow. Inflow from the southwest off the deserts may be a bit drier, but should be more orthogonal to help maintain some convective development.=20 While still uncertain, there is some trend analysis that suggests some spots of training in proximity is possible as the overall cluster drops south then southeast. A spot or two of 1"-1.25" totals would certainly result in localized flash flooding concerns. Overall, the cluster/complex should track through the pool of instability for the next few hours into far southern NV/NW AZ, to maintain a low confidence but possible widely scattered focused incident or two of flash flooding this evening. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4WZurNb_hhtbASxzD4OcMXzWketQ-BWwekjYKyNI8jO_OuSgzKynVykZrPXmBTf1IDBP= hj9ixno456iD3bqCCf5u07U$ for graphic product... ATTN...WFO...FGZ...VEF... ATTN...RFC...RSA...STR...NWC... LAT...LON 37441652 37421487 36951398 36641253 35721215=20 34901250 34961394 35401473 36081546 36891650=20 =20=20=20=20=20=20=20=20=20=20=20=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) .