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FXHW01 KWNH 310753

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
353 AM EDT Wed May 31 2023

Valid 00Z Thu Jun 01 2023 - 00Z Thu Jun 08 2023

Continue to expect trades of varying strength through the period. 
Winds should reach moderate to brisk levels into Thursday and then
weaken during the weekend as a front temporarily disrupts surface
ridging to the north.  The GFS/GEFS mean are somewhat deeper than
most other guidance with the supporting upper trough, so at least
a compromise may be reasonable in terms of resolving differences
in winds during that time.  Either way, there may be a period when
background flow could be light enough to allow for some land/sea
breeze influence on showers versus the prevailing windward focus.

The elongated upper weakness currently over or just north of the
state, helping to elevate precipitable water values above
climatological values, should dissipate after Wednesday or
Thursday.  While there will be a weak lingering trough to the
west/southwest of the state thereafter, recent trends have been
clustering toward there being enough influence from flow to the
north to favor the drying trend during the weekend (with below
normal PWATs).  This scenario turns out to be on the ECMWF/ECMWF
mean side of the prior spread, with the GEFS mean adjusting toward
it by yesterday.  After varying ways of holding onto more moisture
over the Big Island if not more of the state in recent days, the
00Z GFS has finally shifted more fully to the other guidance. 
Moisture may fluctuate by Monday-Wednesday depending on
low-predictability pockets of wetter or drier air carried along
within the trade flow.  Moisture trends should favor rainfall
mostly in the light to moderate part of the spectrum from the
weekend onward.