High Wind and Heavy Rain in California, June 11 to 12, 2017

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
316 PM PDT Sat Jun 10 2017

.SYNOPSIS...A storm system will bring an unseasonably cool
air mass into the district this weekend accompanied by
locally strong and gusty winds and some showers and isolated
thunderstorms over mostly the higher terrain from Fresno county
northward. Dry weather and a major warming trend will occur
during the week with well above normal high temperatures likely
by Thursday.

&&

.DISCUSSION...If you thought today was a cool day for June, just
wait until tomorrow! High temperatures will challenge records for
the coolest June 11th in Fresno and Bakersfield if skies remain
cloudy most of the day. These are long standing records for low
maximum temperatures and are provided below.

So what's responsible for the dramatic cooling trend across
central California lately and for the rest of this weekend? Well,
it's an unusually deep storm system, which only days ago formed
over the Gulf of Alaska. That storm travelled southward to the
Pacific Northwest coast last night, strengthened the onshore flow
across central California, and swept a much cooler air mass into
the district overnight. That onshore flow is keeping clouds banked
up along the west slopes of the Sierra this afternoon where they
will likely persist for the rest of the weekend as the onshore
flow restrengthens. Elsewhere, skies will remain relatively cloud
free tonight, except at the south end of the San Joaquin Valley
and the north facing slopes of the Tehachapi mountains. In these
regions, clouds will redevelop later tonight and linger through
the end of the weekend.

Meanwhile, the storm near the Oregon coast will continue to
gravitate southward. The air associated with it is very cold
aloft so as this system settles into northern California
Sunday, the atmosphere will become very unstable. From about
Fresno county northward, the air will be cold enough aloft
to produce isolated thunderstorms with small hail Sunday
afternoon into Sunday evening. Farther south, where the
atmosphere will be slightly drier and less unstable, skies will
become mostly cloudy. Over the higher elevations of the Sierra
north of Kings Canyon, it will become cold enough for snow
showers Sunday afternoon and evening. Although we're not expecting
much precipitation, some locations above 7,000 feet could receive
a dusting to as much as two inches of snow by Sunday evening.
This is in addition to isolated thunderstorms that could drop a
small accumulation of hail in some locations. Whatever the case,
hikers in the Sierra high country should pack warm clothes and be
prepared for much colder, winterlike weather later this weekend.
Wind chill temperatures will be as low as the teens Sunday evening
and night. Otherwise, high temperatures Sunday will run a good 15
to 25 degrees below normal across the CWA.

Additionally, a strong 110-knot jet aloft to the south of this
late season storm will be directly over central California Sunday
afternoon into Sunday evening. The presence of this 300 mb jet
will support very strong winds not just over the Sierra crest,
but also through and below the mountain passes of Kern County
where local gusts of up to 70 mph are possible. Gusty winds may
hamper travel through the Kern county mountains and desert as
early as this evening and will likely persist through the early
evening hours Sunday.

An improvement in the weather will occur Monday as the storm
system exits into the Great Basin. Other than residual morning
clouds in the upslope regions, Monday will turn out mostly sunny
and a little warmer, but still average much cooler than normal.
Winds will be lighter, too.

A more profound warming trend will begin Tuesday and continue
through next Saturday as an upper level ridge of high pressure
builds into the Golden State from the Eastern Pacific.  Temps
will recover to seasonable levels Wednesday. Further warming will
bring high temperatures close to the century mark in the hottest
locations of the San Joaquin Valley and the Kern county desert
Friday. Widespread triple digit heat is likely in these areas
next Saturday. During the later part of next week, the air mass
will stagnate and this may lead to poor air quality in the San
Joaquin Valley. Additionally, the return of hot weather will also
bring an increase in snowmelt over the high Sierra and rising
water levels along most rivers throughout the CWA.

        RECORD LOW MAXIMUM TEMPERATURES FOR JUNE 11TH
           Fresno...71/1894   Bakersfield...73/1963

&&

.AVIATION...
Local mountain obscurations over the lower Sierra slopes and the
Kern County mountains through 18z Sunday. Scattered and isolated
thunderstorms over the Sierra Nevada and northern San Joaquin Valley
after 18Z Sunday. Otherwise VFR conditions expected elsewhere in 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...
Wind Advisory from 5 PM this afternoon to 11 PM PDT Sunday
CAZ095-098-099.

&&

public...Durfee
avn/fw...Bean
synopsis...Durfee

weather.gov/hanford