Skip Navigation Links weather.gov 
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
   QPF
   PQPF
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Air Quality
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/
Warnings

Satellite and Radar Imagery
   Satellite Images
   National Radar
Product Archive
WPC Verification
   QPF
   Medium Range
   Model Diagnostics
   Event Reviews
International Desks
Development and Training
   Development
WPC Overview
   About the WPC
   Staff
   WPC History
   Accomplishments
   Other Sites
   FAQs
Meteorological Calculators
Contact Us
   About Our Site
 
USA.gov 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 1844Z Aug 13, 2014)
 
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
244 PM EDT WED AUG 13 2014

VALID 12Z SUN AUG 17 2014 - 12Z THU AUG 21 2014

TODAYS WPC ALASKAN MEDIUM RANGE GUIDANCE SUITE HAS BEEN PRIMARILY
DERIVED TODAY FROM AN EQUALLY WEIGHTED BLEND OF 06 UTC GFS
ENSEMBLE MEAN WITH THE 00 UTC ECMWF/ECMWF ENSEMBLE MEAN INTO DAYS
4/5 SUN/MON. THESE GUIDANCE PIECES OFFER FLOW PATTERN EVOLUTIONS
THAT OVERALL SEEM REASONABLY WELL CLUSTERED AND IN LINE WITH
YESTERDAYS WPC GUIDANCE. HOWEVER...THERE IS SOME GROWING
UNCERTAINTY AS THE 12 UTC GFS/CANADIAN AND A SIZABLE NUMBER OF
THEIR RECENT  ENSEMBLE MEMBERS SPLIT MORE LEAD MAIN SYSTEM ENERGY
UPWARD INTO BRISTOL BAY THAN OUT ACROSS THE NRN GULF OF ALASKA BY
SUN/MON. THE 12 UTC ECMWF NOW SHOWS A MORE MILD TREND THIS WAY.
WHILE THIS SOLUTION IS PLAUSIBLE WITHIN THIS AMPLIFIED LONGWAVE
FLOW REGIME...INSTEAD MAINTAINED BETTER WPC CONTINUITY IN OUR
EARLIER RELEASED GUIDANCE PROGS AFTER COLLABORATION WITH THE
ANCHORAGE AND JUNEAU NWS FORECAST OFFICES PENDING NEWER GUIDANCE
INPUT.

PREFER INCREASED WEIGHTING OF THE GFS/ECMWF ENSEMBLE MEANS AT THE
EXPENSE OF THE 00 UTC ECMWF NEXT TUE-THU IN A PERIOD WITH MODESTLY
INCREASING FORECAST SPREAD AND UNCERTAINTY WITH EMBEDDED SENSIBLE
WEATHER FOCUSING SYSTEMS.

THIS AMPLIFIED PATTERN SHOULD HIGHLIGHT THE WEAKENING ROTATION OF
AMPLE LEAD GULF OF AK AND VICINITY SYSTEM ENERGIES AND HEAVIER
PCPN INLAND ACROSS SRN/SERN AK AND TO A LESSER EXTENT INTO THE
INTERIOR AS NEW POTENT TROUGH/LOW ENERGIES DIG BACK INTO THE
BERING SEA/ALEUTIANS. THIS RETROGRADES THE MEAN TROUGH LOW MORE
ERNESTLY THERE NEXT WEEK...WITH LEADING SYSTEMS ABLE TO WORK
DOWNSTREAM UP INTO THE GULF OF ALASKA. THE LATEST 12 UTC ECMWF HAS
TRENDED WEAKER WITH GULF LOW DEVELOPMENT THIS PERIOD THAN ITS 00
UTC RUN AND IS NOW MORE IN LINE WITH THE AFOREMENTINED ENSEMBLE
MEAN BLEND USED DAYS 6-8.

SCHICHTEL