ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1220 PM EST THU FEB 13 2014 VALID 12Z MON FEB 17 2014 - 12Z FRI FEB 21 2014 VERY FEW CHANGES WERE MADE TO THE ALASKA DAY 4-8 MEDIUM RANGE FORECAST PACKAGE PER THE VERY GOOD AGREEMENT BETWEEN THE 13/00Z GEFS/ECENS SOLUTIONS. BOTH OF WHICH CONTINUE TO DEPICT A FAIRLY PROGRESSIVE MID-LATITUDE STORM TRACK FROM THE NORTH CENTRAL PACIFIC EASTWARD INTO THE WEST COAST OF NORTH AMERICA--AND SOUTHWARD ACROSS THE SUBTROPICAL EAST CENTRAL PACIFIC. THERE WERE A EXCEPTIONS... THE 13/00Z DETERMINISTIC GFS/ECMWF RUNS DIFFERED WITH RESPECT TO DEPTH OF ARCTIC AIR DURING A BRIEF 24-36 HOUR WINDOW (DAY5-6) WHEN COLD ARCTIC AIR MIGRATES WESTWARD ACROSS THE YUKON AND THE NORTH COAST BEFORE SPILLING INTO THE NORTHERN BERING SEA. IN TURN...A SUBTLE BUT SHORT-TERM AMPLIFICATION/ADJUSTMENT OCCURS IN THE SHORTWAVE DETAILS OVER THE EAST CENTRAL ALEUTIANS. HOWEVER...THE DIFFERENCES SEEM TO CORRECT THEMSELVES BY 20/18Z...WHEN THE DETERMINISTIC GFS/ECMWF GUIDANCE SETTLES BACK INTO AGREEMENT WITH A 700MB CLOSED LOW AND TROUGH AXIS ALONG 170W. THE DETAILS OF THIS SHORT-TERM WAVE ADJUSTMENT MAY IMPACT TEMPERATURES FOR SOUTHERN ALASKA (BETWEEN 60N AND 63N)...BUT ONLY BRIEFLY...AS SLIGHT DIFFERENCES IN THE DEPTH AND AREAL COVERAGE OF THE 850-700MB LAYER WARM ADVECTION (SHORTWAVE RIDGE) IMPINGES UPON SOUTHWEST AND SOUTH CENTRAL ALASKA. BUT OVERALL...THE SCOPE OF THE DIFFERENCES DO NOT APPEAR TO CONTAMINATE THE FORECAST...OTHER THAN TO BRIEFLY INCREASE THE AMPLITUDE AND ORIENTATION OF THE DOWNSTREAM RIDGE IN THE SOUTHEAST GULF OF ALASKA ALONG 140W. IF ANYTHING...THIS WOULD HAVE MORE IMPLICATION DOWNSTREAM OVER OPEN WATER AND INTO THE PACIFIC NORTHWEST (WASHINGTON/OREGON)...RATHER THAN IMPACT THE ALASKA PANHANDLE. VOJTESAK