Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 730 AM EST Wed Nov 30 2016 Valid 00Z Thu Dec 01 2016 - 00Z Thu Dec 08 2016 ...Heavy Rainfall Pattern for Hawaii... ...Guidance and Uncertainty Assessment... We still generally prefer a composite solution of resonably well clustered model and ensemble guidance at mid-larger scales. However, the slightly more amplified solution aloft near the state as per the last few GFS runs may be on the right track considering upstream flow amplitude and satellie/recent trends. Smaller scale details remain more problematic at longer time frames, but the upcoming pattern should produce a period with excessive rainfall potential. Overall forecast predictability in this flow evolution is above normal. ...Weather Highlights/Threats... Tightened pressure gradients underneath high pressure centered to the northeast of the state will favor moderate to brisk trades over the next couple of days. Modest moisture over the islands should combine with trades to favor windward terrain showers. Trades should gradually weaken and shift southeastward Thu-Fri as a closed low slides just to the south of the state. The closed low is slated to lift slowly over the state Fri-Sat in response to new mid-upper level trough energy digging just to the west of the state. This should induce inverted troughing and act to pull/pool deep layered ITCZ based moisture over the state to fuel an excessive rainfall and runoff threat as precipitable water values rise to at or above 2" over the weekend into early next week. Schichtel