HAWAII EXTENDED FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 722 AM EDT WED SEP 14 2011 VALID 00Z THU SEP 15 2011 - 00Z THU SEP 22 2011 EAST-WEST RUNNING MID-LEVEL RIDGING BETWEEN 30-40N LAT GENERALLY PREVAILS OVER A LARGE PORTION OF THE EAST AND EAST CENTRAL PACIFIC OCEAN THIS FORECAST PERIOD. A WEAK PERTURBATION IN THE WESTERLIES APPEARS TO PINCH OFF NEWD OF THE BIG ISLAND NEARING THE LATTER HALF OF THE FORECAST....BUT LITTLE ORGANIZATION AND/OR TROUGHING IS ANTICIPATED IN THE MID-LATITUDE ZONAL FLOW ALONG THE NORTHERN PERIPHERY OF THE RIDGE PER ECMWF/GFS 14/00Z RUNS. OVER THE TROPICS...EASTERLIES PREVAIL WITH GFS/ECMWF BOTH CARRYING A WEAK/DIFFUSE H5 WAVE WEST-NORTHWARD ON FRI/SAT...PASSING TO THE NORTH OF THE ISLAND CHAIN...THEN STALLING INVOF 25N160W. SUN/MON...H5 FLOW WILL GENERALLY BECOME LIGHT WEST TO SOUTHWEST...WITH LITTLE NOTED DIFFERENCE IN TRADEWIND/GRADIENT FLOW...ASIDE FROM LOCAL ACCELERATIONS ACROSS KALOHI AND PAILOLO CHANNELS. VOJTESAK ñ