ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1236 PM EST SAT DEC 31 2016 VALID 12Z WED JAN 04 2017 - 12Z SUN JAN 08 2017 ...COOLING TEMPERATURES ACROSS THE AK INTERIOR THIS PERIOD... THE GENERAL FLOW PATTERN FEATURES A DEEPENING TROUGH NEAR 160E AND A DOWNSTREAM REX BLOCK, WITH THE NORTHERN MEMBER MADE UP OF A WARM CORE RIDGE WITH 500 HPA HEIGHTS 450+ METERS ABOVE AVERAGE FOR EARLY JANUARY NEAR THE AK PENINSULA/SOUTHWEST AK WHICH EXPANDS INTO THE BERING SEA BY NEXT WEEKEND. A BLEND OF THE 06Z GFS/12Z GFS/00Z UKMET/00Z ECMWF/00Z NAEFS MEAN/00Z ECMWF ENSEMBLE MEAN IRONED OUT DETAIL ISSUES, SUCH AS THE WAVE CLIPPING NORTHWEST/NORTHERN AK LATE TUESDAY NIGHT INTO LATE WEDNESDAY NIGHT. THE ECMWF APPEARED TOO AMPLIFIED WHICH MIGHT MEAN ITS TWO METER TEMPERATURES WOULD BE TOO CHILLY ACROSS EASTERN AK. CONFIDENCE IS ABOVE AVERAGE GIVEN CONSISTENCY AND BETTER THAN AVERAGE ENSEMBLE AGREEMENT. THE ORIENTATION OF THE WARM CORE RIDGE SHOULD ALLOW TRANSIENT/WEAK SYSTEMS TO MOVE OUT OF THE CENTRAL PACIFIC ACROSS THE ALEUTIANS INTO THE BERING SEA AND SIBERIA WHICH MAY THEN CLIP NORTHERN AK AS THEY ROUND TO THE TOP OF THE STRONG RIDGE. TEMPERATURES SHOULD COOL OFF ACROSS THE EASTERN TWO-THIRDS OF THE STATE AS RIDGING RETROGRADES INTO THE BERING SEA WHILE TEMPERATURES REMAIN MILD NEAR THE WEST AND SOUTHWEST COAST WHERE SOUTHERLY FLOW SHOULD PREVAIL. THE STRENGTH OF THE SURFACE HIGH ASSOCIATED WITH THE WARM CORE RIDGE EARLY THURSDAY MORNING WOULD THREATEN RECORD HIGH JANUARY SEA LEVEL PRESSURES AT UNALAKLEET AND BETHEL. RAIN CHANCES WILL BE QUITE DEPRESSED ACROSS SOUTHERN AK FOR MUCH OF THE PERIOD WITHIN THIS NON-CLIMATOLOGICAL PATTERN OF RIDGING AND NORTHERLY, OFFSHORE FLOW OFF EASTERN AK. PRECIPITATION CHANCES ARE HIGHEST ACROSS NORTHERN AND NORTHEAST AK THIS PERIOD NEAR DISTURBANCES MOVING AROUND THE NORTH AND NORTHEAST SIDE OF THE RIDGE WHICH ARE EXPECTED TO DEPOSIT LIGHT AMOUNTS NEAR THEIR ROUTE. THE WETTEST AREA OVERALL SHOULD BE THE WESTERN/LOWER ALEUTIANS NEAR THE INTERNATIONAL DATELINE CLOSER TO THE STORM TRACK AT THE WESTERN PERIPHERY OF THE STRONG HIGH. ROTH