Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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857
FXUS66 KHNX 181025
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
316 AM PDT Fri May 18 2018

.SYNOPSIS...
Isolated afternoon and early evening thunderstorms are
possible over the higher elevations of the Sierra each
day through Wednesday. Otherwise, dry weather will prevail
over the central California interior through the middle
of next week. Winds will be gusty at times through and
below the mountain passes.

&&

.DISCUSSION...Little has changed in the overall weather
pattern across California since yesterday morning. A robust
onshore flow (currently 12 mb between SFO and LAS) is still
bringing ocean cooled air into the San Joaquin Valley. Low
stratus remains rather extensive off the entire central
California coast and in most coastal inland valleys early this
morning. Farther inland over our CWA, skies are generally clear
except for a few cloud patches in the upslope areas of the Sierra
and the Tehachapi mountains. Water vapor imagery also shows some
wraparound moisture associated with the closed low over the Great
Basin bumping up against the Sierra crest from Fresno county
northward. This area will again be the primary focus of afternoon
convection today and, like yesterday, should be very isolated.

Otherwise, that pesky closed low will finally lift out of the
Great Basin by this evening and allow short wave ridging aloft to
move in over central California. Temperatures should bounce back to
seasonable levels this afternoon and again Saturday after spending
the past couple of days on the cool side of normal.

Unless you thoroughly enjoy hot weather, you won`t be very
disappointed with what`s in store for the central California
interior during the next 3 to 5 days. An upper level trough of low
pressure is forecast to develop along the West coast this
weekend. Energy that dives southward into this trough will carve
out another closed low by Sunday night. The models seem to agree
that the center of this low will move right over the central
California interior Monday, then reposition itself over Nevada
where it will remain nearly idle through the middle of next week.
We should expect much the same weather in the Monday through
Wednesday period that we`ve already been experiencing the past few
days. In a nutshell, it will mean we will have a daily threat of
afternoon thunderstorms over the Sierra through the middle of next
week with repeated occurrences of marine intrusions in the San
Joaquin Valley. Additionally, gusty winds will occur through and
below the mountain passes. Temperatures will average slightly
cooler than normal early next week, too. Monday could be the
coolest day with high temperatures possible staying below the
80-degree mark in several locations of the San Joaquin Valley and
the Mojave desert.

After Wednesday, the models finally lift this closed low out of
the Great Basin and build an upper level ridge of high pressure
over California. If so, a dry, warmer and more stable air mass
should move into the CWA later next week. This ridge will put a
lid on any convective development over the high Sierra on days 6
and 7. High temperatures could peak just above 90 degrees in the
warmest locations of the San Joaquin Valley, lower foothills and
the Kern County desert by next Friday, too. The ECM model tries to
bust down the upper level ridge by the end of next week, so
whatever return of unseasonably warm weather we get might be short
lived. But in this month of wild temperature swings, that`s
something we ought to be used to by now.

&&

.AVIATION...
Isolated thunderstorms with local mountain obscuring MVFR/IFR
conditions are expected near the Sierra crest between 20Z today and
03Z Saturday. Otherwise...VFR conditions will prevail across the
Central CA Interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...
None.

&&

.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...Durfee
avn/fw...DS
synopsis...Durfee

weather.gov/hanford



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