Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 712 AM EST Mon Dec 21 2015 Valid 00Z Tue Dec 22 2015 - 00Z Tue Dec 29 2015 Through late this week guidance shows a moderately wet trade regime. Winds should decrease somewhat compared to recent days as strong high pressure northeast of the state gradually weakens and is replaced by an upstream high that will take a farther north track and continue rather quickly into the eastern Pacific. Precipitable water values will be variable in a range centered around 1.25-1.50 inches. Some increase in moisture will be associated with a compact upper circulation tracking northeastward from south of the islands during the first half of the week. Trade showers will likely focus over windward terrain with lighter activity possibly reaching other locations at times. There is still a moderate level of uncertainty in the forecast by Sat-Mon. The majority consensus of models/ensemble means is consistent in showing a front sinking toward the islands with trailing high pressure helping to strengthen trades. However isolated model runs show a stronger bundle of energy pulling off from the mid-latitude upper trough and settling west of the state, leading to a lowering of surface pressures and northward transport of lower latitude deep moisture. The 00z GFS showed this scenario yesterday while the 00z ECMWF does today. The 00z GEFS mean has an intermediate idea with a more amplified upper trough than the majority cluster but still much weaker/faster than the 00z ECMWF. The 00z GEFS mean surface pattern still looks like consensus. Overall would recommend staying close to the majority solution, which might at least increase rainfall focus to some degree with the approach of the surface front. Rausch