Prognostic Meteorological Discussion
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FXAK02 KWNH 192005
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
304 PM EST SUN FEB 19 2017

VALID 12Z THU FEB 23 2017 - 12Z MON FEB 27 2017

OVERALL GOOD AGREEMENT STILL EXISTS AMONG THE GUIDANCE FOR THE
HIGH LATITUDES FOR THE LAST WEEK OR SO OF FEBRUARY. UPPER RIDGING
IS FORECAST TO MOSTLY HOLD OVER THE NORTHEASTERN PACIFIC AS AN
UPPER LOW AND SUBSEQUENT TROUGHING MOVE THROUGH THE BERING SEA.
DIFFERENCES SEEN 24 HRS AGO BETWEEN THE GFS AND ECMWF IN THE GULF
HAVE DECREASED AND THE TREND HAS BEEN TOWARD THE ECMWF-LED IDEA OF
A WEAKER SHORTWAVE MOVING ACROSS THE GULF LATE FRI INTO SAT,
CARRYING A SURFACE COLD FRONT EASTWARD TOWARD THE PANHANDLE.
SOUTHERN PORTION SHOULD CLOSE OFF TO THE SOUTHWEST OF THE DOMINANT
BUT STILL SQUASHED UPPER HIGH ON SATURDAY. GFS REMAINS A BIT OFF
FROM THE BIGGER CONSENSUS OF THE 06Z GEFS MEAN AND 00Z ECMWF/ECENS
MEAN WITH THE BERING SYSTEM EVOLUTION/TRACK/SPEED, SO TRENDED AWAY
FROM THE MULTI-MODEL/ENSEMBLE BLEND THU/FRI TO THE ECMWF CLUSTER.
THIS MAINTAINED GOOD CONTINUITY FROM THE FORECAST YESTERDAY. THAT
COLD FRONT SHOULD MOVE INTO WESTERN ALASKA NEXT SUN/MON PER THE
CURRENT TIMING AS THE UPPER HIGH MAINTAINS ITS E-W ELONGATED SHAPE
RATHER THAN A MORE TYPICAL N-S STRETCH. THIS MAY INTRODUCE ANOTHER
MODEST QPF EVENT FOR THE INTERIOR AFTER THE LEAD EVENT THIS
THURSDAY.


FRACASSO


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