549
AWUS01 KWNH 140922
FFGMPD
CAZ000-141518-

Mesoscale Precipitation Discussion 1223
NWS Weather Prediction Center College Park MD
421 AM EST Fri Nov 14 2025

Areas affected...portions of southern California

Concerning...Heavy rainfall...Flash flooding likely

Valid 140918Z - 141518Z

Summary...Flash flood potential continues across portions of
southern California for at least another 4-6 hours.  Areas of 2-3
inch rainfall totals are expected that could cause excessive
runoff and debris flows.

Discussion...Flash flood potential will continue through at least
15Z/7a Pacific Time this morning.  A fetch of strong onshore flow
continues just ahead of a cold front along the coast extending
from near PRB near VBG.  Just ahead of this front, mesoanalyses
indicate a focused area of 35 knot 850mb flow oriented
perpendicular to the western Transverse Ranges (Santa Barbara and
Ventura Counties).  This orientation, ~1.5 inch PW, and modest
instability was supporting repeating heavy rainfall at times
across the discussion area.  The repeating nature of the rain was
resulting in spots of 1 inch/hr rain rates in local areas from the
Santa Ynez mountains through the Sierra Madre mountains and
surrounding areas.  Low spots were responding with runoff over
area roadways over the past few hours, and reports of flooding
have been received in the discussion area near Highway 101.

The ongoing scenario will continue for another 4-6 hours or so.
The mid-level system partially responsible for the ongoing heavy
rainfall hazard has stalled, and the attendant cold front will
also become stationary.  Meanwhile, 35 knot 850mb flow will
continue to impinge on the Transverse Ranges and prompt several
hours of intermittent heavy rain.  The very high PW values and
local burn scars yield concern that locally significant flash
flooding could occur.  Rainfall totals of 2-3 inches are also
possible in a few spots through 15Z.

At some point around/after 15Z, 850mb wind fields should slacken
some and result in a gradual lessening of heavy rainfall potential.

Cook

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...HNX...LOX...

ATTN...RFC...RSA...NWC...

LAT...LON   35782038 35561882 34761781 34121776 33911846
            34422009 34702073 35072071 35342098