National Weather Service Forecast Discussion

Dicussion provided by the National Weather Service Forecast Office located in San Diego, California

000
FXUS66 KSGX 132036
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
136 PM PDT Mon Jul 13 2020

.SYNOPSIS...
High pressure over the Southwest will weaken and shift east this
week, easing the heat across the region. Onshore flow will increase,
further strengthening the westerly winds over the mountains and
deserts, building the marine layer inland. After one more very hot
day in the deserts, seasonally warm July weather will prevail for
the remainder of the week with some extent of coastal clouds
nights and mornings.

&&

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

The marine layer is back with its enabling buddy the coastal eddy.
The cooling trend is underway, especially west of the mountains
where temps at 1 pm are running 2-10 degrees lower than they were
yesterday at this time. The desert is "cooling" as well, "only"
up to about 111 so far, probably topping out around 115. The
heat warning continues until 8 pm. Skies outside the marine layer
will continue mostly clear, but there`s a batch of higher clouds
to the south off the Baja coast spreading clouds across San Diego
County. Might be just enough to accent a pretty sunset and
sunrise, but otherwise inconsequential. The strong upper ridge
over the Southwest will continue to relent into Tuesday, allowing
SoCal temperatures to actually dip below normal across most areas
Tuesday through Thursday. A weak and intermittent coastal eddy
will continue into at least Tuesday, helping our marine layer
rebuild and extend low clouds into parts of the inland valleys
during the early mornings through at leat Thursday. Most model
guidance shows the Southwest upper ridge to strengthen again
Friday through the weekend, but only slightly. No big heat wave
is expected, but temps will probably edge above average. Coastal
clouds will not make it into inland valleys. Overall, pretty
seasonal weather and coastal cloud coverage for mid July with
temps fluctuating around normal.

&&

.AVIATION...
132015Z...Coast/Valleys...Occasional brief SCT conditions may occur
at the coastal terminals this afternoon. Otherwise, mostly clear
with high clouds and VFR conditions through early evening. Areas of
smoke/haze continuing near downtown San Diego and points
northeastward through the afternoon/evening. Low clouds with bases
1000-1500 ft MSL will redevelop 02-04Z this evening in San Diego
County, 04-06Z in parts of Orange County. High confidence on areal
coverage but lower confidence on exact timing. The other story will
be if these clouds make it into parts of the Inland Empire. Little
higher confidence with brief cigs ~700 ft MSL making an appearance
at KONT 12-16Z Tuesday morning.

Mountains/Deserts...A few high clouds and unrestricted vis through
tonight. Southwest to west winds with sfc gusts 25-35 kt  on the
desert mountain slopes, below the passes, and into the deserts
through early this evening.

&&

.MARINE...
The outer waters will get breezy in the afternoon/evening on Tuesday
and Wednesday, with maximum gusts that may locally approach 20
knots. Otherwise, no hazardous marine conditions are expected
through Friday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 8 PM PDT this evening for Apple and
     Lucerne Valleys-Coachella Valley-San Diego County Deserts-
     San Gorgonio Pass Near Banning.

PZ...NONE.

&&

$$

PUBLIC...MM
AVIATION/MARINE...APR

NWS SGX Office Area Forecast Discussion