Prognostic Meteorological Discussion
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FXAK02 KWNH 111846
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
145 PM EST THU FEB 11 2016

VALID 12Z MON FEB 15 2016 - 12Z FRI FEB 19 2016

FROM THE MULTI-DAY MEAN PERSPECTIVE THE MOST STABLE FEATURES
SHOULD BE RIDGING TO VARYING DEGREES FROM WRN CANADA INTO AT LEAST
ERN MAINLAND ALASKA AND AN UPR LOW OVER THE AREA OF SRN
SIBERIA/KAMCHATKA.  AN UPR TROUGH INITIALLY FROM THE PENINSULA SWD
SHOULD TRAVEL TO THE S OF THE MEAN RIDGE.  UPSTREAM ENERGY IS
LIKELY TO SETTLE OVER THE NERN PAC WHILE ANOTHER SYSTEM COMES INTO
THE PICTURE OVER THE NRN PAC/ALEUTIANS/SRN BERING SEA LATE IN THE
PERIOD.

FROM DAY 4 MON TO 12Z DAY 5 TUE PREFS FOLLOW AN EVEN BLEND OF
MODEL/ENSEMBLE MEAN GUIDANCE BY WAY OF THE 00Z ECMWF/06Z GFS AND
00Z ECMWF MEAN/06Z GEFS MEAN.  THIS BLEND YIELDS A GOOD
INTERMEDIATE FCST AND DECENT CONTINUITY FOR THE WEAKENING SYSTEM
FCST TO TRACK JUST S/E OF THE PENINSULA/KODIAK ISLAND AND NWRN
BERING SEA SYSTEM/LEADING SFC FRONT.  NOTE THAT INDIVIDUAL
ENSEMBLE MEMBERS AND MODEL RUNS STILL SHOW CONSIDERABLE SPREAD FOR
THE SYSTEM NEAR THE PENINSULA THUS KEEPING CONFIDENCE AT OR BELOW
AVG.

FROM LATE DAY 5 TUE ONWARD AN AVG OF THE 00Z ECMWF/00Z ECMWF
MEAN/06Z GEFS MEAN SEEMS TO OFFER THE BEST STARTING POINT TO
REFLECT MAJORITY IDEAS FOR FEATURES OF INTEREST AND TO MAINTAIN
SOME ASPECTS OF CONTINUITY WHERE GUIDANCE SPREAD EXISTS.  AHEAD OF
THE NRN BERING SEA SYSTEM THERE ARE HINTS IN THE GUIDANCE OF A NRN
PAC WAVE TRACKING THROUGH THE ALEUTIANS INTO THE ERN BERING SEA
AROUND TUE-WED BUT SO FAR ONLY THE 00Z NAVGEM AND 12Z UKMET
SUGGEST DEVELOPMENT AS STRONG AS SEEN IN GFS RUNS.  AS UPR ENERGY
SETTLES INTO THE NERN PAC EXPECT SFC LOW PRES TO LINGER OVER THE
NERN PAC TO THE E/SE OF KODIAK ISLAND BY DAYS 7-8 THU-FRI.  AFTER
EARLY THU THE 00Z ECMWF MEAN ADJUSTS EWD FROM PREVIOUS RUNS AND
OTHER MEANS SO THE OTHER TWO SOLNS HELP TO MAINTAIN BETTER
CONTINUITY WHILE AWAITING CONFIRMATION OF THE EC MEAN TREND.
AHEAD OF THE NERN PAC SYSTEMS THERE IS SOME POTENTIAL FOR ANOTHER
WAVE THAT MAY AFFECT PARTS OF THE AK PANHANDLE BUT AT THIS TIME
CONFIDENCE IS TOO LOW TO DEPICT SUCH A WAVE IN A DETERMINISTIC
FCST.  FARTHER WWD ANOTHER NRN PAC-SRN BERING SYSTEM SHOULD COME
INTO THE PICTURE NEXT THU-FRI.  AT THE MOMENT THE BEST SIGNALS
FROM OPERATIONAL MODELS/ENSEMBLE MEAN TRENDS ARE TOWARD A BETTER
DEFINED SYSTEM THAN FCST BY THE 06Z GEFS MEAN.

RAUSCH

$$




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