Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
117 PM PDT Monday Jul 6 2015
Synopsis... low pressure moving slowly inland over central
California through Thursday will continue to deepen the marine
layer...bringing cooler days and gusty westerly winds well inland
into the deserts. The deep marine layer may leak some patchy drizzle
at times...especially late nights and mornings as the cloud layer
thickens. Clearing may be limited some days west of the mountains...
while inland...fair skies prevail. The subtropical high will begin
to build back to the west by the weekend...which will decrease the
marine layer and bring warmer days into next week.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Once again it was a slow burn off of the thick marine clouds today
west of the mts. Some areas even reported a wetting drizzle this
morning. At noon...many locations still had temperatures in the
upper 60s and 70s west of the mountains...while the deserts had
risen into the 90s. Meanwhile full sunshine over the mts had boiled
up a few thunderstorms...mainly in San Bernardino County. Some of
these were strong with possible gusty winds and heavy downpours.
The showers/thunderstorms will decrease around sunset and should not make a
return appearance tomorrow as much drier air overspreads the region
on strong SW winds aloft.
Low pressure off the California coast will slowly move inland over central
portions of the state by Thursday. Falling/heights and thickness will
maintain moderate to strong onshore flow for this time of year and
further cooling through Thursday...especially inland where maximum temperatures will
be around ten degrees f below average. The drying aloft will snuff
out any chance for showers/thunderstorms after today...but the marine layer
and associated clouds will remain unseasonably thick...resulting in
more of a June gloom situation with patchy drizzle possible at times
and limited clearing west of the mountains.
Gradually warmer this coming weekend into early next week as the
marine layer decreases under building high pressure. The subtropical
high center is forecast to retrograde form the Gulf Coast region
Friday...to the southern rockies Monday. This will bully out the low
pressure trough and begin to tease US with monsoonal moisture by Tuesday
as our middle-level winds switch from SW to south.
Aviation... 062000z...coast/valleys...bkn-ovc stratus 1800-2500 feet
mean sea level lingering within 10 sm of the San Diego County coast through
07/0200 UTC...including kcrq and ksan. For Orange County
coast...stratus should continue to gradually clear to the coastal
waters through 2200 UTC. Mostly sky clear and unrestricted visible elsewhere.
07/0200-1500 UTC...overcast stratus filling in over the coast and valleys
again...with bases 1800-2200 feet mean sea level and tops 3000-3500 feet mean sea level.
Forecast confidence moderate-to-high. Slow clearing again after
Mtns/deserts...sct-bkn clouds with isolated showers and
thunderstorms possible through 07/0200 UTC over the mountains and
deserts...with bases 8000-10000 feet mean sea level and cumulonimbus tops to 40000 feet mean sea level.
Otherwise...unrestricted visible through Tuesday morning.
Marine... 113 PM...northwest winds could gust to 25 knots in the outer
waters Thursday evening. Otherwise...no hazardous marine weather is
expected through Saturday.
Skywarn... Skywarn activation will not be needed on Tuesday.
However...weather spotters are encouraged to report significant