Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1258 AM EDT Sun Sep 19 2021

Valid 00Z Mon Sep 20 2021 - 00Z Mon Sep 27 2021

The weather pattern is expected to be relatively uneventful across
the Hawaii domain for the upcoming week with surface high pressure
generally being centered near 35 to 40 degrees north.  Aloft, a
col in the upper level ridge is expected to develop Monday with an
inverted upper trough slowly tracking westward through the week. 
Both the GEFS and EC means are in good agreement on this scenario.
 By Tuesday, a cold front is expected to stall well to the north
of the Islands with perhaps some weakening of the surface pressure
gradient by midweek.

It appears the best moisture and lift associated with the weak
upper trough should remain south of the Islands, with perhaps some
increase in trade wind induced showers on Tuesday and Wednesday
across the Big Island.  Otherwise, easterly flow on the order of
15 to 20 mph can be expected for most of next week with windward
showers.



Hamrick