Maunakea Weather Center

NWS Bulletins for NPAC - MKWC

Menu of Text Products for the Hawaiian Islands and the Tropical Pacific/Atlantic Oceans:
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

216
FXHW60 PHFO 131310
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
310 AM HST Tue May 13 2025

.SYNOPSIS...

Breezy trades deliver showers windward and mauka
through the week with an increase in showers possible into the
weekend and early next week.

&&

.DISCUSSION...

Currently at 3am HST, radar and satellite show cloudy skies with
windward and mauka showers occurring across the island chain. A
few isolated showers are making it over to leeward areas. Most of
these showers are on the lighter side. Showers should continue
riding on the trades through the next several days mostly
overnight into the early morning hours.

A low pressure to the northeast is meandering off the southern
portion of the West Coast, with a high pressure and mid-level
ridging to our north. A subtropical jet is anchored just to the
south of the islands and will remain in place at least through
Friday. As such, expect trades to continue through at least
Thursday afternoon. Showers riding on the trades should be
confined to windward and mauka locations through this time frame.
Thursday evening and into the weekend with the jet moving to the
east and a closed off low overhead expect and increase in showers
with some leeward spots getting in on the action.

Looking into early next week the low overheard begins to move
northeastward while ridging begins to build back in place for the
first half of next week. A few shortwaves riding around a potent
low over Alaska could bring some unsettled weather to the islands.
Its too far out to begin to talk about anything impactful as both
deterministic and probabilistic guidance shows disagreement in
location and strength.

&&

.AVIATION...

Satellite imagery this morning shows a large band of clouds
riding towards the eastern slopes of the Big Island on the trade
winds. Expect periods of MVFR conditions over the next few hours
for the windward Big Island slopes lasting into the afternoon.
Brief showers remains in the forecast for all islands.

AIRMET Sierra remains in effect for mountain obscuration along
north and east slopes of the Big Island.

AIRMET Tango remains in effect for low level moderate turb over
and S thru W of island mountains.

&&

.MARINE...

A surface ridge will remain northeast of the state through the
week and continue to bring fresh to locally strong trade winds
to all local waters. A Small Craft Advisory (SCA) for the typical
windy waters surrounding Maui and the Big Island has been
extended through Wednesday evening. The SCA may need to be
extended through late week as fresh to locally strong winds
persist.

The current moderate period south-southwest swell will slowly
decline today into Wednesday. By Thursday, only small background
south swell will exist.

Surf along east-facing shores will be rough and choppy the next
several days due to the fresh to locally strong trades. A series
of small northwest swells will keep small surf in place along
north facing shores today with no significant swells in the
horizon.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...Walsh
AVIATION...Bohlin
MARINE...Thomas

Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office