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Dec
27
2011

Hawaii Weather Overview

Trade winds will remain strong and gusty, reaching up between 30 to 50 mph in those windiest areas today, gradually calming down through the rest of this last week of 2011, 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 3 hour precipitation accumulations for the north central Pacific

Hawaiian Weather Synopsis:  December, for a month not known for its prolonged trade winds, has been hooked into not only a long lasting stint…but also much stronger than usual too. Each day for the last week at least, our winds have been gusting up over 40 mph, reaching 50 mph several times last week. At the time of this writing, winds were gusting up over 40 in several places in Maui County, and reaching up over 50 mph at one place on the Big Island. This unusual trade wind episode is starting to feel almost normal, although grades pretty heavily against the fact that December normally has the trade winds blowing only 53% of the time….this is turning out to be more like 90% or more!

Looking ahead, it appears that the trade will continue their long run of days, although at least will gradually be winding down as we move through this week. They may not stop altogether through the rest of 2011, although will at least not be gusting up into the 40-50+ mph range soon. A cold front approaching this coming weekend, will push our trade wind producing high pressure ridge down closer to Kauai. This in turn will finally take the winds down several notches, allowing the ocean to smooth out some, after being very choppy and rough for a long time. The high surf advisory along our east shores, and the small craft wind advisory may even be lifted later this week. The strong winds over the mountains on Maui and the Big Island, should expire at some point over the next few days too.

As for rainfall, there was much more last week, at least compared to how this week’s started out. There are still some showers being carried our way, although the atmospheric dynamics are much less shower prone now. The windward sides will be on the receiving end of most of showery clouds, while the leeward sides will likely remain dry…with maybe a couple of drops in a few places. There really aren’t any potential big changes in this regard, at least as far out as the computer models are seeing out into the future from this point.

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 a near 1030 millibar high pressure system far to the northwest of the Hawaiian Islands Tuesday afternoon.  This high pressure cell is well offshore from San Diego, California, with a very long ridge of high pressure extending west-southwest from its center. This ridge runs by the Hawaiian Islands, up around 28 degrees north latitude, and then further west across the International Dateline…into the western Pacific. The location of this high pressure ridge is keeping our very long lasting strong and gusty trade winds blowing across Hawaii. There’s forecast to be a gradual reduction in our wind speeds as we move through this last week of the year, becoming generally light into early next week.

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

32                 Lihue, Kauai – NE
30                 Honolulu, Oahu – NE
38                 Molokai – NE
45                 Kahoolawe – ENE
43                 Kaupo Gap, Maui – NE
44                 Lanai – NE
52                 PTA Kipuka Alala, Big Island – NE

We can use the following links to see what’s going on in our area of the north central Pacific Ocean Tuesday afternoon.Looking at this NOAA satellite picture we see areas of  low level clouds banked up against our windward sides at the time of this writing. We can use this looping satellite image to see towering cumulus and thunderstorms developing over the ocean far southeast of the Big Island. High cirrus clouds to our northeast through northwest appear to be heading towards 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 times.

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

0.26               Mount Waialeale, Kauai
0.21               Punaluu Stream, Oahu
0.05               Molokai
0.00               Lanai
0.00               Kahoolawe
1.09               Puu Kukui, Maui
0.49               Hilo airport, 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 lowering Tuesday and Wednesday. The west sides will be dropping through mid-week as well. 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 locally Tuesday and Wednesday.

North shores –  Surf will be lower into mid-week. Thursday will find the surf coming up from the west to northwest again for several days..into the weekend.

West shores –   Surf lowering into mid-week. A new NW to West swell will arrive around Thursday, lasting for several days.

South shores –  Surf will be very small to small on these leeward shores for a few days. Those beaches that catch some of the new west swell around Thursday, could come up again then locally into the weekend. 

East shores –  Wind swell continues…rough and choppy, gradually lowering after mid-week.

NOAA animated wave model