Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 020602
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1000 PM PST Sun Mar 1 2015

.Synopsis...
A second wave of wet weather arrives Monday with possible
thunderstorms in the afternoon and light mountain snow. Drier and
warmer Tuesday onward.

&&

.Discussion...
A lingering shower in Tuolumne Co. finally dissipating as cyclonic
flow from the upper low affecting Socal weakens over the far Srn
portion of our CWA. Elsewhere...the flow is Nly as the upstream
short wave off the Pac NW Coast dives Swd. By 12z Mon...the effects
of cyclonic flow from the upper low affecting Socal will be relaxing
in our CWA and the energy from off the Pac NW coast dives Swd off
the CA coast on Mon. This system will not have as much moisture to
work with as this past one due to the drier Nly flow. AMSU TPW shows
just a few tenths PW off the W coast as the upstream short wave
dives Swd. However...as this system makes its way Swd on Mon the
flow will turn SWly and begin to tap the remnants of the Srn system.
AMSU TPW shows about 5 to 6 tenths TPW that should become entrained
into the SWly flow for the Mon system. Thus...most of the showers on
Mon should be influenced by upslope flow over the Siernev...with the
heaviest in zone 69 where a few tenths of an inch may fall.

Main short wave energy forecast to remain off the coast so the best
thunder chance could be confined to the coastal range...especially
Srn SFO Bay area in the afternoon...and then to a lesser extent over
the Siernev Foothills due to upslope flow and divergence aloft.
JHM


.Previous Discussion...

Another system dropping down from the north on Monday will bring
more shower and thunderstorm chances to the interior on Monday.
Today the track of the low is centered further east than yesterday
and mostly over land as it drops south. Snow levels look to be
between 4000 and 5000 feet with this storm but may be down to near
3500 feet over parts of Shasta County Monday morning. Snow levels
will start out near the lower end of those values and rise a little
in the afternoon.

This system continues to looks weaker than the last one. What
looks like will happen is that as the system drops southward it
will interact with the low over Southern California and the
moisture that it is bringing up north and wrapping around into the
crest. Very little if any precipitation is expected over the
northern part of the CWA but along the crest several inches will
be possible with up to an inch of snow down to around 5000 feet.
Isolated showers and thunderstorms will be possible for the
valley.

A ridge will begin to build over the the area Tuesday and
Wednesday with dry and warm weather expected both days. Northerly
flow will occur both days...easterly at night in the mountains.

&&


.Extended Discussion (Thursday through Sunday)

Little weather of note through the weekend as high pressure ridge
builds and remains in control off West Coast. Dry weather will
rule with above normal temperatures: daytime highs in the 60s to
70s in the valley and 50s to 60s in the mountains. Mostly clear
skies and light winds are expected into the weekend. Patchy
morning fog may form in northern SJV and southern Sac valley. No
sign of rain until mid to late next week.
CEO


&&

.Aviation...

Mainly VFR conditions expected thru the TAF period. Brief period of
MVFR to IFR BR/FG possible again at KSCK during the morning hours. A
weak system will move through on Monday with the possibility of
scattered showers after 18z but confidence in coverage too low for
inclusion in TAFs. Better chance for showers across the mountains
with snow levels 040-050. Otherwise...clouds AOA 5 kft spreading Swd
over TAF sites on Mon as cold front moves Swd from the Pac NW.

&&

.STO Watches/Warnings/Advisories...
None.

&&

$$








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