Prognostic Meteorological Discussion
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FXAK02 KWNH 301824
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
224 PM EDT THU JUL 30 2015

VALID 12Z MON AUG 03 2015 - 12Z FRI AUG 07 2015

FORECAST OVER ALASKA IS FRAUGHT WITH DISAGREEMENT AROUND 72
HOURS... LEADING TO LOW CONFIDENCE IN THE FIRST FEW DAYS OF THE
FORECAST. THE DISAGREEMENT REVOLVES AROUND HOW ENERGY SOUTH OF THE
ALEUTIANS CONSOLIDATES AND EITHER MEANDERS IN PLACE -- PER THE
MAJORITY OF THE GUIDANCE -- OR SLIDES EAST INTO THE GULF -- PER
THE ECMWF AND ITS MEAN. THE ECMWF/ECENS MEAN REPRESENTS A CHANGE
IN ITS CONTINUITY AND WAS CONSIDERED A LOW PROBABILITY SOLUTION
AFTER COORDINATION WITH THE ALASKA WFOS. 12Z UKMET/CMC SHOWED NO
SHIFT TOWARD THE 00Z ECMWF SOLUTION. QUICK LOOK AT THE 12Z ECMWF
SHOWS MORE SIMILARITIES TO THE 12Z GFS.

A BLEND OF THE 12Z GFS AND 06Z GEFS MEAN OFFERED A GOOD STARTING
POINT THAT KEPT DECENT CONTINUITY. THIS KEPT THE SYSTEM SOUTH OF
THE ALEUTIANS TO START BEFORE CREEPING NORTH NORTHEASTWARD TUE/WED
BEFORE DISSIPATING. NEXT SYSTEM IN THE PACIFIC MAY BE DELAYED
COMPARED TO THE FORECAST YESTERDAY GIVEN A SLOWER PATTERN.

TO THE NORTH... TREND HAS BEEN TOWARD A BIT MORE TROUGHING PUSHING
THROUGH THE NORTH SLOPE... AND HAVE KEPT A FRONTAL BOUNDARY IN THE
AREA THROUGH THE PERIOD. TRENDED AWAY FROM THE 12Z GFS BY NEXT
WED/THU AS THERE IS NOT A LOT OF AGREEMENT ON THE STRENGTH OF ANY
SFC WAVE ALONG THE FRONT... IF IT EVEN FORMS.


FRACASSO

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