Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 05 2025 23:27:37 AWUS01 KWNH 052326 FFGMPD AZZ000-UTZ000-NVZ000-CAZ000-060400- Mesoscale Precipitation Discussion 0373 NWS Weather Prediction Center College Park MD 725 PM EDT Thu Jun 05 2025 Areas affected...Southern NV...Northwest AZ...Southern UT...Extreme Eastern CA Concerning...Heavy rainfall...Flash flooding possible Valid 052325Z - 060400Z SUMMARY...Showers and thunderstorms will likely continue to persist over the next few hours across portions of southern NV, extreme eastern CA, northwest AZ and southern UT. Additional isolated areas of flash flooding will be possible going into the evening hours as a result. DISCUSSION...The late-afternoon GOES-W visible satellite imagery shows multiple convectively reinforced outflow boundaries impacting the Southwest from ongoing small-scale clusters of convection. One axis of well-defined CU/TCU and embedded CBs exists across southern UT and into southern NV, with another one farther south over northwest AZ near the Mogollon Rim and over to the CA/NV border. In between these two outflow boundaries which are both generally settling slowly southward, there continues to be the pooling of instability with as much as 1000 to 1500+ J/kg of SBCAPE. In fact, the latest 3-hourly SBCAPE differentials has been showing localized increases (400+ J/kg) in instability over northwest AZ. Recent IR satellite imagery has been showing some additional cooling of the convective cloud tops over southern NV in particular, and the latest RAP analysis has also been indicating some modest effective bulk shear parameters showing up as an elongated mid-level shortwave trough/shear axis approaches the region from the northwest. The combination of lingering diurnally enhanced instability along with cooling cloud top trends and the aforementioned mid-level trough approaching the region suggests that the ongoing convection should tend to persist for at least a few more hours. A combination of orographic ascent and some potential for these outflow boundaries to interact with one another may also support potential for renewed convective development in the near-term. Some additional 1 to 2+ inch rainfall amounts will be possible with the stronger storms, and given the sensitivities on the ground around some of the local slot canyon areas (especially southern UT) along with any burn scars and the normally dry washes, there may be some additional isolated areas of flash flooding this evening. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4EACyrEbdoZbe-Xky5uQLRI3Jh6lEAFYCcdlcZh1nNPFWpa9VeLqOIz1hLqet5IFYeri= l4TghF_hU00nM8zvC0kiztg$ for graphic product... ATTN...WFO...FGZ...GJT...SLC...VEF... ATTN...RFC...RSA...STR...NWC... LAT...LON 38551154 38461017 37761018 37011142 36341169=20 35631153 34821169 34591240 34781365 34851463=20 34991553 35521592 36281597 37051578 37671515=20 38061409 38361289=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) .