Hawaii Weather Synopsis: High pressure far to the northeast of the State will keep the islands in a trade wind environment over the next several days. Clouds and passing showers will favor windward and mauka areas. An upper low is forecast to move down near the state over the weekend with increased chances of showers and the possibility of some locally heavier showers as well.
No Advisories, Watches, or Warnings are currently in effect.
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Broad Overview of Hawaii’s Weather
Based on the NWS Area Forecast Discussion for Hawaii, issued 26 Oct 2011 at 10:00am HST
NWS Short Term Forecast for the period 6 pm HST this evening through 6 pm HST Friday:
An area of low pressure west of the State will continue to weaken over the next few days. In the meantime an area of high pressure will remain stationary far to northeast of the State (see latest weather map). This places the islands in a light to moderate trade wind environment with the strongest winds around the Big Island and lighter winds near Kauai.
The upper levels of the atmosphere show an upper ridge over the State providing stability. Rainfall will remain on the light side over the next few days primarily affecting windward and mauka areas with some upslope showers over the leeward Big Island slopes each afternoon and evening.
NWS Long Term Forecast for the period 6 pm HST Friday through 6 pm HST Tuesday:
Models are in good agreement with an upper low dropping down from the north and taking up a position over or near the main Hawaiian Islands. This will cause the atmosphere to destabilize in the island vicinity.
At the surface high pressure will remain to our north keeping the islands in a trade wind environment. Showers will continue to favor windward and mauka areas as well as some leeward and interior areas during the afternoon and evening hours. There will likely be some heavier showers due to the upper low’s instability.
As we head into early next week there are some model differences in the placement and strength of the upper low. The GFS model is stronger and closer to the state while the ECMWF is weaker and further east. High pressure will remain to our north so showers will continue to be focused over windward and mauka areas. The placement of the upper low will have an impact on shower activity but for now we will just broad brush things.
In the marine environment, a small north-northwest swell will fill in Thursday night and Friday and linger through the weekend. A larger north-northwest swell is expected to fill in Sunday night and Monday. There will also be a series of small south swells through the forecast period. Trades winds will continue to produce short-period choppy surf along east facing shores.
Winds are expected to remain well below Small Craft Advisory criteria through the middle of next week except for the windier areas around the Big Island where winds may reach Small Craft Advisory criteria over the weekend.
The following numbers represent the strongest wind gusts (mph), along with directions Wednesday morning:
12 Princeville, Kauai – ESE
17 Kahuku, Oahu – E
20 Kahoolawe – E
23 Lipoa, Maui – SE
27 South Point, Big Island – ENE
Here are the 24-hour precipitation totals (inches) for each of the islands as of Wednesday morning:
1.03 Mt. Waialeale, Kauai
0.20 Nuuanu Upper, Oahu
0.01 Puu Kukui, Maui
0.34 Mountain View, Big Island
Here is the latest NWS rainfall forecast
Here are the latest available satellite images:
SURF ZONE FORECAST – OAHU
NATIONAL WEATHER SERVICE HONOLULU HI
900 AM HST WED OCT 26 2011
Surf along north facing shores will be 2 to 4 feet today, lowering to 1 to 2 feet Thursday.
Surf along west facing shores will be 1 to 3 feet through Thursday.
Surf along south facing shores will be 2 to 4 feet through Thursday.
Surf along east facing shores will be 2 to 4 feet through Thursday.
Outlook through Tuesday Nov 1: A small northwest swell will arrive Thursday night and peak on Friday, before slowly diminishing through the weekend. A larger northwest swell will arrive Sunday night and peak on Monday, bringing surf near the advisory level of 15 feet for north facing shores. This swell will begin to diminish on Tuesday.