Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 231041
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
341 AM PDT SAT JUL 23 2016
High pressure aloft will begin to weaken with cooling developing
near the coast today and spreading inland Sunday and Monday.
Patchy low clouds and fog near the coast early this morning will
increase in coverage through Monday. Slow warming will return for
Tuesday through Thursday. Toward the end of next week...an influx
of monsoonal moisture is possible sufficient for a slight chance
of afternoon thunderstorms near the mountains.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
.SHORT TERM (Today through Monday)...
A weak coastal eddy has developed with satellite imagery showing
patchy stratus near the coast. This will bring slight cooling
from the coast inland to the western valleys today. For Sunday
and Monday...high pressure aloft will continue to slowly weaken
and the coastal eddy will bring deepening of the marine layer with
coastal stratus reaching the far western valleys early Sunday
morning...and a little farther into the western valley for early
Monday morning. For Sunday...around 5 degrees of cooling is
expected...except around 10 degrees in valleys. This cooling may
sufficient to trim the heat advisory back to just the deserts and
lower mountain elevations for Sunday. A couple of degrees of
additional cooling is expected for Monday.
.LONG TERM (Tuesday through Friday)...
High pressure aloft will expand westward across Southern
California bringing a slow warming trend for Tuesday through
Thursday and a slowly shallower marine layer with patchier night
and morning coastal low clouds and fog. Toward the end of next
week...there may be enough of an influx of monsoonal moisture
sufficient for a slight chance of afternoon thunderstorms near the
231030Z...Coast/Valleys...Patchy low clouds and fog are persisting
over the nearshore waters and the immediate coast. Bases are 400-700
ft MSL with patchy vis restrictions 1-3 SM near the coast and along
elevated coastal terrain. These clouds and patchy fog will clear out
between 15-17z this morning. More significant coastal stratus is
likely to form after 06z this evening and sweep inland up to 15-20
Mountains/Deserts...Mostly clear with unrestricted vis through
No hazardous marine weather is expected through Tuesday.
South swells from 170-190 degrees will bring elevated surf and
moderate to strong rip currents through Saturday. The higher surf
will be 3-5 feet on S/SW facing beaches. Swells and surf lower on
Skywarn activation will not be needed today.
CA...Heat Advisory until 8 PM PDT Sunday for Apple and Lucerne
Valleys-Coachella Valley-Riverside County Mountains-San
Bernardino County Mountains-San Bernardino and Riverside
County Valleys-The Inland Empire-San Diego County Deserts-
San Diego County Mountains-San Diego County Valleys-San
Gorgonio Pass Near Banning.
Heat Advisory until 8 PM PDT this evening for Orange County
Inland Areas-Santa Ana Mountains and Foothills.