Scientific Forecaster Discussion
fxus66 ksgx 232109
Area forecast discussion
National Weather Service San Diego California
209 PM PDT Fri Jun 23 2017
strong high pressure will continue to bring hot weather to the
Southern California interior while the marine layer will dominate
near the coast. There is a slight warming trend and less
extensive coastal cloudiness for the weekend. Temperatures will
gradually lower next week as the center of the ridge becomes
displaced to the south with more zonal flow across Southern
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
* excessive heat continues high deserts through Sunday and lower
deserts through Monday
* increasing heat for the inland Empire, Mountains below 5000 ft,
and the inland valleys of San Diego County, peaking on Sunday
An expansive ridge over Arizona continues to keep the heat wave
going across the deserts. The ridge will actually strengthen this
weekend as it shifts southwestward with heights increasing across
Southern California by Sunday, before gradually lowering next week
as the ridge pulls south into Mexico and the adjacent Pacific next
week with zonal flow returing. The result will be increasing and
expanding heat for inland areas through the weekend, before
temperatures lower next week.
Temp projections for the weekend have held steady or lowered
slightly. Even so, all heat headlines remain in tact (see
watch/warnings/advisories section below).
An area of high level cloudiness over northern baja and the
adjacent Pacific is moving northwest. This is associated with high
level moisture and some instability aloft rotating around the
southwestern periphery of the massive high over Arizona. The bulk
of the moisture and instability is projected to miss our service
area and move more towards Ventura County and points west where
dry lightning will be possible. There is a brief period of high
level very skinny cape, but this is not forecast to be enough to
allow for any thunderstorms to develop. Locally we just expect an
increase in high level cloudiness for a time tonight into early
Saturday with dry conditions continuing.
The marine layer will continue to influence the coast through the
period with cloudiness hanging tough at the beaches through the
weekend along with highs only in the upper 60s to lower 70s.
Patchy fog is possible each night and morning.
The area finally will see gradual cooling next week but temps
will cool only down to seasonal levels. In other words, the
deserts will still be hot, just not of the excessive heat seen the
past several days so it will feel much better.
The trend in the global models is to show more ridging late next
week and as we head into July, so prospects for any pronounced
trough in the near future are dwindling. Inland heat is favored
more than any cooling as we head into July.
232002z...coast/valleys...through 24/0000 UTC, mostly p6sm vis and
few-scattered clouds at or above 15000 ft msl, except within 3 sm of the coast
where broken-overcast stratus clouds around 1000-2000 ft msl and 5 sm vis
may continue. Chance that ksan and kcrq will not clear at all today.
24/0000-1600 UTC, stratus re-developing 15-25 sm inland, with bases
around 600-900 ft msl, tops around 1300-1800 ft msl, areas of vis 1-
5 sm and local vis down to 1/4 sm over inland mesas/higher coastal
terrain. Low confidence that kont will be impacted with stratus/fog.
Mountains/deserts...p6sm vis through Saturday morning. Increasing
clouds at or above 15000 ft msl through tonight. Scattered cumulus may develop
over the mountains during the afternoon, dissipating by sunset.
northwest wind gusts over the outer waters may reach 25 kt during
the afternoons and evenings from Sunday through Tuesday, potentially
resulting in conditions hazardous to small craft. Otherwise, no
hazardous marine weather conditions expected through Wednesday.
a south swell of 3 ft/13-14 seconds/165-170 degrees combined with
large tidal swings will result in strong and dangerous rip and
longshore currents through this evening. This swell will also
produce surf of 3 to 6 ft at Orange County beaches and San Diego
County beaches north of Carlsbad. Also, the high tides will likely
reach 7+ ft during the evenings through Saturday. Tides this high
may result in minor tidal overflow at low lying beaches. The beach
hazards statement continues through late Saturday evening. High tide
will fall below 7 feet Sunday, lowering the tidal overflow threat.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
California...excessive heat warning until 9 PM PDT Monday for Coachella
Valley-San Diego County deserts-San Gorgonio Pass near
Heat advisory from 10 am to 9 PM PDT Sunday for Riverside County
mountains-San Bernardino County mountains-San Bernardino
and Riverside County valleys-the inland Empire-San Diego
County mountains-San Diego County valleys-Santa Ana
Mountains and foothills.
Excessive heat warning until 9 PM PDT Sunday for apple and