ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 319 PM EST THU NOV 19 2015 VALID 12Z MON NOV 23 2015 - 12Z FRI NOV 27 2015 ...MAJOR BERING SEA/ALEUTIANS LOWS WITH LEAD WARMING INTO AK... ...GUIDANCE/PREDICTABILITY ASSESSMENT... THE WPC ALASKAN MEDIUM RANGE GUIDANCE SUITE WAS PRIMARILY DERIVED FROM A BLEND OF THE VERY COMPATABLE 00 UTC GFS/ECMWF AND SUPPORTIVE 00 UTC ECMWF ENSEMBLE MEAN DAYS 4-6 MON-WED. FORECAST SPREAD AND UNCERTAINTY DOES INCREASES ENOUGH DAYS 6-8 WED-NEXT FRI TO WARRANT REPLACEMENT IN THIS BLEND OF THE DETERMINISTIC 00 GFS WITH THE 06 UTC GEFS ENSEMBLE MEAN. THIS OVERALL SOLUTION MAINTAINS GOOD WPC CONTINUITY. ...WEATHER PATTERN HIGHLIGHTS/THREATS... RECENT MODELS/ENSEMBLES OFFER A REASONABLE CLUSTER OF SOLUTIONS INTO EARLY-MID NEXT WEEK AND TAKES A WEAK LOW ACROSS THE GULF. A STRENGTHENING SURFACE HIGH IN THE YUKON MEANWHILE SHOULD ALLOW COLDER AIR TO WORK INTO THE SERN AK PANHANDLE IN ITS WAKE. IT REMAINS EVIDENT THAT THE LONGWAVE PATTERN OVER THE MID-HIGH LATITUDES WILL TREND TOWARD INCREASED AMPLIFICATION DUE TO UPSTREAM AND DOWNSTREAM BUCKLING OF THE FLOW. THIS WILL BUILD RIDGING UP THROUGH ERN AK NEXT WEEK AHEAD OF A POTENT BERING SEA LOW. THIS DEEP LOW SPREADS WIDESPREAD HEAVY WEATHER WHILE FORCING A LEAD SURGE OF WARMER AIR NORTHWARD OVER THE INTERIOR/N SLOPE. THIS LOW IS EXPECTED TO GRADUALLY WEAKEN WHILE WORKING UP THE PERIPHERY OF THE RIDGE UP THROUGH THE BERING STRAIT INTO THE SRN ARCTIC LATER WEEK...WITH LIMITED PCPN POTENTIAL INLAND INTO WRN/NWRN AK. UPSTREAM...WEATHER FOCUS TURNS TO APPROACHING SYSTEMS FROM THE W PACIFIC. IT REMAINS UNCERTAIN IF TYPHOON IN-FA WILL RECURVE INTO THE WESTERLIES...BUT LATEST JMA/JTWC GUIDANCE AND MODELS ARE STRONGLY TRENDING TO A MORE SUPPRESSED SOLTUION THAT WOULD NOT THREATEN AK. HOWEVER...WE'LL CONTINUE TO MONITOR. INSTEAD...POTENT DYNAMICS ASSOCIATED WITH THE APPROACH OF AN AMPLIFIED AND PROGRESSIVE NRN PACIFIC MID-UPPER LEVEL TROUGH IS NOW EXPECTED TO SUPPORT A DEEP LOW WITH POTENTIALLY HEAVY WIND/WAVES/PCPN ACROSS THE ALEUTIANS IN ABOUT A WEEK. SCHICHTEL