Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 271109
Area Forecast Discussion
National Weather Service Sacramento CA
409 AM PDT Thu Oct 27 2016
Wet and unsettled weather into early next week as several weather
systems move across the area.
Some light rain beginning to spread inland across interior NorCal
early this morning as the frontal system slowly works inland.
Temperatures are very mild across the region, generally in the 50s
to lower 60s.
Mostly light rain along with breezy conditions are expected
across the area today as the front slowly shifts east and deep
moisture continues to feed up from the southwest (TPW in excess of
1.25 inches). Orographic enhancement will lead to higher amounts
over the northern Sierra and mountains north of Redding.
Heavier rain expected to arrive tonight into midday Friday as the
wave currently to the southwest of 30N/130W approaches bringing
stronger lift to the very moist airmass (some of it originating
from Hurricane Seymour). Amounts in excess of an inch will be
possible across the northern San Joaquin Valley and southern half
of the Sacramento Valley by midday Friday while portions of the
northern Sierra may see 2-4 inches. Snow levels will be very high
with no impact to travel expected.
Moist southwest flow will continue precipitation chances across
the area into Saturday, especially in the northern Sierra.
Saturday night and Sunday another stronger system will move
through the region with gusty winds and more heavy precip. Snow
levels will be lowering with snow potentially impacting travel
through the northern Sierra passes.
.EXTENDED DISCUSSION (Monday THROUGH Thursday)
GFS/ECMWF-Hi Res similar in progressing mid latitude extra-
tropical cyclone towards California Monday and tracking it through
Tuesday. Models do however differ significantly with depth of
system and exact track. GEM shows a wave much farther north and
moves it through about 24 hours sooner. Models then bring another
Pacific system inland Wednesday but again differ with strength and
track. GEM/EURO keep bulk of precip north of I-80 with GFS showing
more widespread precip and higher QPF. Thus uncertainties exist
attm through the extended forecast period. Main theme however is
periods of precipitation possible with below normal temperatures.
Models suggest a break in the precip Thursday under weak ridging.
For Intr Norcal, areas of MVFR/IFR conds in pcpn nxt 24 hrs exc
wdsprd omtns with trrn obscd and lcl LIFR. Lcl Sly sfc wnd gsts up
to 25 kts poss in Cntrl Vly this aftn. Lcl SWly sfc wnd gsts up to
40 kts poss ovr hyr mtn trrn thru tngt.