Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 808 AM EDT Fri Aug 01 2014 Valid 00Z Sat Aug 02 2014 - 00Z Sat Aug 09 2014 The August 1/00Z ECENS and GEFS means and their deterministic runs maintained decent continuity through 6/12Z (mid-point_day 5) across a large portion of the northern hemispheric Pacific Ocean. An active tropical pattern and series of systems off the east Asian coast between the Marianas and Japan are creating large spreads in the guidance beyond day 6. The key feature in the northern Pacific is the mid-level and upper-level long wave trough invof 155W and it's quasi-stationary positioning along 150W throughout much of this medium range period--as energy and moisture off the Japan reloads the trough. For the Subtropics, the long wave trough extends sufficiently southward into the Subtropics to produce an appreciable weakness in the Subtropical Ridge axis invof 25N. In turn, this weakness appears to directly impact the Islands with more influence from the Tropics--and an enhancement of the trade wind flow regime. The 31/00Z GFS/ECMWF deterministic runs initialized 'Iselle' with the 00Z cycle producing an additionally slower west-northwestward track west of 140W between 16N (ECMWF solution) and 19N (GFS solution) for days 6-7. fyi...looked like the 31/00Z Canadian had a bad run across the Tropics. After 6/12z, recommend an equally-weighted blend of the 1/00Z ECENS, GEFS AND NAEFS means to handle the large spread across the southern Bering Sea, Gulf of Alaska and with the track of 'Iselle'. For additional information, please consult/refer to the latest updates and bulletins from the Central Pacific Hurricane Center and National Hurricane Center. Vojtesak