Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
640 PM EST Mon Feb 5 2024
Valid 12Z Fri Feb 9 2024 - 12Z Tue Feb 13 2024
...General Overview...
An active winter pattern will continue across the Alaska domain
going into the extended forecast period with multiple North
Pacific storm systems tracking northeast towards the Gulf region
and the Aleutians, bringing rounds of coastal rain and inland
heavy snow for the southern mountain ranges. These low pressure
systems will be pivoting around a broader upper level low centered
roughly over the southern Bering Sea region for the end of the
week and through the weekend. Meanwhile, a downstream upper level
ridge axis is progged to extend from western Canada to the central
and eastern mainland of Alaska, keeping relatively mild conditions
in place, especially compared to the recent brutally cold weather.
...Guidance Evaluation/Preferences...
The 12Z model guidance suite has a decent overall depiction of the
synoptic scale pattern across the state to close out the work
week. There are some minor timing and placement differences with
the incoming low pressure system approaching the western Gulf by
Friday, and there has been an overall faster and stronger trend
compared to yesterday in bringing the low towards the coast.
Looking ahead to the weekend, model spread grows substantially
across the North Pacific and south of the Alaska Peninsula with
the timing of subsequent low pressure systems, but the feature
with the greatest model agreement is the general upper ridge axis
across the eastern half of the state, similar to what was seen in
yesterday's guidance. A general model blend sufficed as a
starting point in the forecast process for Friday into early
Saturday, followed by more of the ensemble means for the Sunday
through Tuesday time period, with more weighting towards the 12Z
NAEFS.
...Weather/Hazards Highlights...
Precipitation prospects increase going into Friday and Saturday
with the strong low pressure entering the Gulf region and
southeasterly winds advecting deep moisture towards the coastal
terrain of the Alaska Peninsula and extending eastward to the
Prince William Sound region. Several feet of mountain snow is
likely for these areas, and a cold and heavy rain for the coast
with 1 to 3 inches of rainfall likely some areas. There has been
an additional upward trend in model QPF during this time period
over the past 48 hours of model runs. Farther north across the
mainland, a mostly dry weather pattern can be expected. In terms
of temperatures, generally above average conditions are forecast
for most inland areas, and closer to average for the coastal
regions. Sheltered valleys with persistent inversions that are
slower to mix out will be substantially colder than surrounding
hillsides.
Hamrick
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html