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Area forecast discussion
National Weather Service Sacramento California
130 PM PDT sun may 27 2018

Synopsis...
temperatures well above normal through early this week. Afternoon
and evening thunderstorms possible mainly over higher terrain
starting on Tuesday. Another cool down is expected for middle to
late next week.

&&

Discussion...
warmer and drier conditions have returned to the region as ridge
of high pressure continues to build into norcal. Afternoon
temperatures are running several degrees warmer compared to 24
hours ago, and are currently in the upper 70s and mid 80s across
valley locations. The back end of a departing upper low could have
enough instability to generate a few isolated showers over the
Sierra crest south of Highway 50 this afternoon.

Peak heating is expected on Memorial Day as ridging remains in
control. Temperatures will reach the mid to upper 90s across the
Central Valley with the warmest readings expected over the
northern Sacramento Valley. As a result, there is the potential
for moderate heat risk for sensitive groups including the elderly
and the very Young. Ridging will keep stable conditions across
the forecast area on Monday.

The upper level ridge is anticipated to flatten on Tuesday as an
upstream upper trough approaches from the west. Thus, daytime
highs will slightly cool down, mainly near the Delta influenced
areas. However, there is still the potential for moderate heat
risk mainly over the northern Sacramento Valley. Elevated
instability could be enough to bring afternoon and evening
thunderstorms on Tuesday over the northern Sierra mainly south of
Highway 50, and over eastern Shasta County and Lassen National
Park.

Synoptic cooling associated with the upper trough, as well as
onshore flow, will result in daytime highs near or slightly below
normal on Wednesday. Expect valley highs in the 80s, and 50s to
70s over the mountains. Afternoon and evening showers and
thunderstorms are possible over the northern mountains, and near
the Sierra crest south of Highway 50 by midweek.

&&

Extended discussion (thursday through sunday)
another trough is expected to cool temperatures back to below
average late this week along with bringing a chance for a few
showers and thunderstorms across the northern portion of the
forecast area. Ridging is forecast to return next weekend bringing
temperatures back to around average. &&

Aviation...
VFR conditions expected the next 24 hours. Local north wind gusts
15-20 kts northern Sacramento Valley starting late morning
through the afternoon. &&

Sto watches/warnings/advisories...

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