Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EST Wed Mar 06 2024

Valid 00Z Thu Mar 07 2024 - 00Z Thu Mar 14 2024

Today's guidance maintains the forecast of brisk to strong trades
persisting through at least the weekend, as strong high pressure
settles to a position north-northwest of the main islands behind a
leading high currently passing by to the north/northeast of the
state.  The strongest pressure gradient still looks to be around
Friday-Saturday.  This trade pattern will focus showers over
windward and mountain locations, with some enhancement possible
around midweek or so as another area of deep moisture passes
through.  Then from late week into the weekend there should be
some fluctuation in moisture but with a general tendency toward
below climatology precipitable water values northwest and near to
above normal southeast.  The upper low/trough persisting over the
area may also enhance rainfall totals at times.  This feature
should weaken somewhat by late in the week.

From late weekend into early next week, the 00Z ECMWF has joined
the GFS/GEFS/CMC and to some degree CMCens which have been showing
upper low redevelopment to the west-southwest of the state and
then tracking over the region.  Moisture values will be very
sensitive to the exact strength and track of the upper feature. 
As has been the case in recent days, the 00Z GFS leans to the high
side of the spread for PWATs.  The GEFS mean shows some increase
in moisture but not to the degree of the GFS.  The typically dry
ECMWF has nudged its moisture values up from some previous runs,
leaving the 12Z ECens mean as the driest solution.  Again favor an
intermediate solution in light of the ongoing spread in the
guidance and no clear clustering.  Meanwhile consensus shows high
pressure to the north of the state as of early Monday accelerating
eastward while a front approaches from the northwest by Wednesday.
 Thus expect trades to slacken and perhaps trend more
east-southeasterly by Tuesday.  By next Wednesday, there is a
majority ECMWF/ECens/CMC/CMCens cluster showing that the
approaching front should reach farther east into the islands
versus the GFS/GEFS.  These differences are well within typical
model spread/error for a week out in time but provide a baseline
for evaluating adjustments in future model runs.

Rausch