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Nov
23
2011

Hawaii Weather Overview

The strong and gusty trade winds will taper off a bit through the next couple of days…with less frequent showers

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

Hawaiian Weather Synopsis:  The trade winds remain blustery today, especially over parts of Maui County and the Big Island. Kauai and Oahu had gusts over 30 mph, although gusts were topping 40 mph further east. The small island of Lanai has been particularly windy the last couple of days, at least at times…with gusts approaching the middle 40 mph mark. High pressure to our northwest through northeast is the source of these gusty winds, in contrast to  lower pressure in the deeper tropics to our south as well, keeping the pressure gradient tighter than usual over the state. The expectation continues to be that these winds will mellow-out a little over the next few days, through most of Friday.

Things will change however as we get into late Friday, and certainly over the upcoming weekend. A strengthening high pressure cell to the north of the state later Friday into Saturday, will push a weak cold front down into the state during the first part of the weekend. The associated showers accompanying this frontal passage won’t be the main event this weekend however. What will be more like headline weather news will be the return of strong and gusty winds into Sunday, and perhaps into next Monday as well. Before we let go of discussing cold fronts, we may see another one arriving about a week from today.

At the moment we have small craft wind advisories active over those windiest coasts and channels around Maui County and the Big Island. They may remain in force through Friday, or may get dropped, depending upon just how much the trade wind speeds relax. However, they will be back fully this weekend, and it wouldn’t be out of the question to see wind advisories over some parts of the islands to be needed as well. The flow may be deep enough that the peaks on Maui and the Big Island could require wind advisories too…it’s going to be windy. As we get into next week, the winds will calm way down by Tuesday or so, that is if the cold front next week actually makes its way here around Wednesday.

Just a brief note on that tropical cyclone over in the eastern Pacific before we sign off. Yesterday’s report about Kenneth showed it to be a category 4 storm! It had dropped to a much weaker category 1 storm last night, and since then has fallen to only a tropical storm today. This is a major change in strength no matter how you look at it, and is as dynamic as how quickly it became so strong over this past weekend into Monday. The way it looks now Kenneth will be in the record books soon, perhaps even over the next couple of days it will have diminished into what we call a remnant low pressure system. As I was mentioning yesterday, it poses no danger to our Hawaiian Islands, and may yet bring a few of its leftover showers our way next week.

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 1027 millibar high pressure system located far to the east of the Hawaiian Islands, with a second 1026 millibar high pressure cell closer to our northwest Wednesday afternoon.  At the same time, there’s a trough of low pressure far out to the west of Hawaii…with a weak cold front to the northeast of our islands.  Our trade winds remain strong and gusty at mid-week. The computer models continue to suggest that our local trades will decrease some on Thanksgiving Day into Friday. They go on to tell us that our strong and gusty trade winds will ride in again behind a cold front this weekend…into early next week.

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

30                 Lihue, Kauai – NE
37                 Makua Ridge, Oahu – SE
31                 Molokai – NNE
42                 Kahoolawe – E
32                 Kahului, Maui – NE
43                 Lanai – NE
40                 Pali 2, Big Island – NNE

We can use the following links to see what’s going on in our area of the north central Pacific Ocean early Wednesday afternoon. Looking at this NOAA satellite picture we find that high and middle level cloudiness is located to the southeast of the state at mid-week. We can use this looping satellite image to see low cloud bands being carried into our windward sides on the gusty trade wind flow. At the same time, we find a considerable amount of thunderstorm rainfall over the ocean well west of the Aloha state. Checking out this looping radar image we see  just a few light showers falling locally over the ocean, arriving along those windward coasts and slopes here and there.

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

0.46               Mount Waialeale, Kauai
0.16               Waiawa, Oahu
0.20               Molokai
0.00               Lanai
0.07               Kahoolawe
3.53               Puu Kukui, Maui
1.46               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:   Rough surf east shores as the trade wind speeds remain active. The north shores will remain active Wednesday and Thursday. The west sides will get a bit larger, and south shores will be small to very small through Thanksgiving Day. 

North shores –  Several small north to northwest swells will keep our surf breaking through the rest of this week. A much larger north-northwest swell arriving during the second half of the weekend…into early next week.

West shores –  These beaches will be active when small northwest swells arrive this week.

South shores –   Small to very small surf through the week. 

East shores –  Surf remaining rough and active, as the trade winds continue. Conditions will be rough and choppy with wind swell.

NOAA animated wave model