Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 714 AM EST Sun Nov 30 2014 Valid 00Z Mon Dec 01 2014 - 00Z Mon Dec 08 2014 High pressure initially to the north of the state will be weakening but remain enough of an influence to provide moderate to brisk trades into the first half of the week. On average windward focused showers should be lightest Sun through Mon or into Tue corresponding to a relative minimum of precipitable water values around or slightly below an inch. Beyond Tue the latest guidance continues to diverge considerably with respect to exact evolution of upstream shortwave energy and impact on the surface pattern. The 00z GFS/UKMET are deepest with their features that form to the west of the area and then strongest with the front that ultimately crosses the islands. The 00z GEFS mean leans this way in less extreme form. On the other hand the 00z ECMWF/ECMWF mean are faster and more amplified with northern stream flow thus suppressing deep moisture to the west/south of the islands, and allowing low level trade flow to persist. The 00z CMC/CMC mean lean more in the GFS direction in principle but with the operational CMC not too enthusiastic about rainfall. Details differ among the 06z GFS/GEFS mean and 00z-06z GFS parallel runs, but as a whole they support a significant toning down of the 00z GFS/GEFS scenario. Therefore would expect some increase in moisture and rainfall late in the week but with at most the passage of a weak surface boundary, or maintenance of trades to a more modest extent than in the ECMWF/EC mean. Rausch