Special Weather Statement, NWS Sacramento, CA

Area Forecast Discussion
National Weather Service Sacramento CA
222 PM PDT Mon May 29 2017

.SYNOPSIS...
Temperatures a little above normal for today followed by a
cooldown Tuesday and Wednesday. Isolated afternoon showers or
thunderstorms possible over the mountains through mid week.

&&

.Discussion...(Today through Thursday)

Water vapor imagery and model analysis indicated a ridge of high
pressure centered over the Great Basin shifting eastward as a
negatively tilted shortwave trough of low pressure off the
northern California coast brought high level clouds inland.
Visible imagery showed a cumulus field developing during the early
afternoon hours in the Sierra foothills and mountains.

Latest short term hires guidance depicts some isolated showers and
thunderstorms developing this afternoon ahead of the upper level
disturbance moving onshore, with initiation sometime between 1
and 5 pm. Models vary on coverage and duration of the storms, but
the main activity for isolated development should remain for the
Sierra mountains along and south of I-80 and diminish by the late
evening. Breezes through the delta will begin to increase through
the evening.

A series of shortwave disturbances rotating around the main upper
level low in the northeast Pacific will bring chances for
continued isolated showers and thunderstorms for the Sierra
mountains and bring cooler weather to the forecast area. High
temperatures Tuesday will drop by 5 degrees to return to near
normal for this time of year. Breezes through the delta will
continue through the day Tuesday.

Showers will continue Wednesday as the upper trough lingers over
northern California under northwest flow. High temperatures will
be on the cooler side of normal. Upper level flow shifts to more
stable flow on Thursday with dry weather expected and a return to
near to slightly above normal temperatures.

&&

.EXTENDED DISCUSSION (Friday THROUGH Monday)

Warm, dry weather will persist through the extended period. High
pressure continues building Friday with most valley locations
reaching high temperatures in the 90s by Saturday. Temperatures
will remain above normal through at least early next week. Current
model runs show a shortwave trough clipping our area Sunday but
not enough moisture to produce any precipitation chances.
Temperatures do not look to be affected by this small system, and
high pressure will continue to build after it passes.

HEC

&&

.AVIATION...

VFR conditions expected through the next 24 hours for TAF sites.
Winds generally 10 kts or less, increasing to up to 15 kt with
gusts up to 20 kt after 00z in the southern Sacramento valley and
northern San Joaquin valley. Gusts to around 30 knots in vicinity
of the Delta. Isolated TSRA possible in the higher mountains,
18z-06z.

&&

.STO WATCHES/WARNINGS/ADVISORIES...

None.

&&

Special Weather Statement
National Weather Service Sacramento CA
318 PM PDT MON MAY 29 2017

CAZ069-292300-
West Slope Northern Sierra Nevada CA-
318 PM PDT MON MAY 29 2017

...SPECIAL WEATHER STATEMENT...

At 318 PM PDT, Doppler radar was tracking a strong thunderstorm over
Kyburz, or 12 miles northwest of Kirkwood. This storm was nearly
stationary.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Kyburz.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3866 12018 3866 12037 3884 12042 3885 12015
      3884 12012 3883 12012
TIME...MOT...LOC 2218Z 158DEG 2KT 3878 12028

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Special Weather Statement
National Weather Service Sacramento CA
320 PM PDT MON MAY 29 2017

CAZ068-292300-
Western Plumas County/Lassen Park CA-
320 PM PDT MON MAY 29 2017

...SPECIAL WEATHER STATEMENT...

At 320 PM PDT, Doppler radar was tracking strong thunderstorms along
a line extending from Lake Almanor Country Club to Caribou. Movement
was north at 15 mph.

Half inch hail and winds in excess of 30 mph will be possible with
these storms.

Locations impacted include...
Chester, Prattville, Lake Almanor Country Club, Seneca, Lake Almanor
Peninsula, Lake Almanor, Caribou, Keddie, Lake Almanor West, Twain,
Hamilton Branch, Canyondam, East Shore, Almanor, Paxton and Indian
Falls.

LAT...LON 4026 12106 4024 12104 4023 12101 3996 12093
      4004 12128 4031 12125 4033 12106
TIME...MOT...LOC 2220Z 160DEG 12KT 4025 12113 4010 12114

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Special Weather Statement
National Weather Service Sacramento CA
355 PM PDT MON MAY 29 2017

CAZ069-292345-
West Slope Northern Sierra Nevada CA-
355 PM PDT MON MAY 29 2017

...SPECIAL WEATHER STATEMENT...

At 354 PM PDT, Doppler radar was tracking a strong thunderstorm over
Riverton, or along Highway 50 between Pacific house and Kyburz,
moving west at 15 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Riverton, Pacific House, Fresh Pond, Pollock Pines and White Hall.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3882 12030 3866 12033 3871 12057 3884 12059
TIME...MOT...LOC 2254Z 101DEG 12KT 3876 12044

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Special Weather Statement
National Weather Service Sacramento CA
421 PM PDT MON MAY 29 2017

CAZ069-300000-
West Slope Northern Sierra Nevada CA-
421 PM PDT MON MAY 29 2017

...SPECIAL WEATHER STATEMENT...

At 419 PM PDT, Doppler radar was tracking a strong thunderstorm over
Cisco, moving north at 5 mph. This storm will likely impact travel
along interstate 80 from Blue canyon to Kingvale.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Cisco, Emigrant Gap, Sugarbowl Ski Resort, Kingvale, Lake Spaulding
and Rattlesnake Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3896 12032 3890 12055 3935 12071 3939 12043
TIME...MOT...LOC 2319Z 165DEG 5KT 3927 12054

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