Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
507 PM EST Wed Mar 08 2023
Valid 12Z Sun Mar 12 2023 - 12Z Thu Mar 16 2023
...Model Guidance/Predictability Assessment/Pattern Overview...
...Guidance Overview...
The guidance generally agrees on troughing being maintained across
Alaska while ridging varies in strength upstream. Detail issues
are larger in today's guidance. To deal with the uncertainty,
used a compromise of the 12z GFS, 12z Canadian, 12z ECMWF, and 12z
UKMET early on before strongly trending in the direction of the
00z ECMWF/12z NAEFS ensemble means, which were the basis for the
500 hPa height, pressures/fronts, winds. There wasn't much
coverage to the QPF, but to deal with the uncertainty there
blended in some 12z GFS and 12z ECMWF with the 19z NBM. The
remainder of the grids were more 19z NBM based, as usual.
...Weather/Hazard Highlights...
Dry conditions are expected to prevail for much of Alaska with
arctic air remaining in place over much of mainland AK, with
South-Central AK (March 14-15) and the Panhandle (March 12-14) the
most below normal thermally. The tight pressure gradient between
the arctic high centered over northwestern Canada and the
lingering low over the Gulf of Alaska could result in bouts of
strong gusty offshore gap winds most likely across the northern
Panhandle into Saturday. Gale force winds will occasionally visit
the northern Aleutians and the AK Peninsula on the backside of the
upper level trough. Most of the snowfall/rainfall is expected in
the AK Panhandle this period, with chances and amounts expected to
slowly increase from this weekend through mid next week.
Roth
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