Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
920 am HST Wednesday Mar 12 2014
a trade wind weather pattern can be expected into Friday thanks to
high pressure far northeast of the state. Clouds and brief light
showers will favor windward and Mauka areas with most leeward
locations remaining dry. A weakening front will move across the
island chain Friday night through Saturday night with an increase
in showers expected. Strong and gusty trade winds will follow the
front over the weekend and into early next week. Clouds and showers
will favor windward and Mauka areas with the winds sufficiently
strong to blow some passing showers over leeward areas at times.
an area of high pressure NE of the area is providing a trade wind
weather pattern across the Aloha state. The airmass is rather dry
and stable so shower activity is rather limited. Radar shows a few
light showers over the coastal waters mainly northeast of Maui
County and The Big Island. Thus a few brief light showers can be
expected today over windward and Mauka areas with abundant sunshine
expected over most leeward locations. We can pretty much expect the
same weather conditions on Thursday.
Wind sensors on Mauna Kea indicate winds have increased to advisory
levels over The Big Island summits thus a Wind Advisory has been
issued for that area. Winds are expected to remain rather strong
through Thursday afternoon.
As we head into Friday...the models are in good agreement with a
front approaching the islands from the northwest. At this time none
of the models show a definitive wind shift...so believe the front
will weaken to more of a shearline by the time as it reaches the
islands Friday night. Limited moisture is expected to arrive with
the front/shearline...but expect showers to expand from windward and
Mauka areas to include other areas of the islands Friday night and
Behind the front a strong high pressure system will build in to our
north. The strength of the high will cause northeast trade winds to
strengthen over the weekend. It is expected to become rather windy
across the area with wind speeds forecast to reach advisory levels.
The strongest winds are expected to occur on Sunday. A few locations
such as leeward kohala may approach warning levels during that time.
Trade winds will begin to weaken a bit Tuesday and Wednesday as the
high moves to a position far to our northeast.
a Small Craft Advisory is up for the Alenuihaha Channel with 20 to
25 knots trade winds expected through Thursday. Winds will drop off
briefly Thursday night and early Friday across the entire area
before strengthening later Friday and on through the weekend. Winds
and seas will exceed Small Craft Advisory levels over the weekend
across the entire forecast area with gale force winds likely over
the typically windy zones by Saturday evening. A gale watch could be
issued as early as Friday morning for this wind event.
The current northwest swell will peak today just below advisory
levels then gradually lower on Thursday. A slightly larger northwest
swell is expected for Friday and Saturday with surf heights
reaching advisory levels. Strong trade winds over the weekend will
cause a significant increase in short period choppy surf along east
VFR conditions with moderate trades will prevail across the Hawaiian
islands today and tonight. Isolated showers and MVFR ceilings will focus
primarily on windward slopes. Airmet Tango is in effect for low
level turbulence...mainly affecting areas over and downwind of the
mountains...and locations subject to funneling of the northeast low
level flow such as Lanai.
Wind Advisory until 6 PM HST Thursday for Big Island summits.
Small Craft Advisory until 6 PM HST Thursday for Alenuihaha