Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 010441
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
941 PM PDT TUE MAY 31 2016
High temperatures will rise throughout the week as high pressure
builds aloft. Highs 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
The 00z RAOB from San Diego shows a strong 10 C marine inversion
and the height is slightly lower than this morning. Coastal stratus
is already accelerating inland and should fill most of the valleys
by Wednesday morning.
During the heat of the day, we did see a few
TCU buildups over the Riverside and San Diego County mountains with
a trace of rain reported by a weather spotter. The atmospheric
profile will be very similar tomorrow, and slightly warmer,
therefore cannot rule out a few showers popping up again during the
heat of the day, mainly over the San Diego and Riverside County
The heat wave is looking to begin Thursday with temperatures
approaching 100 degrees in the Inland Empire and High Desert. Friday
through Saturday will be the hottest days with temperatures reaching
up to 20 degrees above normal for inland locations. Our current
forecast keeps a strong coastal influence into the western valleys
on Friday and Saturday. This will be a tough forecast for those
areas, as more clearing earlier in the day than currently expected
would cause temperatures to skyrocket to much warmer readings for
the western valleys, and even portions of the coastal zones as well.
This forecast will continue to be closely analyzed in the next
couple of forecast cycles...stay tuned!
...Previous Forecast Discussion (issued at 151 PM PDT)...
At 1 PM PDT, water vapor satellite imagery displayed an upper-
level low over northern Mexico, and an upper-level ridge over
northern and central CA. Visible satellite showed low clouds
along the coast 5 to 10 miles inland. A few areas along the coast
may see some sunshine by late this afternoon. 12 UTC model runs
are in overall good agreement with the overall pattern in the
next 7 days.
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 this week, 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 Thermal on
Friday. The forecast is 113 F, and the record high is 113 F set in
1996. 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.
010315Z...Coast/Valleys...OVC010-015 TOPS 019 spreading 25 miles
inland through 14Z. Vis restrictions 3-5sm BR HZ at KONT between 12-
18z. Clouds clearing from the valleys through 18z Wednesday, but
skies remaining BKN-OVC010-015 at KSAN, KCRQ and KSNA through the
Mountains/Deserts...Mostly clear skies with unrestricted visibility
tonight. Scattered cumulus forming over the mountains Wednesday
afternoon with a brief shower possible.
815 PM...No hazardous marine weather is expected through Saturday.
815 PM...A 14-second long period south swell will bring above
average surf and strong rip currents through Thursday. The highest
surf will be on south facing beaches of Orange County and northern
San Diego County. The south swell will subside Friday and Saturday.
For details, check the Beach Hazards Statement (LAXCFWSGX) and 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 through Thursday evening for
Orange County Coastal Areas-San Diego County Coastal Areas.