ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 340 PM EDT MON OCT 26 2015 VALID 12Z FRI OCT 30 2015 - 12Z TUE NOV 03 2015 ...STORMY ALASKA AND ADJOINING WATERS... ...GUIDANCE AND UNCERTAINTY ASSESSMENT... WE STILL PREFER TO LIMIT FORECAST INFLUENCE FROM SOMEWHAT VARIED AND RUN-RUN INCONSISTENT DETERMINISTIC MODELS IN LUE OF A MORE CONSISTENT ENSEMBLE MEAN FORECAST METHODOLOGY...AT LEAST BEYOND FRIDAY MORNING DEEPER INTO MEDIUM RANGE TIME SCALES. ACCORDINGLY...THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A COMPOSITE MODEL AND ENSEMBLE BLEND DAY 4/FRI AND THEN A BLEND OF VERY COMPATABLE GUIDANCE FROM THE 06 UTC GEFS MEAN AND 00 UTC NAEFS/ECMWF ENSEMBLE MEANS ONTO DAY 8/NEXT TUESDAY. FORECAST UNCERTAINTY REMAINS ONLY NEAR AVERAGE GIVEN LINGERING INDIVIDUAL MEMBER VARIANCE AND BLENDING OF THE MEANS WILL CONTINUE TO MASK LESS PREDICTABLE BUT POTENTIALLY SIGNIFICANT SMALLER SCALE SYSTEM DETAIL SOMEWHAT ADDRESSED WITH SOME MANUAL ADJUSTMENTS TOWARD DEEPER SURFACE LOWS GIVEN SUPPORT ALOFT AND/OR COMPLEXITY WITH ENERGY TRANSFER WITH EX-TROPICAL SYSTEM NATURE. THIS MAINTAINS GOOD WPC CONTINUITY...ALBEIT WITH A SLIGHT OVERALL TREND TOWARD AMPLITIDE/LESS PROGRESSION AS PER GUIDANCE. ...PATTERN/SYSTEM HIGHLIGHTS AND THREATS... NRN STREAM TROUGHING ALOFT WILL DIG SEWD INTO N-CENTRAL AK LATE WEEK INTO THE WEEKEND AND SPREAD SOME COOLING AND UNSETTLED WEATHER CONDITIONS WITH MODEST PCPN DOWN ACROSS THE NORTH SLOPE AND INTERIOR. THIS SYSTEM SEEMS A BIT MORE DEFINED IN GUIDANCE NOW AND FEATURES SOME MORE ORGANIZED LATE WEEK LOW PRESSURE POTENTIAL FOR NERN AK TO JUST OFFSHORE INTO THE ARCTIC. THE MORE AMPLIFIED MODEL TREND IS WELL CLUSTERED IN THE GFS/ECMWF MODELS AND LEADS TO INCREASED WEEKEND PHASING OF ENERGY WITH LOWER LATUTUDE ENERGY OVER THE GULF OF AK. THERE...A HIGHLY ENERGETIC/AMPLIFIED AND MOIST/UNSETTLING MID-UPPER LEVEL TROUGH AND DEEP/LARGE SURFACE LOW INCLUDES THE EXTRATROPICAL REMAINS OF CHAMPI. THE COMPLICATED ENERGY AND MOISTURE INTERACTIONS INTO THE LOW ARE UNCERTAIN BUT THE DEEP LOW IS PROGGED OVER THE STORMY GULF OF AK FRI INTO THE WEEKEND. THE SYSTEM SHOULD PROVE TO BE AN EFFICIENT WIND/WAVE/PCPN PRODUCER INTO SRN AND SERN AK. THE FLOW IS AMPLIFIED BUT STEADILY PROGRESSIVE ACROSS THE MID-HIGH LATITUDES UPSTREAM. THE APPROACH OF ENERGETIC MID-UPPER LEVEL TROUGH ENERGIES FROM NERN ASIA SHOULD SUPPORT ADDITIONAL AND DEEP SURFACE LOW SYSTEM/WEATHER DEVELOPMENT INTO THE BERING SEA FOR THE WEEKEND INTO EARLY NEXT WEEK...ALBEIT ON A PACE SLIGHTLY LESS PROGRESSIVE THAN INDICATED OVER THE PAST COUPLE OF DAYS. LEAD/WRAPPING PCPN IS EXPECTED TO SPREAD ACROSS THE UNSETTLED REGION INTO WRN AK AND SW/SRN AK WITH SOME PUNCH INTO NEXT MON/TUE ON DAYS 7/8. SCHICHTEL