Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
346 AM EDT Thu Oct 15 2020

Valid 00Z Fri Oct 16 2020 - 00Z Fri Oct 23 2020

The main weather concern over the state for the upcoming week is
with an upper-level trough pushing a cold front southeastward and
approaching the islands by the weekend. South of the frontal
boundary, warm and humid weather can be expected Thursday and
Friday, along with weakening trade winds. Winds are likely to be
light and shift more southerly than normal easterlies, allowing
for a land/sea breeze pattern. Locally heavy rain is possible
where those convergence boundaries set up.

The threat for heavy rainfall and the potential for flooding ramps
up this weekend across at least the western islands as much above
normal moisture pools along and just ahead of the front. Model
guidance continues to vary a bit on how far southeast the front
will progress. In general the GFS and some GEFS ensemble members
continue to have the front moving slightly farther east toward the
central part of the state, while the ECMWF has the front stalling
near the western islands. If the front reaches farther east, areas
like Oahu could see heavy rainfall as well. It currently appears
the front should lift and stall west of the state early next week
and eventually dissipate.

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