Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Tue Apr 05 2022

Valid 00Z Wed Apr 06 2022 - 00Z Wed Apr 13 2022

From Tuesday into early Wednesday the trades should be lighter
than observed in previous days as a front approaches from the
northwest, while shortwave energy aloft helps to draw moisture
northward into the state.  Highest precipitable water values and
rainfall totals should be over the southeastern islands.  From
late Wednesday into at least Thursday, expect trades to become
quite brisk again as the front stalls north of the state and high
pressure passes by to its north.  Expect primarily
windward/mountain-focused showers to trend lighter as precipitable
water values decline.  The driest conditions should be around late
Thursday into Friday.  With some continued uncertainty in
specifics, trades may take on somewhat of a southeasterly
component from Friday or Saturday onward as the surface high
settles over the East Pacific and another front slowly approaches
from the northwest.

Relative to other guidance, GFS/GEFS mean runs continue to show a
deeper upper trough lingering over/near the state during the
weekend and then a greater eastward extent of the larger scale
upper trough farther northwest.  On the positive side guidance
seems to be showing progress toward finding an intermediate level
of moisture over the state from the weekend into early next week,
as the GFS/GEFS mean have nudged their PWATs downward and the
ECMWF/ECMWF mean have increased a bit over the past day. 
Differences aloft late in the period lead to the GFS being a bit
faster with the front to the west of the main islands but not to
an extreme degree relative to typical spread/predictability 6-7
days out in time.  Consensus still shows a somewhat stronger
gradient around the southwest side of the eastern Pacific surface
high versus the GFS, so favoring a tilt toward the ECMWF cluster
would support slightly stronger trades and a less pronounced
southeasterly component than the GFS.

Rausch