Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Feb 06 2024 16:03:09 AWUS01 KWNH 061603 FFGMPD CAZ000-062130- Mesoscale Precipitation Discussion 0052 NWS Weather Prediction Center College Park MD 1102 AM EST Tue Feb 06 2024 Areas affected...Southern California Concerning...Heavy rainfall...Flash flooding possible Valid 061600Z - 062130Z SUMMARY...A flash flood threat will continue for southern CA through the early afternoon. While the coverage and magnitude of heavy rain will be reduced compared to the previous couple of days, sensitive grounds will maintain the risk for runoff from an additional 1 to 2 inches of rain. DISCUSSION...GOES West water vapor imagery showed an elongated mid to upper level low/trough centered west of the central CA coast with a number of smaller scale vorticity maxima embedded within the base of the trough off of southern CA. Two of the vorticity maxima were located ~125 miles SSW of Point Conception and along 120W at 1530Z, tracking toward the east. 12Z soundings from VBG and NKX indicated PWATs of 0.6 to 0.9 inches, as the core of the moisture plume has shifted east into the lower CO River Valley but 700-500 mb lapse rates of 7.4 C/km at NKX were an indicator of the upstream environment, closer to the core of the mid-level low. Radar and infrared imagery showers ongoing showers into Ventura and Orange counties with moderate to heavy rain. As the mid-level low/trough axis continues to translate southeastward through the afternoon, 850-700 mb winds are expected to vary in magnitude (<10 kt for the Transverse Ranges up to ~30 kt for San Diego County) but veer from their present S and SW orientation. PWATs are expected to remain similar to their 12Z values with only slight lowering through 21Z but the steeper upstream lapse rates will be shifting southeastward with time and supporting up to 250-750 J/kg MUCAPE across southern CA. Forcing ahead of the vorticity maxima off of the southern CA coast should continue to shift east through 21Z with an increase in showers and shallow convective cells beneath the cold core aloft. Brief training should support isolated 0.5 to 0.75 in/hr rates but the majority of rain rates should remain in the 0.1 to 0.3 in/hr range. Given the extreme rainfall observed over the past 48 hours and areas of ongoing flooding throughout southern CA, the addition of 1 to perhaps 2 more inches of rain will continue the threat for flash flooding and debris flows. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_lalEHxSRMfcAQs6gcDNhsPitkt3JSEZursz-xQPArDo5n7aertRhc3CdO_7Q0BwZodD= WhOrUcUJAP2G5RKQwfGciLA$ for graphic product... ATTN...WFO...LOX...SGX... ATTN...RFC...CNRFC...NWC... LAT...LON 34361830 34291782 34231757 34171708 33931676=20 33291656 32791636 32471639 32341697 32321728=20 32571758 33051779 33411812 33831916 34071937=20 34321904=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) .