Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
352 AM EDT Mon Jun 13 2022

Valid 00Z Tue Jun 14 2022 - 00Z Tue Jun 21 2022

Today's guidance generally shows only modest refinements to the
prior forecast.  A surface high initially north of the state along
30N latitude will quickly give way to a larger scale central
Pacific high that should track eastward along 35-40N and
ultimately settle into position well northeast of the state.  This
evolution will likely support moderate to brisk trades with some
fluctuation at times, along with windward/mountain-focused showers
that could occasionally stray elsewhere.

The early part of this week should feature fairly light showers
with precipitable water values below climatology.  Guidance
continues to show that a pocket of moisture from a dissipating
front will pass through from the northeast around Wednesday or so,
likely helping to increase rainfall amounts.  Consensus shows the
highest precipitable water values crossing the northern/central
islands.  Latest operational models suggest that a compact upper
low will track over or just north of the main islands late this
week into the weekend, potentially weakening the trades a bit and
maintaining some potential for localized rainfall enhancement. 
The 00Z CMC tracks the upper low north of the GFS/ECMWF by the
start of next week, but otherwise latest solutions are close
enough to favor a compromise approach.  Predictability for
specifics of such a small feature several days out in time is on
the low side though it is higher for the surrounding overall
weakness.  Eventual departure of the upper low should allow for a
slight rebound in trades by late weekend/early next week.

Rausch