FXUS66 KSGX 181121
Area Forecast Discussion
National Weather Service San Diego CA
321 AM PST Fri Jan 18 2019
A few remaining showers this morning will fade as drier air
continues to move into the region. A warm ridge will build over
Southern California this weekend, followed by a weak trough
on Monday, then a more persistent and amplified ridge next week.
This will bring periods of offshore winds and much warmer and dry
weather next week. Indications are that a dry pattern along with
above average temperatures will likely persist through the end of
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
* Few showers coast to coastal mountain slopes early this morning
* Dry and much warmer pattern developing for California
* Weak Santa Ana Winds Saturday, stronger on Tuesday
Isolated showers continue early this morning from parts of the
coast to the coastal mountain slopes. Did extend the isolated
showers to after daybreak. However, continued drying of the
airmass will gradually end these showers with clouds scattering
out this afternoon.
Heights will be building drastically here through Saturday as an
upper level ridge builds in from the southwest to be centered over
NW Baja by Saturday afternoon. This will lead to abrupt warming
west of the mountains on a weak Santa Ana (as a surface high
builds over the Rockies) with high reaching well into the 70s away
from the immediate coast. Some inland valley locations will
likely even eclipse the 80F degree mark! The mountains and deserts
will warm as well, but to a lesser degree.
Heights fall as an inside slider (upper level trough) moves by on
Monday. This will lead to gradual cooling Sunday through Monday,
but still warmer than it has been. A marine layer cloud deck and
patchy fog (perhaps patches of drizzle) could make a brief return
late Sunday night-early Monday morning before offshore winds and
drying occur. Surface high pressure will build into Nevada
strongly. This will lead to a stronger Santa Ana Wind on Tuesday
with winds on the coastal mountain slopes and through/below passes
30-50 mph, perhaps locally higher. The Santa Ana will subside
An anomalous ridge will be building along the U.S. West
Coast during the middle to later part of next week. The result
will be a locked-in dry and warm pattern. GEFS shows this pattern
likley to persist through months end.
181100Z...Coast/Valleys...Isolated -SHRA will end by late morning.
Multiple low cloud bases, ranging from 300-4000 ft MSL will continue
this morning, with clouds scattering by the afternoon. VIS of 1-3 SM
this morning for portions of the valleys will become P6SM by late
morning. Low confidence in low clouds affecting aerodromes tonight.
Mountains...Low clouds obscuring ridge tops will clear out by late
morning. Breezy east to northeast winds will develop along coastal
slopes, through passes and into adjacent foothills tonight. LLWS is
possible through the period.
Deserts...Areas of BR, with VIS of 2-4 SM, will improve by late
A large west-northwest swell from 280 degrees will peak this
morning, then gradually subside this afternoon and overnight. The
outer coastal waters (30-60 NM from the coast) will have combined
seas 12-16 feet at the peak, with 8-11 feet in the inner coastal
waters (less than 30 NM from the coast). Periods will be 16-18
seconds. Due to large breaking waves, entrances to harbors and bays
will be difficult for small craft. A Small Craft Advisory is effect
until 4 AM Saturday.
A large west-northwest swell of 10-14 ft at 17 sec from 280 degrees
will peak this morning, then generally lowering through tonight.
Surf will be highest at the southern San Diego County beaches.
During the peak period, surf could locally reach 12-14 feet on west
facing beaches south of Encinitas, especially around Sunset Cliffs.
Elsewhere for the San Diego County beaches values of generally 7 to
10 feet are expected at the peak, with 6 to 9 feet for the Orange
County beaches. The high tide around 600 AM today will be around 6
feet, which could combine with the high surf to generate minor
coastal flooding in some spots. A High Surf Advisory is in effect
until 4 AM Saturday.
Skywarn activation is not needed.
CA...High Surf Advisory until 4 AM PST Saturday for Orange County
Coastal Areas-San Diego County Coastal Areas.
PZ...Small Craft Advisory for hazardous seas until 4 AM PST Saturday
for Coastal Waters from San Mateo Point to the Mexican
Border and out to 30 nm-Waters from San Mateo point to the
Mexican Border Extending 30 to 60 nm out including San
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