Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
1253 PM akdt Friday Apr 24 2015
Models...continue to do well in the short term to around 60
hours. There is a little better agreement in the Middle Range...but
the extended periods still show major differences in solutions.
Will lean on a blend of models in the short term...except leaning
toward the NAM for winds. Also...will nudge the current
temperature grids up a degree or two for tomorrow.
Aloft...at 500 hpa...515 dam closed low over western Bristol Bay
will move southeast across the Alaska Peninsula today to 250 nm
southeast of Sand Point by Saturday morning...then to 400 nm
south of Prince William Sound by Sunday morning as it becomes
quasi stationary through Tuesday morning before moving north.
Ridging over the western Bering Sea will slide east to the central
Bering Sea by Saturday morning...then over the pribilofs and
eastern Bering Sea by Sunday morning. A 552 dam high over Canada
with ridging extending to the west over the Arctic coast will
slowly slide to the north. This will leave a col over most of the
state...but a couple weak vorticity maximums will move north over the
alcan border this weekend. Warm advection will push freezing
levels over the southeast interior up to around 6000 feet during
the afternoon and evening hours by Monday. At 850 hpa...weak warm
air advection continues over the interior through the weekend with
temperatures steady over the coastal areas.
Surface...995 mb low 100 nm northwest of Cold Bay will move to the
northeast Pacific by Saturday morning...then move north into the
south central Gulf of Alaska by Sunday morning. A broad area of
low pressure will remain over Mainland Alaska with leeside trough
north of the Alaska and Brooks ranges. Weak southeast flow will
continue to pull a little moisture into the eastern interior.
Thermal trough developing from Tanana east this weekend as strong
ridge persists over interior Canada.
Arctic coast and Brooks range...generally light easterly flow over
the area with winds less than 20 miles per hour...the exception is east of
deadhorse where a gradient pinch will kick winds up this
evening and tonight to 25 to 40 miles per hour...gradient relaxes tomorrow
and winds will drop off to around 15 miles per hour. With the easterly flow
comes the stratus and fog potential...not much showing up on the
microphysics products or the GOES probability products...but the
Arctic stratus will show up. Not expecting much change in the
temperatures through the weekend.
West Coast and western interior...clearing trend will continue
across the area. Light offshore flow along the coast with light
winds inland. Dry conditions through the weekend will continue
the slow melting of the snow pack and ice. Temperatures will be a
couple degrees warmer during the day...but also a couple degrees
colder at night with the loss of the cloud cover.
Central and eastern interior...the quiet pattern continues. Slight
chance of thunderstorms or showers over the hills north and east
of Fairbanks this weekend...otherwise mostly sunny conditions will
prevail. Temperatures in the 50s to lower 60s around Fairbanks and
in the 50s for most other areas south of the Yukon river. Low
temperatures in general will continue to fall below freezing
through the weekend. Light northeast to southeast winds for most
areas...the exception will be near the Alaska Range some channeled
areas and near passes could see gusty wind during the day to 35
miles per hour.
Extended forecast for days 5 to 8...not a lot of changes as
cyclonic flow persists...the low in the Gulf will move overland
and into the matsu valley. The thermal trough still looking good
for development over the eastern interior. So still expecting more
showery type precipitation and higher potential for thunderstorm
activity as we get later in the week.
Fire weather...slight chance for showers Saturday and still
looking like a better chance on Sunday. Slight chance of
thunderstorms east of Fairbanks on the weekend. Relative humidity
will fall into the 30 percent range for most areas during the
day...and into the 10 to 20 percent range near the Alaska Range
this weekend. Expect fair to good recovery to 60 percent or better
at night. Winds generally less than 15 miles per hour...except gusty winds to
35 miles per hour near Alaska Range passes and channeled areas. Temperatures
will continue to fall below freezing at night with a slow warm up
during the day.
Gale Warning for pkz245.
Brisk Wind Advisory for pkz240.
Sdb Apr 15