Prognostic Meteorological Discussion
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FXAK02 KWNH 092023
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
322 PM EST FRI DEC 09 2016

VALID 12Z TUE DEC 13 2016 - 12Z SAT DEC 17 2016

UPPER RIDGING IS FORECAST TO RE-BUILD INTO THE INTERIOR AFTER THE
UPPER HIGH IN THE SHORT TERM SINKS SOUTH INTO THE GULF LATE SUNDAY
INTO MONDAY. AN UPPER LOW IN THE BERING TUESDAY SHOULD LIFT
NORTHWARD WHICH WILL CARRY A SFC LOW AND COLD FRONT THROUGH THE
CENTRAL/EASTERN BERING SEA PAST THE BERING STRAIT. THIS WILL BRING
MUCH MILDER TEMPERATURES TO WESTERN ALASKA WITH TEMPERATURES
RISING TO NEAR RECORD WARM LEVELS (UPPER 20S TO NEAR FREEZING).
SEA ICE HAS GROWN A BIT AWAY FROM THE COAST BUT STRONG SOUTHERLY
FLOW MAY DISRUPT THE SURFACE. USED A GENERAL MODEL COMPROMISE OF
THE 12Z GFS AND 00Z ECMWF/CANADIAN/UKMET TO START.

QUESTION BY ABOUT THURSDAY IS HOW MUCH OF THAT LEAD SYSTEM MAY TRY
TO SNEAK EASTWARD THROUGH THE BEAUFORT SEA ACROSS THE NORTH SLOPE.
THE 00Z ECMWF APPEARS MOST OUT OF LINE WITH THE ENSEMBLES AS IT
MAINTAINS A STRONG UPPER HIGH OVER THE INTERIOR OR SOUTH CENTRAL
REGIONS WHILE THE GFS/CANADIAN AND A GOOD NUMBER OF ENSEMBLES
ALLOW AT LEAST SOME SHORTWAVE ENERGY TO CHIP AWAY AT THE RIDGE.
FOLLOWED THE 12Z GFS WITH THE 00Z GEFS/ECMWF ENSEMBLE MEANS FOR
THE REST OF THE PERIOD. THIS WILL TAKE ANOTHER SYSTEM OVER THE
WESTERN BERING IN RESPONSE TO ANOTHER UPPER TROUGH DIGGING THROUGH
KAMCHATKA. ENSEMBLES WERE IN GOOD AGREEMENT OUT TO NEXT WEEKEND
WITH THIS FEATURE AS THE MOST SPREAD LIED IN THE MID-LATITUDES.


FRACASSO


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