Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 231737
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
935 AM PST Fri Feb 23 2018

.SYNOPSIS...
Below normal temperatures will continue. Snow showers possible
over the mountains Saturday with additional systems next week
bringing more widespread precipitation.

&&

.DISCUSSION...
Update: Dry Nly flow eroding/mixing out the thin band of stratus on
the E side of the Srn Sac/Nrn SJV this morning. Clear, dry, cool N
wind today, with decreasing wind in the afternoon as pressure
gradients relax.

Next system off the B.C. Coast will not be impactful for Norcal, a
weak, rather nuisance wx system. Mostly high clouds expected to
increase over the CWA on Sat with some lower cloud ceilings over the
Mtns with isolated light snow showers/flurries. Another frosty
morning expected on Sat in the Srn Sac Vly, Delta and Nrn SJV, while
the timing of cloud cover for the Nrn portion of the CWA looks to be
around sunrise or a little after, with still a chance of frost
again.

Mon wx system looks like another cold, low QPF, high snow ratio
system with the Valley seeing more rainfall than yesterday`s system.
NAM forecasts around a quarter inch for SAC and this looks like the
last shot of rain this month. DTS rainfall for the month remains at
zero through today, although SAC Exec had .01" yesterday. Here are
the driest Febs for DTS:

0.04 in 1899, 0.16 in 1913, 0.19 in 1995, 0.21 in 1953, and .26 in
1997 and 2013.

March may come in as the "proverbial lion" especially if the 23/00z
ECMWF verifies.   JHM

.Previous Discussion...
System that brought low elevation snow and showers to the valley
yesterday has pushed out of the area this morning. As skies clear,
temperatures dropping into the upper 20s to mid 30s across the
valley with teens and single digits in the mountains. Dry weather is
expected today but breezy northerly winds will develop in system`s
wake. Gusts of 15 to 30 mph possible across the valley with higher
gusts in the mountains. Another chilly overnight into Saturday
morning with frost on tap as valley temperatures drop near or just
below the freezing mark.

Another system will drop southeast in northerly flow, moving into
NorCal on Saturday. This wave looks weaker and drier than
Thursday`s system with showers likely confined to the mountains,
north of the Highway 50 corridor. While snow levels remain quite
low, there`s not much moisture to work with so expecting
accumulations less than an inch or two. Still may be enough to
cause some slick roads. For the rest of the area, expect increased
cloud cover. Could see a brief period of breezy southerly winds,
mainly across northern Sacramento Valley and across higher
terrain.

Sunday looks dry across the area before next system quickly drops
southeast into the area for Monday. Models in decent agreement,
bringing precipitation and another round of breezy winds to the
area during the day. This wave looks similar in strength and
amounts to Thursday`s storm, though perhaps may bring a little
more widespread rain to the valley (regardless, still not very
much). Snow levels will be around the 2000-3000 feet range with
another half foot of snow at pass levels and a dusting down into
the foothills. Those with travel plans should keep an eye on the
forecast as chain controls and delays will be possible.

CEO

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)
Models continue to show gradual retrogression of the large-scale
trough next week, but lots of differences continue in the details.
Mainly dry weather expected Tuesday and Wednesday, then prospects
for more significant precipitation increase later next week. Stay
tuned.

&&

.AVIATION...
VFR conditions next 24 hours except local MVFR Central Valley
south of KOVE til about 18Z. Northerly surface winds develop thru
the Central Valley by 18Z with gusts 20-25 kts.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$



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