Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 13 2025 02:06:03 AWUS01 KWNH 130205 FFGMPD CAZ000-131405- Mesoscale Precipitation Discussion 0059 NWS Weather Prediction Center College Park MD 1005 PM EDT Wed Mar 12 2025 Areas affected...portions of southern California Concerning...Heavy rainfall Valid 130205Z - 131405Z Summary...A frontal band will translate from west to east across southern California coastal ranges, resulting in 1-2 inch rainfall totals - highest in terrain-favored areas. This rainfall will affect burn scars across the region, posing a risk of runoff, flash flooding, and debris flows through at least 13Z/6a PDT. Discussion...A strong Pacific cold front (currently located near KPRB/Paso Robles, CA and KSBP/San Luis Obispo) was making steady southeastward progress over the past several hours, and will continue to do so across the discussion area through 13Z. Along and west of the front, areas of convection have produced 0.5-1 inch of rain over the past 3 hours - highest along coastal areas between San Francisco and San Luis Obispo within the Santa Lucia Range. Minor flooding has also occurred across Alameda County. These rainfall rates will continue to spread southeastward in tandem with the front, while potentially increasing as depicted by CAMs as the rainfall band reaches the Transverse Ranges and adjacent areas near Los Angeles Metro through 06-12Z (11p-5a PDT) As these rates spread southeastward, they will encounter fresh burn scars from recent fires across the region. These and other sensitive areas will promote runoff along with the potential for flash flooding and debris flows. Models/obs indicate that a 3-5 hour period of moderate to heavy rain will affect the region, with peak flash flood risk potential occurring in the 08Z-12Z (1a-5a PDT) timeframe around the Los Angeles metro and adjacent areas of the Tranverse Ranges. The risk will peak farther southeast toward San Diego and adjacent mountainous areas in the 12-14Z (5a-7a PDT) timeframe. Storm totals of 1-2 inches are expected (locally higher in terrain-favored areas), and peak hourly rain rates should mostly remain in the 0.5-0.75 inch range, locally higher. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9l63Z6R_esTVdrCecbqOAtG3lr6pabvSCrQmDjG1DDk7QWEkBZ39gano74qcppqcUoRa= xE81mbjsCZVb5r5_TWGABXY$ for graphic product... ATTN...WFO...HNX...LOX...SGX...VEF... ATTN...RFC...CNRFC...NWC... LAT...LON 35732024 35711942 35461831 35081719 34491661=20 33541642 32851661 32601709 32941746 33571821=20 33871899 34142000 34632080 35342090=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) .