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Dec
09
2011

Hawaii Weather Overview

Moderately strong trade winds with locally stronger gusts, windward biased showers for the most part…gradually lowering surf along our north and west facing beaches into the weekend.

PDC Global Hazards Atlas centered on the central Pacific Ocean near Hawaii is displaying 3 hour precipitation accumulations over the last three hours

Hawaiian Weather Synopsis:  The trade winds continue to blow steadily, with no definite end in sight through the next week. High pressure systems to our north through northeast will keep these active late autumn winds blowing. This in turn has made our marine coastal and channel waters rough and choppy…necessitating small craft wind advisories in most areas around the state. These gusty winds are expected remain quite breezy through early Sunday, although may ease up a touch later Sunday into Monday…before picking up again later Tuesday onwards into the week.

Rainfall isn’t expected to be very much of an issue through the rest of today into the weekend. As we have the trade winds blowing, there will as usual be those passing windward biased showers arriving. The trade winds will be strong enough that a few showers could spill over into the leeward sides on the smaller islands. There could end up being a change in frequency and intensity of these showers brought our way…as we push into the new work week ahead. Several weather factors would have to come together just right, including moisture arriving from the east, and cold air aloft, for this to manifest into something of note…although its looking quite likely at the moment.

Click on the following link for the latest National Weather Service advisories and warnings:   Wind/Surf/Flood related advisories or warnings

Details of Hawaii’s Weather – Wind/Precipitation/Surf

As this weather map shows, we find a 1031 millibar high pressure system located far to the northeast of the Hawaiian Islands Friday afternoon.  This high pressure cell remains nearly stationary offshore from the Columbia River mouth, between the Oregon and Washington borders.  Meanwhile, we see a  1033 millibar high pressure cell closer, to the north of the islands.  Finally, we have troughs of low pressure located to the east and north of the state. The long and short of all this keeps moderately strong trade winds blowing across our latitudes of the north central Pacific…strongest over the Maui and Big Island end of the chain as usual.

The following numbers represent the strongest wind gusts (mph), along with directions Friday afternoon:

25                 Port Allen, Kauai – NE
25                 Waianae Valley, Oahu – SE
30                 Molokai – NE
37                 Kahoolawe – E
35                 Kaupo Gap, Maui – NE
35                 Lanai – NE
38                 PTA Keamuku, Big Island – NE

We can use the following links to see what’s going on in our area of the north central Pacific Ocean early Friday afternoon. Looking at this NOAA satellite picture we find that high and middle level cloudiness are located over the ocean to the east and southeast, along with fairly minor low clouds stretched across the windward sides, most concentrated on the Big Island and Maui. We can use this looping satellite image to see low clouds being carried over the islands on the trade wind flow here and there…although skies were quite clear in some areas today.  We can see a large area of thunderstorms over the ocean to the southeast and east of the Big Island, with high cirrus clouds flying off the tops of those storms…carried by the strong upper level winds in that area. There’s an area of high cirrus clouds moving by not too far south of Maui County and the Big Island as well. Checking out this looping radar image we see showers over the ocean, most of which are in the light to moderately heavy category, the most active  areas are coming into the  windward sides…with a few sliding over into the leeward sides on Oahu. 

Here are the 24-hour precipitation totals (inches) for each of the islands as of late Friday morning:

0.37               Mount Waialeale, Kauai
0.45               Manoa Lyon Arboretum, Oahu
0.24               Molokai
0.00               Lanai
0.00               Kahoolawe
1.34               Puu Kukui, Maui
1.66               Piihonua, Big Island

Here is the latest NWS rainfall forecast

Here are the latest available satellite images:

Hawaii Infrared satellite image
Animated Satellite image of Hawaii region
Latest satellite image – Close-in visible satellite view
Latest radar image – Looping

SURF OUTLOOK:   The north shores will be large Friday…slipping some Saturday. The west sides will be large Friday, then slowly lowering in height Saturday as well. Surf along the east shores will remain active, rough and choppy Friday and Saturday. South shores will be small Friday and Saturday…locally larger where westerly energy can catch.

North shores –   A large northwest swell will remain active for several days…gradually lowering through the weekend. The largest surf Friday will range between 6-10 feet or so…locally a bit larger. Looking ahead, the next northwest swell, although quite a bit smaller than the one that’s active now, will arrive Tuesday, lasting for a few days along these beaches, and on our west sides too.

West shores –   The large northwest swell will keep these beaches up Friday, gradually lowering Saturday and Sunday. The largest surf Friday will range between 5-8+ feet…locally a bit larger. Chance that some of this swell will impact the Big Island’s west or south facing shores…where it’s usually smaller.

South shores –    Surf will remain small on these leeward shores through the weekend at least…although locally larger

East shores –   Surf will gradually rise…as the strengthening trade winds bring choppy and rough conditions into the weekend and beyond.

NOAA animated wave model