Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
819 AM EDT Thu Jul 23 2015

Valid 00Z Fri Jul 24 2015 - 00Z Fri Jul 31 2015

23/00Z ECENS/GEFS ensembles and their deterministic runs were
decent pieces of forecast guidance through day 4 (next Monday July
27th). The current synoptic-scale flow pattern continues to favor
tropical cyclone formation off the southernmost waters of Mexico
and Central America. And this period---the west-northwestward
migration of these 'disturbances' appears to be reasonably
depicted by the global model guidance. Likewise, an active ITCZ
and the embedded energy within it---are handled decently by the
23/00Z GFS/ECMWF runs.

In short, there were no surprises offered by the 23/00Z cycle and
the current forecast for Hawai'i look to be on track.

Both deterministic runs (the 23/00Z ECMWF/GFS) have similar
prospects for what remains of 'Enrique' ---currently invof 24N
142W. It's core vorticity should become entrained in the
Trades---along the southern periphery of the East Pac surface
ridge--- and accelerate westward as it makes a pass just north of
the Islands this weekend. At least one 'track-able' shortwave
(currently near 150W) precedes the entity formerly known as
'Enrique'---and is well-defined on the current Pacific satellite
imagery.  

Beyond day 4--- there are a few difference in forward speed and
strength of a disturbance 'rooted' in the extreme southeast
Pacific---that has potential to become another organized tropical
disturbance. The ECMWF is a slower and stronger solution versus
the GFS---and for now, suggest blending the ECENS and ECMWF to
initiate and begin tracking the wave invof 15-20N and 130W. Like
this approach because of the track record---the ECMWF-based
guidance has displayed decent accuracy with tropical activity over
the past 5-10 days.

Vojtesak