Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 050421
Area Forecast Discussion
National Weather Service Sacramento CA
921 PM PDT WED MAY 4 2016
An upper level disturbance will continue to bring chances for
showers and thunderstorms the next several days. Chances for
showers and thunderstorms should increase in coverage across
Northern California Thursday. The storm system will linger through
most of the weekend, which will cause more chances for showers and
.Short Term Discussion...
Low pressure area along the coast will continue to keep unstable
conditions over the interior overnight. The threat of isolated
shower activity will likely occur overnight along with the
possibility of thunderstorms for all locations. The models do
hint at some scattered showers possibly popping up in the Sierra
Nevada late tonight.
On Thursday the center of the low will be along the central coast
to provide continued instability over the interior and another day
of showers and thunderstorms. A greater area over the interior
should see showers and thunderstorms during the day than today.
The low will begin to drift southward Thursday night. A couple of
inches of snow may occur over the pass along highway 88 in the
evening but the other major passes should be OK for travel from
On Friday the center of the low will move into Southern
California with wrap around moisture continuing showers over the
northern part of the state. At this time it looks like a shortwave
will rotate around the top of the low westward and into the
Sacramento valley. Friday still looks unstable enough for some
thunderstorm activity. Temperatures will cool into the low to mid
70s in the valley and mainly in the 50s for the mountains
Thursday and Friday.
Saturday the center of the low looks to be near the southern
Nevada area and may continue to bring more wrap around moisture
back into the area. The models are hinting at a dry morning for
the valley with possible showers for the afternoon. Most of the
activity is expected to be occurring over the western slopes.
Little change in daytime high temperatures is expected for
.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)
Warmer and drier weather pattern will be developing over Norcal
during the EFP. Lingering cyclonic flow from closed 5H low over
the 4-Corners will keep unsettled wx over Norcal on Sun...especially
over the Sierra...followed by high pressure building into Norcal for
the rest of the extended forecast period.
At times...the models indicate some instability or light precip
developing over a small portion of the Nrn portion of our CWA
spilling over or developing within the amplifying ridge. This activity
should be diurnal in nature as a result of differential heating and
topographic forcing...and will continue the low PoPs over the higher
mtns for now. Some large-scale ascent is possible as a trof...
moving through the Pac NW and Nrn Rockys...brushes Norcal early
next week especially if the ECMWF verifies.
Temps will gradually warm through the period. Maxes will start out
just a little below normal (up to 5 degrees or so most areas) on Sun
before warming to 5-10 degrees above normal on Tue/Wed. Forecast
highs mostly in the 70s in the Central Vly on Sun warm into the
80s for the rest of the period. JHM
Sly flow alf with upr low off the CA cst. VFR conds ovr Intr NorCal
nxt 24 hrs exc isold MVFR poss in shwrs or tstms...mnly ovr fthls
and mtns. Sfc wnds genly blo 15 kts exc gsty nr tstms.