Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 171135

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
335 AM PST Wed Jan 17 2018

High pressure will rebuild over the area and keep mild
temperatures and dry conditions across the region through
Thursday -- aside from persistent low clouds and fog in the San
Joaquin Valley. A weather disturbance will bring rain and
mountain snow to the region Thursday night through Friday night.
Another storm will move through the area early next week.


Fog continues to dominate Central California`s weather as the
San Joaquin Valley experiences another morning of hazardous
driving conditions. A dense fog advisory has been posted until
noon as visibility reports show values at or below a quarter mile
this morning. After the passage of a weak disturbance across
Northern California last night, the region will now be under the
influence of a short-wave ridge that will exist over the West
Coast for the next 36 hours. As the ridge pattern remains over the
area for another day, will potential exist for one more days of
possible dense fog. Yet, a change in the weather pattern can been
seen over the horizon which may lead to a temporary end to the
valley fog situation.

GFS mod-trend along with other deterministic models remain very
consistent in resolving a stronger trof pattern affecting Central
California toward the end of the week. GFS mod-trend along with
over ensemble models show very little uncertainty with the passage
of the next trof pattern in the late Thursday night/early Friday
morning time frame which is leading toward high confidence in the
potential for measurable precipitation on Friday. Yet, atmospheric
river moisture analysis for the next storm does not favor the
Central California region during the storm passage. While
plentiful moisture exist as the storm enters Northern California,
models show the moisture diminishing as it shifts south into
Central California toward Friday morning. However, enough moisture
will filter south to increase the potential of measurable rain
and snow. Therefore, the question remains just how much
precipitation will fall over the Central California Interior
during the storm passage. Currently, models precipitation
accumulation amounts continue to show up to a quarter of an inch
across the valley and up to an inch of liquid precipitation over
the mountains.

Therefore, the main focus will remain on the storm expected to hit
Central California by the end of the week. As models show little
uncertainty, will carry high probability of measurable of rain and
snow for the late Thursday night through early Friday morning
time frame as snow could reach almost reach the 3000 foot line
toward the end the storm later on Friday into early Saturday
morning. The bulk of the storm is still expected on Friday which
is the time the areas will see the highest precipitation rates
over the mountains and the lower valley locations. The inch of
liquid over the mountains will translate into a possible foot of
new snow over the Sierra from Yosemite to Kings Canyon.

Afterward, a northwesterly flow aloft will keep the area unsettled
with spotty showers Friday night into early Saturday morning.
Ridging during the latter half of the weekend will terminate the
precipitation as yet another storm moves into the region toward
the beginning of next week. Will introduce a slight chance of
possible precipitation as uncertainty is still too high to
determine the strength of the storm. Will continue to watch next
weeks storm as the trend is now to keep this storm further north
and outside of the district.


Widespread IFR and LIFR until 19Z today. Afterward, areas of MVFR
conditions in clouds and mist/haze with patches of IFR conditions
will persist across the San Joaquin Valley until around 08Z
Thursday. Otherwise, VFR conditions will prevail across the
Central CA Interior during the next 24 hours.


On Wednesday January 17 2018... Unhealthy for sensitive groups in
Kern County.  Firepalce/Wood Stove Burning Status is: No Burning
Unless Registered in Fresno, Kern, Kings, Madera, Merced and
Tulare Counties. Further information is available at



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 for additional information
an/or to provide feedback.


.HNX Watches/Warnings/Advisories...
Dense Fog Advisory until noon PST today across the Central and
Southern San Joaquin Valley /CAZ089>092/.



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