Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 211642

Area Forecast Discussion
National Weather Service Sacramento CA
942 AM PDT Mon May 21 2018

Afternoon and evening thunderstorms possible over higher terrain
this week into the weekend. Seasonal temperatures continue across
the region.


Partly cloudy conditions this morning, with some lingering showers
in the Sierra south of Highway 50. An upper level low is centered
around Bakersfield, with easterly return flow into Northern
California. Northerly winds over the northern Sacramento Valley
are bringing much warmer temperatures, already 73 degrees at 9 am
in Redding and Red Bluff, about 12-13 degrees warmer than the same
time yesterday. Highs there are expected to reach the low 90s. A
weaker Delta breeze is bringing cool temperatures this morning in
influenced areas, this time without a marine stratus incursion, as
the marine layer is more shallow and the pressure gradient is
weaker. By this afternoon, highs over much of the Valley and
Delta will warm by about 5-10 degrees over yesterday, reaching low
to mid 80s.

Showers and thunderstorms are expected to develop once again this
afternoon and continue into this evening. They focused over the
northern Sierra, while the northern Coastal Range should get a bit
of a break. Storms are not expected to be strong, but could have
a brief periods of heavy rain, small hail, and lightning. EK



Guidance shows an upper level low off the CA coast approaching
interior NorCal late this week. The upper low will push inland on
Saturday. Forecast models indicate enough instability for a
threat of showers and afternoon/evening thunderstorms over higher
terrain, and possibly in the Northern Sacramento Valley. Drier
conditions expected early next week as upper level system moves
into the Great Basin. Daytime highs expected to remain near
seasonal normals through the forecast period with Valley
temperatures in the upper 70s to mid 80s, and 60s to 70s over the
foothills and mountains.



Mainly VFR conditions over interior NorCal next 24 hours except
MVFR/IFR conditions possible in showers and thunderstorms over
the northern Sierra Nevada after 18z Monday. Gusts up to 25 kts
in Delta until 00z Tuesday, increasing to 30 kts overnight. Winds
less than 15 knots at TAF sites.


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