Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
254 PM EDT Sat Mar 30 2019
Valid 12Z Wed Apr 03 2019 - 12Z Sun Apr 07 2019
Models and ensembles reasonably agree that a closed upper
high/ridge will split with a main portion set to slowly retreat
from mainland Alaska northwestward to northeastern Russia over the
next week. This will allow ample arctic troughing and height falls
dig southward through the cooling/unsettled but moisture limited
Interior. Guidance has been inconsistent with the handling of this
energy conduit. The WPC product suite was primarily derived from a
composite blend of the compatable 12 UTC GEFS mean and the 00 UTC
ECMWF ensemble mean. This solution is between recent ECMWF
solutions that cut more troughing underneath the closed high and
GFS runs that become eastward displaced over time. These are
characteristc biases of both models. Underneath, this pattern will
coincide with a focus of mid-upper level mean troughing along and
south of 50N, holding a main Pacific storm track south of Alaska
even the Gulf of AK for much of next week. The potential phasing
of uncertain Arctic trough energies from the interior and Pacific
system energies underneath could lead to more northward deepened
low motions back up into the Gulf of Alaska by next weekend.
Precipitation will be mainly limited to parts of the Aleutians and
increasingly over the Panhandle and into southern coastal Alaska
with onshore flow ahead of the potential system to threaten the
Gulf of Alaska by next weekend.
Schichtel
Bullet points from the WPC Days 3-7 Hazards chart can be found 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