Area Forecast Discussion
Issued by NWS Honolulu, HI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

000
FXHW60 PHFO 290647
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
847 PM HST Thu Mar 28 2024

.SYNOPSIS...

Strong and gusty easterly trade winds will gradually ease Friday
in the weekend as a strong high pressure slowly drifts northeast
then weakens. Showers will favor windward and mountain areas with
some reaching the leeward areas. Drier and more stable conditions
will return over the weekend, while the easterly trades become moderate
to breezy. Rainfall chances could trend up again early next week
as an upper level disturbance moves through and trade winds
increase.

&&

.DISCUSSION...

A 1034 mb surface high north of the area will drive strong trade winds
through tonight. A Wind Advisory for the typically windier areas of
Maui County and the Big Island remains in effect through tonight. In
addition to the winds, spotty windward shower coverage is expected,
especially overnight through the morning periods due to a sufficient
amount of low level moisture and a weak upper trough in the area. These
showers will be moving through swiftly with minimal accumulations
anticipated.

Drier and more stable conditions will briefly return over the weekend
as upper heights rise and precipitable water dip to around an inch.
Trade winds are expected to ease into the moderate range Sunday as
the high weakens far northeast of the state and a front passes
north of the state.

A return of breezy to strong trades is possible through the first
half of next week as high pressure builds north of the state
(near 1050 mb). The 00Z GFS shows a surface trough building over
the state that could create lighter winds while the ECMWF holds a
more moderate solution. Regardless of these differences, both
depict an upper trough digging southward over the region and
precipitable water increasing creating an increased chance of
heavier trade wind showers Monday through midweek.

&&

.AVIATION...

Surface high pressure north of the state will maintain strong and
gusty winds through tomorrow. Low level moisture carried in on
these trades will bring clouds and showers to windward and mauka
areas, with the best chance of seeing brief MVFR conditions across
these areas overnight into the morning hours when shower activity
will be at its peak. If the showers become more widespread
tonight, AIRMET Sierra for tempo mountain obscuration may be
needed for windward portions of the island terrain. Otherwise,
VFR conditions will prevail.

AIRMET Tango is in effect for tempo moderate turbulence lee of
the island terrain. This AIRMET will likely be needed through
tomorrow. It is also in effect for 30 kt or greater winds from
Molokai to the Big Island through tonight.


&&

.MARINE...
Strong- to gale-force winds will continue overnight, then ease
into the fresh to strong category Friday through Saturday as the
ridge begins to weaken north of the state. This will support
transitioning the gales in place over the Pailolo and Alenuihaha
Channels back to a Small Craft Advisory (SCA), and potentially
reducing the coverage of the SCA in the Friday morning forecast
package. The weakening trend will continue through the weekend as
a front passes far to the north, likely enough to lower the SCA
for all waters Sunday into Monday. For the extended forecast
(Tuesday through midweek), confidence remains low due to model
discrepancies and inconsistent solutions from cycle to cycle over
the past few days. Although we would typically anticipate strong-
to gale-force easterly trades with the ~1050 mb high setting up
north of the state, the positioning of the tail-end of the
aforementioned front between this high pressure system and the
Hawaiian waters is making this challenging to predict.

Surf along exposed north and west facing shores will remain small
through early next week, with mainly overlapping small northwest
medium- to long-period swells moving through. An upward trend is
possible beginning Tuesday as a potential moderate sized, short-
to medium-period north swell arrives from a decent sized area of
north to northeast winds focused at the islands nearby to the
north between the strong high pressure system and tail-end of the
front. Again, confidence in the details for this setup remains low
at this time.

Surf along east facing shores will remain rough and choppy due to
the strong winds impacting the area locally and upstream. As the
winds lower over the weekend, expect the surf to ease and remain
small into Monday. Similar to north facing shores, an upward trend
is possible by midweek depending on how the scenario evolves.

Surf along south facing shores will remain small with mainly a
combination of background south-southwest swells and shorter
period southeast trade wind energy moving through. For the
extended (late next week/weekend), a small medium-period southeast
swell can`t be ruled out. Guidance continues to show a decent
sized batch of persistent strong southeast winds setting up
southeast of the Tuamotu Islands late this weekend into early next
week that is focused at the islands within the 150 deg
directional band.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 6 AM HST Friday for Lanai Mauka-Maui
Windward West-Maui Leeward West-Kohala-Big Island Interior-Lanai
Windward-Lanai Leeward-Maui Central Valley North-Maui Central
Valley South-Windward Haleakala-South Haleakala-Big Island
Southeast-Big Island North.

Small Craft Advisory until 6 PM HST Friday 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-Maalaea Bay-
Big Island Windward Waters-Big Island Leeward Waters-Big Island
Southeast Waters.

Gale Warning until 6 AM HST Friday for Pailolo Channel-
Alenuihaha Channel.

Small Craft Advisory from 6 AM to 6 PM HST Friday for Pailolo
Channel-Alenuihaha Channel.


&&

$$


DISCUSSION...Almanza
AVIATION...Farris
MARINE...Gibbs


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.