NWS Bulletins for NPAC - MKWC
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Hawaiian Islands Synoptic Discussion and Guidance
073
FXHW60 PHFO 130108
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
308 PM HST Mon May 12 2025
.SYNOPSIS...
Breezy trades deliver showers windward and mauka through the
week.
&&
.DISCUSSION...
Strong mid-level ridging positioned north of the islands supports a
corridor of active subsidence in maintenance of the rather uniform
7kft trade wind inversion evident on this morning's soundings. The
batch of moisture that brought showers to much of Oahu this morning
now resides over and upstream of Kauai where trades will remain on
the wetter side for the next several hours. Breezy trades will usher
this moisture west of island during the first half of tonight.
Stable trades then prevail with little in the way of change through
at least Thursday.
The resident subtropical jet remains a fixture through the week
mainly serving to funnel pockets of high clouds across area skies. A
potively tilted mid/upper trough axis remains anchored along the
northern periphery of this jet and is presently positioned well west
of the islands. As the week progresses, however, this feature will
evolve eastward tending to close off and deepen with time. This will
assist in slightly weakening the local pressure gradient as subtle
surface pressure falls commence leading to slightly weakened trades.
The low latitude origin of the low will limit available instability,
but it will nonetheless weaken the inversion and will likely give
existing trade wind showers a boost as early as Thursday night or Friday.
&&
.AVIATION...
VFR from Oahu through Big Island as breezy, stable trades prevail.
An area of enhanced moisture will bring MVFR to windward and
interior sections of Kauai for the next several hours before
trades finally usher it west of the area. VFR then prevails
areawide for the second half of the night through Tuesday
afternoon with MVFR limited to isolated instances within heavier
showers.
AIRMET Sierra remains in effect for windward Kauai.
AIRMET Tango remains in effect for moderate lee turb.
&&
.MARINE...
Fresh to locally strong trade winds will persist through much of
the week as as an area of high pressure remains far northeast of
the state. A Small Craft Advisory (SCA) covers the typical windy
waters near Maui and the Big Island through Tuesday. This SCA
will likely be extended through mid to late in the week.
The current moderate period south-southwest swell will bring
elevated surf to south facing shores through tonight, then slowly
decline through mid-week. By the end of the week, only small
background south swell will exist.
Surf along east-facing shores will be rough and choppy due to the
breezy trade winds through the week. A series of small northwest
swells will keep small surf in place along north facing shores
through the week.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.
&&
$$
DISCUSSION...JVC
AVIATION...Vaughan
MARINE...Foster
Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office
Narrow the Menu List
Select Time Limit: 12 hours | 24 hours | 48 hours | 72 hours | No time limit
Select Product Type: All | Routine Bulletins/FCSTS | Warnings/Watches/Advisories | HAWN Weather | Tropical | Marine | Aviation | Daily Obs | Special
Hawaiian Islands Synoptic Discussion and Guidance
073
FXHW60 PHFO 130108
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
308 PM HST Mon May 12 2025
.SYNOPSIS...
Breezy trades deliver showers windward and mauka through the
week.
&&
.DISCUSSION...
Strong mid-level ridging positioned north of the islands supports a
corridor of active subsidence in maintenance of the rather uniform
7kft trade wind inversion evident on this morning's soundings. The
batch of moisture that brought showers to much of Oahu this morning
now resides over and upstream of Kauai where trades will remain on
the wetter side for the next several hours. Breezy trades will usher
this moisture west of island during the first half of tonight.
Stable trades then prevail with little in the way of change through
at least Thursday.
The resident subtropical jet remains a fixture through the week
mainly serving to funnel pockets of high clouds across area skies. A
potively tilted mid/upper trough axis remains anchored along the
northern periphery of this jet and is presently positioned well west
of the islands. As the week progresses, however, this feature will
evolve eastward tending to close off and deepen with time. This will
assist in slightly weakening the local pressure gradient as subtle
surface pressure falls commence leading to slightly weakened trades.
The low latitude origin of the low will limit available instability,
but it will nonetheless weaken the inversion and will likely give
existing trade wind showers a boost as early as Thursday night or Friday.
&&
.AVIATION...
VFR from Oahu through Big Island as breezy, stable trades prevail.
An area of enhanced moisture will bring MVFR to windward and
interior sections of Kauai for the next several hours before
trades finally usher it west of the area. VFR then prevails
areawide for the second half of the night through Tuesday
afternoon with MVFR limited to isolated instances within heavier
showers.
AIRMET Sierra remains in effect for windward Kauai.
AIRMET Tango remains in effect for moderate lee turb.
&&
.MARINE...
Fresh to locally strong trade winds will persist through much of
the week as as an area of high pressure remains far northeast of
the state. A Small Craft Advisory (SCA) covers the typical windy
waters near Maui and the Big Island through Tuesday. This SCA
will likely be extended through mid to late in the week.
The current moderate period south-southwest swell will bring
elevated surf to south facing shores through tonight, then slowly
decline through mid-week. By the end of the week, only small
background south swell will exist.
Surf along east-facing shores will be rough and choppy due to the
breezy trade winds through the week. A series of small northwest
swells will keep small surf in place along north facing shores
through the week.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.
&&
$$
DISCUSSION...JVC
AVIATION...Vaughan
MARINE...Foster
Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office