Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
309 AM EDT Sat Sep 17 2022

Valid 00Z Sun Sep 18 2022 - 00Z Sun Sep 25 2022

Guidance generally agrees that the retrogressive passage of deep
layered closed low to the north of the state today is acting to
disrupt trades. Modest pooling moisture may fuel a few local and
land/sea boundary downpours until upper ridging settles overtop
the islands later in the weekend to limit activity despite an
emerging windward terrain focusing rainfall pattern with the
rebuilding of moderate trades as high pressure becomes established
into early-mid next week over the east-central Pacific. There is
also a growing signal supporting the digging of additional upper
trough/closed low energies to the northwest of the state mid-later
next week that would again disrupt trades and allow the digging of
an associated rainfall/moisture focusing front down to just
northwest of the state into next weekend in amplified flow. There
is certainly room for ampification given the upstream upper ridge
position/amplitude and recent flow history and the latest 00 UTC
GFS/ECMWF/UKMET/Canadian model runs are now much more in agreement
with this scenario, bolstering forecast confidence into these
longer time frames.

Schichtel