Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
812 AM EDT Fri Nov 03 2017

Valid 00Z Sat Nov 04 2017 - 00Z Sat Nov 11 2017

Rex block pattern with an axis well west of Hawaii north to Alaska
is forecast to persist through the next week, keeping the flow
pattern across Hawai'i relatively stable. Upper ridging centered
overhead is forecast by all guidance to slowly weaken into next
week, although, weakly positive height anomalies are forecast by
the ECMWF ensemble to remain in place across the Islands through
the next week. At the surface a weakening high initially centered
well northeast of Hawai'i will result in gradually weakening
easterlies, from 20 kt today to 10-15 kt by the middle of next
week. This flow pattern will keep relatively low precipitable
water values in place, especially from Sunday onward when guidance
shows very dry air originating in the northeastern Pacific
advecting across Hawai'i. Therefore, expect showers to be
generally focused along windward terrain, becoming even more
sparse by next week. A trough forecast to amplify across the
northeastern Pacific by early-mid next week will force a cold
front toward the Islands, although the model consensus is that the
front should remain north of the Islands through next Friday.

Ryan