Ewa Gentry, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

890
FXHW60 PHFO 230114
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
314 PM HST Mon Dec 22 2025

.SYNOPSIS...
Strong trades tonight and Tuesday will ease during late week
eventually veering to southeasterly. A band of showers will focus
showers primarily windward and mauka tonight.

&&

.DISCUSSION...

Longwave ridging centers over the islands through late this week in
maintenance of a rather transient period of trade wind weather. A
brief period of strong trades anchored along the lead edge of
building high pressure will sweep through the area tonight through
Tuesday bringing with it a convergent band of showers. This band is
seen on afternoon visible imagery immediately offshore and
approaching the islands from the east and is poised to arrive late
this evening. Solid presentation on satellite suggests a high
coverage of showers some of which be ushered leeward at times by
strengthening trades within a weakly stable boundary layer.

Progression of mid-latitude troughing across the N Central Pacific
then ushers governing high pressure east causing trades to weaken
through midweek then veer to SE this weekend. The gradient over
the western end of the state further weakens as attendant surface
pressure falls spread eastward potentially favoring a couple days
of a land/sea breeze pattern over the smaller islands early next
week.

Modeling suggests the Pacific jet will once again nose into the
lower latitudes in the introducing potential for low pressure
west of the islands and a potentially more active pattern
reemerging by mid/late next week.

.AVIATION...

Breezy trade winds continue across Hawaii into Tuesday. AIRMET
Tango for tempo moderate turbulence downwind of terrain on all
islands below 8000 feet will likely continue through then.

Increasing showers late tonight as an old boundary embedded in
the trade wind flow brings MVFR ceilings and visibility to most
windward areas. AIRMET Sierra has been posted for tempo mountain
obscurations above 2500 feet this afternoon, with other islands
expected to be included in AIRMET Sierra tonight. Brief mountain
obscurations may also occur as clouds and showers pass to leeward
sides of the smaller islands at times. Expect improving conditions
to VFR Tuesday morning.

&&

.MARINE...

Fresh to strong easterly trade winds will prevail through Tuesday
night. Trades have held in the moderate to locally strong range
today as robust high pressure far north-northwest of the islands
drifted eastward and broad area of low pressure northwest of
Kauai remained nearly stationary. Trade winds will increase
overnight as a band of moisture moves over the area from the
northeast, with widespread fresh to strong winds holding through
Tuesday night. A Small Craft Advisory (SCA) remains in effect for
the typically windy waters around Big Island and Maui and will
expand to most waters tonight as winds and seas increase. The
high will weaken as it passes north of Hawaii on Wednesday, and
the low to the northwest will lift northward, leading a gradual
decline in trade winds locally. Winds may decline further and
shift out of the southeast late Friday and Saturday as the low
redevelops and pushes a surface ridge toward Kauai.

A small north swell will continue to gradually decline into
Wednesday. A moderate, medium period north-northeast (010-030
degrees) swell will arrive late Wednesday and peak Thursday and
Friday. Surf along north facing shores could approach the High
Surf Advisory level during the peak, with the largest swells
favoring the eastern end of the island chain, and a Marine
Weather Statement may be needed for harbor surges at Kahului and
Hilo. The north swell will decline over the weekend as a small
northwest swell arrives.

For east facing shores, wrapping north swell will produce small
surf across exposed coastlines tonight, while building trade
winds lead to an increase in short period trade wind energy.
Breezy trades will produce rough conditions above seasonal
average Tuesday and Wednesday. Short period trade wind swell will
decline by Christmas, but wrapping northerly swell will affect
exposed eastern shores into Friday. Surf along south facing shores
will remain very small through the week.

&&

.FIRE WEATHER...
Strong trades tonight through Tuesday ease Wednesday through the
end of the week. RH remains elevated through the period.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory from 6 PM this evening to 6 PM HST Tuesday
for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward
Waters-Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters-
Kaiwi Channel-Maui County Windward Waters-Maui County Leeward
Waters.

Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...JVC
AVIATION...Foster
MARINE...Wroe
FIRE WEATHER...JVC