Hawaii Weather Synopsis: An upper level trough over the state will keep unsettled weather through at least Friday. For today, wetter conditions and a higher chance for unsettled weather will be over the Big Island. Showers will be focused across windward and mauka areas, though trade winds will spread showers to leeward sections at times. Strong high pressure passing far north of the state will cause trade winds to strengthen for the second half of the work week.
A Small Craft Advisory is in effect until 6 am HST Wednesday for Maalaea Bay, Pailolo channel, Alenuihaha channel, Big Island leeward waters, Big Island southeast waters.
A Small Craft Advisory is in effect from 6pm this evening to 6am HST Wednesday for Kauai channel, Kaiwi Channel.
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
Based on the NWS Area Forecast Discussion for Hawaii, issued 8 Nov 2011 at 1013am HST
A complex weather situation exists over the islands, featuring low level ridging with locally breezy trades and a stubborn upper level trough with unstable conditions aloft. For today, the low level ridge, which is evident on the overnight soundings and recent aircraft data, should hold over the smaller islands and keep a lid on convection. Expect showers to be focused over windward areas, with a chance of showers leeward. Wetter conditions are in store for the Big Island as deeper moisture rides in on the trade wind flow. In addition, the coldest temperatures aloft associated with the upper trough axis are parked over the Big Island. This combination of moisture and instability will lead to a slight chance of thunderstorms over the Big Island and adjacent waters. The summits may also experience a snow shower this afternoon. An update has been sent to reflect this scenario.
Unsettled weather is possible state-wide tonight into Wednesday morning. The moisture currently near the Big Island will spread westward to the smaller islands, likely bringing an increase in showers. The main increase in rainfall will be over windward and mauka areas, though trades will carry periodic showers across leeward sections. During this time, an upper level disturbance will drop into the upper level trough and erode the low level inversion. This will lead to a slight chance of thunderstorms pretty much anywhere overnight.
A brief drying period near the surface could bring a lull in shower activity Wednesday night and Thursday. The models show a surge in moisture centered around Thursday night through early Saturday associated with the remains of a dissipated front and will be expecting a generally wet pattern during that time.
At the surface, winds will remain moderate to locally breezy today with an increase in store Wednesday. High pressure far east northeast of the state will give way to a stronger high building in far north of the state tomorrow. Winds are expected to increase on Wednesday as a result and remain strong into Friday, eventually weakening over the weekend. The stronger winds will result in more passing leeward showers the second half of the week, especially Thursday night and Friday as surface moisture remains high.
Marine Forcast:A Small Craft Advisory remains in effect for the typically windier waters near Maui County and the Big Island. Beginning at 600 pm HST all Hawaiian channels will be under the Small Craft Advisory as trade winds gradually strengthen, and will likely include all coastal waters by Wednesday morning. A northeast swell combined with rough, locally-generated seas will likely produce surf well above the advisory level for east facing and possibly north facing shores during the holiday weekend.
The following numbers represent the strongest wind gusts (mph), along with directions Tuesday morning:
16 Port Allen, Kauai – ENE
23 Bellows AFB, Oahu and Honolulu Apt, Oahu – ENE/E
30 Molokai – NE
12 Kahoolawe – N
24 Kapualua-West, Maui- NE
20 Lanai – ENE
28 Upolu Airport, Big Island – W
Here are the 24-hour precipitation totals (inches) for each of the islands as of Tuesday morning:
1.54 Mt. Waialeale, Kauai
0.43 Oahu Forest NWR, Oahu
0.21 Puu Kukui, Maui
0.93 Kawainui Stream, 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 TUE NOV 8, 2011
Surf along north facing shores will be 3 to 6 feet Wednesday.
Surf along south facing shores will be 1 to 3 feet today, rising to heights of 2 to 4 feet Wednesday.
Surf along west facing shores will be 2 feet today, rising to heights of 2 to 4 feet Wednesday.
Surf along east facing shores will be flat to occasional 2 feet through Wednesday.
Outlook through Monday Nov 14: Trade winds will maintain head high short period chop along windward reefs and beaches over the next several days. A larger north northeast swell will bring high surf advisory level surf for east facing and possibly north facing shores during the holiday weekend.