Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 221137
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
437 AM PDT Mon Sep 22 2014

.Synopsis...
Dry and warmer temperatures early this week. Cooler and wetter
weather expected for the middle to end of the week.

&&

.Discussion...
Mostly clear skies across the interior of NorCal early this
morning as skies have cleared in the wake of the weekend low
pressure system that`s now moving across the Great Salt Lake.
Temperatures are considerably cooler than 24 hours ago and range
from the 40s to lower 50s in the mountain valleys to the upper 50s
to mid 60s elsewhere.

Short-wave ridge will result in dry and warmer weather early this
week as fall arrives this evening (729 PM PDT). A couple weakening
weather systems will ride over the ridge early this week bringing
some clouds, but otherwise will have little effect for NorCal.
High temperatures today are expected to warm around 5 degrees
compared to Sunday`s highs, and little change is then expected
heading into Tuesday. Warmest readings in the Central Valley will
return to around the 90 degree mark both days.

Seasonal change is in the air as the ridge weakens and shifts
further east by mid-week as upstream upper low deepens off the
PacNW coast and trough approaches NorCal. While precipitation is
forecast to begin across far NW CA by late Tuesday, the
progression of precipitation further inland will be a slow process
as the front becomes parallel to the mid and upper-level flow
slowing its eastward progress. The initial impacts over interior
NorCal will be cooler temperatures along with breezy to windy
conditions, especially over the mountains.

By later Wednesday night and Thursday, there is good agreement in
the models that the upper trough will shift closer to the west
coast and push the frontal system inland across NorCal. Appears
the best chance for precipitation will be mainly from about the
I-80 corridor northward, and while rain amounts are not expected
to be high, this will be the first really significant system of
the fall.

Appears post-frontal shower potential will linger into the weekend
as the EC is favored with its slower eastward progression of the
resulting closed low, then warmer and drier weather forecast to
return by early next week.

&&

.Aviation...
Generally VFR conds next 24 hrs except local MVFR/IFR conds due
to smoke around King Fire including nearby foothill locations.

&&

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

&&

$$



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