Prognostic Meteorological Discussion
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FXAK02 KWNH 241901
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 PM EDT WED AUG 24 2016

VALID 12Z SUN AUG 28 2016 - 12Z THU SEP 01 2016

ENSEMBLES CONTINUE TO FORECAST A RATHER AMPLIFIED NORTH PACIFIC
PATTERN, DUE IN PART TO THE EXTRATROPICAL TRANSITION OF TYPHOON
LIONROCK NEXT WEEK NEAR JAPAN BUT ALSO A RATHER VIGOROUS NORTHERN
STREAM. DETERMINISTIC MODELS HAVE BEEN FAIRLY INCONSISTENT AND
SENSITIVE TO SOMEWHAT MINOR FEATURES IN THE FLOW. ECMWF MAY HAVE A
BETTER HANDLE ON THE FORECAST UPSTREAM WHILE THE GFS MAY BE A BIT
MORE REASONABLE OVER EASTERN ALASKA INTO NW CANADA. MOSTLY SPLIT
THAT DIFFERENCE VIA A BLEND OF THE RECENT 06Z/12Z GFS WITH THE 00Z
ECMWF AND A HEALTHY DOES OF THE ENSEMBLES. THIS GAVE A MORE
AMPLIFIED LOOK TO THE FORECAST COMPARED TO THE FORECAST YESTERDAY
AND BETTER DEFINED THE INCOMING SYSTEM DROPPING THROUGH THE
WESTERN BERING MON-TUE.

AFTER A PESKY LOST UPPER LOW FADES NEAR THE BERING STRAIT AFTER
SUNDAY, RIDGING WILL MOSTLY HOLD THROUGH THAT REGION AND NW
ALASKA. THIS WILL KEEP WESTERN AREAS MILD (AT LEAST ABOVE AVERAGE
TEMPERATURES) AND DRY WHILE SE AREAS WILL RUN THE RISK OF SHOWERS
AND COOLER THAN AVERAGE TEMPERATURES. PREDICTABILITY MAY INCREASE
WITH TIME GIVEN THE TENDENCY FOR A MORE WELL-DEFINED LONGWAVE
PATTERN, BUT SMALLER SCALE FEATURE ARE BOUND TO MODIFY THIS AS
WELL.


FRACASSO

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