Area Forecast Discussion
Issued by NWS San Diego, CA

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870
FXUS66 KSGX 120513
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
915 PM PST Mon Dec 11 2017

.SYNOPSIS...
High pressure aloft and weak offshore flow at the surface will
continue warm dry weather through at least this weekend. Locally
gusty northeast to east winds will occur in the coastal foothills,
slopes and in the passes and canyons. Skies should be mostly clear
except for occasional high clouds.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

KNKX radar will be down through Friday due to refurbishment of the
transmitter.

Skies were mostly clear this evening. Local gusty east winds were
occurring with gusts around 40 MPH, mainly near and just west of
mountain crests. Slight increases in the MSLP gradients and 850-mb
winds and temp gradient will occur Tuesday as the upper low to our
south strengthens, which will result in a little more wind. A few
gusts around 50 MPH could occur. However, support will only be
enough for local versus widespread winds. Forecast looks on track,
and no precipitation is expected through early next week.

From previous discussion...

Water vapor satellite shows an upper level ridge over the Great
Basin and the aforementioned upper level low over Baja. Offshore
flow will continue through Thursday but remain weak, with strongest
winds of 10-20 mph with 30-35 mph gusts and locally up to 45 mph in
the coastal foothills/slopes and passes/canyons through Wednesday
and even lighter Thursday. The weak offshore flow and dry atmosphere
will continue to bring warmer than normal weather (highs mostly 5-15
degrees above normal) to the region today through much of the week,
and possibly into the weekend and early next week as well, with
models not indicating any significant trough moving down into
Southern California. Thus, rain or cooler weather is not expected
through early next week. There really isn`t even a hint of the
marine layer coming back to the coast except for possibly Friday
when there may be a brief return of onshore flow as the upper level
ridge gets pushed west and a trough moves down through the Inter-
mountain West. However, models show the offshore flow returning on
Saturday and continuing possibly into next Monday.

&&

.AVIATION...
120500Z...SCT clouds AOA FL200 and unrestricted vis through Tuesday
night.

&&

.MARINE...
No hazardous marine weather is expected through Friday.

&&

.FIRE WEATHER...
Although the offshore/Santa Ana winds will be much weaker today
through at least Thursday, day-time humidity for everywhere
except coastal areas will be very low (down to 5-10 percent each
day) with very poor overnight humidity recovery. Strongest winds
will be in the coastal foothills/slopes and passes/canyons where
winds of NE to E winds 10-20 mph with gusts to 30-35 mph and
locally 45 mph can be expected through Wednesday. Elsewhere, wind
gusts will mainly be 15 mph or less. Red Flag Warnings not
anticipated as winds will be too weak, with strongest winds pretty
localized. However, elevated fire weather conditions will
continue.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC/FIRE WEATHER...Maxwell/Harrison
AVIATION/MARINE...JMB



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