Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 121853
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
853 AM HST Tue Mar 12 2024

.SYNOPSIS...
High clouds will decrease today as winds weaken across the state.
Sea breezes will favor afternoon clouds and showers over island
interiors today and Wednesday while a passing disturbance brings a
chance to showers to the islands tonight through Wednesday.

&&

.DISCUSSION...

Dry air has filtered into this morning`s Hilo sounding as the
resident mid-level shortwave shifts east of the islands. Satellite
shows deeper moisture peeling eastward leaving behind pockets of mid-
level clouds over the eastern end of the state. These clouds are not
deep or cold enough to produce snow on the Big Island Summits but
will probably be effective at depositing freezing drizzle from time
to time. Elsewhere and otherwise, southeast flow blocked by the Big
Island will lead to an expansion of sea breezes over the smaller
islands today. As such, cloud build-ups and a few showers will be
possible over island interiors during the peak heating period. Land
breezes will bring clearing for at least the first half of tonight.
By late tonight into early tomorrow morning, the southern periphery
of an upper wave nestled within the left exit region of a digging
125-kt jet will provide a glancing blow of forcing for ascent over
the islands. As it pulls deeper moisture northward an expansion in
clouds and light to moderate showers is expected to develop and
advance eastward through the island chain during Wednesday.  At the
surface, winds will remain light and land breezes may even persist
through early Wed morning. However, SW flow aloft should prove
effective in steering showers over leeward areas, especially given
the depth of the incoming moist airmass. As surface winds remain
light, sea breezes may once again capitalize on the resident moist
airmass to produce a round of interior clouds/showers during
Wednesday afternoon.

A cold front moving southeastward through the state will then usher
in some cooler air and bring increasing showers to north and
northeast facing slopes and coasts as it moves through Wednesday
night through Friday. Model solutions are showing some differences
in the progressiveness of the front during this time which decreases
forecast confidence. Overall, it appears that the chance for
measurable rain will be highest over the eastern end of the state
Friday through the weekend as the front stalls out and dissipates in
this area. Meanwhile, the western islands may see very little rain
as the drier and slightly cooler post-frontal airmass settles in.


&&

.AVIATION...

Light to moderate winds will further weaken through tomorrow as
the pressure gradient relaxes in response to the eastward
progressing ridge. With this lighter flow at low levels and an
increase in low to mid level moisture, showers will trandistion
from being windward-favoring to interior-favoring as a sea/land
breeze pattern begins to develop. Brief periods of MVFR ceilings
and visibility will be possible in any of the heavier showers.
Patches of mid level clouds will gradually dimish through the
forecast period as the upper trough moves further away from the
region.

AIRMET Tango remains in effect below 8000 feet over and south
through west of mountains for tempo moderate turbulence. These
conditions will likely improve by this afternoon. AIRMET Tango
also remains in effect for tempo moderate turbulence aloft between
120-FL280. See SIGMET PAPA series over the islands for areas of
severe turbulence between Fl280-Fl350. This area of moderate to
severe turbulence aloft will gradually move eastward and begin to
weak later today.

&&

.MARINE...

Light to moderate winds will further weaken through tomorrow as
the pressure gradient relaxes in response to the eastward
progressing ridge. With this lighter flow at low levels and an
increase in low to mid level moisture, showers will trandistion
from being windward-favoring to interior-favoring as a sea/land
breeze pattern begins to develop. Brief periods of MVFR ceilings
and visibility will be possible in any of the heavier showers.
Patches of mid level clouds will gradually dimish through the
forecast period as the upper trough moves further away from the
region.

AIRMET Tango remains in effect below 8000 feet over and south
through west of mountains for tempo moderate turbulence. These
conditions will likely improve by this afternoon. AIRMET Tango
also remains in effect for tempo moderate turbulence aloft between
120-FL280. See SIGMET PAPA series over the islands for areas of
severe turbulence between Fl280-Fl350. This area of moderate to
severe turbulence aloft will gradually move eastward and begin to
weak later today.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST this evening for Maui County
Windward Waters-Pailolo Channel-Alenuihaha Channel-Big Island
Windward Waters-Big Island Leeward Waters-Big Island Southeast
Waters.


&&

$$


DISCUSSION...JVC
AVIATION...Farris
MARINE...Vaughan


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