Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Sacramento California
914 PM 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.
temperatures are cooler this evening over the northern areas to
slightly warmer for the Sacramento region this evening. Winds in
the Delta are lighter this evening but are expected to pick up
slightly late tonight then some more during the day on Wednesday. In
the mountains the winds have settled down and are shifting
downslope. Smoke from the Kings wildfire will be moving toward the
foothills overnight again...mainly from El Dorado County
northward into Nevada County.
Low pressure area off the coast will spread some clouds over the
region in advance of the system. Winds will become breezy through
the Delta and breezy from the south to southwest in the mountains
and valley on Wednesday...windy over the crest. Humidities will
remain low during the daytime and combined with the winds, low relative humidity
and dry fuels conditions will continue to cause poor conditions
for fighting the wildfires at times.
The low will move onto the coast late Wednesday to bring a chance
of showers to the coastal range. The low will then move over the
interior on Thursday and winds will be decreasing while humidities
should be increasing. Chances of showers will develop over the
remainder of the interior Wednesday night and Thursday.
Unfortunately the models are not indicating any precipitation over
the Kings wildfire area again this evening. Temperatures will
continue to cool each day through Thursday. Instability looks the
greatest Thursday afternoon over the southern Sacramento Valley.
Isolated thunderstorms look possible as the system moves through
with scattered showers.
The center of the low will move along the central coast for
Friday. Instability looks greatest over the Sierra Nevada
mountains at this time. This might bring a better opportunity for
showers and thunderstorms to move over the Kings wildfire for the
afternoon and evening hours. Winds will be shifting northerly and
temperatures in the valley will be rebounding closer to seasonal
Extended discussion (saturday through tuesday)
Latest 12z European model (ecmwf)-hires showing a more progressive solution,
similar to the oper GFS with handling of Omega pattern over the
western U.S. Models continue to slowly fill trapped upper low over
socal Saturday then progress it downstream along with upper
ridging early next week as epac upper ridging amplifies and build
into norcal. This will result in dry weather with temperatures
around 5 to 10 degrees above normal. Highs expected mostly in the
90s for the Central Valley with 70s to around 90 for the mountains
Incrsg swly flow Alf as pac stm apchs the west CST. VFR conds ovr
intr norcal nxt 24 hrs with isold shwr/tstm poss ovr wrn
Shasta/cstl rng Wed aftn. Conds dtrtg Wed ngt into Thu. LCL swly
sfc wnd gsts to 25 kts poss ovr hyr mtn trrn this aftn into eve and
in the Delta tngt.