Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 180131 CCA

Area Forecast Discussion...CORRECTED
National Weather Service San Joaquin Valley - Hanford CA
631 PM PDT Tue Jul 17 2018

Updated air quality section

Strong high pressure will remain over the region for the next
several days keeping hot weather in place. Easterly flow over the
region will bring a chance of thunderstorms to mainly the
mountains and desert areas this week. Heat returns next week.


Per latest GOES satellite imagery, widespread smoke is present in
Mariposa and Madera county from the Ferguson Fire. The smoke is
currently edging to the south into Fresno County, and will make it
to Tulare County later this evening. The smoke has been
especially heavy in Mariposa County due to a persistent inversion
that has been trapping the smoke in the lowest levels of the
atmosphere. Current thinking is that this inversion will hold
tonight, but I am not certain on the strength of the inversion on
Wednesday night and Thursday. Due to the heavy smoke, The San
Joaquin Valley Air Pollution Control District has put out a Air
Quality Alert. We are encouraging people to remain indoors if you
smell smoke.

Like yesterday the San Joaquin Valley is quite warm, with
widespread high temperatures easily eclipsing the century mark.
Tomorrow looks like it could be a degree or two warmer, and then
we will see a slight cooling trend starting Thursday into the
weekend. As high pressure begins to build again next week, a
warming trend will resume by next Monday.

In regards to the upper level pattern, the ridge of high pressure
that has been keeping temperatures seasonably high over central
California will drift to the east by Wednesday night. Although
temperatures are expected to trend down a few degrees over the
weekend, temperatures will still remain average or even slightly
above average. As the ridge drifts to the east, a window of
opportunity for showers and thunderstorms to form over the
Tehachapi`s and High Sierra can be expected starting Wednesday
through Monday in the afternoon and evening hours. By Tuesday,
stronger ridging will affect central California which will
suppress the opportunity for thunderstorms.


Areas of MVFR visibility in smoke will continue in the vicinity of
the Ferguson Fire in Mariposa County for at least the next 24 hours.
Isolated thunderstorms are possible near the Sierra crest between
20z today and 03z Wednesday and again Thursday. Otherwise, VFR
conditions will prevail over the central California interior
during the next 24 hours.


Please see SFOAQAHNX for an Air Quality Alert

On Wednesday July 18 2018... Unhealthy for sensitive groups in
Fresno... Kern and Tulare Counties and Sequoia National Park and
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...


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