Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 311640
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
940 AM PDT TUE MAY 31 2016
High temperatures will rise throughout the week as high pressure
builds aloft. High for inland areas could rise 10 to 20 deg F
above normal Friday and Saturday. A shallow marine layer will
maintain seasonal weather along the coast throughout the week. Low
pressure moving over the area early next week will create seasonal
weather across the region.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
At 9 AM PDT, water vapor satellite imagery displayed an upper-
level low over southern AZ, and an upper-level ridge over northern
and central CA. Visible satellite showed low clouds over the coast
and portions of the valleys. The 31/1200 UTC KNKX sounding
displayed a 10 deg C marine layer inversion. The strong inversion
will make it difficult for low clouds to clear today, with the
beaches likely remaining cloudy throughout the day.
The aforementioned ridge will build over the region through the
end of the week, with H500 heights peaking around 594 DM
Saturday. H850 temperatures around 27 deg C will yield inland high
temperatures in the 100s F in the Inland Empire and High Desert
Thu-Sat, and highs between 110-115 deg F in the Coachella Valley
and SD County Deserts. Friday and Saturday look to be the warmest
days, with inland highs rising 10 to 20 deg F above seasonal
normals. A Heat Watch remains in effect for the areas previously
mentioned for Friday and Saturday. The only location at this time
that may break or tie a record high this week is Borrego on
Friday. The forecast is 113 F, and the record high is 113 F set in
2006. A shallow marine layer will keep high temperatures at
coastal locations near normal for this time of year.
Upper-level heights will quickly lower Sunday as an upper-level
low pushes the ridge to the east and moves over SW CA. This will
strengthen onshore flow, deepen the marine layer, and help high
temperatures return to seasonal normals around the region. No
precipitation is expected over the next week at this time.
311530Z...Coast/Valleys...Low clouds and fog will continue stagnant
through around 31/1800z west of the mountains before slowly eroding
towards the coast. Vis is reduced where these clouds are nearing
terrain, such as KRNM and KONT where vis has lowered to 2.5 miles.
Bases of these clouds 1100-1400 ft msl and tops 2400-2900 ft msl.
Besides a few passing high clouds this afternoon, sct/bkn conds are
expected near the coast and skc inland. Between 01/0300-0600Z this
evening, low clouds with slightly lower bases and tops will push
inland once again.
Mountains/Deserts...Mostly clear skies with unrestricted visibility
today and tonight.
800 AM...No hazardous marine weather is expected through
800 AM...A south swell will begin to build today, peak Wednesday and
Thursday, and diminish Friday. The long period of this swell will
help to produce bigger than average surf Wednesday and Thursday
particularly for south facing beaches. Strong rip and longshore
currents can be expected. For details, check the Beach Hazards
Statement (LAXCFWSGX) along with the surf forecast (LAXSRFSGX).
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
CA...Excessive Heat Watch from Friday afternoon through Saturday
evening for Apple and Lucerne Valleys-Coachella Valley-San
Bernardino and Riverside County Valleys-The Inland Empire-
San Diego County Deserts-San Gorgonio Pass Near Banning.
Beach Hazards Statement from Wednesday morning through Thursday
evening for Orange County Coastal Areas-San Diego County