Wildfire in California, June 2 to 8, 2018

Area Forecast Discussion
National Weather Service San Diego CA
133 PM PDT Sat Jun 2 2018

.SYNOPSIS...
Weak high pressure aloft will bring warmer weather through Sunday,
followed by gradual cooling into midweek as a low pressure trough
redevelops off the coast. A shallow marine layer will keep some
clouds and fog along the coastal strip nights and mornings,
otherwise skies will be fair. Seasonable weather is on tap much of
next week, with warm, dry days inland, while marine air keeps
coastal areas cooler with higher humidity.

&&

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

Except over the outer coastal waters, satellite imagery indicated
clear skies across the forecast area. Surface pressure gradients
were offshore 1 MB from SW NV to KSAN, but onshore 6-7 MBS to the
lower deserts. At 1 PM PDT...Peak wind gust reports were under 25
MPH, even in wind prone areas.

Once the weak cut-off low over the area moves east tonight, heights/
thickness will rebound under an expansive ridge over the SW U.S.
This, coupled with the strong June sun, will result in very warm
afternoons over the interior. Hottest weather will occur well
inland, away from the marine influence on Sunday, with slight
cooling in these areas on Monday. An Excessive Heat Warning is in
effect for the lower deserts both Sun/Mon where max temps are
forecast to reach or exceed 110 F.

The ridge axis becomes better defined and drifts east on Monday as
troughing develops over the far EastPac. Concurrently, the
subtropical high strengthens over the Southern Plains. This sets up
a moderate SW flow aloft over CA much of next week, resulting in a
typical June pattern with warm days inland, while the coastal strip
is heavily influenced by the marine layer. Expect clouds and some
fog each night and morning along the coast and into the western
valleys, while far inland areas remain fair. Temperatures will be
within a few degrees of average most days.

The 12Z operational ECMWF/GFS run solutions in the extended period
are fairly close, with a strong ridge over the Plains, and a weak
trough along the West coast. The ECMWF does show more retrogression
of the subtropical high next weekend, which results in warmer
conditions over the SW. So we are trending warmer then, after some
cooling mid next week.

&&

.AVIATION...
022000Z...Coast/Valleys...VFR conditions will continue through this
evening, then stratus will develop along the coast and inland to
around 10 miles by Sun morning. Bases will be around 800 ft MSL,
with tops near 1200 ft MSL. Coastal mesas will have reduced VIS of 2-
4 SM BR through the period, with isolated areas of lower VIS.
Stratus will quickly clear towards the coast between 15-17Z Sun.

Mountains/Deserts...Mostly SKC with P6SM VIS through Sun morning.

&&

.MARINE...
Patchy fog, with visibility around 1 SM, will develop over the
waters tonight and Sunday night. Otherwise, no hazardous marine
weather is expected through Wednesday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning from 11 AM Sunday to 8 PM PDT Monday for
     Coachella Valley-San Diego County Deserts-San Gorgonio Pass
     Near Banning.

PZ...NONE.
&&

PUBLIC...10
AVIATION/MARINE...JJT