Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 282020
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
120 PM PDT THU JUL 28 2016
Fair and hot weather will continue with scattered cumulus over
the mountains this afternoon. A few isolated showers are possible
in the San Bernardino mountains, but not very likely. An increase
in monsoonal moisture this weekend will increase the chance of
showers and thunderstorms in the mountains and deserts each
afternoon and evening. It will also be slightly cooler this
weekend into early next week.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Mostly clear this afternoon, except for some cumulus clouds over
the San Bernardino mtns. Although there is no shortage of
moisture, deep convection is being inhibited by a lack of
instability. Temperatures are generally near or a few degrees
higher than this time yesterday, except for the Orange County
coastal areas and the Inland Empire where temps are a few degrees
lower. This is most likely due to the increased marine layer
influence in the O.C. and the I.E.
Temperatures will likely be marginally lower on Fri as the high
over southern Nevada weakens in response to a low pressure trough
moving into the PAC NW. The adjustments in the position of the
upper high will enable the monsoonal flow to bring more moisture
into southern CA while conditions become less stable. This will
increase the chances for afternoon/evening convection over the
mtns and deserts.
The pattern changes little for the weekend into the first half of
next week. Expect temperatures to remain near or slightly above
seasonal averages, with a shallow marine layer moderating temps
near the coast. The mid level flow aloft will remain
east/southeast and will continue to bring monsoonal moisture for
chances of showers/tstms in the mtns and deserts during the
afternoons and evenings.
Current model solutions indicate that the best chances for
widespread deep convection will be on Mon.
281530Z...Patchy stratus will redevelop late this evening and
spreading locally 10-15 mi inland overnight. Little change in cig
heights expected, again between 800-1100 ft MSL. Local vis 2-4 SM
possible again where status nears higher coastal terrain. Otherwise,
a few clouds above 20000 ft through Friday.
Valleys/Mountains/Deserts...FEW-SCT clouds above 20000 feet and
unrestricted vis through Friday. Cumulus clouds will form over the
mountain crests this afternoon, dissipating by sunset.
No hazardous marine weather is expected through Monday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
CA...Heat Advisory until 8 PM PDT this evening for Apple and Lucerne
Valleys-Coachella Valley-San Diego County Deserts.