Drought in Hawaii, March 1 to 29, 2022

Area Forecast Discussion
National Weather Service Honolulu HI
833 PM HST Mon Feb 28 2022

.SYNOPSIS...
A surface trough will move over the islands tonight, keeping
winds light and variable for the next few days. An upper trough
will pass over the area early Thursday through Thursday night,
bringing unstable weather across the central and eastern parts of
the state.

&&

.DISCUSSION...
A weak surface trough to our northeast will move over the area by
Tuesday morning, keeping local winds light and variable for the
next few days. Our benign weather pattern across the islands
continues this evening, with latest soundings indicating a stable
airmass, strong subsidence inversions and PW just over an inch.
Satellite loop shows earlier cloud cover across the islands
beginning to decrease with the onset of nighttime cooling. Patchy
broken low clouds linger across mauka areas of Kauai and Maui,
but Oahu has mostly clear skies. Broken to overcast low clouds
persist across many areas of the Big Island. Radar shows very
little shower activity.

Expect the current pattern to hold through Tuesday night, with
daytime sea breezes increasing cloud and shower coverage across
mauka areas, followed by nighttime land breezes and clearing.
However, models show an area of showers tracking in from the east
and reaching windward portions of the Big Island Tuesday night.
This moisture will then stall and linger for a few days as the
next weather system tracks in from the northwest. A light
wind/convective pattern will continue statewide on Wednesday, with
increased showers expected over the Big Island Wednesday
afternoon.

Models show a an upper trough digging southeastward across the
islands and destabilizing our airmass Wednesday night through
Friday. The cold pool with bring 500 mb temperatures down to -14 C
as it passes over the smaller islands Thursday morning and over
the Big Island later on Thursday. A cutoff surface low will
deepen northeast of the state on Thursday, keeping our winds
light and variable. Heavy rainfall and thunderstorms are possible,
mostly on Maui and the Big Island, particularly Thursday
afternoon as the lingering moisture taps into by the instability.
There will also be a chance for snowfall/freezing rain on the Big
Island summits.

The upper trough will depart on Friday, with weak ridging
expected to build in from the west. Conditions will briefly
stabilize this weekend, but models show a fairly active, wet
weather pattern at the beginning of next week. Details will fill
in as we get closer to the weekend.

&&

.AVIATION...
Land and sea breeze conditions will persist due to a weak front
positioned nearby to the north. Some moisture associated with
this boundary has made it to Kauai, leading to periods of MVFR
CIGS/VSBYS in and around passing light showers. Elsewhere, shallow
stratocumulus clouds will cause CIGS to periodically dip into the
MVFR category overnight through the early morning hours Tuesday.
Otherwise, VFR conditions will prevail.

AIRMET SIERRA for mountain obscuration due to clouds and showers
will be needed for Kauai this evening. The Big Island may need
one later tonight through the morning hours Tuesday.

&&

.MARINE...
The ongoing long-period west-northwest swell is continuing to
subside. Surf heights will continue to lower through early
Thursday before beginning to rise again by Thursday afternoon
into Friday as another long-period west-northwest swell is
expected to arrive. This swell is likely to peak Friday with surf
heights possibly reaching low-end High Surf Advisory levels. Model
guidance also indicates that a moderate northeast swell is also
probable around the same time period. Additional northwest swells
are expected into the long range, beginning around Monday of next
week.

Light to moderate trade winds will prevail through Wednesday as a
front stalls and weakens north of the state. Winds will shift
more northerly and increase to more widespread moderate speeds
beginning Thursday as a surface trough develops northeast of the
islands, though speeds are expected to remain below the Small
Craft Advisory threshold. The trough will linger there for at
least a couple of days, as an upper trough develops in tandem.
This will allow for increased shower coverage, as well as a slight
chance of thunderstorms for the windward coastal waters of Oahu,
Maui County, and the Big Island.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION...Powell
AVIATION...Gibbs
MARINE...Kinel