Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 011805
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1105 AM PDT Fri Aug 1 2014

.Synopsis...
Hot temperatures with a cooling trend beginning Sunday. A return
to Sierra showers and thunderstorms possible again early/mid week
next week.

&&

Discussion...
Today will be another very hot day across NorCal with temperatures
above 100 degrees at valley locations. These type of readings are
about 10 degrees above normal. Temperatures are already a few
degrees warmer than yesterday at this time. High temperatures
should remain a few degrees below record values.

Increasing southwest flow will keep thunderstorms mainly in Nevada
and will mainatain a mainly dry forecast. Except for an isolated
storm possible over the southern Sierra during the afternoon.

.Previous Discussion...
Warm air mass with the upper level high pressure over the western
US will continue to bring another few days of triple digit heat
over the valley and above normal temperatures for the mountains.
Current satellite image is showing a large area of smoke where the
Bald Fire is located just south of Fall River Mills in Shasta
County, and potentially another fire just south of Burney showing
up on IR satellite this morning. This is in addition to a larger
fire heat signature near the border of Shasta County located in
Modoc County believed to be now named the Day Fire. Light drainage
winds are likely bringing some of this smoke into the lower
elevation valleys and affecting nearby areas in Shasta County
before southwesterly flow develops in the late morning/early
afternoon.

Drier air is expected today as a weak trough offshore sets up a
southwest flow pattern aloft which will hang around through the
weekend. This will keep thunderstorm activity mainly east of our
area for the next few days. Temperatures are expected to cool
slightly for Saturday, and then a few more degrees of cooling
are expected for Sunday and Monday as onshore flow and delta
breeze develops. Moisture will remain east of the area keeping
thunderstorms over Nevada. Shen

&&

.Extended Discussion (Tuesday through Friday)

Extended models are suggesting a return of some moist southerly
flow over the area by next week as a weak low edges closer to the
coast and some ridging lingers somewhere over the western US.
NAEFS mean precipitable water ensembles continue to show an
increase in moisture for next week over the area especially for
the Tuesday through Thursday time frame. In addition, GFS MUCAPE
and Total Totals during the extended show an increase over the
higher terrain beginning mainly Tuesday afternoon for a threat of
thunderstorms, and then appearing more favorable for Wednesday
afternoon for additional thunderstorm development. Signatures are
not as abundant for Thursday and Friday afternoons, though
thunderstorms over the higher terrain cannot be ruled out.
Temperatures will be near to slightly above normal through the
extended. Shen


&&

.Aviation...

VFR conditions all TAF sites next 24 hrs under upper level high
pressure ridge. A slight threat of Sierra thunderstorms today
18-00z well south of U.S 50. Winds generally below 15 knots except
through the delta west 10 to 20 knots.


&&

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

$$






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