Mountain View, Hawaii Weather Forecast Discussion

688
FXHW60 PHFO 210144
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
344 PM HST Sat Sep 20 2025
.SYNOPSIS...
Breezy trade winds will push a band of moisture over the islands
late tonight and Sunday morning. An upper low moving over the
islands will enhance these showers. Winds will taper slightly as
incoming showers continue to impact windward slopes Monday and
Tuesday.
&&
.DISCUSSION...
A 1026 mb surface high is centered far north of the islands
driving breezy trade winds this afternoon. Water vapor imagery
shows an upper low over just northeast of the area nudging closer
to state. Visible satellite and radar show a band of clouds pushing
east to west approaching the islands. The upper low moving over
the islands will create somewhat unstable conditions enhance
these showers. Expect these showers to track in through the night
into Sunday morning focusing over windward slopes.
Drier conditions expected Tuesday into the end of the week while
the trades begin to taper off due to disturbances moving across
the northeast Pacific. Long range model solutions show a low
developing northeast of the state by the end of the week, but
confidence is low if there will be direct impacts to Hawaii.
&&
.AVIATION...
Moderate to breezy trades will persist for the next several days.
Low clouds and showers remain possible along mainly windward and
mauka areas as moisture embedded in the trades move across the
islands. Conditions remain predominately VFR with periods of MVFR
likely in showers.
AIRMET Sierra remains in effect for mountain obscuration along
windward portions of Oahu and Molokai with conditions slowly
improving overnight. AIRMET Sierra may be necessary for windward
portions of the remaining islands tonight.
AIRMET Tango remains in effect for moderate low level turbulence
over and downwind of all island terrain. Expect these conditions
to continue through the weekend as breezy trades persist.
&&
.MARINE...
High pressure north of Hawaii will maintain moderate to locally
strong trade winds through Sunday, and a Small Craft Advisory
(SCA) remains in effect for the typically windy waters around the
Big Island and Maui. Trades will gradually ease late Sunday as
the high weakens, and we are confident that the SCA will be
dropped by Monday. Trades should remain in the moderate to
locally fresh range Tuesday and Wednesday. Developing low
pressure northeast of the islands on Thursday will likely weaken
local winds and may cause the direction to shift out of the
northeast.
A pair of south-southwest swells are due this week. The first
swell was slow to build in today, with the local CDIP buoys
showing inconsistent energy at around 2 feet 15 seconds. Expect
south shore surf to peak around seasonal average tonight and
early Sunday, then decline later Sunday and Monday. A smaller
south-southwest swell may build on Tuesday and peak on Wednesday.
Tiny to small surf will prevail along north facing shores through
midweek, mainly from northwest swell. A sharp trough northeast of
Hawaii will likely generate a short period north-northeast swell
that will reach the islands on Thursday. This swell could produce
moderate surf by Friday.
East facing shores will experience near seasonal average surf
through Sunday due to short period trade wind swell. Surf along
east facing shores will gradually decline Monday through
Wednesday, followed by a potential increase on Thursday from the
above mentioned source out of the north-northeast.
&&
.FIRE WEATHER...
Breezy trade winds will push a band of moisture over the islands
late tonight and Sunday morning. Humidity levels will remain a bit
higher overnight due to the influx of moisture. Inversion is fairly
weak and elevated around 9,000 feet. Trade wind speeds will taper
off early next week with incoming clouds and showers focusing
over windward slopes.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.
&&
$$
DISCUSSION...Foster
AVIATION...Ahue
MARINE...Wroe
FIRE WEATHER...Foster

NWS HFO Office Area Forecast Discussion