Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
805 am PST sun Nov 29 2015
Synopsis... the cold low pressure system that has dominated the
west throughout the Holiday weekend will begin to drift eastward
today and be replaced by a high pressure ridge through middle week. This
will bring gradual warming into Wednesday...although the nights will
continue to be quite cool with patchy frost in some valleys. Cooler
late in the work week as another low pressure trough swings through
the region with gusty westerly winds. Then...warmer and dry next
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
The sheet of higher clouds that developed over the region last night
has moved east this morning leaving clear skies. The 12z Miramar
sounding had two inversions. One surface based...and another weak one at
6k feet. Winds were generally light and variable below the inversion.
Surface pressure gradients were weak offshore from the lower deserts
and around 4 mbs offshore from Nevada. Most areas reported light winds
with only localized NE winds of 10-15 miles per hour with higher gusts. Some
spots in central San Diego County had temperatures in the middle
30s...otherwise most west of the mts were in the 40s at 7 am PST.
Look for a fine day to wrap up the Holiday weekend under sunny skies
with light winds. It will turn quite cool again tonight with light
winds and clear skies. Many spots in the valleys could see
temperatures close to the freezing mark by Monday morning so a frost
advisory is in effect for tonight. Sunny and a bit warmer to start
the long work week Monday.
The cold low pressure system that has been hovering over the west
will begin to drift east today allowing heights/thickness to rise
across the region. Still...with light winds...very dry air...and
clear skies...it will be quite cool tonight. High pressure will build
in the wake of the low...continuing height/thickness rises into
midweek with warmer days.
A weak trough will approach the West Coast on Thursday...turning surface
winds back onshore. Some marine clouds may return and the humidity
will be more comfortable...but no precipitation is expected. As the trough
swings east on Fri/Sat...warmer and dry weather will return for the
weekend with weak offshore flow. While the low pressure trough is
expected to bring some rain to northern portions of the state later
this week...no additional rainfall is foreseen across socal through at
least the first week of December.
291600z...unrestricted visible through Monday morning. Few-scattered clouds
at or above 10000 feet mean sea level becoming sky clear after 2100 UTC...then becoming few-scattered
at or above 25000 feet mean sea level after 30/1200 UTC. Forecast confidence is high.
800 am...no hazardous marine conditions are expected through
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
California...frost advisory from midnight tonight to 8 am PST Monday for San
Bernardino and Riverside County valleys-the inland Empire-
San Diego County valleys.