Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
410 am akdt Thursday Sep 18 2014
Upper air...models are in good general agreement today through
Friday then begin to disagree in details with incoming upper
level low and trough. Broad low over southwest Alaska will shift
eastward Thursday night and Friday as ridge in central Bering Sea
builds east. A trough with axis over the western interior will
develop Friday night. This is the first of two troughs expected to
move south into Alaska. The first trough will move east across
northern Alaska Saturday through Monday. A second trough will
enter from the northwest Sunday night and Monday then move east
Tuesday through Wednesday.
Surface...low pressure in the northern Gulf of Alaska will move
inland across the Alaska Range...then northeast across the
interior Saturday to the eastern Brooks range by Saturday evening.
Another low will develop over the Gulf of Alaska Saturday night
and move north over the eastern Alaska Range into the western
Yukon territory on Sunday. Models are not yet in agreement on the
details of this second low.
North Slope...pressure gradient between high north of the Arctic
coast near 80 north and lower pressure over interior of Alaska
will produce a moderate east wind through the rest of the week. A
colder airmass will spread across western sections of the North
Slope Thursday night through Saturday with rain showers changing
to snow showers and dense fog ending. Winds may approach advisory
levels on Friday.
West Coast...pressure gradient between low over the Gulf of alaksa
and high over eastern Russia will produce moderate north winds
from the Chukchi Sea...through the Bering Strait...and over Saint
Lawrence Island. High pressure building over the northwestern
Alaska coastal waters Thursday night through Saturday will
diminish the winds. A cold front will move south across the south
Chukchi Sea coast Friday and to Kotzebue Sound Friday night.
Interior...models continue in agreement with developing areas of
rain over much of the central and eastern interior on Saturday.
The focus of the rain will be ahead of an upper level trough
moving east across the interior. Also...a surface low moving north
from the Gulf of Alaska to the interior will be over the Fairbanks
area Saturday morning...then track northeast the rest of the day.
Rain will diminish Sunday morning as the axis of the upper level
low shifts east. For Sunday and Sunday night...rain will increase
over the southeast interior as another low develops over the
southern Yukon territory of Canada. Rainfall amounts Saturday
through Saturday night will vary considerably across the
interior. Greatest amounts...with up to one half inch of rain...
will extend from the western Alaska Range...to Fairbanks...Fort
Yukon and to Arctic Village. More rain for the southeast interior
Sunday through Monday could produce one half inch in that area.
Coastal hazard potential days 3 and 4...none
Small Craft Advisory for pkz210-pkz220-pkz225-pkz235-pkz240-
Gale Warning for pkz210.
Da Sep 14