Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 340 AM EDT Wed Jul 21 2021 Valid 00Z Thu Jul 22 2021 - 00Z Thu Jul 29 2021 Over the next seven days guidance shows a transition from a regime that favors brisk trades and relatively light windward/mountain showers toward some slackening of the trades and a wetter pattern. High pressure to the north and northwest of the state will be strong enough to support fairly strong trades through about the end of the week. As models/ensembles have been advertising in recent days, the northern periphery of moisture from Felicia should brush at least the Big Island around Thursday-Friday and possibly increase rainfall totals. The moisture associated with Guillermo should arrive by Sunday-Monday while upper troughing that develops just to the north/northwest of the area may keep precipitable water values fairly high over the state through midweek. Accompanying the increased moisture, a surface trough should pass through and decrease the trades in its vicinity--lessening the windward rainfall focus for a time. Looking at guidance comparisons during the Sunday-Wednesday period, a reasonable consensus persists in showing the greatest moisture from Guillermo passing to the north of the state though the ECMWF still hedges a little south of most other solutions. In principle the models/ensembles are trending closer together for how the upper trough may evolve but the 12Z ECMWF mean strays faster than other guidance with its moisture shield by next Wednesday. Rausch