Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
359 PM EDT Thu Jun 20 2019
Valid 12Z Mon Jun 24 2019 - 12Z Fri Jun 28 2019
It appears that a retrograding synoptic pattern will gradually set
up across Alaska during the medium-range period. This is in
contrast with a couple of deep level high pressure systems that
are forecast to be nearly stationary over the northeastern and
northwestern Pacific Ocean. Meanwhile, a low pressure system
between Hawaii and the Aleutians is forecast lift northward and
then retrograde toward the western portion of the Aleutians during
the weekend into next week. Global models are in good agreement
with this overall pattern evolution. It appears that much of the
increment weather will be focused across the western Aleutians for
much of next week due to the retrograding cyclone. Farther to the
east, the Alaska Panhandle should be far enough north from the
system to see much impacts if at all, even though the EC ensemble
mean places the trough axis slightly north of all other guidance.
Elsewhere, warm afternoon temperatures and cool mornings should
prevail over the interior sections of Alaska, with occasional
showers due to the presence of a stationary front. Meanwhile,
northern Alaska will remain cool/chilly under a cold upper trough
and a persistent onshore flow from the Arctic Ocean.
The WPC Alaskan grids were derived from a blend of the 12Z ECMWF
and the 12Z GFS together with the 00Z EC mean and the 12Z GEFS
mean, leaning more toward the 00Z EC mean for the longer range
period (days 6-8). This resulted in a forecast fairly close to
yesterday's WPC continuity.
Kong
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
No significant hazards are expected over Alaska during this
forecast period.
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