NWS Bulletins for NPAC - MKWC
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Hawaiian Islands Synoptic Discussion and Guidance
630
FXHW60 PHFO 051331
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
331 AM HST Thu Sep 5 2024
.SYNOPSIS...
Expect light to moderate trade winds through Friday, with slight
strengthening possible this weekend. Light showers will favor
windward and mauka areas, with afternoon interior and leeward
showers possible when winds are lightest. Winds will decrease
after the weekend as a weakening front approaches the state from
the north.
&&
.DISCUSSION...
A front several hundred miles north of the main Hawaiian Islands
has put a big dent in the subtropical ridge, keeping trade winds
in the light to moderate range across local waters this morning.
Satellite loop shows cloud cover across the Big Island diminished
dramatically overnight as cooling and local land breezes set in.
Only scattered low clouds are noted across windward slopes there
this morning. Scattered low clouds to clear skies are also noted
across the smaller islands. In contrast, broken low clouds are
noted across waters lee of Kauai and Oahu, where the bulk of
shower activity is occurring on radar. Overnight soundings show
the subsidence inversion weakening and rising since yesterday
afternoon, likely due to the influence of an upper trough over and
northwest of the main island chain.
Models show the governing features not moving much before the
weekend, so expect continued light to moderate trade winds through
Friday, along with light showers at most, mainly across windward
areas. The pressure gradient may steepen a bit this weekend as
high pressure rebuilds to our northeast. However, the front to our
north is forecast to settle southward towards the islands after
the weekend, knocking trade winds back down again Monday and
afterward. This front will weaken as it approaches, so our weather
should remain rather dry even as trade winds decrease next week.
&&
.AVIATION...
Light to moderate trades continue through Friday. SHRA should
favor windward and mauka locations. Brief MVFR conds can be
expected but VFR should prevail.
No AIRMETs in effect.
&&
.MARINE...
Moderate to fresh easterly trades will persist through Friday
over the windier channels and waters around Maui County and the
Big Island, while light to moderate breezes continue elsewhere. A
brief return of fresh to strong trades is anticipated early this
weekend, before trending lighter Sunday through early next week as
the tail-end of a frontal boundary drifts southward into the
area.
Surf along north-facing shores will steadily rise through the day,
peak tonight, and then slowly ease late Friday through the
weekend. This swell has been slowly filling in within the 12 to
15 second bands at the offshore and nearshore buoys overnight.
Looking ahead, guidance suggests a tightening pressure gradient
between a weak, broad low within the aforementioned stalled trough
to the north and the building high pressure south of the
Aleutians over the weekend. Fresh to strong northerly breezes
focused at the islands around 700 nautical miles away between
these features could send another small, short- to medium- period
north swell through the area from next Tuesday through midweek.
Surf along south-facing shores will remain small through early
next week, with mainly a combination of short-period southeast and
background medium- to long-period south-southwest swells moving
through. Guidance does show a potent storm/hurricane-force low
passing south of New Zealand from Friday through Saturday, with
seas peaking in the 30-40 ft range east-southeast of New Zealand
on Saturday. If this materializes, we could see a decent, long-
period south-southwest swell next weekend (09/14-09/15).
Surf along east-facing shores will remain small and choppy
through early next week due to the lack of fresh or strong breezes
upstream of the state over the eastern Pacific.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Powell
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
630
FXHW60 PHFO 051331
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
331 AM HST Thu Sep 5 2024
.SYNOPSIS...
Expect light to moderate trade winds through Friday, with slight
strengthening possible this weekend. Light showers will favor
windward and mauka areas, with afternoon interior and leeward
showers possible when winds are lightest. Winds will decrease
after the weekend as a weakening front approaches the state from
the north.
&&
.DISCUSSION...
A front several hundred miles north of the main Hawaiian Islands
has put a big dent in the subtropical ridge, keeping trade winds
in the light to moderate range across local waters this morning.
Satellite loop shows cloud cover across the Big Island diminished
dramatically overnight as cooling and local land breezes set in.
Only scattered low clouds are noted across windward slopes there
this morning. Scattered low clouds to clear skies are also noted
across the smaller islands. In contrast, broken low clouds are
noted across waters lee of Kauai and Oahu, where the bulk of
shower activity is occurring on radar. Overnight soundings show
the subsidence inversion weakening and rising since yesterday
afternoon, likely due to the influence of an upper trough over and
northwest of the main island chain.
Models show the governing features not moving much before the
weekend, so expect continued light to moderate trade winds through
Friday, along with light showers at most, mainly across windward
areas. The pressure gradient may steepen a bit this weekend as
high pressure rebuilds to our northeast. However, the front to our
north is forecast to settle southward towards the islands after
the weekend, knocking trade winds back down again Monday and
afterward. This front will weaken as it approaches, so our weather
should remain rather dry even as trade winds decrease next week.
&&
.AVIATION...
Light to moderate trades continue through Friday. SHRA should
favor windward and mauka locations. Brief MVFR conds can be
expected but VFR should prevail.
No AIRMETs in effect.
&&
.MARINE...
Moderate to fresh easterly trades will persist through Friday
over the windier channels and waters around Maui County and the
Big Island, while light to moderate breezes continue elsewhere. A
brief return of fresh to strong trades is anticipated early this
weekend, before trending lighter Sunday through early next week as
the tail-end of a frontal boundary drifts southward into the
area.
Surf along north-facing shores will steadily rise through the day,
peak tonight, and then slowly ease late Friday through the
weekend. This swell has been slowly filling in within the 12 to
15 second bands at the offshore and nearshore buoys overnight.
Looking ahead, guidance suggests a tightening pressure gradient
between a weak, broad low within the aforementioned stalled trough
to the north and the building high pressure south of the
Aleutians over the weekend. Fresh to strong northerly breezes
focused at the islands around 700 nautical miles away between
these features could send another small, short- to medium- period
north swell through the area from next Tuesday through midweek.
Surf along south-facing shores will remain small through early
next week, with mainly a combination of short-period southeast and
background medium- to long-period south-southwest swells moving
through. Guidance does show a potent storm/hurricane-force low
passing south of New Zealand from Friday through Saturday, with
seas peaking in the 30-40 ft range east-southeast of New Zealand
on Saturday. If this materializes, we could see a decent, long-
period south-southwest swell next weekend (09/14-09/15).
Surf along east-facing shores will remain small and choppy
through early next week due to the lack of fresh or strong breezes
upstream of the state over the eastern Pacific.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Powell
Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office