Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 722 AM EST Mon Dec 08 2014 Valid 00Z Tue Dec 09 2014 - 00Z Tue Dec 16 2014 The guidance agree that an upper ridge will hold strong across the Hawaiian island chain throughout the week. By the weekend, it appears a trough will amplify east of the islands with the 00Z ECMWF being notably slower with a bit more amplitude. At the surface, a weak frontal passage is expected early in the week with northeasterly winds responding to the surface anticyclone building over 30N latitude. A light band of precipitation is possible on Wednesday/Thursday in response to the crossing baroclinic zone. Eventually a return to the trade wind regime should occur as the surface ridge moves eastward. The next cold front moving through the islands will take place by the weekend as a more pronounced upper trough crosses east of Hawai`i. This will raise the north to northeasterly low-level winds to the 20 to 25 knot range during this period. Precipitation is not expected to be too significant with this frontal passage given the progressive nature of the system and quick transition to below 0.50 inch precipitable water values. Rubin-Oster