Area Forecast Discussion
Issued by NWS Sacramento, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KSTO 301532
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
832 AM PDT Sat May 30 2015

.Synopsis...
Above normal daytime temperatures as high pressure slides across the
west coast. Cooler early next week with a slight chance of showers
and thunderstorms over the northern Sacramento valley and
surrounding mountains as the tail end of a Pacific trough brushes
through. Warmer temperatures may return mid to late next week.

&&

.Discussion...
Little change, other than an increase in high clouds, expected
across NorCal today from Friday as upper ridge shifts east ahead of
approaching upstream trough over the eastern Pacific. Temperatures
will remain warm, and may bump up a few degrees inland. Increasing
onshore gradients and synoptic cooling will develop Sunday and mark
the beginning of a cooling trend heading into early next week. No
updates.

&&

.Previous Discussion...
Quiet weather this morning, with a delta breeze gusting around 30
mph, and generally light winds elsewhere. The marine layer along the
coast is shallower this morning, so just seeing some low clouds into
the Vallejo/western Delta area. High clouds are spread across
northern California this morning.

High pressure will bring another warm, dry day today with afternoon
highs similar to those on Friday. This means upper 80s and lower 90s
for the Valley. The upper level ridge which has been bringing the
above normal temperatures is shifting eastward, though. An upper
level will approach on Sunday. This will cool afternoon high
temperatures down about 5 degrees, which will still be a little
above normal levels. Onshore flow will bring breezier southwest
winds, and potentially some morning low clouds through the Delta
into the southern Sacramento Valley. Some afternoon showers and
thunderstorms are possible into the coastal mountains, though there
is a better potential by early evening. Could see a few showers into
the northern Sacramento Valley overnight Sunday.

Monday there is the potential for showers and afternoon
thunderstorms across the northern mountains/foothills with marginal
instability. A slight chance of showers extends through the northern
Sacramento Valley Monday morning through Tuesday morning as another
shortwave passes through. By Tuesday afternoon, just a slight chance
some lingering showers over the Shasta County mountains are forecast.

Temperatures on Monday cool down to below normal levels.
Temperatures on Tuesday will rise slightly but still remain below
normal. EK

&&

.Extended Discussion (Wednesday through Saturday)...
Weak upper trough moves into the Pacific Northwest on Wednesday but
any precipitation associated with it likely to remain north of the
CWA. Airmass even warms a bit on Wednesday so daytime highs are
likely to nudge up a few degrees to a little above normal. Models
diverge after Wednesday with GFS and GEM slowly pushing in a ridge
off the eastern Pacific Thursday and Friday while the ECMWF digs a
trough southward down the coast eventually forming a low centered
over the central part of the state leaving the north state under
somewhat unstable conditions. Will keep with the GFS/GEM solution
for now as the ECMWF still having run to run inconsistencies. By
Friday...daytime highs push up to several degrees above normal under
the ridge. Next weak trough approaches the coast next Saturday
allowing daytime highs to level off. Current forecast shows no
significant precip chances through the extended period. Smith

&&

.Aviation...
VFR conditions all TAF sites under upper level high pressure ridge.
Scattered coastal stratus Carquinez Strait through 18Z with variable
high clouds at times all areas. Local SW wind gusts to 25-30 knots
through Carquinez Strait/Delta.

&&

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

&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.