Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 291625
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
825 AM PST Thu Jan 29 2015

.Synopsis...
Dry weather expected into the weekend with night and morning
valley fog and above normal temperatures. Some breezy wind
possible Friday into Saturday. A slight chance of showers northern
areas Monday...otherwise mostly dry weather likely to continue
through mid week.

&&

.Discussion...
Areas of dense fog developed again this morning in the Northern San
Joaquin Valley prompting issuance of an advisory. The densest fog is
around the Stockton southward to Manteca with visibilities expected
to improve later this morning. At the synoptic scale, elongated
upper trough/low along the California coast this morning is forecast
to drift through the area today. Satellite showing some mid to high
level cloudiness associated with it. Models indicating main threat
of any associated shower activity will be over the Sierra Nevada,
generally south of the forecast area, later today into this evening.

Closed upper low develops over SoCal Friday as EPAC upper ridging
builds into the PacNW. At surface, inverted trough extends through
CA into OR as surface high builds into the the Great Basin. This
pattern will result in some breezy N to E winds over Interior NorCal
Friday. This may help limit valley fog development or allow for
faster clearing for areas that have some.

Upper ridging builds into NorCal over the weekend with locally
breezy wind into Saturday. Night and morning valley fog and low
clouds expected to continue and possibly be more widespread under
increased subsidence and lighter Sunday. Above normal temperatures
continue over the weekend with upper 50s in the Northern San Joaquin
Valley to lower 70s in the Northern Sacramento valley with mainly
50s to 60s for the mountains and foothills.

PCH

&&

.Extended Discussion (Monday through Thursday)

Well, the ridge has indeed trended toward greater amplitude,
which has diminished the precipitation chances for Monday,
generally from Clear Lake to Quincy and northward. No significant
precipitation is expected through the extended. Fog and low
clouds are expected in the morning in the Valley. Beyond the
extended, long range models indicate a possible pattern change to
wetter weather beginning around Feb 7th. Stay tuned. We need the
ridge to shift east, rather than just break down and remain near
the west coast.       JClapp

&&

.Aviation...

Wdsprd IFR/LIFR conds in fog in the San Joaquin Vly this mrng with
mnly VFR conds elsw. Fog wl dsipt in the Nrn San Joaquin Vly arnd
midday. Areas IFR/LIFR in fog poss in Cntrl Vly, fm Sac area Swd,
agn Fri mrng.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








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