Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 192056

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
156 PM PDT Fri Apr 19 2019

.SYNOPSIS...Low pressure will move across Southern California
tonight before a secondary trough of low pressure drops into the
Central California Interior from the northwest on Saturday. This
will bring a small chance of showers and thunderstorms through
Saturday night. Low pressure aloft will then set up over the Great
Basin on Sunday and Monday for an offshore flow and warming


.DISCUSSION...Lots of mid and high clouds streaming northward
across the forecast area early this afternoon as a southern stream
low approaches from the southwest. GOES-17 water vapor imagery
shows the center of the low about 400 miles southwest of Los
Angeles this afternoon with a leading area of difluence aloft
moving into SoCal ahead of the low. Although moisture is limited
in the lower levels, forecast models, especially the GFS continue
to project shower activity over Kern County and pockets of the
Sierra as the low approaches this evening. Higher resolution
models are more bullish on the threat of precipitation, but a
couple have some spotty showers through the evening hours over
these same areas. I have kept the slight chance of thunderstorms
over the south later this afternoon and evening.

Part two of the weather scenario then sets up on Saturday as the
southern low ejects quickly to the east as a trough of low
pressure now located near 40N/133W drops southeast into the Sierra
during Saturday afternoon on its path into the Great Basin.
Enough instability and moisture is available for showers and some
higher elevation snow showers lasting into the early evening
before the low heads too far east.

The low then closes off over Northeast Nevada Saturday night and
drifts south to a position north of Las Vegas by Monday morning.
This will shift the flow aloft to the north and northeast and the
surface winds over the mountains and desert as well. Could see
some gusty winds through the wind favored areas of the Sierra in
northeast flow however I don`t see a Mono Wind set up just yet.

By Tuesday and Wednesday the low moves away to the east with
models building strong high pressure into the region for a big
warm up for late April. Will need to keep a close watch on
stream flows from melting snow in the Sierra next week.


Isolated thunderstorms are possible over the southern Kern County
mountains between 20Z Fri and 03Z Sat. Otherwise expect VFR
conditions across the Central California interior over the next 24





The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit for additional information
an/or to provide feedback.


.HNX Watches/Warnings/Advisories...


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