Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 252130
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
230 PM PDT Tue Jul 25 2017

.SYNOPSIS...
A chance of thunderstorms over the Mountains and Kern Desert
This afternoon. A few lingering storms possible over the Sierra
Crest on Wednesday. Temperatures will be around seasonal averages
through Wednesday, then warming back up for the remainder of the
week.

&&

.DISCUSSION...
Convective activity starting-up this afternoon. This activity is
mainly affecting the Sierra Nevada and Tehachapi ranges, along
with the Mojave Desert. The San Joaquin Valley has remained
relatively clear today as cooler air filters into the area from
the coast. Fort Ord temperature and wind profiler showed the
marine layer up just above 2500 feet msl which is a good
indication of cool air reaching the Central Valley. Therefore,
will see afternoon temperatures at more seasonal levels before
another warm-up begins. The cool down was the results of an upper
level disturbance approaching Northern California and pushing
through overnight. While upper-air observational analysis still
shows some instability over the mountains, the onshore flow is
stabilizing the atmosphere and reducing the threat of afternoon
convection. Upper-air and model analysis show the subtropical
moisture that had been surging north now shifting eastward as the
district begins to dry out.

Short range model upper-air analysis show the disturbance pushing
through Northern California on Wednesday. While model instability
continues on Wednesday, the extent and magnitude is much lower
then today. Therefore, confidence is high with drying out the
district and starting a slow warming trend for the rest of the
week. The signal toward good height rises start toward the end of
the week as valley temperatures return to above normal conditions.
Max temperature reaching above the century mark will become
widespread by the end of the week and into the weekend. Upper air
pattern by the weekend has a four corners high developing as the
heat returns to the valley. In addition, the four corners high
pattern will allow for the return of subtropical moisture early
next week.

Currently, models do show a weak disturbance pushing into Northern
California during the weekend. Certainty is still low on this
disturbance being able to flatten the developing ridge pattern.
Therefore, will expect the high pressure ridge to dominate the
region by the start of next week and remain anchored over the west
through the middle of next week. Therefore, once the ridge
settles over the four corners area, will expect the return of
mountain convection each afternoon. However, with only a weak flow
coming up from the southeast, will not expect the subtropical
moisture to penetrate beyond the mountains. In addition, models
show higher confidence in maintaining the pattern through the long
term period.

&&

.AVIATION...
Areas of MVFR visibilities in smoke from area wildfires. A chance
of thunderstorms developing this afternoon between 20z and 04Z
over the Sierra Nevada and Kern county mountains and desert.
Otherwise, VFR conditions will prevail across the central CA
interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...
Please see SFOAQAHNX for an Air Quality Alert.

&&

.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/avn/fw...Molina
synopsis...Molina

weather.gov/hanford


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