Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
930 am PDT Tuesday Sep 2 2014
fair weather will prevail through early next week. A low pressure
system to the north will bring some cooling through Wednesday with
little temperature change Thursday. Low clouds will extend into most
valleys during the nights due to a deeper marine layer...and there
will be locally gusty winds in the mountains and deserts...mainly in
the late afternoons and evenings. High pressure from the southeast
will build a little Friday through the weekend to bring slight
warming and fewer low clouds...then some cooling will return early
next week as the high weakens.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Stratus...which extended through many valleys earlier...was clearing
rapidly this morning...with just a few patches stratus remaining in
around Riverside and Corona at 830 am. The coastal eddy is further
offshore and appears to be pulling the coastal stratus away from the
coast. Inversion strength was again around 8 degree c with acars
soundings at Lindbergh Field showing a base around 2000 feet mean sea level.
Skies should be sunny...with slight cooling again...with greatest
cooling in the far inland valleys due the deeper inversion.
A low pressure trough will gradually deepen and expand over Oregon
and northern California Wednesday through Thursday while the high
pressure ridge will extend from Sonora east through the Southern
Plains/Gulf states. Height falls will help maintain a relatively
deep marine layer...though the models show the inversion weakening.
Temperatures aloft will continue to lower and bring temperatures averaging
about 5 degree f below normal Wed/Thu...more in some of the valleys and
western foothills. Some locally windy conditions will occur as
onshore pressure gradients local WRF shows some local sustained
surface winds of 25 knots in the windiest desert/desert slope
locations for Wednesday and Thursday late afternoons/evenings...so gusts could
reach 45 miles per hour. This will only in places that normally get winds like
this such as through/east of San Gorgonio Pass...so we do not plan
on a Wind Advisory right now.
High pressure aloft over the southern US will build west a little
bit Friday and have an axis from northern Baja California California east to
Texas over the weekend. The trough will continue over northern
California...but height rises here will mean the high will dominate
and result in warming and a more shallow marine layer for less
extensive nocturnal stratus. The upper high shifts south a bit early
next week as long-wave troughing forms over the intermountain west
and northern plains...so some cooling could occur here then...mainly
inland. A possible tropical system to our southwest will likely not
bring much moisture aloft here as the westerlies will prevail early
next week...so dry weather will continue through early next week.
021530z...coast/valleys...stratus...with bases from 1600 feet mean sea level to
2000 feet mean sea level and tops near 2200 feet mean sea level...will continue to clear over
land areas over the next few hours. VFR conditions will prevail this
afternoon. Low clouds...with slightly higher tops and bases...will
return along the coast this evening and push around 30 statute miles
inland around 10-12 UTC Wednesday morning. Visibility at or below
1-3 statute miles due to fog/br will be possible where stratus nears
Mountains/deserts...VFR conditions prevailing through the next 24
hours...with isolated breezy westerly winds gusting to 35 knots through
mountain passes and Desert Mountain slopes late this afternoon and
830 am...no hazardous marine weather expected through Saturday.
spotter activation will not be needed today.