Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 02 2025 04:34:45 AWUS01 KWNH 020433 FFGMPD NMZ000-AZZ000-020900- Mesoscale Precipitation Discussion 0342 NWS Weather Prediction Center College Park MD 1232 AM EDT Mon Jun 02 2025 Areas affected...central to eastern AZ Concerning...Heavy rainfall...Flash flooding possible Valid 020430Z - 020900Z Summary...Showers and thunderstorms are expected to expand in coverage and intensity across central to eastern AZ over the next 4-5 hours. Rainfall of 0.5 to 1.0 inches in an hour or less with repeating and training could result in a few instances of flash flooding. Discussion...GOES West imagery at 04Z showed a closed mid to upper-level low over the Baja California/Sonora border, about to move into southwestern AZ with a secondary subtle vorticity max moving north out of Pima County into south-central AZ. A RAP estimated 70-80 kt upper level jet streak was located over the northern Gulf of California, just southeast of the low's center, with divergent and diffluent flow downstream of the upper jet streak across a good portion of AZ. MRMS composite reflectivity and infrared satellite loops over the past 3 hours have shown waves of more intense rain/thunderstorms moving into southeastern AZ from Mexico (compared to earlier in the day) along with a number of embedded transient mesoscale circulations contained within. Recent gauge reports over eastern Santa Cruz County have shown between 0.5 and 0.7 inches of rain in an hour. SPC mesoanalysis data from 04Z showed MLCAPE of 500-1000 J/kg south of the AZ/MX border, but quickly dropping off to less than 500 J/kg into south-central and southeastern AZ. Over the next few hours, rounds of heavy rain will likely continue to move into southeastern and eastern AZ following the favorable upper level forcing ahead of the closed low along with instability and anomalous precipitable water values (1.45 inches at the TUS 00Z sounding...well above the SPC sounding page's climatological max). Southerly to south-southwesterly flow at 700 mb (20-30 kt) along with deeper layer steering flow of the same orientation will support repeating and training cores of heavy rain at times, allowing for 0.5 to 1.0 inches in an hour or perhaps as short as 30 minutes. Over central to south-central AZ, as the closed low center edges closer, RAP forecasts show MLCAPE increasing into the 250-750 J/kg range given an increase in low level moisture and cooling mid-level temperatures. This may allow for the development of a few thunderstorms by 08-09Z given DPVA, capable of hourly rainfall near 1 inch. Across both central to eastern AZ, a few areas of flash flooding may develop given overlap with areas of sensitive terrain, remnant burn scars, and/or urban centers. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5EFel7LqznqhVkm4NuMyIYXyG178WNCUCf7aBI8uJi3sZOq_sWXz0sR5OaCRtZ-GSjRA= 0eo2ys1j2nvLqm4tn0DwWzs$ for graphic product... ATTN...WFO...EPZ...FGZ...PSR...TWC... ATTN...RFC...STR...NWC... LAT...LON 35251122 34770987 33760912 32020894 31040934=20 31091098 31431181 32121264 33981269 35091234=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) .