Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
818 AM EDT Thu Jul 31 2014
Valid 00Z Fri Aug 01 2014 - 00Z Fri Aug 08 2014
The 31/00Z ECENS and GEFS means and their deterministic runs
maintained decent continuity through 6/12z---with a trend for more
eastward progression of a moderate/stronger shortwave through the
The northeastward migration of a closed h5-to-sfc low through the
central gulf of Alaska into day 5-6 has taken a slight
twist...with the 31/00Z GFS deterministic taking the system into
northern British Columbia at a faster pace than the deterministic
ECMWF by the end of day 7. From a continuity perspective, thought
the GFS has been a better indicator of medium range surface
features in the Gulf of Alaska vs the ECMWF.
In the Subtropics, the 31/00Z GEFS/ECENS means and their
deterministic runs do not waver much at all with the surface ridge
strength and central pressure location invof 35-40N 140W between
days 4-6. What will be a key feature emerging in the latter half
of the medium range in the eastern Gulf of Alaska appears to have
a significant impact on the subtropical ridge axis and northward
transport of tropical moisture from the deep Tropics.
Blending the 31/00Z GFS/ECMWF deterministic runs continues to
indicate a disturbance invof ~146W @ 7/00Z and ~149W @ 7/12Z---the
late day 6-early day 7 time frame. This blend yields a slightly
slower trend versus 24 hours ago---and the 30/00Z cycle. But a 1
degree eastward adjustment is not a bad starting point for a
feature that has also trended a degree or two north and west in
the last 24 hours.
Please monitor information from the Central Pacific Hurricane
Center and National Hurricane Center concerning tropical weather
developments impacting Hawai'i.