ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 254 PM EDT SUN MAR 13 2016 VALID 12Z THU MAR 17 2016 - 12Z MON MAR 21 2016 ...GUIDANCE/UNCERTAINTY ASSESSMENT AND WEATHER PATTERN HIGHLIGHTS/THREATS... THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE WAS MAINLY DERIVED FROM THE 00 UTC ECMWF ENSEMBLE MEAN...WITH SMALL INPUT FOR BETTER DETAIL FOR THE COMING WEEK FROM THE LARGELY COMPATABLE BUT MORE VARIED 12 UTC GFS AND 00 UTC ECMWF. OF THE ENSEMBLE SYSTEMS...THE ECMWF ENSEMBLE MEAN BEST MATCHED RECENT DETERMINISTIC MODEL TRENDS THAT INCLUDE MORE PRONOUCNED MEAN TROUGHING ALOFT DOWN THROUGH THE INTERIOR AT THE EXPENSE OF PREVIOUSLY FAVORED RIDGE DEVELOPMENT. WPC MANUAL ADJUSTMENTS WERE ALSO APPLIED TO INSURE DEPICTION OF DEEPENED MARITIME LOWS CONSIDERING SUPPORT ALOFT AND CONTINUITY. GUIDANCE CONTINUES AN OVERALL TREND TOWARD MORE AMPLIFIED AND COOLING/UNSETTLING MID-UPPER LEVEL TROUGH DEVELOPMENT DOWN OVER THE NORTH SLOPE...INTERIOR AND POSSIBLY SW AK THROUGH LATER WEEK INTO NEXT WEEKEND DOWNTREAM OF AN AMPLIFIED NERN ASIAN TO ARCTIC RIDGE ALOFT. WHILE THERE REMAINS VARIANCE WITH SMALLER SCALE SPECIFICS...FEATURE DEPTH OFFERS SOME SNOW POTENTIAL. ACCORDINGLY...A WARMING RIDGE NOW BUILDS NORTHWESTWARD ALOFT FROM SERN AK AND THE ERN AND CENTRAL GULF OF AK ONLY UP THROUGH SRN AK FOR MUCH OF THIS WEEK. MEANWHILE...AN UPSTREAM APPROACH OF POTENT SYSTEM DEVELOPMENT FROM OFF ERN ASIA TOWARD THE ALEUTIANS AND VICINITY WED-SAT COULD THEN FAVOR DEEP SURFACE LOW DEVELOPMENT AND WRAPPED PCPN IN AN INCREASINGLY STORMY PATTERN. THE GRADUAL EASTWARD PROGRESSION OF THIS SYSTEM WILL COINCIDE WITH MORE UNCERTAIN DEEP LOW APPROACH NORTHWARD FROM THE NERN PACIFIC TO OFFSHORE SWRN AK AND INTO THE WRN GULF OF AK LATE WEEK/NEXT WEEKEND INTO NEXT WEEK. THIS LOW SHOULD PROVE SLOW TO LIFT NUDGING INTO THE AFOREMENTIONED BUILDING RIDGE TO ITS NORTHEAST. SCHICHTEL