Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
620 PM EST Fri Jan 29 2021
Valid 12Z Tue Feb 02 2021 - 12Z Sat Feb 06 2021
...Overview and Guidance/Uncertainty Assessment...
Punctuated upper ridging will linger over the northeastern Pacific
next week as troughing remains in the Bering Sea. Split flow
across the Dateline will keep a southern upper low well south of
the region in the mid-latitudes. This will keep the storm track
largely through the Bering and Gulf as systems try to thread the
needle between positive anomaly centers in the Arctic and Gulf/NE
Pac.
The 12Z GFS and ECMWF paired rather well with their ensemble means
overall, with some agreement from the UKMET/Canadian early in the
period (Tue-Wed) before differences south of the AKPen increased.
The parallel GFS differed much more to the south, bringing the
southern upper low northward to the Aleutians when the ensembles
showed mostly high pressure. By the end of the period, the
models/ensembles showed more timing differences off eastern Asia
into the western Bering with another system, so trended toward the
ensemble mean consensus positions for now. Overall this maintained
good continuity from the forecast yesterday.
...Weather/Hazards Highlights...
Precipitation across the northern Gulf/southern mainland next week
will generally be on the light to modest side, perhaps enhanced by
weaker areas of low pressure into the Panhandle. By next Thu-Fri,
system into the eastern Bering will spread snow across the
Interior as its old triple point weakens but carries moisture
eastward. Differences exist in how much (and when) will be
realized north of the Alaska Range (GFS wetter earlier, but ECMWF
wetter later) as another system late Fri will spread its moisture
eastward as well. For now, a middle ground solution yields a
modest snowfall for Interior locations at least along the west
coast of Alaska. Temperatures will trend milder than normal
through the Tue-Fri period, limiting the below normal temperatures
to the Panhandle and far northeastern areas.
Fracasso
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards 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