Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 710 AM EST Tue Jan 20 2015 Valid 00Z Wed Jan 21 2015 - 00Z Wed Jan 28 2015 Expect low level winds to range between southeasterly and southwesterly through Thu. The state should be at the very southwestern periphery of high pressure over the extreme eastern Pacific early in the period, while a sharpening trough aloft should bring a surface front toward the northwestern islands by Fri. Stronger southwesterly flow should be present just ahead of this front. After that time models agree that the northern part of the front should continue eastward but differ on the southeastward progression across the islands. The 00z/06z GFS runs are flatter with the upper trough than most other guidance and thus have difficulty in pushing the front through the islands, keeping some 1.25 inch or greater precipitable water values over the Big Island through next Mon. The more amplified trough of the 00z ECMWF would push much drier air into the region. With the 00z CMC mean supportive of the ECMWF cluster and even the 00z GEFS mean somewhat more amplified aloft than the operational runs, would prefer to lean at least 2/3 toward the ECMWF scenario. Passage of the front and trailing high pressure will bring northerly and then northeasterly winds to the islands from the weekend into early next week. Initially light shower activity may be enhanced somewhat with the front. Then expect windward focused showers from the weekend into next week. Rausch