Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 808 AM EDT Tue Mar 31 2015 Valid 00Z Wed Apr 01 2015 - 00Z Wed Apr 08 2015 Albeit with some uncertainty for precise strength and direction at times, guidance as a whole shows moderate trades from the east or southeast during most of the forecast period. A weak shortwave that may briefly enhance shower activity over/near the northern islands will pass by in the next 12-24 hours. Upstream trough energy is expected to close off into a compact upper low to the northwest of the islands by Thu-Fri, then open up soon thereafter. Currently the majority of guidance including the 00z GEFS mean suggests that the 00z-06z GFS runs may track this upper low center somewhat too far southward. Based on the majority track for the upper low, what moisture that may lift toward the Big Island should be a little less than indicated in GFS runs but even the 00z ECMWF scenario would lead to some increase in rainfall over windward locations of the Big Island around Fri-Sat. From Sun-Tue guidance shows little agreement with the exact details of flow aloft over and just to the north of the state, as demonstrated by the 00z NAEFS/ECMWF means being 180 degrees out of phase by next Tue. The most common theme seems to be an evolution toward a hint of cyclonic flow but with less pronounced troughing than in the 00z ECMWF by next Tue. Ridging in the 00z ECMWF mean to the north of the state appears to be least agreeable solution relative to this idea. Based on less troughing than in the 00z ECMWF late in the period, would favor holding onto modestly higher precipitable water values than forecast by that model run at that time. Rausch