Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
729 AM EST Mon Nov 24 2014
Valid 00Z Tue Nov 25 2014 - 00Z Tue Dec 02 2014
Vigorous mid-level wave near 30N 158W on track to introduce a
cooler, lower dew point airmass---and scattered showers across the
Islands during the next 24 hours. This wave will rapidly close off
into a moderately-intense surface cyclone and migrate
northeastward towards the Mainland.
The differences in the Subtropics between the 24/00Z deterministic
GFS/ECMWF runs concern the timing of a second mid-latitude trough
progression across the Dateline. At the surface, the GFS/ECMWF are
in better agreement with the depth and track of the upper-level
feature---and more importantly---have settled on a mid-latitude
track for this wave---along 45N.
This will reinforce a weak post-frontal shear line scenario north
and northwest of the islands for day 3...possibly day 4. Beyond
day 4, the GFS is more aggressive with mid-level energy from the
mid-latitude wave train descending into the Subtropics.
Suggest a blend of the 24/00Z ECENS/GEFS for days 5-7.