Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 16 2023 02:32:02 AWUS01 KWNH 160231 FFGMPD AZZ000-160800- Mesoscale Precipitation Discussion 0111 NWS Weather Prediction Center College Park MD 1031 PM EDT Wed Mar 15 2023 Areas affected...central/southern AZ to the NM border Concerning...Heavy rainfall...Flash flooding possible Valid 160229Z - 160800Z Summary...Areas of flash flooding will remain possible across portions of central, southern and eastern AZ over the next few hours with peak 15 minute rainfall of 0.25 to 0.5 inches and peak hourly totals near 1 inch. Weakening CAPE/increasing CIN and progressive upper level forcing shifting east is expected to dampening the flash flood threat by 08Z. Discussion...02Z regional radar imagery continued to show a fairly active display of convection across western AZ with some of the heaviest rain over southern Mohave County with gauge reports showing 1 to just over 2 inches since midnight but rates of 0.25 to 0.5+ inches in 15 minutes. The orientation of cells in this region has also allowed for some repeating of heavy rain cores as mean cell motion tracks from west to east. This region of AZ was showing 500 to 1000 J/kg MUCAPE on the 02Z SPC mesoanalysis along with up to about 1 inch of precipitable water. Aloft, strong forcing was observed as western AZ was positioned within the left exit region of a 120-130 kt speed max near 300 mb over southern CA along with diffluence aloft, all pushing toward the east. Current convection over western and southwestern AZ is expected to continue to advance eastward, out ahead of a negatively tilted upper trough axis over the region. Surface dewpoints in the low to mid 50s will continue to support weak instability over the next few hours given fairly steep 700-500 mb lapse rates of 6.5 to 7.0 C/km but nocturnal cooling at the surface should lower available instability with time. Upper level forcing shifting eastward will also advect in drier air in the lowest 3 km AGL, ending the flash flood threat from west to east with time. However, lingering instability and upper level forcing will continue the threat for short term heavy rainfall with 15 minute rainfall up to about 0.5 inches and an additional 1 to 1.5 inches through 08Z for portions of central, southern and eastern AZ. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6NwgxPrYluUURBMv5IIYUb0B_3ADb29o1t79GjkjAEwVc14oaliA3L40MK5P6KkjwrFL= -e6aeUUGiagq6dt6UfMu_XY$ for graphic product... ATTN...WFO...FGZ...PSR...TWC...VEF... ATTN...RFC...CBRFC...NWC... LAT...LON 35241320 35041220 34571076 34180938 33370921=20 32430995 32271151 32421305 32781368 33171352=20 33811345 34471399 35051385=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .