Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 041112
Area Forecast Discussion
National Weather Service San Diego CA
312 AM PST Sun Dec 4 2016
Gusty northeast winds will continue to decrease today. Warmer
today with weak offshore flow and a short wave ridge aloft.
Cooler with increasing clouds, higher humidity, and onshore Monday
and Tuesday. Offshore flow and warming will follow for the latter
half of next week, with minor cooling towards the weekend.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Winds continue to lower this morning as surface pressure gradients
rapidly weaken. Wind gusts are generally under 30 MPH. The dry
airmass in place along with lighter winds and clear skies have
allowed temperatures to plummet in some of the valley locations.
Meanwhile the mountains and high desert are significantly warmer
than this time yesterday with the lack of cold air advection from
the north. Despite the chilly start, warmer weather is expected
today with the continuation of offshore flow and a weak upper
level ridge moving overhead. Highs across the region will be a few
degrees above normal...in the upper 60s to mid 70s in the coastal
areas, valleys, and low deserts, and in the mid 50s to mid 60s in
the mountains and high deserts.
Broad cyclonic flow develops over the West on Monday as an upper
low drops south off the British Columbia coast. This will bring
some cooling, increasing high clouds, and a return of onshore
flow. High res model guidance suggests a return of coastal low
clouds and fog by early Monday morning as a coastal eddy develops.
The upper low moves inland across the Pac NW on Tuesday bringing
further cooling, gusty onshore winds in the mountains and deserts,
and a deep marine layer. While any appreciable moisture remains
well to the north, the deep marine layer may be enough to squeeze
out some drizzle or light showers west of the mountains late
Monday night into Tuesday morning.
The low moves southeast towards the Four Corners region on
Wednesday. Surface high pressure builds over the Great Basin
behind the departing trough, bringing another round of moderate
offshore flow. This will also bring more cooling to the mountains
and deserts, but minor warming in the coasts and valleys.
Widespread warming on Thursday and Friday with offshore flow
prevailing and a weak upper ridge moving. Another weak trough
moves through late Friday and Saturday for cooler weather and
041000Z...Northeast winds will continue to decrease this morning,
with a weak sea breeze at the coast this afternoon. Otherwise, clear
skies and unrestricted vis will prevail through Monday morning.
No hazardous marine weather is expected through Thursday.
Winds continue to weaken this morning with most gusts under 30
MPH. Humidity recovery is poor near the foothills and inland
valleys. Warmer and dry today with widespread humidity in the
teens, except along the coast. However, winds will be much lighter
today. Conditions will improve further Monday and Tuesday as
onshore flow returns. Another round of gusty Northeast to East
winds and very dry conditions will develop late Wednesday morning
and continue through Thursday, weakening friday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.