Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 300430
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
930 PM PDT WED JUN 29 2016
High pressure aloft will weaken and result in a cooling trend the
rest of this week. There is a very small chance of a mountain
thunderstorm Thursday, with dry conditions prevailing by the
weekend. Areas of night and morning coastal low clouds and fog will
expand slightly through the end of the week, along with gusty west
to southwest winds over the mountains and deserts. The high pressure
ridge will rebuild early next week and bring slight warming.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
A few thunderstorms formed over northern Baja California this
afternoon, but none occurred over southwestern California. The
afternoon cumulus had also dissipated. Near the coast, stratus was
slowly developing and will start to spread inland shortly.
The high pressure ridge centered over Utah will shift southeast
Thursday as weak trouging occurs on the west coast. This will result
in slight cooling, some deepening of the marine layer and increased
onshore flow which will result in moderate west/southwest winds in
the mountains and deserts. Some lingering mid-level moisture and
surface-based instability will occur over the mountains Thursday,
though this looks marginal for thunderstorm activity, especially
since that did not quite make it to our forecast area today. For
now, will leave the slight chance of thunderstorms in the forecast
for Thursday, though Friday looks highly unlikely since both
moisture and instability decrease. Secondary short waves should keep
the weak troughing along the west coast through about Sunday before
the seasonal east-west oriented upper ridge rebuilds over the region
from southern California east to New Mexico and west Texas. This
will bring warming again early next week, though current progs show
monsoonal moisture remaining to the east/southeast through at least
300300Z...Coast/Valleys...Expect BKN-OVC low clouds with bases from
700-1000 feet MSL and tops near 1200 feet MSL to develop first along
the coast through 06z and on inland to the mountains by 12Z. Clouds
will again clear Thursday, between 17-19Z, except a few clouds may
linger along the immediate coastline. Low clouds Thursday evening
are likely to return earlier, but with bases above 1000 feet above
MSL. Forecast confidence medium to high.
Mountains and Deserts...SKC and unrestricted visibility will prevail
through Thursday night. Forecast confidence is high.
800 pm...No hazardous marine weather is expected through Sunday.
800 pm...A long period southerly swell from 200 degrees will impact
local beaches. The swell is expected to peak Thursday at 3-4 ft with
a period of 17-19 sec. This will produce 3-6 ft surf with local sets
to 7 ft along southwest facing beaches this afternoon through Friday
evening. Strong rip and longshore currents are also expected. Please
see the Beach Hazard Statement for additional details.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
CA...Beach Hazards Statement through Friday evening for Orange County
Coastal Areas-San Diego County Coastal Areas.