HAWAII EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 823 AM EDT WED APR 24 2013 VALID 00Z THU APR 25 2013 - 00Z THU MAY 02 2013 A 24/00Z CYCLE GFS/ECMWF SOLUTION BLEND SHOULD CAPTURE THE OVERALL FLOW PATTERN ALOFT FOR THE ISLANDS AND CENTRAL/NORTHEAST PACIFIC THE NEXT 7 DAYS. DURING THE NEXT 12-36 HOURS...THE WEAKENING COLD FRONT CURRENTLY INVOF HAWAI'I IS EXPECTED TO DRIFT WEST AND NORTH AS A SURFACE HIGH PRESSURE RIDGE ATTEMPTS TO BUILD IN FROM THE NORTHEAST. AFTER 36 HOURS... MODELS CONTINUE THE TREND FOR RISING HEIGHTS AND MORE STABLE CONDITIONS...WITH THIS RIDGE OF HIGH PRESSURE BUILDING IN THE EAST PACIFIC AND OFF THE WEST COAST OF THE MAINLAND. THE RETURN OF SEASONAL TRADEWINDS REMAINS CENTERED ON THE UPCOMING WEEKEND. HIGH PRESSURE ALOFT THEN ANCHORS OVER THE FORECAST AREA DURING THE MIDDLE PART OF NEXT WEEK...WITH THE ENSEMBLE MEAN GUIDANCE AVERAGING A 587DM HIGH DIRECTLY OVERHEAD OF THE CENTRAL ISLANDS. THE 24/00Z MODEL CYCLE AND DETAILS IN THE NORTH CENTRAL PACIFIC REMAIN IN FLUX WITH THE GFS/ECMWF CONTINUING TO HAVE THEIR DIFFERENCES WITH THE TIMING OF ENERGY MOVING INTO THE GULF OF ALASKA AND DOWNSTREAM INTO THE NORTH AMERICAN COAST LINE. LIKEWISE...THE DETAILS ALOFT REGARDING THE POLAR VORTEX AND ITS RETROGRESSION INTO AND OVER ALASKA PROPER REMAIN IN FLUX. FOR HAWAI'I HOWEVER---THESE DIFFERENCES ARE NEGLIGIBLE--UNTIL NEXT TUESDAY (DAY 6) WHEN THE BROAD CUTOFF H5 LOW INVOF 40N 165-170W ATTEMPTS TO LIFT NORTHEASTWARD INTO THE CENTRAL GULF OF ALASKA. AT THIS TIME FRAME...A SURFACE TROUGH/COLD FRONT BEGINS TO MIGRATE EAST-SOUTHEASTWARD INTO THE SUBTROPICS. VOJTESAK