ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 253 PM EDT THU AUG 13 2015 VALID 12Z MON AUG 17 2015 - 12Z FRI AUG 21 2015 TODAY'S BLEND WAS AN EQUALLY-WEIGHTED BLEND OF THE 13/00Z ECENS/GEFS WITH SOME ASSISTANCE FROM THE 13/12Z DETERMINISTIC GFS FOR THE SMALLER-SCALE DETAILS TO THE 19TH (DAY 6). UNLIKE PRIOR DAYS---WITH LARGE RUN-TO-RUN MODEL SPREAD AND TIMING CONCERNS---THE MASS FIELDS LOOKED VERY STABLE THROUGH DAY 7---EVEN WITH SOME REMNANT TROPICAL MOISTURE AND ENERGY POISED TO ENTER THE WEST COAST OF ALASKA. THIS TROPICAL ENERGY WILL GENERATE A BROAD CYCLONIC FLOW ACROSS THE STATE...PULL SOME 'AUTUMN-LIKE' AIR ACROSS THE INTERIOR...AND ESTABLISH A WEST-TO-NORTHWEST LOW-LEVEL/MID-LEVEL FLOW ACROSS THE GULF OF ALASKA (DAY 6 THROUGH DAY 8). THIS COOLER PATTERN WILL HOLD BEYOND THIS PARTICULAR MEDIUM RANGE FORECAST PERIOD---THEN ANOTHER SET OF TROPICAL SYSTEMS IN THE SOUTHWEST PACIFIC---WILL BECOME ENTRAINED IN THE MID-LATITUDE WESTERLIES AND ATTEMPT TO 'RESHUFFLE' THE PATTERN ALONG THE DATELINE BETWEEN 35N AND 45N. VOJTESAK