Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
840 PM PDT Sat Aug 29 2015
high pressure aloft will be replaced by a weak low pressure trough
that will settle over the West Coast the next few days. This will
result in a cooling trend as onshore flow increases and the marine
layer slowly deepens. Marine clouds and fog will develop overnight
and move progressively farther inland through Monday. Temperatures will
run a bit below average in the valleys...mountains and deserts next
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Even though Saturday was a couple degrees cooler west of the
mountains...it was still quite hot. No record highs were set...but
there were a few close calls. Lindbergh Field had a high of 87 and
just missed the record of 88 set in 2009. The high of 84 at Newport
Beach was one degree shy of their record. The deserts were actually
hotter today than yesterday...but Palm Springs (115) and thermal
(114) were both three degrees short of their records.
Sunday will be a little cooler...and Monday will be cooler still as
the upper ridge over The Four Corners region gets forced farther
east by an upper trough advancing from the Pacific. 500 heights of 591dm
this evening lower to 589dm Sunday afternoon...and then to 587dm
Monday. This West Coast trough will be the dominate feature all of
next week bringing a break from the Summer-time heat with stronger
onshore flow and a moderately deep marine layer.
Aviation... 300330z...coast/valleys...clear skies with unrestricted
visible will prevail through 09z. Between 09z and 16z...patchy broken-overcast
stratus with bases 700-1000 feet mean sea level with tops to 1200 feet mean sea level will
occur within 5-10 miles of the coast along with areas of visible 3-5
Michigan...though confidence is moderately low for timing/occurrence.
Local visible below 1 Michigan could occur over higher coastal terrain/mesas.
After 16z...clear skies with unrestricted visible will prevail in most
areas until stratus arrives at the coast sometime Sunday evening.
Mountains/deserts...areas of surface winds 15-25 knots with gusts 30-40
knots will occur on through San Gorgonio Pass and along Desert Mountain
slopes/foothills through 09z...with associated up/downdrafts and low level wind shear.
Winds will increase to similar levels after 22z Sunday.
Otherwise...mostly clear with unrestricted visible will prevail through
Marine... 830 PM...Small Craft Advisory is in effect through 2 am
Monday for northwest winds gusting 20-25 knots over portions of the
outer coastal waters this evening and again Sunday afternoon and
evening. Winds and seas will improve by early Monday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
Pz...Small Craft Advisory until to 2 am PDT Monday for
waters from San Mateo Point to the Mexican border
extending 30 to 60 nm out including San Clemente Island.