Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
814 AM EDT Thu Oct 18 2018

Valid 00Z Fri Oct 19 2018 - 00Z Fri Oct 26 2018

Water vapor satellite imagery early this morning show a
mid/upper-level shortwave northwest of Hawaii moving
southeastward. Models show good consensus that this feature will
move across Hawaii through Saturday before upper ridging begins to
build across the state by late in the weekend. The shortwave will
result in a period of relatively weak trades, with scattered to
numerous showers over the eastern islands where the deepest
moisture will be in place. As upper-level heights rise across
Hawaii early next week and and expanding surface high north of the
islands increases trades, models/ensemble show general agreement
than an easterly wave will cross Hawaii by Tue-Wed. The wave will
result in an enhancement of trades, perhaps into the 20-30 kt
range with higher gusts, and an increase in moisture/shower
potential. A rather active mid-latitude flow-regime and frontal
zone should remain north of Hawaii through the next week, with
some model solutions suggesting the potential for amplification of
a larger trough across the north central Pacific by late next
week, perhaps pushing a cold front closer to Hawaii.

Ryan