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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska
259 am akdt Tuesday Oct 21 2014

Discussion...

Models...initialized well against 06z surface. Continue to handle
features well in the short term with models starting to diverge
beyond day 5. Will nudge current forecast to a blend of the
latest models in the short term.

Aloft...at 500 mb...512 dam low continues to move south over the
Alaska Peninsula this morning and will combine with a 516 dam low
over the southern Gulf of Alaska by Wednesday afternoon...then
move southeast as it weakens and drifts into Canada. As the low
drifts into the Gulf weak ridging will develop west to east over
the interior beginning this afternoon. Ridging over the western
Bering Sea will move over the central Bering Sea by Wednesday
morning...and over the West Coast by early Thursday morning. A 535
dam high over the high Arctic will weaken and dissipate by
Wednesday morning. A trough extending from a low in high in the
Canadian Arctic will back over the Arctic coast with a 527 dam
low developing over Barrow by Wednesday morning. A 496 dam low
over western Siberia will remain quasi stationary through Friday
then drift over the Sea of Okhotsk by Sunday morning. A 510 dam
low will develop just west of the Gulf of Anadyr by Thursday
morning and remain stationary into Saturday morning. A shortwave
associated with the low will move over the West Coast late
Thursday night. At 850 hpa...temperatures in the interior cool 4
to 6 degrees celsius next 48 hours. Temperatures over the coastal
areas remain steady into Thursday...then a slight warm up over the
southwest coast Thursday afternoon into Friday.

Surface...a 1040mb high in the high Arctic remains quasi
stationary through Friday as it weakens to 1033mb...then moves
west late Friday. A complex low pressure pattern over southwest
Alaska with a trough lying over the north slopes of the Alaska
Range this morning will continue to fall apart with the trough
filling by late morning and the low being absorbed by a 973mb
low in the northwest Pacific this afternoon. The low will spin
back up over the southern Gulf of Alaska by Wednesday
morning...then move south. As the low moves south a weak ridge of
high pressure will build over the eastern and central interior
early Thursday...remaining over the area through the weekend. A
1000mb low will develop in the northern Gulf of Alaska Thursday
evening then deepen to 998mb over Prince William Sound Saturday
morning. A ridge of high pressure that extends south from the
high Arctic to a 1021mb high over eastern Siberia and then south
over the western Aleutians will move to the central Bering Sea by
Wednesday morning...then over the West Coast by early Thursday
morning...and to the eastern interior by Friday morning. A 996mb
low in Kamchatka Bay will move east to the northwest Gulf of
Anadyr by early Thursday morning at 986mb. A weather front
associated with the low will move across St Lawrence Island
Thursday morning and to the West Coast by Thursday
afternoon...weakening as it works its way into the middle Yukon
valley and dissipating.

Arctic coast and Brooks range...strong easterly flow continues.
Winds will diminish on Thursday...but until then some short
periods of stronger winds can be expected. No break in the low
clouds...flurries...snow showers...occasional freezing
drizzle...patchy fog...local blowing snow...low stratus ceilings.
Temperatures will remain pretty steady. No significant snow or
ice accumulation is expected. Cloud top phase from GOES at
210815z indicates most areas east of Barrow have only ice...this
indicates to ME less chance for freezing drizzle in that area
right now.

West Coast and western interior...as low moves south and ridge
moves over the area flow falls apart and light winds will move
over the area Wednesday. Today expect northerly winds in the
Bering Strait of 20 to 30 miles per hour. Inland winds northeast to east at 5
to 15 miles per hour with some gusts over the hills to 25 miles per hour. Flurries and
scattered snow showers over the lower Yukon Delta will end late
this morning. Additional snowfall up to an inch locally. Elsewhere
expect just a few flurries as weak upper level shortwave moves
over the area. Temperatures over the coast steady with inland
areas seeing temperatures fall a couple degrees through early
Thursday.

Central and eastern interior...shortwave aloft spinning up over
the area will continue the mostly cloudy conditions and kick off
some flurries across most of the region. Could see a little
enhancement over the White Mountains and fortymile country that
may produce some measurable snowfall...but still expect it to be
less than an inch. Still maintaining a fairly strong gradient
across the interior today that will not fall apart until Wednesday
so expect some gusty northeasterly wind gusts to 35 miles per hour on
summits...mainly north of Fairbanks. A slow cool down the
remainder of the week across the interior.

&&

Coastal hazard potential days 3 and 4...front approaches the West
Coast Thursday then west to southwest winds persist into Saturday.
This may push water into Norton Sound for an extended period of
time.

&&

Afg watches/warnings/advisories...

Heavy freezing spray warning for pkz220-pkz225-pkz230-pkz235-
pkz240-pkz245.

Gale Warning for pkz225-pkz230-pkz240-pkz245.

Small Craft Advisory for pkz210-pkz220-pkz235.

&&

$$

Sdb Oct 14

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