Current Conditions
Temp-1.1 C
RH9 %
WindWSW 16 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

FXHW60 PHFO 042004

Area Forecast Discussion
National Weather Service Honolulu HI
1004 AM HST Thu Mar 4 2021

Breezy trade winds will continue for the next couple of days as
high pressures lies far to our north. Winds will increase over the
weekend and on into early next week as the high to our north
strengthens. An upper trough will linger over the area throughout
the forecast period. This will cause for a rather wet trade wind
pattern setting up. Clouds and passing showers will favor windward
and mauka areas with the trade winds sufficiently strong enough
to blow some passing showers over to leeward areas at times.


Strong high pressure is centered far to the north northeast of
the state resulting in breezy trade winds across the area.
Moisture embedded in the trades is providing for some brief
passing showers over windward and mauka areas with most leeward
locations remaining dry. Expect little change in this weather
pattern today.

The high is forecast to drift east southeast and weaken slightly
over the next couple of days. Also a weak low level trough will
develop along an old frontal boundary. This will allow for a
slight downward trend in trade wind speeds. Meanwhile, an upper
trough will sharpen up over the area. This will keep the airmass a
bit less stable which will allow for a wetter trade wind shower
regime to set up especially for windward and mauka areas. Winds
will be sufficiently strong enough to blow some passing showers
over to select leeward areas at times. The upper trough may also
allow for the thickening up of high clouds over the area from time
to time.

By Saturday, a surface high will strengthen north of the state
with trade winds speeds increasing once again to breezy and windy
levels. The upper trough will continue to linger over the area
resulting in the wet trade wind pattern continuing through at
least Sunday.

This wet trade wind weather pattern will continue on into early
next week as the trough aloft remains near the area and abundant
low level moisture moves into the islands from the east. Trade
winds will remain elevated as strong high pressure remains to our


With high pressure far northwest of the islands, moderate to
locally breezy northeast trade winds will persist over the next
couple of days. Lower ceilings and showers, with accompanying MVFR
conditions, will mainly affect windward and mauka sections. A
surface trough is expected to form near the state later today into
Friday, which is likely to increase showers over the smaller isles
beginning tonight. And high cloudiness will be streaking over the
area from the west.

No AIRMETs are in effect. One may be needed later today and/or
tonight for mountain obscuration as shower coverage increases.


A Small Craft Advisory (SCA) includes waters around Kauai, the
Kauai Channel and windward Oahu waters for combined seas near 10
feet. SCA conditions will spread to most waters Friday and over
the weekend due to building seas and winds as the high to our
north strengthens.

A bump in east shoreline surf will occur over the weekend as
the trade wind swell increases and an arriving north swell wrap
fills in. A northwest swell arriving today will peak below the
HSA threshold along north and west-facing shores late today into
Friday. A secondary, reinforcing north swell will arrive Friday
night and may boost north facing shore surf to HSA heights Friday
into Saturday and slowly diminish Sunday. Background south swells
will provide small surf to south facing shores.


Tsunami Watch until 6 PM HST this evening for all Hawaii islands.

Tsunami Watch until 6 PM HST this evening for all Hawaiian

Small Craft Advisory until 6 AM HST Friday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters.




Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office