Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 826 AM EDT Thu Sep 21 2017 Valid 00Z Fri Sep 22 2017 - 00Z Fri Sep 29 2017 A large scale upper ridge north of the islands will gradually shift eastward through the northeast Pacific this weekend (expected to align along 145W 00Z Friday and then near 130W by 00Z Monday), while a weak upper low remains centered just northeast of the state. At the surface, a large dome of high pressure expanded over the northeast Pacific will keep easterly trades intact through the weekend. Model guidance is in good agreement with the large scale pattern over the next few days, and the agreement continues into early-mid next week as the upper ridge continues to progress eastward and an upstream trough brings a cold front north of the islands. Gerhardt