ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 228 PM EDT MON OCT 10 2016 VALID 12Z FRI OCT 14 2016 - 12Z TUE OCT 18 2016 ...GUIDANCE AND UNCERTAINTY ASSESSMENT... THE UPPER PATTERN FEATURES AN OMEGA BLOCK CONFIGURATION WITH A PERSISTENT CLOSED HIGH ACROSS NORTHERN AK THAT DRIFTS WEST ACROSS THE BERING STRAITS INTO SIBERIA. IN ITS PLACE A RETROGRADING UPPER TROUGH AND EMBEDDED CLOSED LOW DRIFT WEST ACROSS THE ARCTIC OCEAN. TIMING AND PHASING DIFFERENCES WITH THIS TROUGH ARE THE MOST UNCERTAIN PORTION OF THIS FORECAST. AS A CONSEQUENCE...A CONSENSUS APPROACH WAS TAKEN UNTIL BETTER AGREEMENT BEGINS TO DEVELOP IN LATER FORECASTS. THE RESULTANT OVERALL TREND WAS FOR THE WARM ANOMALIES TO GRADUALLY GET REDUCED OVER NORTHERN AK AND POSSIBLE EVEN SWITCH TO COOL TEMPERATURE ANOMALIES EARLY NEXT WEEK. FURTHER SOUTH...THE MEAN TROUGH AXIS EXTENDS ACROSS THE LOWER ALEUTAINS AND NORTHERN PACIFIC OCEAN...WITH CYCLONES OVER THE NORTHERN PACIFIC MOVING INTO THE GULF OF AK TO SLOWLY DECAY. THE MODELS AND ENSEMBLES ARE IN BETTER AGREEMENT IN THE NORTHERN PACIFIC AND GULF OF AK...WITH MANUAL FORECASTS USING A BLEND OF THE 06-12Z GFS/00Z ECMWF/00Z CANADIAN GLOBAL/06Z GEFS MEAN/00Z ECMWF ENSEMBLE MEAN FOR FRONTS/SEA LEVEL PRESSURES/500 MB HEIGHTS. GIVEN THE LARGE SCALE AGREEMENT THERE WAS LOW WEIGHTING ASSIGNED TO EACH MODEL/ENSEMBLE IN THE FORECAST. THE OVERALL PATTERN SUPPORTS MOISTURE STREAMING ONSHORE INTO SOUTHEAST AK PERSIST WAVES ROTATING ONSHORE TO SUPPORT EXTENDED SHOWERY PERIODS EARLY NEXT WEEK. PETERSEN