Scientific Forecaster Discussion
Area forecast discussion...corrected
National Weather Service Honolulu HI
427 am HST sun Jan 25 2015
breezy north-northeast winds due to high pressure northwest of the
state will focus showers across windward and Mauka areas of Maui
County through tonight and The Big Island through Monday. Clouds
will linger across all windward slopes today. Winds will veer
easterly on Monday...then southeast on Wednesday. Another front is
expected to be over or near the islands Thursday night into early
infrared satellite and radar shows mostly cloudy skies over the
windward areas...with shallow but numerous showers across windward
slopes of Maui County and The Big Island this morning. The clouds
and showers are resulting from remnant moisture left over from a
front that is now southeast of The Big Island. A 1023 mb surface
high is centered at 28n167w...or about 600 miles northwest of Kauai
this morning. The high is ushering in breezy north-northeast winds
which are pushing the clouds and showers onto the windward slopes.
The 12z Lihue sounding shows a fairly stable inversion at around
6000 feet with precipitable water /pw/ values at around 0.9 inches.
With still quite a bit of cloud cover upstream...anticipating much
of the clouds and showers to linger through tonight...with most
of the showers focused over windward sides of Maui County and The
Big Island. The shallow nature of the showers will keep most of
the them confined to windward and Mauka areas due to the stable
air associated with the high pressure to the northwest. Showers
may continue through Monday for windward Big Island.
The surface high is expected to track east-northeast over the next
couple of days...resulting in the winds veering eastward and
tapering off on Tuesday as the high moves away from Hawaii.
The trade winds will give way to southeasterly winds on Wednesday
and Wednesday night as a front approaches from the northwest. The
front will arrive on Kauai around Thursday night or Friday morning
and move eastward down the island chain Friday and Saturday...
a quick burst of rainfall. At this time it appears most of the
upper level dynamics with the front will remain north of the
state. Winds will shift out of the northwest behind the front.
Winds at The Big Island summits are elevated but remain below
advisory levels at this time. Winds at the summits will decrease
during the first half of the week...before ramping up again with the
next system Thursday night. With the Thursday night event...winds
may reach advisory levels at the summits.
widespread MVFR/isolate IFR ceilings and visible associated with the
remnants of a front continues to plague most of the islands this
morning. Litle improvement expected through 04z as the remnants to
the front gets blown and piled onto the windward side of all islands
exposed to this low level NE wind flow. This layer of NE winds is very
shallow...no higher than 5k feet. Winds above 5k are from the west and
northwest. Thus this moisture laden airmass from an excessive-front is trapped on
the windward side. So...airmet Sierra for mountain observation will continue and
likely to persist for a good part of today. Lanai may get lucked out
since Maui is in the way but windward Kauai is being threatened with
airmet Sierra as moisture just north of the island is poised to move
Low level NE winds are rather gusty in spots statewide this morning
which is expected to strengthen as the day progresses as the center
to a surface hi passes north of the islands this afternoon and tonight.
Airmet Tango is in effect and will be extended through 22z.
the northwest swell affecting the islands will gradually lower
today and tonight. The high surf warnings along north and west
facing shores have been downgraded to advisories for today and
tonight...with the exception of west facing shores of The Big
Island where the warning remains through today. Surf will likely
drop to advisory levels along west facing shores of The Big Island
The current swell...combined with some stronger northeast winds are
bringing Small Craft Advisory /sca/ conditions to all of the
coastal waters today. We expect some areas to drop out of the
Small Craft Advisory for tonight as the swell drops. Some zones may continue
tonight and Monday due to the breezy trade winds.
high surf advisory until 6 am HST Monday for north and west
facing shores of Niihau Kauai Oahu and Molokai and north facing
shores of Maui.
High surf warning until 6 PM HST this evening for Kona-kohala.
Small Craft Advisory until 6 PM HST this evening for all