Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jul 18 2025 18:02:34 AWUS01 KWNH 181801 FFGMPD TXZ000-COZ000-NMZ000-AZZ000-190000- Mesoscale Precipitation Discussion 0744 NWS Weather Prediction Center College Park MD 201 PM EDT Fri Jul 18 2025 Areas affected...Southeast AZ...Southwest and Central NM Concerning...Heavy rainfall...Flash flooding likely Valid 181800Z - 190000Z SUMMARY...Monsoonal moisture entrenched across portions of the Southwest U.S. will favor heavy showers and thunderstorms developing and expanding in coverage over the next several hours. Isolated to scattered areas of flash flooding will be likely where these heavier rains impact the more sensitive dry washes and burn scar locations. DISCUSSION...The latest GOES-W Day Cloud Phase RGB along with LightningCast data shows that convective initiation is imminent across large areas of central NM and down into southeast AZ. The airmass is very unstable due to strong diurnal heating/solar insolation, and SBCAPE values are currently on the order 2000 to 3000 J/kg across portions of central and eastern NM, with somewhat lesser values across eastern AZ through western NM. However, the airmass is quite moist with PW anomalies locally as high as 1.5 standard deviations above normal, with the greatest concentrations of moisture across central and southern NM. A combination of strong thermodynamics and terrain-driven circulations/orographics should facilitate the development and expansion of scattered areas of heavy showers and thunderstorms going through the afternoon hours. The storms will be embedded within a relatively weak steering flow regime around the western periphery of the subtropical ridge over the southern U.S. Generally the activity should be pulse in nature given weak shear through the column, but some of the cells may tend to be locally anchored near the terrain given the influence of orographic ascent. The latest 12Z HREF suggests rainfall rates may reach 1 to 2 inches/hour with the stronger cells, and with the aforementioned steering environment, some localized storm totals by late this afternoon may reach 2 to 3+ inches. There will be notable concerns for flash flooding around the normally dry washes that see heavy rainfall or runoff from nearby storms, and several burn scar locations will be susceptible to flash flooding impacts/runoff concerns from the storms that materialize over the next several hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-7YtCWMj3Jc3IXOCVYXEedpZJl-F2xdh-VWPnW955fNFoxHnP7pJlNyZSdassBwARqLT= UVpSKLN5CDqYfi4OinwjaK4$ for graphic product... ATTN...WFO...ABQ...EPZ...FGZ...MAF...PUB...TWC... ATTN...RFC...FWR...STR...TUA...NWC... LAT...LON 37130490 36260394 33560476 32150481 31710694=20 30950862 30941037 31661075 32341043 32830972=20 33390935 34460887 35380777 36890642=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) .