Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 162219
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
319 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.
Upper level ridging is shifting eastward bringing noticeable
cooler temperatures over the region. Current temperatures over the
forecast area are anywhere from 2 to 10 degrees cooler than
yesterday. Breezy southwest winds have picked up in the Sierra,
now gusting to 24 mph at Blue Canyon. The southwest winds are also
pushing the smoke from the King Fire northeast into Nevada.
Approaching Pacific trough will spread precipitation into the
Coastal Range by Wednesday afternoon, along with breezy southwest
winds. Afternoon heating and elevated instability look sufficient
for afternoon and evening thunderstorms in that area, especially
if enough heating from the sun occurs through breaks in clouds. A
vort max tracking through northern California late in the day will
provide some lift. More stable conditions expected overnight, with
general showers spreading across the Valley Wednesday night into
early Thursday as the main trough moves inland.
Rain showers and seasonably cool temperatures expected for
Thursday. Increasing instability is expected by Thursday
afternoon, with a slight chance of thunderstorms across the area.
Rain amounts overall should be light, except locally with
thunderstorms. By evening, precipitation should be mainly
lingering convection over the mountains.
Friday is expected to be dry with temperatures rebounding to near
normal levels, which is upper 80s to mid 90s. EK
.Extended Discussion (Saturday through Tuesday)
Latest 12z 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 W 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.