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Dec
23
2011

Hawaii Weather Overview

Trade winds will remain strong and gusty, reaching up between 30 to 50 mph in those windiest areas, continuing through the rest of this week into the early part of next week, passing windward showers at times…spreading over into the leeward sides here and there. Rough and choppy ocean conditions, especially on the north and east facing shores.

PDC Global Hazards Atlas displaying clouds and 3 hour rainfall accumulation in the north central Pacific...with the islands in the middle of the picture

Hawaiian Weather Synopsis:  The unusually long lasting trade winds have been around all this week, and are forecast to continue unabated through the upcoming Christmas holiday. Winds have been gusting up over 40 mph, all the way up to 50 mph at a couple of those windiest spots…especially on the small island of Lanai in Maui County. It appears that this prolonged episode of stronger than normal winds will hold onto us through the next several days, at least. If the computer models have it right, our local winds may even nudge up another notch this weekend. This is the reason behind the NWS forecast office in Honolulu issuing a gale warning for those windiest channels beginning early Saturday morning. We already have small craft advisory flags whipping in the blustery waters over the entire state’s marine environment. Meanwhile, the winds are strong enough atop the Haleakala Crater on Maui…that a wind advisory is in force up there too.

Under these circumstances, showery clouds will be carried in towards our windward coasts and slopes, which is of course common. These will keep things off and one rather wet into the weekend, with some of those showers being carried over into the leeward sides of the smaller islands…through the Christmas weekend into Monday. We also have an area of cold air aloft, which is heading our way, which once it gets here…will enhance the incoming shower clouds. This will help to wring out extra showers, as the air mass will be a bit unstable. As we’re into our winter season now, there will be the good chance of more snow showers falling atop the Mauna Kea summit on the Big Island…as they have been lately.  The latest computer forecast models still don’t show any active cold fronts pushing down into our area through the end of the year…which would help to knock this windy weather episode for a loop. This time of year things can change quickly however, so some unexpected changes could happen in our Hawaiian Island weather picture with the blink of an eye…or two.

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 have two 1032 millibar high pressure systems to the northwest and far northeast of the Hawaiian Islands Friday afternoon.  The high pressure cell to our northwest is moving quickly eastward, and will become the dominant trade wind producer for our islands as we move into the weekend. At the same time, we find two surface troughs of low pressure to the east of the islands. These trade winds are expected to continue through the rest of this week…and even pick up a notch or two Saturday and Sunday. These strong and gusty trades will carry forth into the new work week ahead, although gradually become somewhat lighter during the week.

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

38                 Port Allen, Kauai – NE
35                 Kahuku, Oahu – ESE
39                 Molokai – NE
37                 Kahoolawe – E
33                 Lipoa, Maui – SE
44                 Lanai – NE
42                 Waikoloa, Big Island – NE

We can use the following links to see what’s going on in our area of the north central Pacific Ocean Friday afternoon.Looking at this NOAA satellite picture we see areas of high level clouds located to the northwest of Kauai. At the same time we have lower level clouds banked up against our windward sides from the Big Island up through Maui and Oahu at the time of this writing. We can use this looping satellite image to see towering cumulus and thunderstorms developing over the ocean to the far southeast and east of the Big Island. Those high cirrus clouds to our northwest appear to be heading towards Kauai, and perhaps the rest of the state. Checking out this looping radar image we see showers over the ocean, most of which are light to moderately heavy, coming into our windward sides at this hour.

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

1.52               Mount Waialeale, Kauai
0.26               Manoa Lyon Arboretum, Oahu
0.10               Molokai
0.00               Lanai
0.00               Kahoolawe
0.85               Puu Kukui, Maui
2.42               Kawainui Stream, 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 generally small or a bit larger Friday and Saturday. The west sides will be small through Saturday. Surf along the east shores will remain rough and choppy both days…as the strong trade winds continue. South shores will be very small to small through the next two days.

North shores –  Small to lower medium northwest swells will keep waves breaking through Saturday…choppy ocean conditions continuing. A new larger northwest swell arrive Sunday into next Monday…a smaller northwest swell will arrive next Tuesday into Wednesday.

West shores –  Generally small northwest swells will keep these beaches active, although smaller than the north shores as usual.

South shores –  Surf will remain very small to small on these leeward shores

East shores –  Wind swell continues…rough and choppy

NOAA animated wave model