Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Feb 06 2024 22:01:45 AWUS01 KWNH 062201 FFGMPD CAZ000-070600- Mesoscale Precipitation Discussion 0054 NWS Weather Prediction Center College Park MD 501 PM EST Tue Feb 06 2024 Areas affected...Southern California Concerning...Heavy rainfall...Flash flooding possible Valid 062200Z - 070600Z SUMMARY...Localized flash flooding will remain over southern CA over the next several hours. Peak rainfall rates near 0.5 in/hr are expected but should remain very localized across the region. However, saturated grounds will continue a threat for additional flooding and debris flows. DISCUSSION...GOES West water vapor imagery and KSOX reflectivity at 2120Z showed a low level vorticity max spiraling into the Los Angeles metro, out ahead of the base of a large scale mid to upper level trough advancing eastward across CA. Water vapor imagery also showed a pair of mid to upper level vorticity maxima offshore of southern CA with locally moderate to heavy rain ongoing across eastern Ventura County into Los Angeles County in association with lift ahead of the vorticity maxima. Cold mid-levels, 500 mb temperatures near -26 C, were supporting weak instability near 500 J/kg along the coast as seen on the latest SPC mesoanalysis. Earlier rainfall rates peaking near 1 in/hr were observed in the Los Angeles metro, but precipitable water values are beginning to lower and better large scale forcing has shifted to the east. Across Santa Barbara, Ventura and Los Angeles counties, slow movement of moderate to heavy rain is expected ahead of the offshore vorticity maxima with 0-6 km mean winds of less than 10 kt across the region and only slow translation of forcing. Farther south down the coast, onshore 850-700 mb winds of 20-30 kt into Orange and San Diego counties should maintain over the next several hours. Scattered showers and perhaps a thunderstorm are expected to impact the region through early overnight and while wetter antecedent conditions were located farther north up the coast, localized potential for flash flooding from hourly rainfall up to about 0.5 inches will still remain. The entire southern CA coast to roughly 6000 ft in elevation along the Transverse and Peninsular Ranges will continue to have a localized threat for flash flooding and debris flows from heavy rainfall. Additional rainfall totals through 06Z of 1 to 1.5 inches are expected. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5mNVYSXMU93QkMhZtgbdKLRQO-3AjrOEZIS_LG_CCodp8BE8mGwNn_rqLfISf3ikednn= vvNfJX6zI14CRuBjAf_gXOI$ for graphic product... ATTN...WFO...LOX...SGX... ATTN...RFC...CNRFC...NWC... LAT...LON 34801981 34581917 34281807 34261713 33991683=20 33451658 32811648 32581641 32391643 32341697=20 32411720 32811747 33261777 33441800 33621851=20 33791878 33961917 34171968 34432014 34722010=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .