Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 161656
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
956 AM PDT Tue Sep 16 2014
Temperatures cooling to below normal later this week with a chance
of showers and thunderstorms returning to the region later
Wednesday into Thursday.
A noticeably cooler start to the day today with temperatures 3 to
9 degrees cooler than this time yesterday. The upper level ridge
which has been bringing unseasonable warmth to the area is giving
way as a cool Pacific ridge approaches. Today will be dry and
sunny, with some high thin clouds spreading in from the west later
today and tonight. Highs this afternoon look on track to be 4-5
degrees lower than yesterday, though this will still be a little
above normal levels. Some breezy southwest winds will pick up
again this afternoon, especially in the mountains.
Smoky/hazy conditions continue from the King Fire in portions of
the Sierra and the foothills. Visible satellite shows smoke in a
v-shape, with some smoke that spread down the American River
Canyon with easterly winds now being pushed to the northeast with
southwesterly winds. Breezy southwest winds this afternoon may
further enhance the spread of the fire.
Approaching trough will spread precipitation into the Coastal
Range by Wednesday afternoon. Elevated convection parameters with
the 12z NAM are looking more favorable. May need to add the potential
for a few thunderstorms there late afternoon and early evening.
More significant precipitation spreads in by Thursday. Lift and
atmospheric moisture are adequate for potential rainfall over the
area, but most areas should see fairly light amounts.
Forecast looks on track for today, no updates necessary. EK
.Extended Discussion (Saturday through Tuesday)
Medium range models continue to have difficulty with handling
trapped upper low. 12z ECMWF-HiRes has come more inline with the
Oper GFS in keeping the low farther south and building stronger
ridging over the weekend into Monday. So will follow these
solutions for now with understanding progs do poorly with trapped
lows. Thus expect dry weather Friday through Monday for Interior
NorCal with above normal temperatures. Highs expected mostly in
the 90s for the Central Valley with 70s to around 90 for the
mountains and foothills.
General VFR conditions over interior Northern California through
early Wednesday with an upper level trough in the the Eastern
Pacific approaching the California coast. Smoke from King Fire
near Pollock Pines will locally reduce visibility over portions of the
Sierra. Local SW surface wind gusts to 30 kts over the higher Sierra.