Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
243 AM EST Wed Jan 26 2022

Valid 00Z Thu Jan 27 2022 - 00Z Thu Feb 03 2022

Expect fairly light shower activity through the rest of the week
into the weekend as precipitable water values hover at near or
somewhat below normal levels.  A high passing by to the
north/northeast will support moderate to brisk trades and
windward/mountain shower focus on Wednesday.  Trades should weaken
later in the week as a front approaches/stalls to the north of the
state, with some potential for sea/land breeze influence on
showers, followed by a rebound over the weekend with passage of
the trailing high.

Some forecast specifics for the early-mid week period remain very
uncertain but at least the spread for potential rainfall amounts
has narrowed somewhat as the GFS/GEFS have trended lower with
moisture/rainfall over the past day.  There is still a lot of
model and ensemble spread for exactly what will happen with the
upper trough approaching from the northwest Sunday-Monday, with
GFS runs and some GEFS members continuing to be on the amplified
side of the full envelope.  The key today is that the
amplification/sharpening in the GFS is far enough east that the
front moving into the state has less moisture with it. 
Interestingly the 00Z ECMWF has jumped to a less amplified version
of the GFS and even closes off a low to the north/northeast of the
islands, so now the ECMWF brings a front through the islands like
the GFS instead of keeping it northwest and maintaining trade
flow.  On the other hand the GEFS mean has trended less amplified
aloft and keeps the front farther northwest than before, while the
CMC continues to hold the front to the northwest.  So overall
today's mix of guidance has lowered confidence in whether the
front will stay northwest of the main islands or progress
into/through the area, with some intermediate solution favored. 
On the other hand, confidence is now better that any increase in
rainfall should not be too extreme. 

Rausch