ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1249 PM EST THU JAN 28 2016 VALID 12Z MON FEB 01 2016 - 12Z FRI FEB 05 2016 ...GUIDANCE AND PREDICTABILITY ASSESSMENTS... THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE HAS BEEN PRIMARILY DERIVED FROM A BLEND OF COMPATABLE 00 UTC GEFS/NAEFS/ECMWF ENSEMBLE GUIDANCE. TODAYS 12 UTC GFS AND 00 UTC ECMWF CLUSTERED FAIRLY WELL WITH ENSEMBLES INTO DAY 4/5 MON/TUE AND PROVIDE MORE DETAIL. DETERMINISTIC MODEL VARIANCE IS OTHERWISE MUCH GREATER THROUGH LATER MEDIUM RANGE TIME SCALES. MANUAL ADJUSTMENTS ALSO ADD A BIT MORE SMALLER SCALE LOW DEPTH/DETAIL CONSISTENT WITH DYNAMIC SUPPORT AND SLIGHTLY BELOW NORMAL FORECAST SPREAD/UNCERTAINTY WITH THE OVERALL PATTERN EVOLUTION. WPC CONTINUITY IS WELL MAINTAINED. ...PATTERN HIGHLIGHTS AND WEATHER THREATS... A MEAN RIDGE IS SET FROM THE GULF OF AK INLAND THROUGH SRN AK AND THE INTERIOR THIS PERIOD. THIS RIDGE ACTS TO LIMIT THE ADVANCE OF A SERIES OF DEEPENED PACIFIC SURFACE LOWS OVER MUCH OF THE NEXT WEEK. DEEP SYSTEM ENERGY INSTEAD LIFTS/WRAPS ON THE WRN PERIPHERY OF THE RIDGE TO PRIMARILY EFFECT THE ALEUTIANS/BERING SEA/SW AK WITH ENHANCED WINDS/PCPN UNDER INFLUENCE OF AN AMPLIFIED MID-UPPER LEVEL MEAN TROUGH. A LEAD MOISTURE INFLOW PATTERN MEANWHILE SPREADS MORE INTO SRN/SERN AK MID-LATE NEXT WEEK AS ADDITIONAL ENERGIES GRADUALLY WORK MORE IN ERNEST INTO THE GULF OF AK. SCHICHTEL