Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 160117 CCA
AFDHNX

Area Forecast Discussion...CORRECTED
National Weather Service San Joaquin Valley - Hanford CA
617 PM PDT Sun Jul 15 2018

Updated air quality section

.SYNOPSIS...
Scattered showers and isolated afternoon and evening thunderstorms
are possible over the crest of the southern Sierra Nevada today.
Chances will decrease the next couple of days then increase again
Wednesday through the end of the week. Otherwise, dry weather will
prevail along with a continuation of above normal temperatures.

&&

.DISCUSSION...
Visible satellite imagery showing smoke from the Ferguson Wildfire
in Mariposa County has spread out over a good portion of the central
San Joaquin Valley this morning. Thick smoke appears to be impacting
Yosemite National Park too as evident on the Yosemite Valley webcam.
Expecting some improvement with ventilation this afternoon but a
repeat occurrence is likely again tonight into Monday.

Otherwise, high pressure aloft remains centered off the southern
California coast while a weak s/wv trough nears the CA/OR border.
Precipitable water values remain a little above normal over the
district and some cumulus are developing over the southern Sierra.
Based on the latest hi-res models, expecting a few showers along
the crest of the Sierra again this afternoon with some isolated
thunderstorms possible as well. Steering flow is very weak like
yesterday, so any storms would mostly remain quasi-stationary. It
is unlikely, but will need to watch for potential outflow winds
from any storms developing to the east of the Ferguson Fire.

High pressure will build inland the next couple of days leading to
a diminishing chance of showers/storms, but cannot completely rule
out. The high becomes centered around the Four Corners region by
Wednesday. A southeasterly flow aloft will bring a resurgence of
monsoon moisture into central CA. This will bring an increase in
chances and coverage of aftn/eve showers/storms to the Sierra as
well as for the Kern County Mountains and Desert. The models show
s/wv energy rounding the high pressure and moving up from SoCal
later this week. Will have to watch this as it could produce an
uptick in convection and possibly expand the coverage as well.
Will hang on to low chance POPs for the Sierra into next weekend
as well.

Little change in temperatures is expected through the week with
afternoon highs generally a few degrees above normal for mid July.
Tuesday looks to be the hottest day of the week as the upper high
strengthens over the area. Heat risk conditions do not currently
meet advisory criteria.

&&

.AVIATION...
A slight chance of thunderstorms over the crest of the Southern
Sierra Nevada through 06Z Mon and again after 18Z Mon. Areas of
MVFR visibility in smoke in the vicinity of the Ferguson Fire in
Mariposa County. Otherwise, VFR conditions will prevail across
the Central CA Interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Monday July 16 2018... Unhealthy for sensitive groups in
Sequoia National Park and Forest.
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.php for additional information
an/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
NONE.
&&

$$

public...DCH
avn/fw...DCH
synopsis...DCH

weather.gov/hanford


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