Area forecast discussion
National Weather Service San Diego California
900 am PDT Friday may 24 2013
Synopsis...
daytime temperatures will remain slightly below seasonal averages
through Memorial Day...with only minor day-to-day variations.
Onshore flow with gusty winds in the mountains and deserts will also
continue...along with areas of low clouds extending into the inland
valleys during the nights and mornings. For Tuesday through early
Wednesday...increasing clouds with even lower temperatures and a
chance for precipitation. Dry and warmer for Wednesday and Thursday
with stronger northwest winds in the mountains and deserts.
&&
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
counties...
This morning...low clouds are clearing out of San Diego County but
extensive clouds remain over Orange County and the inland Empire.
Surface pressure gradients remain onshore...but are trending weaker with
+1.5 mb san-tph. The morning nkx sounding shows the marine layer
about 3400 feet deep with southerly winds near the surface and west winds
above a weak inversion.
Through Memorial Day...the large-scale low/trough over the West
Coast will maintain the onshore flow for gusty west winds in the
mountains and deserts. Daytime temperatures will continue to be a little
below seasonal averages...and the marine layer will remain
relatively deep with night and morning low clouds extending into the
inland valleys. Small day-to-day variations in the marine layer
depth are expected as minor shortwaves move through the mean
cyclonic flow aloft.
For late Monday night through Tuesday night...a stronger shortwave
moving through the northwest flow aloft...is expected to deepen the
trough...forming a closed upper low over central California by Tuesday morning.
There is not yet a clear consensus among the deterministic models as
to the exact timing and track of the low as it progresses eastward
through Tuesday night...and the individual models continue to make
minor adjustments to their various solutions. However...confidence
is growing that this system could produce rain and showers late Monday
night through Tuesday night. Preliminary rainfall estimates are for one
tenth to one quarter inch near the coast and one half to one inch in
the mountains.
Dry and gradually warmer for Wednesday through Friday in northwest flow aloft as the
trough moves east and heights rise over socal. This will bring
stronger...gusty northwest winds in the mountains and deserts and a shallower
marine layer.
&&
Aviation...
241600z...coast/valleys...areas of few-scattered stratus will continue
west of the mountains with bases 2500-3500 feet mean sea level and tops to 4500
feet mean sea level through the remainder of this morning into the late
afternoon. Visible will remain p6sm. Stratus returning tonight between
25/0200-0400z. A weaker coastal eddie and slightly higher pressure
aloft will lead to a cloud deck a couple hundred feet lower than
this mornings. Bases around 2500 feet and tops near 3500 feet. Visible
is expected to remain above 5sm.
Mtns/deserts...westerly wind gusts around 35 knots will occur over the
Desert Mountain slopes and through/east of San Gorgonio Pass late this
afternoon/this evening. Otherwise...mostly clear with unrestricted
visible through Saturday afternoon.
&&
Marine...
astronomical high tides to 7.2 feet and below normal low
tides...with swings of 8.9 feet...will combine with slightly above
normal surf to bring a small chance of minor coastal flooding today
through Memorial Day. Strong rip currents will continue through
Memorial Day...partly due to the swings in The Tides.
&&
Sgx watches/warnings/advisories...
California...none.
Pz...none.
&&
$$
Public...pg
aviation/marine...jt
