Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
230 am PDT Wednesday Sep 2 2015
A low pressure trough along the West Coast will continue the fair
and cool weather this week...with night and morning coastal low
clouds extending well into the valleys. Locally gusty west winds
will develop each afternoon and evening along Desert Mountain slopes
and through mountain passes. Slightly warmer weather will occur this
weekend...with a more shallow marine layer.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Coastal clouds are filling all the coastal and valley areas quite
efficiently this morning and will push all the way to the mountain
slopes by sunrise. A weak coastal eddy and a trough of low pressure
along the West Coast have allowed our marine layer to deepen to
about 3000 feet. The eddy will remain rather intermittent but the
marine layer will continue quite deep through Saturday because the
low pressure trough will deepen over the west. Coastal clouds will
be rather extensive and persistent in the coming days...but still
lots of sunshine late mornings through sunset. A smaller shortwave
that has brought US the higher clouds will slowly move northeast and
push aside the high clouds eventually today. Temperatures will be
unseasonably cool through the first part of the Holiday weekend.
Highs will be well below average for this time of year. Nights will
continue on the mild to warm side particularly near the coast
because of the cloud cover and a warm sea surface in the middle 70s.
Gusty westerly winds will develop each late afternoon in the usual
corridors of mountain passes into adjacent deserts. These will be
fairly localized and top gusts in top spots will be around 40 miles per hour.
The low pressure trough pushes into the interior west over the
weekend and high pressure builds just a little Sunday and Monday.
That will bring a mini warming trend and suppress the marine layer
for less extensive coastal clouds for the holiday; Labor Day looks
quite nice with seasonal temperatures. As usual...model consensus
GOES awry for days 6 and 7. Right now they hang on to a neutral
pattern...neither a trough nor a ridge...that says a fair and
seasonal forecast is the best bet for now.
020900z...coast/valleys... low clouds have spread inland to the
coastal slopes of San Diego County and cover portions of the inland
Empire...impacting kont. Bases are around 2000 feet mean sea level and tops are
near 3000 feet mean sea level. Expect visible 3sm or less where clouds and terrain
intersect...with higher terrain obscured. Expect clearing to the
coast between 16z and 18z...however a few low clouds may linger at
the beaches into the afternoon. Low clouds could begin spreading
inland again after 02z Thursday.
Mtns/deserts...scattered to broken clouds at or above 20000 feet with unrestricted visible
200 am...no hazardous marine weather is expected through Sunday.
200 am...southwest swells from tropical cyclones will continue at
local beaches through today...producing elevated surf and strong rip
currents. Surf will be highest today with maximum sets to 5 feet along
southwest facing beaches north of Oceanside. The south swells will
subside Thursday through early Saturday..before a long period
southern hemisphere swell arrives at local beaches early next week.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.