Prognostic Meteorological Discussion
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FXAK02 KWNH 281906
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
305 PM EDT WED JUN 28 2017

VALID 12Z SUN JUL 02 2017 - 12Z THU JUL 06 2017

UPPER PATTERN OVER ALASKA NEXT WEEK WILL LARGELY STAY THE SAME --
TROUGHING IN THE BERING SEA AND RIDGING/UPPER HIGH OVER THE
EASTERN INTERIOR WITH ADDITIONAL TROUGHING NEAR OR SOUTH OF THE
GULF OF ALASKA. ENSEMBLES CONTINUE TO SHOW A GRADIENT OF SPREAD
FROM WEST TO EAST (HIGHER TO LOWER) NORTH OF 60N WHICH ROUGHLY
CORRELATES WITH PREDICTABILITY. A MODEL/ENSEMBLE BLEND WAS USED TO
DAMPEN SMALLER SCALE DIFFERENCES IN TIMING/AMPLITUDE UNTIL ABOUT
NEXT TUE. AFTER THAT, THE GFS/ECMWF DIFFER IN THE WESTERN BERING
SEA THOUGH FARTHER EAST THEY GENERALLY COME TO THE SAME RESULT
NEXT WED WITH A LOW SW OF THE PANHANDLE (THOUGH FROM DIFFERENT
PLACES). SOMEWHAT FAVORED THE ECMWF LATER IN THE FORECAST BUT ITS
ENSEMBLE MEAN WEIGHTING WAS USED AS A PROXY WITH LESS DETAILS
GIVEN THE LOWER PREDICTABILITY.

UPPER LOW IN THE BERING SUPPORTS FAIRLY WEEK SYSTEMS ROTATING
AROUND IT BUT NOT MAINTAINING A SFC REFLECTION EAST OF 160W. JET
ACROSS THE NORTH PACIFIC SHOULD CARRY A SYSTEM NORTHEASTWARD
TOWARD THE PANHANDLE NEXT WED/THU -- THOUGH THE GFS EMPHASIZED THE
SOUTHERN STREAM WHILE THE ECMWF FAVORED THE NORTHERN STREAM THAT
BOTH END UP IN ROUGHLY THE SAME PLACE. THIS SHOULD FAVOR RAIN
ALONG SOUTHCENTRAL COAST THEN INTO THE PANHANDLE AND INLAND
CONVECTION WITH WIDESPREAD 70S FOR MAX TEMPS.


FRACASSO


$$





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