Current Conditions
Temp1.3 C
RH16 %
WindNNE 10 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

FXHW60 PHFO 250203

Area Forecast Discussion
National Weather Service Honolulu HI
403 PM HST Sun Jun 24 2018

A strong high will remain far northeast of the area and a trough aloft
will linger near the area through the week.


Satellite loops and surface observations show locally breezy
easterly trade winds blowing over the islands. Scattered to broken
low clouds are riding in with the trade winds. Skies are mostly
cloudy over windward areas with partly cloudy skies over lower lee areas
of the smaller islands. Broken to overcast low clouds cover most
of the Big Island of Hawaii with isolated to scattered clouds over
leeward Kohala and over the interior above about 8000 feet of
elevation. Radars show scattered to numerous showers moving over
windward areas from the east.

Surface analyses show fairly strong 1033 mb surface high about
1300 miles north of the main Hawaiian Islands. The high will move
east through tomorrow night, shift southwest Tuesday through
Wednesday night, then move north again into the weekend. The
pressure gradient southwest of this high will maintain breezy
trade winds over the islands through most of the week.

An area of showery low clouds that has been moving over the
islands has partly broken up and is starting to move away to the
west. There will still be showers moving over the islands in the
trade-wind flow, but the weather will turn drier tonight and
Monday. Another area of showers east of the islands will move over
the area Monday night through Tuesday morning.

Water vapor satellite loops show a low aloft about 650 miles
northeast of the main Hawaiian islands with a trough extending
west southwest from the low. This trough, a common summertime
feature sometimes called a TUTT or tropical upper tropospheric
trough, is forecast to linger north of the islands. The trough
will help make the low clouds moving over this islands rather
showery at times.

Trade winds will continue to push emissions from Halemaumau crater
and the East Rift Zone of Kilauea Volcano southwest across the Kau
District. Eddies west of the Big Island will push some of the vog
over the Kona area. The emissions will move off to the west southwest
well south of the smaller islands through at least Friday.


Breezy, occasionally strong, trade winds will persist as a ridge
of high pressure remains northeast of the state. AIRMET Tango
remains in effect for low level turbulence over mountains and
leeward sections of all islands due to the breezy trades. AIRMET
Tango may continue over the next couple of days due to the
persistent wind speeds.

VFR conditions will prevail with passing low clouds and showers
bringing MVFR conditions to windward and mauka sections. AIRMET
Sierra is in effect for tempo mountain obscurations this evening
for windward sections of Kauai, Oahu and the Big Island. AIRMET
Sierra may be extended into tonight for some windward sections.


Fresh to strong trades associated with high pressure to the north
will continue through the week. A Small Craft Advisory remains in
effect for the windy areas around Maui and the Big Island through
Tuesday night. Surf along east facing shores will remain rough
due to these winds.

Surf will build along south facing shores this week as swells arrive
from the south Pacific. The first swell build Tuesday and the second
swell will arrive Wednesday. Surf may reach advisory levels along
south facing shores by Thursday.

A recent ASCAT pass showed a gale-force low passing just south of the
Tasman Sea. The WAVEWATCH III shows a swell from this low reaching
reaching Hawaiian waters early next week, but swells from Tasman
Sea are partly blocked on their way to Hawaiian waters.


Small Craft Advisory until 6 AM Wednesday for Maalaea Bay, the
Pailolo and Alenuihaha Channels and waters south of the Big Island.



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