Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 211112
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
312 AM AKDT Sat Apr 21 2018

.DISCUSSION...

Models...They have handled this latest system in the interior
quite well. The continue to show good run to run continuity,
though there are some minor differences in the precipitation
forecast with the NAM being an outlier early in this set of
solutions. They continue to handle the shortwave digging
southwest across the state with no significant differences.
Will use mainly the SREF solution for precipitation, otherwise
will lean on an equal blend of the solutions.

Aloft...at 500 hpa...Ridging over the Dateline with a 545 dam
center has moved over the Siberian Coast this morning with
ridging extending south over the Dateline across the Bering Sea,
and east over the Arctic Coast. By Sunday morning the center will
move 200 nm southwest of Wrangel Island with ridging south over
the Western Bering Sea, and east over the Arctic Coast. A 500 dam
center 200 nm northeast of Banks Island continues to move
northeast over the Archipelago. The 504 dam center that was over
MacKenzie Bay yesterday continues to dig southwest over the state
and is over the Lower Yukon Delta this morning, and will continue
to the Pribilof Island by Sunday morning. A trough remains across
the state from the low over Demarcation Point. Ridging is building
over the Southeast Interior this morning as a weak trough spins
into the interior and dissipates. The ridging will continue to
build into the interior with 540 dam heights over the southeast
interior by Sunday afternoon. By Monday morning the low over the
Pribilofs will merge with a low that moves to the Central
Aleutians into a 500 dam low 100 nm north of Adak, and a shortwave
associated with it will swing north into the interior and
dissipate. Then, by Tuesday evening the low will be near St
matthew Island at 502 dam and 540 dam heights associated with the
ridging will push into the Central Interior. At 850 hpa...-10C
isotherm has already started moving back north and lies from Eagle
to Tanana to Grayling to Nunivak Island. By Sunday morning it
will lie from Chalkyitsik to Bettles to Ambler, then north to
Point Barrow. The -20C isotherm will exit stage northeast later
this morning. Some above 0C patches will make an appearance over
the southern interior starting Monday.

Surface...High pressure remains over the Arctic, with low pressure
to the south. The high pressure to the north consists of a 1026
mb high 150 nm east of Wrangel Island and a 1026 mb high over the
Central Arctic Plains. Ridging extends east over the Arctic
Coast, and south over the Dateline into the Central Bering Sea.
Low pressure to the south consists of a trough extending from a
983 mb low south of Unimak Island to a 995 mb low over Kuskokwim
Bay to a 1006 mb low over the southern Yukon Territory. The low
over Kuskokwim Bay will merge with the low south of the Alaska
Peninsula this afternoon, then another low will spin up over
Bristol Bay and move over the Pribilofs by Sunday afternoon. The
low to the south will move east, then north to be over Kodiak
Island by Monday morning at 995 mb as a broad low pressure system
moves into the Southwestern Bering Sea at 978 mb absorbing the low
over the Pribilofs. The riding over the Arctic Coast will
gradually slide to the east and by Monday morning a 1026 mb center
will be 250 nm north of Deadhorse. Leeside troughing develops
north of the Alaska Range tonight, then weakens Sunday. Leeside
troughing will build back in stronger on Sunday night and Monday.
Northeast to southwest oriented pressure gradient will persist
across the state.

North Slope and Brooks Range...Will be a pretty nice day in the
Arctic. Mostly clear conditions will prevail though some high
clouds will be moving through the area east of Point Barrow. There
is also some stratus out over the Arctic, but do not expect it to
make it to the coast until tonight at the earliest. Winds
generally 5 to 15 mph from the southwest and west will gradually
swing around to northeast and east. Temperatures 5F to 15F warmer
by Sunday afternoon.

West Coast and Western Interior...Pretty quiet again today.
decaying front will spin into the area bringing some showers to
the areas south of Galena. Expect it to start out as snow but
change to rain from Anvik south. Locally up to 2 inches of snow
could fall around McGrath. Most areas will see some clouds as the
front decays, but a trough develops over the coast. Relatively
strong winds of 10 to 20 mph gusting to 30 mph locally will
continue through the morning as they slowly diminish to 5 to 15
mph by late afternoon. Temperatures warming 5F to 15F by Sunday
afternoon.

Eastern and Central Interior...Flurries tapering off early this
morning then clearing across the area as the front spins to the
west and decays. Winds northeast 5 to 15 mph with winds gusting to
30 mph locally over summits. Winds near the Alaska Range Passes will
increase from the south gusting to 35 mph Sunday morning as
leeside troughing develops then weaken in the afternoon. The gusty
winds will redevelop in the Passes late Monday with gusts to 45 mph
expected. Temperatures on the rise and will be 5F to 15F warmer by
Sunday afternoon. High will be in the 50s starting Monday for most
of the Middle Tanana Valley.

&&

Coastal Hazard Potential Days 3 and 4...None.

&&

.Fire Weather...Minimum Relative Humidity values above 30 percent
again today. High temperatures in the 30s to lower 40s today.
Winds northeast 5 to 15 mph with local gusts to 25 mph. There is
no threat of thunderstorm activity.

&&

Extended forecast for days 4 to 7...A broad area of low pressure
around a low near the Pribilofs will persist with a trough
extending across the state north of Fairbanks. Showers over the
Lower Yukon Delta mid week, with showers over the Central and
Eastern Interior Late in the week as a low pressure center develop
over the Upper Yukon Flats. Expect temperatures to warm to near
seasonal normals across the forecast area. In the Central Interior
highs will be in the upper 40s to mid 50s, with overnight lows
around 30.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Heavy Freezing Spray Warning for PKZ200-PKZ210.

Small Craft Advisory for PKZ200-PKZ210-PKZ220.

Brisk Wind Advisory for PKZ225.&&

$$

SDB APR 18



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