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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska
405 am akdt Wednesday may 27 2015


Models...good consensus in the short term and the models have had
good run to run continuity the last couple days. Will nudge the
current gridded forecast to a blend of the latest models but
expect that will not change anything very much. Per normal GFS
precipitation coverage seems a bit overdone so will blend with the
NAM to pare it back a bit. Will use a blend of models to come up
with quantitative precipitation forecast values for the Brooks range and Arctic plain Thursday
and Friday. 500 hpa...a 570 dam high with a closed center has
developed over the northern Yukon territory and will drop south
over the upper Yukon and fortymile country this morning. This
will produce some strong subsidence over the area today and
tonight. The high continues to strengthen to 575 dam as it is
absorbed into the ridge over the northwest Pacific Thursday. The
558 dam closed low that is undercutting the high will move
continue to move south over the southeast Panhandle through
Thursday morning...then move into the central British Columbia
interior. A weak shortwave associated with a 521 dam low over the
western Bering Sea will move over the lower Yukon Delta this
morning then north to the Brooks range by late afternoon.
Another...stronger shortwave will move over the pribilof island
by late this afternoon then continue northeast into the interior.
The shortwave will move to lie from the Bering Strait to Prince
William Sound by Thursday morning continuing northeast to lie
from Point Hope to Glennallen by Thursday afternoon...and from
Point Lay to Northway by Thursday evening...then from Barrow to
Old Crow by Friday morning.

Surface...the thermal trough lies from Kotzebue to just north of
Fairbanks to Northway and will slowly move north and pull back
into the Yukon territory today as a weather front moves up the
West Coast. The thermal trough will lie from Ambler to feet Yukon
and east by late this afternoon...then be confined to the upper
Yukon Flats and eastern fortymile country Thursday. It will reform
over the upper Tanana Valley Saturday. A 1029 mb high 200 nm
northwest of Barrow will move to 200 nm north of Barrow by
Thursday afternoon...then remains stationary through Friday. A 990
mb low in the western Bering Sea will weaken and dissipate as a
976 mb low moves from the northwest Pacific to the western
Aleutians by early Thursday...then into the west central Bering
Sea by Thursday night then slowly moves northwest until it is
absorbed by a 987 mb low in the Sea of Okhotsk on Saturday. A 1034
mb high in the northeast Pacific will remain quasi stationary
through Saturday. A decaying occluded front will work its way
north up the West Coast today bringing showers to the lower Yukon
Delta...Norton Sound...and the Bering Strait this
morning...spreading north this afternoon to include the Seward
Peninsula and parts of Kotzebue Sound and the upper Noatak and
Kobuk basins.

Arctic coast and Brooks range...with the high center just north of
Barrow expect onshore flow from Barrow east and offshore flow to
the west of Barrow. In either case the stratus will not be moving
very far or going away. Areas of dense fog this morning so will
headline zones 202...203 and 204. Chance of freezing drizzle this
morning...then patchy drizzle through the day...but not looking
for any accumulation. Visibility improving to above 1 mile for
most areas after 9 am. Winds generally 5 to 15 miles per hour through
Thursday afternoon then picking up a bit as the front moves
through the area on Thursday evening. Showers likely across the
area with the front from Thursday afternoon in the west spreading
east through Friday morning. Precipitation could be heavy in some
areas as models are indicating over an inch of rain possible in
the Brooks range and central Arctic plain.

West Coast and western interior...decaying occluded front
spreading rain showers north along the coast from the lower Yukon
Delta to Norton Sound to the Bering Strait this morning. Showers
work inland a bit through the day but remain mostly west of the
middle Yukon River Valley. Rainfall amounts will be less than one
tenth of an inch for most areas. Some showers developing in the
upper Noatak and Kobuk valleys later today may develop into
thunderstorms as models show some weak instability in the area.
The remnants of the front get picked up by the upper level
shortwave moving northeast across the state on Thursday and will
spread some heavier amounts of rain into the Noatak...Kobuk and
Koyukuk basins Thursday evening and Friday morning...this bears
watching as models are making significant amounts of precipitation
of over an inch in some of those areas. Northeast to southeast
flow across the area with mainly offshore flow along the coast and
light winds inland.

Central and eastern interior...mostly cloudy conditions will
prevail over the area today as the upper level low spins moisture
out of the Gulf into the interior. Some showers or sprinkles today
across the area...but not expecting too much. The only area for
potential thunderstorm activity will be along the border in the
far southeast interior. The upper level high over the area will
squash any convection. Some clearing in the afternoon will allow
for temperatures to climb into the 70s for most areas. Winds
westerly at 5 to 15 miles per hour for most area today and tonight.


Fire weather...some drying today but most areas will see relative
humidity values above 25 percent. Winds will generally be light
so no need for red flags today...however with the upper level
trough moving across the area on Thursday winds may be gusty into
the thermal trough to 25 miles per hour requiring red flags. Will need to
take a good look at guidance for zones 218...219...220...221...223
and 224. Fuels remain very dry...but Greenup continues and it
looks like relative humidity values are starting to react to the
greener conditions.


Hydrology...models are trying to make quite a bit of
precipitation over the central Brooks range and central Arctic
plain starting Thursday afternoon. With already saturated
conditions in the Arctic plain and rivers and streams running high
this could be problematic. Will need to keep a keen eye on the
next couple model runs for that area. Will have the next shift
check with the river forecast center to see how their models runs
are handling the quantitative precipitation forecast amounts over the area and what if any
reaction the rivers will have.


Afg watches/warnings/advisories...

Brisk Wind Advisory for pkz225-pkz230.



Sdb may 15

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