Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
345 PM EDT Fri Jun 21 2019
Valid 12Z Tue Jun 25 2019 - 12Z Sat Jun 29 2019
A relatively benign weather pattern will persist across Alaska
during the medium range, with a persistent upper-level ridge axis
extending from the North Pacific across western mainland Alaska
north to the Arctic. Shortwave energy will traverse a mean upper
trough centered across the western Bering Sea/western Aleutians,
with a couple waves of low pressure traversing a weakening surface
front across those areas. Meanwhile, on the eastern periphery of
the upper ridge, weakening arctic cold fronts should move
southward, bringing a return to near or slightly below average
temperatures to the North Slope and eastern portions of the
Interior, along with the potential for isolated to scattered
showers.
The WPC forecast was based heavily on the 12Z GFS and the GEFS
ensemble mean, which resulted in a forecast relatively close to
WPC continuity. The GFS has shown a much higher degree of
run-to-run consistency across the past several runs relative to
the ECMWF. The ECMWF has struggled with large changes as to
whether the upper ridge breaks down and the resultant interactions
of arctic and Pacific shortwave energy.
Ryan
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