Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FXAK02 KWNH 281837
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EDT SUN AUG 28 2016

VALID 12Z THU SEP 01 2016 - 12Z MON SEP 05 2016

...GUIDANCE/UNCERTAINTY ASSESSMENT AND WEATHER
HIGHLIGHTS/THREATS...

THE UPCOMING MEDIUM RANGE MID-UPPER LEVEL FLOW PATTERN NEAR ALASKA
WILL BE HIGHLIGHTED INTO THU BY A BERING STRAIT TO SWRN AK RIDGE
SQUEEZED BETWEEN CLOSED LOWS/TROUGHS NEAR THE WRN ALEUTIANS AND
SERN GULF OF AK. LEAD ENERGY ALOFT AND AN ASSOCIATED SURFACE LOW
WILL DIG SLOWLY SEWD TO FOCUS PCPN AND UNSETTLED WEATHER INTO THU
OVER THE SERN GULF OF AK/SERN AK.

THE AFOREMENTIONED BERING STRAIT RIDGE RETROGRADES INTO NERN
RUSSIA TO LEAVE AN ILL-DEFINED WEAKNESS ALOFT OVER THE ALASKAN
INTERIOR WITH ALBEIT GENERALLY LIMITED PCPN POTENTIAL.
MEANWHILE...THE EXTRATROPICAL TRANSITION OF TYPHOON LIONROCK OFF
ERN ASIA SHOULD HELP AMPLIFY THE OVERALL DOWNSTREAM FLOW FROM THE
MID TO UPPER LATITUDES...FAVORING ONLY A SLOWLY PROGRESSIVE TREND
FOR SIGNIFICANT MID-LATE WEEK DOWNSTREAM LOW DEVELOPMENT/HEAVY
WEATHER OVER THE ALEUTIANS/SW AK AND ADJOINING WATERS. PREFER AN
ENSEMBLE MEAN BASED SOLUTION WITH EMPHASIS ON THE 06 UTC GEFS
ENSEMBLE MEAN TO BEST MATCH WPC CONTINUITY AND FAVORED SLOWED
PROGRESSION TREND. 00 UTC NAEFS/ECMWF ENSEMBLE MEANS ARE ALSO
GENERALLY IN LINE AND DETERMINISTIC MODEL RUN TO RUN FORECAST
VARIANCE HAS DECREASED OVER THE PAST FEW DAYS...BOLSTERING
FORECAST CONFIDENCE. THE SIGNIFICANT LOW MAY GRADUALLY WORK INTO
THE SRN BERING SEA LATER WEEK IN AMPLIFIED FLOW AS UNSETTLED
WEATHER/HEAVY RAINS SPREAD DOWNSTREAM THROUGH SW/WRN AK. WEEKEND
TO EARLY NEXT WEEK ACTIVITY SHOULD THEN SPREAD INTO SRN/SERN AK
WITH NRN GULF OF AK TRIPLE POINT LOW DEVELOPMENT SUPPORTED BY
HEIGHT FALLS/UPPER JET FLOW.

SCHICHTEL

$$





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