Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXAK02 KWNH 171844
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
244 PM EDT WED SEP 17 2014

VALID 12Z SUN SEP 21 2014 - 12Z THU SEP 25 2014

WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500MB PROGS
ALONG WITH ASSOCIATED SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY
DERIVED FROM A BLEND OF COMPATABLE GUIDANCE FROM THE 00 UTC
GFS/ECMWF/NAEFS ENSEMBLE MEANS. RECENT DETERMINISTIC MODELS SEEM
TOO RUN TO RUN INCONSISTENT.

RECENT DETERMINISTIC GFS AND ECMWF MODEL RUNS HAVE BEEN ROBUST AT
TIMES BUT OVERALL QUITE RUN TO RUN INCONSISTENT WITH
TIMING/POSITION OF MID-UPPER LEVEL TROUGH ENERGY DIGGING FROM THE
ARCTIC INTO THE ALASKAN INTERIOR THIS WEEKEND INTO NEXT WEEK AND
AS WITH ANY POTENTIAL INTERACTION WITH MORE SRN STREAM BASED FLOW.
ABOVE AVERAGE FORECAST SPREAD WITH THE FEATURE MAY BEST PORTEND AN
ENSEMBLE MEAN APPROACH. THE ENSEMBLE MEAN BLEND BY NATURE SHOWS
DECENT COOLING MEAN MID-UPPER LEVEL INTERIOR TROUGH DEVELOPMENT.

AMPLE MID-UPPER LEVEL TROUGHING SETTLES OVER THE GULF OF ALASKA
THIS WEEKEND INTO EARLY NEXT WEEK IN AMPLIFIED MID-UPPER LATITUDE
FLOW THAT SHOULD FAVOR HEAVIER PRECIPITATION FROM SRN TO SERN AK.
THIS ENERGY AND WEATHER/QPF FOCUSING LOW BECOMES REPLACED NEXT
WEEK BY UPSTREAM NRN PACIFIC KICKER ENERGIES. IN THIS
PATTERN...WELL ORGANIZED LOW ENERGY AND WEATHER FOCUS SINKS SEWD
FROM THE WRN ALEUTIANS THIS WEEKEND TO REACH THE GULF OF ALASKA BY
EARLY-MID NEXT WEEK...FEEDING ENERGY INTO A RENEWED MEAN TROUGH
POSITION THAT LEADS TO A THREAT FOR DEEP GULF OF ALASKA
CYCLOGENESIS.

SCHICHTEL

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.