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

FXUS66 KSTO 191658

958 AM PDT Sat Apr 19 2014

A weak system well to the north will bring slightly cooler
temperatures today. Building high pressure on Sunday will result
in northerly winds and warmer temperatures. A stronger Pacific
trough will approach the coast Monday bringing increasing clouds
and a chance of rain and higher elevation snow on Monday night and
Tuesday. Some areas may also see a chance of thunderstorms. Weak
high pressure will dry things out some Wednesday and Thursday but a
threat of precipitation will continue across the far northern
sections of the state. Another trough will bring another chance of
rain to all of interior Northern California Friday into Saturday.


.Short Term Discussion...
A system is moving through the Pacific Northwest today bringing
some clouds and cooler temperatures today with synoptic cooling
and onshore flow. The Delta Breeze is blowing this morning with SF0-SAC
gradient around 3 mb and SUU winds SW around 30 mph. Temperatures
today will warm up into the upper 70s to low 80s in the valley and
low 70s in the delta and 50s and 60s in the mountains. Weak ridge
over the area tomorrow as this systems shifts east and a stronger
system approaches the west coast. This will bring warmer
temperatures and some northerly winds Sunday. The onshore flow
will turn Northerly tonight as surface high pressure moves into
the Pacific Northwest. Although the MFR-SAC gradient expected to
only be about 7 MB and 925 MB winds only about 20 kts so Northerly
winds not expected to be very strong. The Northerly downslope winds
will keep some overnight temperatures warmer tonight than last
night. Temperatures Sunday afternoon will warm into the mid 80s in
the valley and around 80 in the delta and 60s and 70s in the
mountains. Temperatures cool down on Monday into the mid to upper
70s in the Valley and 50s and 60s in the mountains with the
trough off the California coast bringing synoptic cooling and
onshore flow. Temperatures cool down to below normal for this time
of the year on Tuesday with highs in the mid 60s to around 70 in
the valley and 40s and 50s in the mountains as the trough moves
through the area. Precipitation may begin over the Coastal range
and Shasta county Monday afternoon and spread southeast across the
area by Tuesday morning. The 12z NAM is much quicker with the
trough and moves it east of the area by Tuesday afternoon making
convection less favorable. The GFS is a little slower with a
piece of energy moving through Northern California Tuesday
afternoon. The current forecast goes with the GFS solution but may
decrease precipitation amounts and pops for afternoon forecast with
drier NAM. Snow levels will start out around 7000 ft Monday night
and lowering to around 5000 ft Tuesday morning. Not a lot of snow
or precipitation is forecast at this time but a couple of inches
of snow near pass level look possible.

.Extended Discussion (Wednesday through Saturday)

Slight warming trend begins on Wednesday as the upper low from
Monday and Tuesday moves east of our region and ridging re-
develops along the west coast. This ridge is not forecast to be
strong so lingering light showers are possible over the northern
mountains Wed & Thurs. Additional warming on Thursday as valley highs
return to the mid-upper 70s. However, by Friday and into the
weekend, another upper trough will move across our CWA bringing a
return of more widespread precipitation and cooler temperatures.



VFR conditions will continue next 24 hours for Central Valley TAF sites.
Generally light winds up to 12-15 kt with local gusts to 21 kt
expected at from KSMF southward through today. Breezy/windy in the Delta
region WS winds 15-25 kt gusting to around 35 kt.


.STO Watches/Warnings/Advisories...

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