Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 222204
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
204 PM AKDT Fri Sep 22 2017

.DISCUSSION...

Models...Some significant changes from the solutions yesterday,
but all of them have picked up on them and there continues to be
very good agreement in the near term. Minor height differences
between solutions, but only 2-4 hpa for the major features.
Surface solutions initialized well against the 22/18Z analysis.
Will be utilizing a equal blend for most elements in the short
term with the exception of precipitation will be dominated by the
NAM solution since it has been handling the downslope effect
better than the others. Precipitation type not too complicated
today with snow mainly north of the Brooks Range and rain to the
south.

Aloft at 500 hpa...No significant change fro m the last couple
days as the longwave trough will remain in one form or another
northeast to southwest across mainland Alaska. The ridging over
the Arctic will pull back into Siberia as a 501 dam low near the
pole spins shortwaves south over the Arctic. This afternoon the
trough extends southwest from the Southeastern Beaufort Sea to a
543 dam low over the Eastern Arctic Plain to a 532 dam low over
eastern Norton Sound and southwest over Dutch Harbor. A 547 dam
low that moved across the north Pacific is merging into the flow
south of Sand Point. By Saturday afternoon the trough will lie
from a 544 dam low over MacKenzie Bay to a 528 dam low just south
of Nunivak Island to a 577 dam low in the north Pacific. The low
that merges into the flow will be just south of Kodiak Island at
538 dam as it continues to move northeast. A strong shortwave
swinging south from the pole will approach the Dateline Saturday
evening pushing the ridge over the coast. Ridging over the
southeast mainland will persist into Saturday then get pushed back
to the east Saturday night as the low near Kodiak Island
continues to move northeast to be over Prince William Sound by
Sunday afternoon. The longwave trough will retrograde Monday and
Tuesday and reorient to a more north to south configuration with s
At 850 hpa...Zero isotherm is drifting back to the north and west
and lies from Eagle to Livengood to Togiak, and will push back to
the north and west tonight to lie from Chalkyitsik to Brevig
Mission then south to Togiak. By Sunday afternoon it will lie from
Old Crow YT along the crest of the Brooks Range to Point Hope,
but there will be a large pocket of cold air over Bristol Bay.

Surface...Weak leeside trough developed overnight, but not strong
enough to produce the strong gap winds we normally see, but
expect it to strengthen tonight with winds increasing near Alaska
Range passes. A weather front lies from Burwash Landing YT over
the Alaska Range then southwest to Bristol Bay and will be quasi
stationary through Sunday morning as it weakens. High pressure
will persist north of the Brooks Range with a 1027 mb high 300 nm
north of Prudhoe Bay Saturday morning drifting northeast to merge
with a high over the Canadian Archipelago, but high pressure will
persist over the offshore waters extending west to a 1021 mb high
west of Wrangel Island. A weather front will move southeast
across the Arctic Saturday with the tail of the front approaching
the northwest coast Sunday morning, but will be held offshore by
the high pressure over the area as it continues east. The inverted
trough over the west coast will persist as the low in Bristol Bay
moves over mainland Alaska.

Arctic Coast and Brooks Range...Situation remains similar tonight,
with only some minor changes. High pressure remains over the area
with the high center just offshore. From Point Barrow east expect
low clouds, some light rain or snow and patchy fog with the
onshore flow. Winds will be north to east at 10 to 20 mph east of
the high. To the west some clouds, but periods of clearing skies
with winds east to south at 10 to 25 mph. Over the Brooks Range
and Plains the northeast flow will produce mostly cloudy skies
with occasional light snow or rain in the Plains and occasional
light snow in the central and eastern Brooks Range. No significant
snowfall is expected. Winds will be northeast to east at 5 to 15
mph. Temperatures warming into the mid to upper 30s during the
day, and in the 20s at night.

West Coast and Western Interior...A patch of rain is moving
southwest across the Seward Peninsula this evening and will move
offshore. Inverted trough will remain over the area so a mix of
clouds can be expected with a few showers. The low over Bristol
Bay is sending rain into the Upper Kuskokwim Valley and that will
continue through the night. As the low moves into mainland Alaska
the area of rain will push north over the middle Yukon River
Valley tonight and move southwest over the lower Yukon Delta
Saturday. No significant rainfall is expected through the weekend.
Winds northeast to east 10 to 20 mph along most of the coast,
with winds to 35 mph near the Bering Strait. Inland winds
northeast to east 5 to 15 mph. Temperatures steady with lows in
the 30s, and highs in the 40s.

Central and Eastern Interior...Light rain will taper off this
evening from Fairbanks south, but continue to the north. Cloudy to
Partly Sunny conditions will prevail through the weekend.
Northeast to east winds across the area will range from 5 to 25
mph with the strongest winds north of the Yukon River, the
exception will be the Alaska Range where gap winds near passes
will peak overnight from the south at 35 to 45 mph.

&&

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

&&

.Hydrology...Rivers continue to slowly fall so no flooding issues
at this time.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Small Craft Advisory for PKZ200-PKZ210-PKZ220-PKZ225-PKZ230.

&&

$$

SDB SEP 17



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