ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 208 PM EDT WED APR 08 2015 VALID 12Z SUN APR 12 2015 - 12Z THU APR 16 2015 THE 8/00Z ECENS...NAEFS AND GEFS ENSEMBLE MEANS WERE IN GOOD AGREEMENT THROUGH DAY 5...THEN DEPART SIGNIFICANTLY---BUT WELL DOWNSTREAM OF THE ALASKA FORECAST AREA ALONG 130W LONGITUDE. BETWEEN DAY 6-7...THE GEFS---IN GENERAL---WERE THE STRONGER SOLUTIONS OVER WESTERN ALASKA BETWEEN 150W-160W WITH SHORTWAVE ENERGY ROTATING NORTHEASTWARD FROM A PARENT LOW IN THE CENTRAL ALEUTIANS...BUT NOT SO MUCH---AS TO TOTALLY DISCOUNT THAT OUTCOME AS AN 'OUTLIER'. BOTTOM LINE...THE FLOW PATTERN WILL BE TAKING ON A MORE AMPLIFIED CONFIGURATION IN THE NORTHEAST PACIFIC AND INTERIOR ALASKA DURING THE LATTER HALF OF THIS MEDIUM RANGE PERIOD. WHAT WAS SOMEWHAT UNUSUAL---THE 8/06Z GFS AND 8/00Z ECMWF DETERMINISTIC RUNS WERE IN RATHER GOOD AGREEMENT WITH THE FLOW PATTERN DURING THE DAY 4-7 PORTION OF THE MEDIUM RANGE. THESE TWO SOLUTIONS DO HAVE THEIR DIFFERENCES AT THE SURFACE (TRACK AND INTENSITY)---WITH RESPECT TO--- THE DAY 7 SHORTWAVE PASSING INTO THE SOUTHWEST GULF OF ALASKA. BUT...WAS ABLE TO MAINTAIN GOOD CONTINUITY WITH THE PREVIOUS WPC SURFACE GRAPHICS HEADING INTO 15/12Z (DAY 7). EXPECT SOME ALTERATIONS IN THE DAY 8 (16/12Z) TIME FRAME---BUT ONCE THE SURFACE LOW HAS BECOME INITIALIZED---SHOULD GET REASONABLE STABILITY WITH THE TRACK OF THIS FEATURE AND ADDITIONAL SHORTWAVE ENERGY EMITTED FROM ITS CORE CIRCULATION. VOJTESAK