Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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510
FXUS66 KHNX 250030
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
146 PM PDT Wed May 24 2017

.SYNOPSIS...An area of low pressure will move into the area from
the Pacific. Temperatures will further cool due to increased
onshore flow and cooler air aloft on Thursday and Friday. A ridge
of high pressure will then become reestablished this weekend for
another warming trend.


&&

.DISCUSSION...Latest satellite imagery continue to show the
closed upper low off the coast of central CA. Mid-level clouds
have been streaming inland into our CWFA from the southwest,
although the cloud cover has done little to mitigate daytime
heating so far this afternoon. Our radar has shown some weak
echoes over parts of the SJ Valley and along the west side since
late this morning, but any precip is likely not reaching the
ground. Temperatures are generally trending down as advertised
and are down up to several degrees in most locations compared to
this time yesterday. By late this afternoon and into this evening,
winds will likely pick up along the west side of the SJ Valley
and in the favored passes and canyons in eastern Kern County with
mainly breezy conditions expected.

On Thursday and into Friday, expect noticeable cooling as the
trough of low pressure moves southward into our area from
northern. Breezy conditions will prevail again by Thursday
afternoon as onshore, or westerly, flow continues. On Friday, an
upper level disturbance moving over the Great Basin could bring
enough instability for a return of showers and isolated
thunderstorms over the high country of the Sierra Nevada, mainly
around Yosemite to Kings Canyon NP, so have included slight chance
POPs for this area. At this time, am not very confident of
showers and thunderstorms returning to the Sierra, at least before
the upcoming Memorial Day weekend.

For the holiday weekend, temperatures will trend back up to above
average by Sunday and into Memorial Day as high pressure
redevelops over the western states. Also, have included slight
chance POPs during the afternoons and evenings during the
Memorial Day weekend and even through the middle of next week
along the Sierra Nevada crest as instability is forecast to be
sufficient over these areas combined with continued surface
moisture available from evaporation of snowpack over the high
country.

Temperatures are progged to continue above average for the last
few days of the month, as high pressure will remain in control.
More significant model disagreement, as expected this far out, is
shown for Tue-next Wed period, although both the GFS and Euro
models show the ridge of high pressure weakening and allowing a
closed low pressure system to develop somewhere of the coast of
southern CA or northern Baja. Stay tuned, especially as we get
closer to next week.

&&

.AVIATION...
A slight chance of thunderstorms over the Sierra Nevada crest
through 06Z Thursday. Otherwise VFR conditions are expected across
the central CA interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Thursday May 25 2017... Unhealthy for sensitive groups 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.php for additional information
an/or to provide feedback.

&&

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

$$

public...BSO
avn/fw...Bean
synopsis...BSO

weather.gov/hanford



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