The Weather Prediction Center

College Park, MD

Hawaii Extended Forecast Discussion

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
819 AM EDT Mon Sep 29 2014

Valid 00Z Tue Sep 30 2014 - 00Z Tue Oct 07 2014

The models/ensembles show ridging staying in place west of the
Dateline but building over/toward California which favors
troughing along the longitude of Hawai'i. With a rather deep upper
low forecast to move toward Kamchatka by early next week and
ridging remaining in the Bering Sea, a split flow in the north
central Pacific should result. The 00Z/28 ECMWF/GFS showed this
well yesterday but the 00Z/29 ECMWF appears too quick with the
flow compared to the ensembles. The 00Z GFS may have a better
handle on the flow but other contributing factors may influence
the forecast over the next few days.

Closer to the 50th state, trades should slacken as the sfc high
moves away from the state in the short term and veer more
east-southeasterly to southeasterly. PW values should hover near
to above normal through the period, supporting more scattered
showers than an otherwise average pattern. Would suggest a 00Z
GFS/ECENS mean blend which should still keep the sfc cold front NW
of the state by next Monday 6 October.


Last Updated: 819 AM EDT Mon Sep 29 2014