Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
400 PM HST sun Jan 25 2015
high pressure north of the area will produce breezy trade winds
through Monday. Moisture from a front will keep many windward
areas cloudy and rainy tonight. The weather will turn drier and
sunnier Monday as the frontal moisture moves off to the south. Dry
weather will continue through mid-week...and winds will weaken as
high pressure moves south near the islands. Clouds and showers will
increase again late in the week as a front approaches.
surface analyses show a 1022 mb high centered about 540 miles
northwest of Kauai near 30n159w. The clockwise circulation around
the high is producing locally breezy trade winds over the main
Hawaiian islands. The trade winds are pushing remnants of a frontal
cloud band over the windward sides of the islands...making windward
areas quite cloudy and wet this evening. Moisture from the old front
is quite shallow near Kauai...but becomes gradually deeper towards
The Big Island of Hawaii. The 200 PM balloon sounding from Lihue
showed little moisture above 6100 feet...while the 200 am Hilo
sounding showed moisture up to 8300 feet. The shallow moisture from
Kauai to Molokai will produce mainly drizzle and light rain and the
moisture will be too shallow to reach the leeward sides. The deeper
moisture over Maui and The Big Island will support moderate showers
and higher rainfall totals.
The high north of the main Hawaiian islands will maintain the
locally breezy trade winds through Monday. The trades will gradually
push the moisture from the old frontal band off to the south of the
islands and clouds and showers over the islands will decrease.
Clearing will spread from north to south and the windward side of
The Big Island will remain rather cloudy and wet through Monday
The global models remain in good agreement showing the high moving
off to the east northeast over the next few days. The atmosphere
over the islands will become rather dry and stable starting Monday
and rainfall will become sparse. A ridge trailing west from the high
will move south over the main Hawaiian islands by Thursday evening
ahead of a front approaching from the northwest. Winds over the
islands will become light and variable and vog will increase over
the smaller islands.
There is still quite a bit of disagreement in the global models by
late next week. Some model runs show a front pushing down past the
main Hawaiian islands while others are stalling the front farther
north. In either case it looks as if there will be an increase in
clouds and showers by the end of next week.
remnants of a front will produce widespread MVFR/isolate IFR ceilings
and visibilities over NE areas on most of the islands through
tonight. Airmets for mountain obscure are likely to remain in effect
through 26/16z for most islands. Lanai may be an exception
since the shallow moisture is being blocked by Maui.
Strong low level NE winds and strong and low inversions will create
turbulence south through southwest of the islands. Airmet Tango for
this turbulence is likely to remain in effect through 26/16z...and
may be extended beyond that.
the northwest swell affecting the islands will gradually diminish
through Tuesday. Surf from this swell will likely drop below
advisory levels by tomorrow morning. The next northwest swell will
likely produce advisory-level surf Tuesday night through Thursday.
Another large northwest swell is expected to arrive Friday.
The high north of the area will produce near-gale force trade
winds in the Alenuihaha Channel and fresh to strong winds over the
rest of the coastal waters. The combination of strong trade winds
and a large northwest swell will create Small Craft Advisory...
Small Craft Advisory...conditions for all coastal waters tonight. We expect to drop
the Small Craft Advisory for some areas by tomorrow morning as the swell subsides.
The Small Craft Advisory is likely to continue for the windier zones around The Big
Island and Maui through Monday evening or later.
high surf advisory until 600 am Monday for north and west
facing shores of Niihau Kauai Oahu and Molokai...north facing
shores of Maui and west facing shores of The Big Island of Hawaii.
Small Craft Advisory until 600 am Monday for all Hawaiian waters.
Small Craft Advisory until 600 PM Monday for waters around The Big
Island and Maui.