Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
708 PM EDT Mon Jun 14 2021
Valid 12Z Fri Jun 18 2021 - 12Z Tue Jun 22 2021
...Guidance/Predictability Evaluation...
The WPC Alaskan medium range product suite was primarily derived
from a composite blend of well clustered guidance of the 12 UTC
GFS/ECMWF, 12 UTC GEFS/NAEFS/ECMWF ensemble means and the 19 UTC
National Blend of Models Day 4-8 (Friday-next Tuesday). Improved
guidance forecast spread and continuity over the past two days now
portends above normal predictability for this forecast period.
...Weather/Threats Highlights...
A lead system track from south of the Aleutians to the Gulf of
Alaska will continue to produce a complex series of lows and
frontal systems this week that are expected to produce unsettled
maritime conditions along with a periodic rain focus into the
Alaskan Peninsula and southern to southeast Alaska. Meanwhile, a
warming mean upper ridge is expected to linger over much of the
Interior and North Slope into the weekend, but embedded small
scale impulses may support spotty local activity.
The upper ridge transitions from the weekend into early next week
as the pattern modifies to allow potentially vigorous ocean storms
lift toward the Aleutians, the Alaska Peninsula, and
Southwest/Southern Alaska. This is slated to occur as ample upper
trough/system energies approach from eastern Asia and the Pacific
mid-latitudes to interact with lingering northern stream energies
and entrain deeper moisture. This offers an emerging maritime and
regional threat to monitor for a much wetter pattern.
Schichtel
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