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Nov
17
2011

Hawaii Weather Overview


Hawaiian Weather Synopsis: 
Despite the extensive cloudiness that overlies the island chain at the moment, not all that much precipitation is falling. This is primarily due to the higher altitudes that these clouds reside at the moment. These include the high icy cirrus, and the middle level altostratus varieties. These clouds generally aren’t known for their precipitating qualities, although are infamous to our local sun worshippers…for their sun muting and filtering capabilities. Nonetheless, there have been some showers around, falling from lower level clouds, especially over the Big Island, and to a lesser degree Kauai during the last 24+ hours.

This satellite image shows that there are lots of clouds around, in no uncertain terms. The majority of this multi-layered cloudiness is well southwest, south, and southeast of our islands at the moment.The northern fringe of this stuff extends over the state, and to the northeast. The source of this cloudiness is the deep tropics, scooped up by the counterclockwise air circulation associated with an upper level trough/low pressure to our west. The computer forecast models are suggesting that this cloudier than normal reality will stick around likely through the rest of this week…perhaps even into early next week.

As for our winds, they will be generally from the NE to east, the trades. As this weather map shows, we still have a 1030 millibar high pressure system to our northeast. It will provide gradually increasing trade wind speeds, with the gusts already topping 30 mph in a few of those windier locations around the state. There are no marine advisories active now, although as the trades accelerate going forward, we could see small craft wind advisories going up in those windiest places around Maui County and the Big Island. They will continue to be rather strong and gusty this weekend into at least early next week.

Looking further afield (I mean over the ocean), we have an area of disturbed weather active in the far eastern Pacific, offshore from southern Mexico. This satellite image, with an orange circle around this disturbance…has a 30% chance of developing into a tropical cyclone. It is the only such area of disturbed weather anywhere in the world at the moment. The computer models are showing it spinning up into something with time…we’ll see. It poses no danger to the Hawaiian Islands whatsoever.

 

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

 

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

Broad Overview of Hawaii’s Weather

As this weather map shows, we find a 1030 millibar high pressure system located to the northeast of the Hawaiian Islands Thursday afternoon. This high pressure cell has an elongated ridge extending from its southwest flank, which continues into the area far northeast and east of the state. At the same time, there’s a 1021 millibar low pressure system parked to the north of Hawaii. There’s a short cold front that is associated with this low pressure center, along with a trough of low pressure over the ocean well west of the islands. Our trade winds will build in strength gradually into Friday, which will remain on the stronger and gust into next week.

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

24                 Port Allen, Kauai – E
25                 Honolulu, Oahu – NE
23                 Molokai – NE
25                 Kahoolawe – E
28                 Kahului, Maui – NE
12                 Lanai – NNE
33                 South Point, 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 Thursday afternoon. Looking at this NOAA satellite picture we can’t see any lower level clouds, due to the copious amount of cloudiness being carried overhead from the west and southwest. We can use this looping satellite image to see a counterclockwise rotating low pressure system well west of Kauai. This low is like a conveyor belt, dragging considerable amounts of high and middle level clouds over our island chain. Checking out this looping radar image we see  showers falling locally over the ocean, most of which are light, although a few are heavier to the south of Kauai. It appears that the Big Island continues to receive the most generous showers so far.

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

1.62               Mount Waialeale, Kauai
0.17               Nuuanu Upper, Oahu
0.00               Molokai
0.00               Lanai
0.02               Kahoolawe
0.11               Puu Kukui, Maui
2.53               Glenwood, 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:    Small conditions on all shores through Saturday…locally flat

North shores –   Small surf, with a north swell arriving early Sunday, turning northwest Monday…lasting into mid-week

West shores –     Very small to flat surf…with a mnor bump from the new NW swell locally on Monday…lasting a few days

South shores –    Small to very small surf…locally flat into early next week at least

East shores –   Small surf, then picking up as the new surge of trade winds arrives this weekend into next week

NOAA animated wave model