Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
315 am PDT Thursday Jul 24 2014
strong high pressure building over the southwest will bring
another hot day today...followed by slow cooling and increasing
humidity through the weekend. A shallow marine layer will moderate
temperatures near the immediate coast. Monsoon moisture may
produce a few afternoon showers or thunderstorms over the
mountains this weekend. Continued warm early next week as strong
high pressure remains over the southwest.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Marine layer low cloud deck is slowly pushing west around San
Clemente Island and a few patches of low clouds are developing
along the San Diego coast this morning. Some scattered high clouds
from earlier convection over Arizona and Mexico are drifting into
extreme Southern California as well. Expect any low clouds along
the coast to clear quickly this morning and variable high clouds
to continue through the day.
Expect another hot day away from the coast as an upper level high
builds over the Desert Southwest. Temperatures in the low deserts will
once again climb into the 114 to 118 degree range. Temperatures in the
high deserts and inland Empire will be in the low 100s...middle 80s
to middle 90s in the mountains...low 90s to around 100 in the western
valleys...and upper 70s to middle 80s near the beaches. The first of
several plumes of middle and upper level monsoon moisture will begin
to move in late tonight into Friday morning as flow aloft turns
more southerly. There is weak elevated instability associated with
this moisture...however low levels remain dry. Marginal drying
occurs by the afternoon. At this point just expect increasing
cloud cover and some virga for Friday...though a drops may reach
the surface over the mountains. Minor cooling will occur Friday
with this increase in clouds...though increasing humidity will
offer little relief from the heat.
Moisture continues to increase for Saturday and Sunday for
continued middle and high cloudiness and a slight chance of
showers and thunderstorms over the mountains. The best chances
will be on Sunday when moisture peaks and a weak wave rotates
north around the eastern edge of the upper high and over Southern
California. Main threats with these storms will be gusty outflow
winds and lightning. Otherwise expect warm weather to prevail with
patchy low clouds and fog along the coast during the nights and
Moisture decreases early next week behind the wave and the upper
high expands slightly further westward over California. Otherwise very
warm weather will continue with some middle and high clouds at times.
Moisture begins to increase slightly late in the work week...but
overall is marginal. Have left the forecast dry for now.
240930z...coast/valleys...clear skies and
unrestricted visibilities should prevail. Ksan and kcrq 24/0900z-
1400z...sct/bkn clouds with bases 600-1000 feet above mean sea level
with tops to 1300 feet above mean sea level will bank along coast
and occasionally drift inland over the airports. After 24/1400z few
high clouds at or above 15000 feet. After 25/0800z scattered/broken clouds
may form between 700-1200 feet above mean sea level and push 5-10
miles inland. Forecast confidence is moderate.
Mountains/deserts...few clouds at or above 15000 feet above mean sea level and
unrestricted visibility through Friday. Forecaster confidence high.
at 2 am PDT...northwest winds in the outer waters continue to drop and the
Small Craft Advisory will be allowed to expire at 5 am. Otherwise
fair weather is expected in the local coastal waters. Forecaster
confidence is high.
spotter activation will not be needed today.
California...heat advisory from 11 am this morning to 9 PM PDT Friday for the
Coachella Valley...Riverside County mountains...San
Bernardino County mountains...San Bernardino and Riverside
County valleys-the inland Empire...San Diego County
deserts...San Diego County mountains.
Pz...Small Craft Advisory for winds until 5 am PDT early this morning
for the waters from San Mateo Point to the Mexican border
extending 30 to 60 nm out including San Clemente Island.