Skip Navigation Links 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
The Weather Prediction Center



Follow the Weather Prediction Center on Facebook Follow the Weather Prediction Center on Twitter
NCEP Quarterly Newsletter
WPC Home
Analyses and Forecasts
   National High & Low
   WPC Discussions
   Surface Analysis
   Days ½-2½ CONUS
   Days 3-7 CONUS
   Days 4-8 Alaska
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/

Satellite and Radar Imagery
  GOES-East Satellite
  GOES-West Satellite
  National Radar
Product Archive
WPC Verification
   Medium Range
   Model Diagnostics
   Event Reviews
   Winter Weather
International Desks
Development and Training
WPC Overview
   About the WPC
   WPC History
   Other Sites
Meteorological Calculators
Contact Us
   About Our Site is the U.S. Government's official web portal to all federal, state, and local government web resources and services.
Alaska Extended Forecast Discussion
(Caution: Version displayed is not the latest version. - Issued 1943Z Jun 20, 2018)
Version Selection
Versions back from latest:  0   1   2   3   4   5   6   7   8   9   10   
Abbreviations and acronyms used in this product
View Alaska Map

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
343 PM EDT Wed Jun 20 2018

Valid 12Z Sun Jun 24 2018 - 12Z Thu Jun 28 2018

Uncertainty remains high, especially across the Aleutians and the
Bering Sea, through Day 8 next Thursday as multiple disturbances
both from the south and the north could potentially converge over
the vicinity.  Ensemble means from major global models basically
depict two scenarios regarding the interaction of a couple of
upper-level vortices near the Bering Sea.  Scenario 1: The GEFS
shows that a new vortex tracking northeastward from the Pacific
will merge with and then expand the old occluded vortex over the
Bering Sea.  Scenario 2: The EC mean and Canadian ensemble mean
indicate the old occluded vortex will dissipate over the Bering
Sea before the new vortex from the Pacific moves along the
Aleutians.  The 12Z ECMWF even shows a third scenario in which a
polar vortex from Arctic Ocean gets involved later in the period. 
In any event, expect highly changeable weather to persist across
the Aleutians and Bering Sea into western Alaska through the
middle of next week.  Meanwhile, more stable weather can be
expected for the rest of Alaska with occasional showers inland
while damp and rainy weather will persist down the Alaska

The WPC Alaska forecast grids are based on a blend of the 00Z EC
mean and the 06Z GEFS mean mixing in with the deterministic 00Z
ECMWF, the 06Z and the 12Z GFS.


WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can be found at: