Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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201
FXUS66 KHNX 201153
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
353 AM PST Wed Feb 20 2019

.SYNOPSIS...
The next storm system will impact Central California
today through Thursday. This storm system will have limited
moisture, with precipitation amounts much less than what fell in
the forecast area this past weekend. This system will also be
slightly colder than the last. Temperatures will remain below
normal for this time of year for at least the next several days.

&&

.DISCUSSION...
A very interesting forecast scenario is shaping up for the area.
The amount of precipitation is not really notable. But the type of
moisture could be, especially in parts of the San Joaquin Valley.
Yes, I mean the four lettered word that begins with S and ends
with NOW. Believe me, I am not trying to get everyone super excited
about the prospect of snow in the valley, such as I am. But, it
is a distinct possibility that needs to be monitored. A polar
airmass is moving southward into the Great Basin. A low pressure
system progged to bottom out at 529 decameters at the 500 mb
height will be centered just to the east of our CWA by early
Thursday morning. This would be the optimal timing for snow
chances when temperatures are coldest during the night and the
that coupled with some moisture and upward vertical motion with
the PVA max (area of greatest lift) moving over central
California could result in the formation of very low elevation
showers that are in the frozen variety. Snow levels are amazingly
progged to drop below 1000 feet and even lower on the northeast
side of the southern SJV during this period. Having said all of that,
the expected QPF with this system will be on the low side and if
snow does manage to fall in parts of the valley, accumulations
would be little to none. But, any snow falling in areas that
drivers are not accustomed to seeing this could make for an
increasingly challenging commute. So this does have huge
implications if this were to transpire. At this time it looks as
if the eastern parts of the SJV would have the highest chances to
see some snow showers.

Another interesting characteristic of this system is that the
aforementioned southward moving PVA max will remain over the
eastern and central parts of the CWA. This will keep the highest
chances of precipitation over the western two thirds of the CWA,
which is a bit different than what we are used to. Usually we
think higher chances of precipitation over the highest elevations,
and the western two thirds of the area sees lower chances. As this
energy moves southward, Kern County mountains will see chances
for precipitation increase as early as late afternoon on
Wednesday when snow levels will be right around 3500 feet and drop
through the night to around 2000 feet in the Grapevine area on
Thursday morning. That is well below pass level and travel plans
should account for this. At this time, up to 4 inches of snowfall
could fall. It would be highly recommended to either travel before
this happens or after the system passes and roads are cleaned up,
or simply try to use an alternate route which can be iffy with
this system. Road closures would be possible and more to the point
expected with this system.

Weak shortwave ridging will move into the region beginning Friday
morning and a return to a more zonal pattern is expected next
week, but not before a weak system with very little moisture moves
through the area on Sunday. The main areas impacted with this
system will be the higher elevations and snow amounts will be
minimal.

&&

.AVIATION...
Beginning later this morning, areas of mountain obscurations in low
clouds and precipitation in the Sierra Nevada, foothills, and Kern
County mountains. Also MVFR and local IFR conditions in low clouds
and showers across the San Joaquin Valley are expected through
Wednesday afternoon. Otherwise, VFR conditions can be expected
across the central CA Interior for 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.html for additional information
an/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
Winter Weather Advisory from 4 PM this afternoon to 4 PM PST
Thursday ABOVE 2000 FEET FOR THE CAZ095.

&&

$$

public...Andersen
avn/fw...JEB
synopsis...Andersen

weather.gov/hanford



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