Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 271319
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
319 AM HST Wed Mar 27 2024

.SYNOPSIS...
Breezy easterly trade winds will become strong and gusty later
today through the second half of the week as high pressure
strengthens north of the state. Windward shower coverage may
increase through this period, with some showers occasionally
making it to leeward areas of the smaller islands. Drier and more
stable conditions will return over the weekend, with the easterly
trades easing into the moderate to breezy range. Rainfall chances
could trend up again early next week as an upper disturbance moves
through.

&&

.DISCUSSION...
Guidance remains in good agreement through the second half of the
week and shows high pressure building north of the state. The
easterly trades will respond and become strong beginning later
today, then likely strong enough for localized wind advisories
through the day Thursday over the typically windier locations of
Maui County and the Big Island. In addition to the strengthening
winds, windward shower coverage could trend up due to a
combination of a weak mid- to upper-level trough and a sufficient
amount low-level moisture in the area. Some of these showers will
manage to make it over to leeward areas of the smaller islands,
especially overnight through the mornings. Rainfall accumulations
should remain light.

Drier and more stable conditions will briefly return over the
weekend as upper heights rise and PWs dip to around an inch. Trade
winds are expected to ease into the moderate range due to a
weakness forming in the ridge as a front passes to the north.

The forecast confidence lowers early next week due to significant
differences shown between the various model solutions. While the
GFS solutions are more aggressive and depict the tail-end of the
aforementioned front moving through the area with strong
northerly winds trailing it, the ECMWF shows it hanging up to the
north with easterly trades holding (agrees with the blended
guidance). Regardless of these differences, the attendant upper
trough digging southward over the region drawing moisture into the
area should be enough to support a transition to a wetter pattern
Monday through midweek.

&&

.AVIATION...
Moderate to breezy easterly trades will continue through
the remainder of this morning as surface high pressure remains
anchored to the north of the state. Scattered showers will mainly
be confined to windward locations with the occasional spill over
to leeward sides. Brief periods of MVFR ceilings and visibility
may occur with any of the more robust showers. By this afternoon,
trades will strengthen further and become windy at times. This
stronger flow will persist this evening into tonight and bring
scattered to numerous showers to windward locations.

AIRMET Sierra has been issued above 2000 feet for north through
east sections of Oahu due to tempo mountain obscuration from low
clouds and showers.

&&

.MARINE...
High pressure north of the main Hawaiian Islands will move
eastward and strengthen over the next few days, resulting in
increased trade wind speeds across local waters through the rest
of the work week. The Small Craft Advisory (SCA) remains in
effect for the typical windy zones around Maui County and the Big
Island but has been expanded to include windward and leeward
waters around Maui County and Oahu.

Strong trades will create rough and choppy surf along east facing
shores which will continue into next week. Moderate west-
northwest (310 degree) swell will gradually decrease today.
Expect additional small northwest (310-320 degree) swells from
Thursday into early next week. Mainly background surf will
continue for south facing shores through the weekend with some
long period energy arriving early next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Thursday for Oahu Leeward
Waters-Kaiwi Channel-Maui County Windward Waters-Maui County
Leeward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha Channel-
Big Island Leeward Waters-Big Island Southeast Waters.

&&
$$

DISCUSSION...Gibbs
AVIATION...Thomas
MARINE...Powell


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