Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 282144
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
244 PM PDT Sun May 28 2017


.SYNOPSIS...
Warming temperatures for the rest of the holiday weekend followed
by a cooldown Tuesday. Isolated afternoon showers or
thunderstorms possible over the mountains into mid-week.

&&

.Discussion...
1 pm temperatures were about 4-8 degrees warmer than yesterday
across much of the valley as the ridging over NorCal strengthens.
Daytime highs today should peak in the upper 80s to low 90s for
the valley while foothill and mountain regions range mid 60s to
mid 80s. Ridge will still be in place on Monday allowing for
another 1-2 degrees of warming to the daytime highs. Looking at
radar and out our office window, the cumulonimbus clouds are
developing this afternoon as we see another round of isolated
showers and thunderstorms over the Sierra which we`ll likely see
on Monday as well.

The ridge over NorCal shifts eastward Monday night into Tuesday as
a trough approaches the west coast. This will start a cooling
trend in our temperatures as a cooler airmass aloft arrives and
onshore flow is enhanced. Tuesday temperatures will drop several
degrees putting the valley highs firmly in the 80s as the delta
breeze picks up with gusts 25-35 mph. Additional cooling on
Wednesday by a few degrees, but the delta breeze won`t be as
strong. In addition to the cooling trend, instability over the
mountains looks much weaker on Tuesday and Wednesday. Have removed
mention of thunderstorms for those days. Shower activity will be
minimal on Tuesday...mainly over the coastal range as the trough
moves inland. Overnight Tuesday into Wednesday, chance for showers
increases across NorCal over to the Sierra and including portions
of the valley with the trough`s eastward track.  JBB

&&

.EXTENDED DISCUSSION (Thursday THROUGH Sunday)

Dry weather now begins Thursday and will last through the weekend
as a trough axis shifts east. The 12Z GFS & ECMWF model runs have
shifted the following shortwave farther north than yesterday`s
runs, resulting in the precipitation chances shifting north of the
area as well. Temperatures begin increasing Thursday and will
continue to slowly increase through the weekend with Delta highs
in the high 80s, valley highs reaching low to mid 90s, and
mountain highs mid 60s to 70s. The Delta breeze will diminish
slightly by the weekend allowing the southern Sacramento valley
highs to reach the low 90s.

HEC

&&

.AVIATION...

VFR conditions expected next 24 hours. Winds generally 10 kts or
less for TAF sites with gusts to around 30 knots in vicinity of
the Delta.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$


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