High Wind in California, January 1, 2020

Area Forecast Discussion
National Weather Service Hanford CA
451 PM PST Wed Jan 1 2020

.UPDATE...
Updated for air quality section

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.PREV DISCUSSION... /issued 207 PM PST Wed Jan 1 2020/

SYNOPSIS...Gusty winds will continue through and below the
Kern county mountain passes tonight into Thursday morning.
Otherwise, dry weather can be expected over the district
through the middle of next week. Friday and Saturday will
be the mildest days of the next 7 days with morning fog in
the San Joaquin Valley.

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DISCUSSION...The weather on this first day of 2020 and a new
decade is mellow and rather mild over much of the central CA
interior. That's good news for motorists traveling home from
their holiday visits with family and friends this afternoon.
Northwesterly winds are ramping up through the Kern County
mountain passes this afternoon and they'll remain gusty into
the morning hours Thursday as an upper level trough drops into
the Great Basin. This 'inside slider' system should provide
enough atmospheric mixing to mitigate fog formation in the San
Joaquin Valley tonight. Nonetheless, a strengthening northwest
flow aloft will inevitably create and embank low clouds along the
north facing slopes of the Kern County mountains and the west
slopes of the Sierra from late this evening through a good part
of the day Thursday. There could even be a little drizzle out of
those clouds in the Tehachapi mountains toward daybreak. Low
clouds could also form over much of the south valley later
tonight and linger into Thursday morning. Otherwise, Thursday
will be dry with high temperatures remaining on the mild side of
normal.

From late Thursday through Friday, an upper level ridge of high
pressure over the Eastern Pacific will build inland over central
California. Any low clouds that linger in the upslope regions will
erode quickly Thursday evening as this ridge brings drier air in
aloft. Below the developing inversion Thursday night, fog will
likely develop in the San Joaquin Valley. Fog could become dense
in many areas of the valley before daybreak Friday and potentially
disrupt or delay travel for morning commuters. Saturday could also
begin foggy in the San Joaquin Valley. Otherwise, Friday and
Saturday will bring a good deal of sunshine over much of the
central California interior with very mild afternoon temperatures.

The medium and long range models forecast the storm track to
remain north of the Golden State in the 3 to 7 day period. At
least two upper level troughs will traverse eastward through the
Pacific Northwest during this period and suppress the high pressure
ridge southward into Baja. The first trough will pass through on
Sunday then be followed by a second one late Tuesday. The ECM
forecasts the Tuesday trough to track a little farther south than
the GFS. If this were to happen, light precip could occur over
the mountains late Tuesday into Wednesday. We're currently
favoring the GFS solution which forecasts a much shallower
'inside slider' type trough to move through the intermountain
West one week from today. This agrees with the ensembles which
generally keep central California under a dry northwesterly flow
aloft during this period. Otherwise, seasonable temperatures can
be expected Sunday through the middle of next week.

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AVIATION...Wind gusts of 35 knots or greater will occur through
and below the Kern county mountain passes until 18z Thursday. MVFR
ceilings can be expected along the west slopes of the Sierra and
the north facing slopes of the Kern county mountains between 06z
and 20z Thursday with local IFR/LIFR in fog and drizzle on valley
facing slopes of the Tehachapi mountains. Local IFR visibilities
are possible in fog in the San Joaquin Valley from Fresno county
north between 06z and 18z Thursday. VFR conditions will prevail
elsewhere over the central California interior during the next 24
hours.

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AIR QUALITY ISSUES...
On Wednesday January 2 2020... Unhealthy for sensitive groups in
Fresno... Kern 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

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.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.

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.HNX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until noon PST Thursday for CAZ196-197-199.

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Synopsis... Durfee
public... Durfee
aviation/fw... Durfee
PIO/IDSS... DS

weather.gov/hanford