Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
310 am PST Monday Jan 26 2015
a low pressure system from the southwest will bring periods of
showers through this evening...decreasing late tonight and early
Tuesday. The most significant precipitation is expected during the
afternoon through early evening with greater amounts for inland
areas. Dry for Wednesday. Another weak low pressure system from the
southwest will bring a chance of showers for late in the week.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Short term (today through wednesday)...
satellite imagery shows a weak upper level low pressure system
centered off the coast of northern and central Baja California. It will move
slowly toward the northeast and inland across Southern California
tonight. Middle and high level moisture continues to stream
northwestward across Southern California early this morning with
lower levels of the atmosphere still quite dry. Radar returns thus
far have been nothing more than virga with no measurable
precipitation at any reporting sites thus far.
Showers will spread northward into Southern California this morning
with the greatest coverage and precipitation amounts expected for
this afternoon and evening. Precipitation should begin accumulating
first in the higher elevations and eventually into lower elevations
as the lower levels of the atmosphere saturate. Rainfall amounts for
the mountains are expected to range from one half to one inch with
locally greater amounts with one third inch or less in the deserts
and inland valleys with lesser amounts toward the coast. The coldest
air aloft and resulting greatest instability will move northward
across the coastal waters early this evening. This could locally
enhance shower intensity and bring a slight chance of
thunderstorms...mainly across the coastal waters. While overall
rainfall amounts are expected to be less towards the coast and over
the coastal waters...there is the possibility of briefly heavy
rainfall over portions of this area...mainly during the early
The snow level will lower to around 7500 feet with 4 to 8 inches of
snowfall possible on the higher peaks of the mountains in San
Bernardino and Riverside counties.
Showers are expected to end from south to north for late tonight
through early Tuesday. Dry and a little warmer weather is expected
Long term (thursday through sunday)...
another weak low pressure system off the Baja California coast will move slowly
northeastward toward Southern California Friday...then may drift
southeastward into Baja California for the weekend with the forecast leaning
towards the slightly slower European model (ecmwf). This would bring chances for
showers for late Thursday and Friday...possibly continuing into
Saturday or early Sunday.
261000z...clouds above 15000 feet will gradually thicken and lower
this morning leading to some showers across the region today and
tonight. Rain showers will be most widespread over the mountains and
deserts from 22-06z this afternoon and evening. Clouds will lower to
about 4000 to 6000 feet mean sea level during the evening...and could briefly
drop to around 3000 feet...although no visible restrictions are
expected. Showers will move out from south to north overnight...but
some of the lower clouds will persist.
200 am...no hazardous marine weather is expected through Friday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
California...Winter Weather Advisory from 6 PM this evening to midnight PST
tonight above 7500 feet for the San Bernardino County
mountains and the Riverside County mountains.