Prognostic Meteorological Discussion
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FXAK02 KWNH 221937
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
337 PM EDT THU JUN 22 2017

VALID 12Z MON JUN 26 2017 - 12Z FRI JUN 30 2017

MODELS REMAINED IN GOOD AGREEMENT WITH THE LARGE SCALE PATTERN
OVER ALASKA NEXT WEEK...WHICH WILL FEATURE AN EXPANSIVE UPPER
VORTEX CENTERED OVER THE BERING SEA AND UPPER RIDGING OVER THE
EASTERN HALF OF THE INTERIOR.  THERE IS STILL SOME UNCERTAINTY
WITH SOME OF THE SMALLER SCALE FEATURES OF THE FORECAST.
HOWEVER...THERE IS SOME CONFIDENCE THAT A CLOSED MID-LEVEL LOW
WILL TRACK EASTWARD NEAR THE ALEUTIANS EARLY NEXT WEEK BEFORE
LIFTING NORTHWARD ALONG THE WEST COAST OF ALASKA ON WEDNESDAY.
THERE IS ALSO THE POTENTIAL FOR THE NEXT SURFACE LOW TO LIFT
TOWARDS KODIAK ISLAND/BRISTOL BAY LATE NEXT WEEK...BUT THERE
CONTINUES TO BE A CONSIDERABLE AMOUNT OF SPREAD IN DETERMINISTIC
GUIDANCE AND ENSEMBLE MEMBERS WITH THE EXACT TIMING/TRACK OF THIS
SYSTEM.

THE GFS(06Z/12Z) APPEARED TO BE ON THE FASTER SIDE OF MODEL
SPREAD...BOTH WITH THE CLOSED MID-LEVEL LOW TRACKING NEAR THE
ALEUTIANS EARLY NEXT WEEK AND WITH THE POSSIBLE SYSTEM LIFTING
TOWARDS KODIAK ISLAND/BRISTOL BAY LATE NEXT WEEK...SO THE WPC DAY
4-8 ALASKA FORECAST WAS WEIGHTED MORE TOWARDS A THE 00Z ECMWF/GEFS
MEAN/ECWMF ENSEMBLE MEAN.  THE PREFERRED BLEND RESULTED IN MINIMAL
ADJUSTMENTS TO CONTINUITY.


GERHARDT


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