Scientific Forecaster Discussion
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Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
208 PM akst Sat Dec 15 2018
the long wave pattern consisting of a trough over the Bering Sea,
western Alaska and the Gulf of Alaska with a ridge over western
Canada will persist through most of next week, with ridging
building back over eastern Alaska next weekend. Weak south flow aloft
will persist through much of next week over the interior and
North Slope of Alaska. A series of short wave troughs will bring
periods of snow to the interior and North Slope the first part of next
week, with most of the snow in the western interior and south
slopes of the Brooks range. As flow weakens by mid-week snow will
develop in the eastern interior as well. Near normal temperatures
will persist over the interior through mid-week, while the North
Slope and West Coast remain colder than normal.
A 4950m h500 vertically stacked low near Point Lay will remain in
place through 3pm sun then drift north. An area of flurries
around this low will persist.
A short wave trough extending south from the Point Lay low will
move along the West Coast of Alaska sun PM then over the western
interior Mon. Snow showers along and behind this trough are
occuring along northwest facing shores with open water to the north such
as zone 213 and 214.
a 1002 mb low 60 nm north of Point Lay will persist through 3pm
sun then move north and weaken Mon. A low pressure extending
east from this low and north of the Arctic coast of Alaska will
move north through sun.
A low pressure trough from Point Lay to the Yukon Delta will
persist through sun and then move inland on Sun night. Snow
showers are occuring west of this trough along north facing
coasts. Expect north winds 10-20 kt west of this trough to
increase to 15-25 kt sun PM and continue into Mon and Tue.
This will cause some blowing snow sun PM-Tue along western CAPES.
An Arctic warm front stretching from Old Crow to Livengood to
Denali will move to Arctic Village to a 992 mb wave near Coldfoot
to Nikolai by 3am sun. By 3pm sun there will be a 992 mb low 100
nm east of Demarcation Point with the front from there to Arctic
Village to Nikolai. By 3am Mon there will be a 990 mb low 200 nm
north of Demarcation Point with the front to Old Crow to
minchumina, then persisting in place through Tue. There is a
narrow band of snow along this front now that will taper off
tonight. Will see less than 1 inch of snow along this front
tonight in zones 227 226 221 220 219 218. Temperatures will be
less cold under the snow and clouds along this front. As the
frontal wave low moves north of the Arctic coast sun PM, expect
winds to turn west 15-20 kt over zones 203 and 204 late sun
causing some blowing snow and cold wind chills.
A strong low in the Gulf of Alaska is spinning a warm front north
that will move over the southeast interior on sun, and then over the
western and northern interior by Mon. A low developing along
this front over the western interior Mon will move to the central
Brooks range by Tue. This will cause snow to develop over the
western and northern interior Mon and continue into Tue. Expect
2-4 inches of snow Mon-Tue over the western and central interior
from this front and low. This feature will bring limited moisture
into the eastern interior due to weak to moderate Chinook winds
there Mon and Tue. This feature will also increase the gradient
and cause north winds to increase along the West Coast and western
Brooks range Mon and continue into Tue causing areas of blowing
snow in those areas.
at the surface models initialize at 12z about 4 mb too weak on
high pressure located over NE Russia, and about 8 mb too weak on
low in southern Gulf of Alaska. Low in the Gulf of Alaska is now slowly
filling, so expect models to come closer to reality by tonight on
the Gulf low, but expect them to remain too weak on NE Russia
high pressure. For this reason will bump up model winds 3-5 kt
along West Coast where gradient between these two features meet
from tonight through Tue.
Models initialize well aloft and similar solutions through Mon.
Differences show up Mon night and Tue with areal coverage of
precip in interior where the GFS moves precip further east than
the NAM and ecmf. Given the weak southerly flow with downslope
conditions forecast Mon night and Tue, favor the NAM and ecmf in
keeping the precip mainly west of Fairbanks and zone 222.
Beyond Tue, looks like models again have agreement on long wave
persisting over Mainland Alaska through late next week, with ridging
building back over eastern Alaska next weekend.
Coastal hazard potential days 3 and 4...
north winds 25g35 knots over zone 213 Mon and Tue will cause
elevated surf and limited freezing spray at Savoonga. With ice
edge now near the Bering Strait waves/surf will be limited.
heavy freezing spray warning for pkz210.
Small Craft Advisory for pkz210.
Brisk Wind Advisory for pkz220.