Dense Fog in California, February 8, 2021

Area Forecast Discussion
National Weather Service Hanford CA
245 AM PST Mon Feb 8 2021

.SYNOPSIS...Dry weather and mild afternoon temperatures can
be expected through Monday. A cold frontal passage Tuesday
will be accompanied by gusty westerly winds through and below
the mountain passes and a slight chance of showers in the higher
elevations of the Sierra north of Fresno County. Cooler, wet
weather will return by the end of the week and continue off and on
through next weekend.

&&

.DISCUSSION...
Upper level ridge axis will move eastward this morning and this
will produce a bit more dense fog albeit patchy this morning with
visibilities down to 500 feet possible in many parts of the San
Joaquin Valley. Current 1015z satellite imagery is already
showing more fog development than the last couple of nights. A
dense fog advisory is in effect until 9 AM this morning to
address this issue. The patchy nature can be more dangerous since
you can go to decent visibility to very little in a short distance
so be aware of this when driving and slow down to avoid an
accident.

A transition from a more northerly flow to zonal flow will take
place over the next couple of days as a Gulf of Alaska trough
squeezes the Pacific ridging later today. A weak trough will move
through the region Tuesday evening and will increase chances for
light showers over the higher elevations, primarily Fresno County
northward. Increased winds across the area will bring mostly
breezy conditions at times with the trough passage. However, gusty
winds will also be possible below and through the mountain and
coastal passes. At this time winds look to remain below advisory
criteria.

Ridging will once again move in on Thursday but only briefly as
another trough from the north Pacific moves into the region on
Friday. This system looks a little more potent than the Tuesday
system but just barely. Another shortwave ridge will arrive on
Saturday giving us another brief break before a fairly strong cold
core trough moves into the region on Sunday. This system will need
to be watched as 500 mb heights of around 540 dm will be centered
near central California, a bit more moisture looks to be
associated with this so precipitation in many parts of the area
look to be a good bet at this time. But keep in mind this is still
about 6 days out so some changes to the forecast will be likely.
However, prospects for colder and wetter conditions next weekend are
looking good at this time.

&&

.AVIATION...Areas of IFR with local LIFR in fog can be expected
in the San Joaquin Valley through 17z Monday. Otherwise, VFR
conditions will prevail over the central California interior
during the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Monday February 8 2021... Unhealthy for sensitive groups in
Fresno... Kern... Kings and Tulare Counties.  Fireplace/Wood Stove
Burning Status is: No Burning Unless Registered in Kings...
Madera... Merced and Tulare Counties. No Burning For All in Fresno
and Kern Counties.
Further information is available at Valleyair.org

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM PST this morning for CAZ180>189.

&&

public...Andersen
aviation....Durfee

weather.gov/hanford