Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 823 AM EDT Mon Jul 30 2018 Valid 00Z Tue Jul 31 2018 - 00Z Tue Aug 07 2018 Upper high to the north of the region will strengthen this week along 170W (about +2 sigma 500mb heights) as a weakness slips southwestward and then westward along 25N to its south. To the east, another upper high will strengthen between 140-150W this weekend and move toward 155W next Monday. Models/ensembles have been relatively stable in this evolution. Moisture is forecast to increase late Friday into Saturday before heights smartly rise on Sunday, allowing some modest rain to overspread parts of the island chain. The 00Z ECMWF was just a bit farther southwest (just offshore from Hawai'i) with the rain axis while the GFS axis was a bit closer. For now, a blended solution should suffice. Rising heights into next Monday will suppress the rainfall to start next week as a tropical wave or perhaps developed system is forecast to stay south of the area near the ITCZ. Fracasso