Scientific Forecaster Discussion
Area forecast discussion...corrected
National Weather Service Honolulu HI
905 PM HST Thursday Feb 11 2016
moderate to locally strong trade winds will prevail state-wide
through Friday. The windward and mountain areas of most islands
will observe a slight uptick in trade showers but more so for Maui
and The Big Island. Winds will shift out of the southeast over the
western end of the island chain late Friday and Saturday as a new
front approaches. The front is forecast to weaken into a remnant
front as it nears Kauai Monday. The remnants then ease eastward
to Oahu by Wednesday while breezy and gusty trades spreads across
the entire area.
the remnants of a front that stalled just north of Kauai yesterday
are now coming in with the trade winds that will affect primarily
the smaller islands tonight. It is not much...so just a few
showers during the overnight hours. Meanwhile...a band of low
clouds continues to drift westward with the trades towards The Big
Island. The leading edge to this band is between 75 and 100 Michigan off
the puna coast. The band should be reaching the puna area a few
hours after midnight tonight. Some of this moisture will continue
westward to Maui County tomorrow and to Oahu tomorrow evening.
At the same time...the trades will start veering to the southeast
/se/ across the smaller islands starting at day break...while The
Big Island stays under an easterly wind flow. Over the weekend...the
smaller islands may settle under an hybrid situation with a light
easterly wind and sea breeze pattern leading to some afternoon
clouds and a slight chance of a shower over interior and leeward
areas. The windward and mountain areas will also have a few
showers especially during the night and morning hours.
Parts of The Big Island will remain breezy as a tight pressure
gradient holds on to this part of the island chain. The surface
high supplying the winds will be parked some 1700 miles northeast
of Maui through the weekend with a central pressure of around
1030 millibars. So The Big Island is likely to be under this
locally breezy condition through most of not all of the three day
During the first half of next week...a strong high pressure cell
parked northwest of the islands...will push a dissipating front
toward the islands. Kauai County will likely experience increasing
trade showers Sunday night or Monday...spreading to Oahu Monday
night or Tuesday. Also...the NE trades will be strengthening
across the area Monday...hooking up with the breezy easterly
winds around The Big Island. Both the European model (ecmwf) and GFS are in fair
agreement of this occurring.
VFR will prevail over the islands through the nighttime hours...with
only a chance of brief MVFR conditions in lower ceilings over
windward sections of Kauai and Oahu. Windward and southeast
sections of The Big Island may also see MVFR in lower ceilings and
showers later in the night and Friday morning.
No airmets are currently in effect.
the data from the Waimea buoy is about 2 hours old with the last
report at 6 PM HST. Hopefully it comes back on line soon. But
readings from the Hanalei buoy is a very slow lowering trend. At
8 PM HST...the swell height was 12.5 feet at 15 secs translating to
surf heights of between 25 to 30 feet for the north facing
shores. Readings from buoys 51001/51101 shows a slightly quicker
lowering trend...and should be spreading to our local buoys later
tonight. If any...we may have to extend the warning for the north
and west facing shores to beyond 6 am HST Friday.
The other area we are monitoring is the north facing shores of The
Big Island where the Hilo buoy is showing elevated surf conditions
near or at warning level there.
A Small Craft Advisory remains in effect for most Hawaiian waters
now...either due to the large northwest swell or the breezy trades
especially waters around The Big Island and Maui. Some of these
marine zones will drop out by 6 PM HST Friday as the swell lowers.
But the marine zones around The Big Island may be extended into
the weekend due to the breezy trades. The Small Craft Advisory will likely be
extended to other marine zones due to the strengthening trades