Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 714 AM EST Sat Jan 12 2019 Valid 00Z Sun Jan 13 2019 - 00Z Sun Jan 20 2019 At least into next Friday the models and ensemble means are fairly similar regarding the overall pattern and significant features. High pressure positioned to the northeast of the state will change in shape/location from day to day but overall will support light to moderate trades into midweek. An upper ridge centered southwest of the main islands will expand over the area this weekend and then gradually recede as an upper trough approaches after midweek. The combination of ridging aloft and below average precipitable water values should keep showers on the light side. Expect most rainfall to have a windward focus though trades may be weak enough to allow for some sea breeze focus during the afternoon. The approach/arrival of the progressive shortwave aloft will bring a front and likely some organized rainfall into the northwestern islands by Thursday and locations farther southeast into Friday, along with a disruption of trade flow. Some brief enhancement of rainfall is possible though frontal progression and moisture levels only modestly above normal should temper overall rainfall totals. After early Friday there is some divergence for southeastward progress of the front. The 00Z/06Z GFS have the front and associated moisture axis hanging up over the southeastern islands and then lifting northward in response to a system off to the west/northwest. To varying degrees most other solutions, including the 00Z GEFS mean, suggest that the front should push farther southeastward. Compared to the full guidance spread the 00Z GFS looks particularly questionable with its upstream height falls. Thus would prefer to lean at least 2/3 toward the 06Z GEFS mean and 00Z ECMWF/ECMWF mean for this part of the forecast. Rausch