Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 192107
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
207 PM PDT Mon Jun 19 2017

.SYNOPSIS...
Building high pressure aloft will continue to increase afternoon
temperatures through mid week, creating very hot weather Tuesday
and Wednesday for inland areas. A shallow marine layer will
develop night/morning low clouds and fog along the coast through
the week, and keep high temperatures closer to seasonal normals.
Slightly lower high temperatures for the end of the workweek, then
a slight increase in temperatures again for the weekend.

&&

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

At 1 pm PDT, water vapor satellite imagery displayed an upper-
level ridge centered over the AZ/NM border, with south-
southeasterly flow aloft over Southern CA. Visible satellite
showed patchy low clouds over the waters hugging the coast.

The aforementioned ridge will continue to build over the next few
days. This will continue the warming trend, especially over the
deserts where record-breaking heat is expected. 32-24 deg C H850
temps will yield surface temperatures of...

113-122 deg F in the Coachella Valley and S. D. County Deserts
108-114 deg F in the High Desert
100-112 deg F in the Inland Empire
95-106 deg F in the mountains below 5000 ft
90-105 deg F in the inland valleys

for Tuesday and Wednesday (see climate section below for record
information). The Excessive Heat Warnings and Heat Advisories
remain in effect through mid week (See LAXNPWSGX for additional
details). The very hot weather weather will linger Wednesday, then
lowering heights aloft will drop temperatures a few degrees
Thursday and Friday. Unfortunately, models show the ridge
lingering near the region through the weekend, with a slight bump
in high temperatures Saturday through next Monday for the valleys
and mountains. Luckily for the coast, a shallow marine layer will
help to moderate temperatures, keeping highs near seasonal normals
through the week. Night/morning low clouds and fog is expected to
continue along the coast through the week, with lowest visibility
expected Tuesday and Wednesday morning due to the ridge aloft
peaking. Slight deepening will develop by the end of the week as
heights aloft lower.

The position of the high this weekend might be able to pull some
monsoonal moisture into the region. Right now, only one model is
showing precipitation over the mountain ridges, so will keep the
forecast dry for now. However, it will be something to keep an
eye on.

&&

.AVIATION...
191940Z...Coastal airports...SKC-SCT005 through 03Z at KSAN, KCRQ
and KSNA. Beaches and coastal waters BKN005-008. After 03Z...BKN-
OVC005-010 moving onshore with CIGS lowering to OVC002-005 between
10-15Z. Vis lowering to between 1/2 and 3 miles in fog. Clouds and
fog clearing from coastal airports between 15-16Z Tuesday.

Valleys, Mountains and Deserts: Clear skies and unrestricted
visibility through Wednesday. High density altitude at KPSP and
KTRM with max temperatures between 118-122.

&&

.MARINE...
Areas of late night through mid-morning fog with visibility 1 mile
or less through Thursday. Building south to southeast swell mixing
with the west swell Tuesday through Thursday.

&&

.BEACHES...
Beach Hazard Statement for strong rips currents in effect through
Thursday. A mix of southerly and westerly swells Tuesday-Thursday
with large tidal swings (high tides 7 ft with low tides -1.0 ft)
will result in strong and dangerous rip currents.

&&

.CLIMATE...

...Sites Expected to Break or Tie High Temp (deg F) Records...

                         TODAY
               Forecast  Record  Year
Palm Springs     121      119    2016

                        TUESDAY
               Forecast  Record  Year
Palm Springs     122      122    2016
Thermal          121      121    2016

                       WEDNESDAY
               Forecast  Record  Year
El Cajon          94       92    2001
Idyllwild         94       94    1970
Campo            106      105    2008
Palm Springs     122      118    1968
Indio            118      116    1981
Thermal          120      117    1968

                        THURSDAY
               Forecast  Record  Year
Palm Springs     119      119    1959

&&

.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 9 PM PDT Thursday for Apple and
     Lucerne Valleys-Coachella Valley-San Diego County Deserts-
     San Gorgonio Pass Near Banning.

     Heat Advisory until 9 PM PDT Wednesday for Orange County Inland
     Areas-Riverside County Mountains-San Bernardino County
     Mountains-San Bernardino and Riverside County Valleys-The
     Inland Empire-San Diego County Mountains-San Diego County
     Valleys-Santa Ana Mountains and Foothills.

PZ...NONE.
&&

$$

PUBLIC...JJT
AVIATION/MARINE/BEACHES...Moede



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