Scientific Forecaster Discussion
fxus66 ksgx 200432
Area forecast discussion
National Weather Service San Diego California
932 PM PDT Wed Jun 19 2019
an upper level trough will move south over the intermountain west
Thursday through Saturday. This will bring cooler weather, more
clouds, stronger west winds in the mountains and deserts, and
some drizzle or light showers in the coastal basin Thursday night
into Friday morning. Upper level high pressure will build in
briefly from the west early next week before another upper trough
digs into the U.S. West Coast. So after brief warming early next
week, temperatures will likely cool again for the middle to latter
part of next week under a continued dry weather regime.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Highs today across our service area ranged from 67 at del Mar
Beach and Imperial Beach to 106 at thermal, a typical large temp
gradient from the marine-influenced coastal locales to the lower
deserts. Clouds cleared most areas this afternoon, but a few
coastal locales of South Dakota County held on to some cloudiness.
The low clouds have formed along most of the coast this evening with
bases of around 1500 ft MS. The clouds will continue to spread
inland overnight, reaching into western portions of the inland
Empire and into the San Diego County valleys perhaps as far east
as Ramona. No significant updates were needed to the forecast this
..previous discussion (issued at 135 PM PDT Wed Jun 19 2019)...
Low clouds did a pretty good job of clearing today, even from the
coast. Good for June standards anyway. Temperatures were several
degrees higher at 1 PM today than on Tuesday at the same time.
High pressure overhead has brought US our warmest day of the week.
Some thin moisture has brought some cumulus clouds to the High
Desert and mountains. A low pressure trough will push through the
west Thursday through Saturday. This will deepen our marine
layer, assisted by a coastal eddy, and extend the clouds fully
inland up the mountain slopes. The lifting and deepening of clouds
should produce areas of drizzle Thursday night and Friday
morning. Any accumulations will be very light; it's June.
Clearing on Friday will be slow, if clearing happens at all:
a damp and murky start to Summer in the coastal basin (solstice
at 854 am PDT friday). Strong winds will develop Thursday and
Friday afternoons and evenings in parts of the mountains and
deserts. Some areas will get gusts over 40 mph, with isolated
gusts topping 50 mph. High pressure rebounds with a touch of
offshore flow over the weekend and the marine layer will obey by
going more shallow. That will mean less extensive coastal clouds
during the nights and mornings and a warming trend Sunday and
beyond. Next week model guidance features a building trough along
the Pacific northwest coast, but at the same time a building ridge
over Texas and New Mexico. Socal will be stuck in the middle of
this pressure Sandwich under dry southwest flow aloft. Previous
model runs had shown the ridge to win out for a warming trend, but
latest model runs depict the trough holding its ground. All that
will mean is we'll get seasonal weather for the first week of
Summer and temperatures at or slightly below average.
200400z...coast/valleys...bkn-ovc with bases 1500-2000 ft mean sea level
along the coast will continue spreading into the inland valleys
overnight. Local vis 3-5 sm in br/haze in the valleys between
10-16z. Clearing inland 16-18z and moderate confidence of clearing
18-20z along the coast. Coastal clearing will be short-lived as
the low clouds will make another comeback Thursday evening with
again bases of 1500-2000 ft mean sea level. Drizzle will even be possible
Mountains/deserts...clear skies with unrestricted vis through
Thursday. West winds with gusts of 25-30 kt will pick up over the
mountain crests, Desert Mountain slopes, and below passes 02-10z,
tapering off a bit during the morning/early afternoon Thursday
before becoming stronger with gusts along the desert slopes to
40-45 kt Thursday afternoon and evening. Areas of moderate
updrafts and downdrafts over and east of the mountains are
no hazardous marine conditions are expected through Monday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
California...Wind Advisory from 11 am to 10 PM PDT Thursday for apple and
Lucerne valleys-Coachella Valley-Riverside County mountains-
San Bernardino County mountains-San Diego County deserts-
San Diego County mountains-San Gorgonio Pass near Banning.