Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 827 AM EDT Tue Jun 27 2017 Valid 00Z Wed Jun 28 2017 - 00Z Wed Jul 05 2017 Models and ensembles show an upper trough moving westward later this week (Fri into next week) just north of Hawai'i as an upper high develops to the north and northwest of the region. Just prior to the upper trough's approach, a surge in precipitable water is forecast to swing through the area from the northeast as it splits off front a frontal boundary around 40N. The upper trough itself will maintain elevated PW values into next week. Upper high to the north will support a surface high pressure (about 1032-1035mb) and a stronger pressure gradient which will increase trades next week after a brief weaker period this weekend as the upper trough passes through. ECMWF ensembles generally showed higher heights over the area by next Tuesday compared to the GEFS members (00Z) via stronger ridging to the northwest and northeast of the region. Unclear if this is more likely than the GEFS so a blended solutions seems reasonable. Fracasso