Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 824 AM EDT Wed Jul 19 2017 Valid 00Z Thu Jul 20 2017 - 00Z Thu Jul 27 2017 The large mid-latitude surface high centered to the northwest of the Islands around 40 degrees north today is forecast to drift westward through the end of the week. Another surface high is expected to become established northeast of the state by this weekend and this should also slowly drift westward. The weak tutt low west of the Islands should continue progressing to the west with upper level ridging gradually building in as suggested by the latest ensemble mean guidance. The future remnants of what is now Hurricane Fernanda will be worth monitoring for the second half of the forecast period. This system is expected to weaken substantially over the next few days per the latest NHC advisory, with a remnant low likely passing to the north of Hawaii early next week. Both the GFS and ECMWF agree in taking the core of deepest moisture well to the north of the state, with perhaps some locally enhanced showers on the northwest Islands if the system tracks farther south than expected. This may also weaken the trades some as the system passes by before intensifying by the end of the forecast period next Wednesday. Hamrick