Scientific Forecaster Discussion
fxak69 pafg 251046
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
246 am akdt Tue Apr 25 2017
Models...does not appear much has changed the last few days as
the GFS, ECMWF, and sref seem to be overdoing the precipitation
coverage and probabilities over the southern interior in the short
term, so will lean on the NAM for coverage today. Aloft the
models are in pretty good agreement out to around 90 hours, and
they initialized well against the 25/0600z surface analysis.
Aloft...at 500 hpa...ridging extends persists across the interior
extending from Whitehorse yt to a 534 dam high over the Chukchi
Sea, but will weaken a bit in place as a 508 dam center over the
eastern Arctic moves to Banks Island by Wednesday afternoon, and
an associated trough pushes south over the Brooks range. The low
will continue to move east and drag the trough with it. A 513 dam
low over the central Aleutians will wobble around today, then move
slowly east to be over Unalaska by Thursday morning at 525 dam.
The 534 dam high over the Chukchi Sea will slowly move east to be
Over Point Barrow by Thursday afternoon at 537 dam, then merges
with the ridge as it moves over the eastern Brooks range Friday.
The low over Unalaska will continue to weaken as it moves east to
northern British Columbia and dissipates. A 519 dam low in the sea
of ohkotsk will move east to be over Shemya by Saturday
afternoon. At 850 hpa...temperatures a bit cooler as they fall 5
to 7 celsius over the next couple days across the forecast area
before starting to warm again.
Surface...a 1022 mb high over the western Arctic with ridging
extending southeast over the Arctic coast will slowly move
southeast then merge with a 1023 mb high over the northwest
territories Thursday while ridging persists over the Arctic. Weak
leeside troughing in the upper Tanana Valley today with a 1000 mb
low developing around Delta Junction will fall apart tonight. A
987 mb low over the central Aleutians will slowly weaken as an
associated weather front moves north across the Gulf of Alaska.
The front will move over the coast Wednesday and gradually fall
apart as the low continues to weaken and dissipates over the
Alaska Peninsula Friday.
Arctic coast and Brooks range...cold front pressing down over the
Arctic coast will bring some flurries to most areas with low
ceilings. No significant accumulations. Patchy fog. Winds
generally northeast to east at 10 to 20 mph with the strongest
winds over the northwest coast.
West Coast and western interior...some showers of rain and snow
mainly south of the Bering Strait the next couple days. Mainly
rain, but mixing or changing to snow overnight north of the lower
Yukon Delta. Strong winds out on St Lawrence Island will be
gusting around 40 mph.
Central and eastern interior...cloudy the next day or so, with
sprinkles over the southern interior, and sprinkles or flurries
from the Yukon Flats north. Some gusty gap winds to around 30 mph
in the Alaska Range today, otherwise winds northeast to east at 5
to 15 mph.
Fire weather...cloudy today with sprinkles, but no wetting rains
expected. Relative humidity values falling to around 30 percent
in the upper Tanana Valley near Northway for a short time this
afternoon. Cloudy conditions will persist through most of the
week. Slightly drier later in the week. No significant winds
expected through the weekend.
Small Craft Advisory for pkz210.
Brisk Wind Advisory for pkz220-pkz225-pkz230.