Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
415 am HST sun Feb 14 2016
expect light to moderate east winds to persist across Maui County
and The Big Island today...while light southeasterly flow will allow
for leeward land and sea breezes and a few passing showers on Oahu
and Kauai. Trade winds will strengthen during the first half of the
work week as a strong high pressure system builds northwest of the
state. Showers are expected to increase over the area as frontal
remnants are carried across the state from Monday night through
Wednesday. Drier conditions are then expected during the second half
of the week.
a surface high pressure system centered far NE of the area will
gradually strengthen during the next several days while a cold front
boundary about 450 miles northwest of Kauai continues to gradually approach
the islands. The front is veering winds across the west half of the
island chain...keeping a weak southeast flow over Oahu and Kauai...and
light to moderate east winds over The Big Island and Maui County today.
The relative dry and stable airmass dominating the area will keep
rainfall activity on the lower end today...but early morning radar
data shows that coverage of passing showers is increasing.
However...with the presence of ridging aloft and strong inversions
between 7 to 9 thousand feet...any showers that develop today should
remain shallow and brief.
For early next week...models show the frontal boundary will be
dissipating just northwest of Kauai...while the aforementioned surface high
intensifies. This synoptic scenario will bring a transition to
moderate to breezy trades Monday through Wednesday. The remnant moisture
associated with the decaying front will bring an increase in showers
on Kauai by Monday night. Then...an increasing high pressure system far
northwest of the islands will help in pushing the moisture into Oahu and
Maui County by Tuesday. Any remaining moisture should reach The Big
Island by Wednesday. Global models agree in depicting moderate to breezy
trade winds developing across the state from late Monday through middle
week with rainfall focusing over windward and Mauka areas. Some of
the larger showers may reach leeward locations at times. The best
dynamic support is expected to remain well to the northwest of the
islands...thus rainfall should remain moderate with no thunderstorm
activity anticipated at this time.
Model solutions show a surface ridge...associated with the strong high
to the northwest...gradually moving closer to the state during the second
half of next week. This will push the lingering moisture further to
the S of the island chain...with a drier airmass descending across
the area. The breezy trades will decrease a little...but likely
remaining moderate through the end of next week.
VFR will prevail over most areas today. Brief MVFR conditions are
possible due to lower ceilings and reduced visibilities in low
clouds and showers...mainly along windward facing slopes...as well
as over interior sections of some of the smaller islands this
afternoon. Prefrontal convergence bands ahead of a front approaching
Kauai tonight may cause an increase in showers in the vicinity of
Kauai starting this evening. No airmets are currently in effect.
a Small Craft Advisory remains in effect for areas around The Big
Island and Maui County...except for Maalaea Bay...due to breezy east
winds produced by a strong high pressure system far to the
northeast. The advisory will be extended and expanded in coverage
for seas later this morning due to an incoming west northwest swell
to the islands. The advisory will likely be needed across the entire
area by Monday for strong northeast trades pushing in with a strong
high to the northwest.
The aforementioned west northwest swell will spread west to east
across the island chain today producing advisory level surf
heights across most north and west facing shores of the smaller
islands...and west facing shores of The Big Island through Monday.
The strong trades produced by an intensifying high pressure system
to the northwest may also bring high surf along east facing shores
of some islands Monday through Wednesday.
high surf advisory from 9 am this morning to 6 PM HST Monday for
Niihau-Kauai windward-Kauai leeward-Waianae coast-Oahu North
Shore-Oahu koolau-Molokai-Maui windward west-windward Haleakala-
Gale watch from Monday evening through Tuesday afternoon for
Alenuihaha Channel-Big Island leeward waters-Big Island
Small Craft Advisory until 6 PM HST Monday for Alenuihaha
Channel-Big Island leeward waters-Big Island southeast waters.
Small Craft Advisory until 6 PM HST Wednesday for Maui County
windward waters-Pailolo Channel-Big Island windward waters.
Small Craft Advisory from noon today to 6 PM HST Wednesday for
Kauai northwest waters-Kauai windward waters-Kauai leeward
waters-Kauai Channel-Oahu windward waters-Kaiwi Channel.