Area Forecast Discussion
Issued by NWS Sacramento, CA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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

FXUS66 KSTO 022306

406 PM PDT WED SEP 2 2015

Below average the remainder of the week as a weather system moves
into the region. Showers and thunderstorms are possible across the
northern portion of the state Friday into early Saturday. Milder
conditions return for the latter portion of the Labor Day weekend
into next week.


.DISCUSSION...Upper level ridging is giving way as low pressure
troughing from the Gulf of Alaska approaches. This is also
bringing onshore flow with breezy southwesterly winds over the
area gusting to around 20 to 30 mph. This is also bringing cooler
temperatures, which are currently around 3 to 7 degrees lower
than yesterday. The trough will continue to deepen through Friday
bringing even cooler temperatures along with more breezy to
locally windy conditions as the pressure gradient tightens.

A cold front moving through far northern California will drop
southward through the area tonight through Thursday. Another surge
of cool air on Friday will bring even cooler temperatures for the region
for the rest of this week. The coolest day is expected to be
Friday, with the Valley experiencing highs only in the upper 70s
to lower 80s, well below normal. Increased cloud cover will keep
temperatures over northern portions of the forecast area
especially cool.

Moisture is lacking with this system, especially initially, so
may just see a few showers Thursday afternoon over eastern Shasta
County. Better moisture, instability and dynamics are expected on
Friday, as the a jet streak rounds the base of the trough over
northern California. This could bring some afternoon thunderstorms
along with showers across the northern mountains and into the
northern Sacramento Valley. The cold air with this system cold
even allow some light snow over higher mountains north of I80,
such as Lassen Peak.

The system moves east by early Saturday with lingering showers
over the crest ending in the afternoon. Decreasing clouds and a
return of ridging will bring slightly warmer temperatures Saturday
afternoon. EK


Dry weather with a gradual warming trend is expected early next
week as the upper trough shifts eastward and high pressure slowly
returns. There may be a period of locally breezy north winds
Sunday through Tuesday. Temperatures by the middle of next week
will likely be a bit warmer than normal.




VFR conditions expected the next 24 hours. Stratus may spread
through the Delta into Sacramento area TAFs between 12-17z
Thursday morning. South to west winds 10-18 kt with gusts to 25
kt across the Valley will diminish late this evening.




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