Prognostic Meteorological Discussion
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FXAK02 KWNH 181927
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 PM EST THU JAN 18 2018

VALID 12Z MON JAN 22 2018 - 12Z FRI JAN 26 2018

MODELS AND ENSEMBLES REASONABLY AGREE TO DEVELOP AND MAINTAIN A
MORE AMPLIFIED AND  BLOCKY LARGER SCALE MEDIUM RANGE FLOW PATTERN
OVER THE ALASKAN REGION AND VICINITY NEXT WEEK. THIS PATTERN WILL
BE HIGHLIGHTED ALOFT BY A NEAR DATELINE CENTERED RIDGE SANDWICHED
BY TROUGHS OFF NERN ASIA AND ANOTHER COLD TROUGH FROM THE ARCTIC
AND NORTH SLOPE DOWN ACROSS THE INTERIOR TO THE NERN PACIFIC. GULF
OF ALASKA MARITIME INTERESTS AND SRN/SERN ALASKA COASTAL
COMMUNITIES/TERRAIN WILL ALSO BE THREATENED BY PERIODS OF ENHANCED
MOISTURE AND WINTERY PRECIPITATION WRAPPING AROUND A SERIES OF
ORGANIZED OFFSHORE LOWS NEXT WEEK.

THE WPC PRODUCT SUITE WAS PRIMARILY DERIVED FROM A COMPOSITE BLEND
OF REASONABLY WELL CLUSTERED GUIDANCE FROM THE LATEST GFS/ECMWF
AND GEFS/ECMWF ENSEMBLE MEANS. APPLIED GREATER BLEND WEIGHTING THE
THE DETERMINISTIC MODELS MONDAY/TUESDAY AND TRANSITIONED TO A
MAINLY ENSEMBLE MEAN BASED BLEND BY DAYS 6/7 AMID GROWING FORECAST
SPREAD WITH THE SMALLER SCALE SYSTEMS AND INTERACTIONS. THIS
COLLABORATED SOLUTION MAINTAINS GOOD WPC FORECAST CONTINUITY IN A
PATTERN WITH GENERALLY ABOVE NORMAL PREDICTABILITY.

SCHICHTEL

$$





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