Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 281051
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
351 AM PDT THU APR 28 2016

.Synopsis...
Breezy north winds today then again over the weekend. Isolated
showers possible over the northern Sierra today and through the
weekend with a slight chance of thunderstorms there. Otherwise dry
with above normal temperatures through Sunday.

&&

.Discussion...
Upper low that brought active weather to Norcal on Wednesday has
now moved eastward with its center now over the southern Great
Basin. IR Satellite shows some scattered clouds over the Sierra
Cascade crest this morning but showers remain east of the crest.
Shortwaves rotating around back side of low still may bring some
scattered showers over the northern Sierra today with enough
instability for a threat of afternoon or evening thunderstorms.
Circulation around back side of low combined with a 7 mb surface
gradient from MFR to SAC bringing breezy north winds to the
northern CWA this morning and this wind likely to spread
southward during the day although not strong enough to warrant
wind advisory. A fairly significant warm up is expected today as
upper ridging builds in along with the northerly winds with
daytime highs coming in several degrees above normal. Friday looks
mainly dry and continued warm as a small inside slider low drops
into the Pacific Northwest. This system drops into the Great Basin
on Saturday bringing just a threat of showers to the Northern
Sierra crest. The rest of the forecast area will see continued
warm and dry conditions with another round of breezy north winds
behind the low. GFS, ECMWF AND GEM all show a wave rotating
southwest around top of Great Basin low and into eastern
California on Sunday. With this model consistency, have included
chance of showers and thunderstorms along the entire Sierra
Cascade range Sunday afternoon.

&&

.EXTENDED DISCUSSION (Monday THROUGH Thursday)

Models showing upper ridging over NorCal Monday which shifts east into
the Great Basin Tuesday as offshore upper low approaches. Upper
low progged inside of 130 W Wednesday with potential for showers
mainly over the mountains. Models differ with track of low
Thursday but overall pattern suggests deformation zone sets up
over Interior NorCal with potential for more widespread showers
and possibly isolated thunderstorms. High temperatures in the
Central Valley cool from the low to mid 80s Monday to 70s
Thursday.
&&

.AVIATION...

Upr low movs into Desert SW tda as upr rdg alg W Cst blds inld. VFR
conds ovr Intr NorCal nxt 24 hrs exc isold MVFR/IFR conds poss in
shwrs ovr Siernev til arnd 03z Fri. Areas Nly sfc wnd gsts up to
25 kts poss in Cntrl Vly tda btwn 15z Thu and 02z Fri.
&&

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

$$



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