Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
245 AM EST Mon Jan 25 2021

Valid 00Z Tue Jan 26 2021 - 00Z Tue Feb 02 2021

Today's guidance maintains good continuity with the general
pattern during the period.  For the first half of the week there
will be very moist southeasterly flow over the state, between a
deep-layer ridge to the north/northeast of the area and a trough
off to the west.  As has been the case in recent days there is
good agreement on the potential for heavy rainfall over the
windward portions of the Big Island.  However differences still
exist for the magnitude of rainfall totals over the northwestern
islands with the GFS again heaviest.  An intermediate solution
appears most reasonable as the mass field discrepancies seen 24
hours ago have dampened out but the GFS still brings slightly
higher precipitable water values to the northwestern islands
versus other guidance.  Meanwhile the UKMET implies potential for
meaningful rainfall to reach a little farther east than the
ECMWF/CMC--plus the 00Z ECMWF trended wetter than the prior run. 
From Thursday onward anticipate lighter rainfall and a continued
primary focus over windward areas.  Near to slightly below normal
precipitable water values will settle into the area through early
next week while an upper ridge to the north will drop down closer
to the islands before weakening.  At the same time orientation of
surface high pressure will adjust trades back to a more easterly
direction while the gradient will be sufficient to maintain fairly
brisk wind speeds.

Rausch