Trade winds will remain strong and gusty, more so than normal, continuing through the rest of this week…passing windward showers at times, especially around the Big Island – where a flash flood watch remains in place this afternoon.
Hawaiian Weather Synopsis: The two main weather features influencing the Hawaiian Islands at this point are the strong and gusty trade winds, and the generous windward biased showers. The eastern islands continue to receive the most showers, which will continue to be the case for the time being. The gusty trades are working in tandem with the incoming showers from the east, providing the transportation mechanism. The top of the West Maui Mountains [the Puu Kukui gauge] had received the most rainfall in the state as of late Monday morning, showing an impressive 3.73″ during the last 24 hours, while the bucket at Pua Akala on the Big Island, had picked up the second largest accumulation…with 2.44″.
This satellite image shows that towering cumulus and thunderstorms continue to fire-off over the ocean to the south and southeast of the Big Island. This activity is being sparked by the counter-clockwise rotating upper level low pressure system over the ocean to the south of the islands. At the time of this writing, almost all of the heavy stuff was still over the ocean well offshore from the Big Island. There is more precipitation coming our way according to this looping radar image. As shown, the bulk of this moisture is moving by to the south of the Big Island…although quite a bit is impacting the east and southeast sides of that island too. Most of these showers are light to moderately heavy, although a few look like they are edging up towards the heavier side of medium at the time of this writing.
Back to the trade winds for a minute, they continue to be good and gusty, reaching up towards 50 mph at times…at least in those windiest locations around the state earlier today. High pressure to the northeast, and low pressure to the south have tightened our pressure gradient across our islands. This in turn continues to keep the trade winds stronger than normal, with no definite end to this prolonged late autumn trade wind episode…in sight yet. These winds are strong enough to have recently triggered a high surf advisory along our east facing coasts. This rough and choppy reality is covered in the advisory through early Thursday morning. At the time of this writing, the strongest gust around the state was 39 mph on the small island of Lanai…where it had been gusting to 47 mph just a short time ago.
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 1035 millibar high pressure system located far to the northeast of the Hawaiian Islands Monday afternoon…located well offshore from the northwest coast of California. This high pressure system has a ridge that runs southwest from its center, into the area north of the state. At the same time a weak cold front, extending far southwest from a storm low pressure system in the Gulf of Alaska, which is moving quickly inland over western Canada. Finally, there is a trough of low pressure to the south of the Big Island, which is helping to enhance the strength of our local trade wind speeds.
The following numbers represent the strongest wind gusts (mph), along with directions early Monday afternoon:
31 Lihue, Kauai – NE
35 Waianae Valley, Oahu – ESE
42 Molokai – NE
42 Kahoolawe – E
37 Kahului, Maui – NE
47 Lanai – NE
36 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 Monday afternoon.Looking at this NOAA satellite picture we find that the high and middle level clouds are located just to the south through southeast through east of the islands at this hour. We can use this looping satellite image to see lots of towering cumulus and thunderstorms developing to the south and east over the ocean, associated with a counter-clockwise rotating upper level low pressure system…to the south of the islands. Checking out this looping radar image we see showers over the ocean, most of which are light to moderately heavy, although some are heavier coming into the east through south sides of the Big Island…with just a few arriving along the windward sides on the other islands.
Here are the 24-hour precipitation totals (inches) for each of the islands as of Monday morning:
2.64 Kilohana, Kauai
1.15 Moanalua, Oahu
3.73 Puu Kukui, Maui
2.44 Pua Akala, Big Island
Here is the latest NWS rainfall forecast
Here are the latest available satellite images:
SURF OUTLOOK: The north shores will gradually lower through Monday into Tuesday…although remain active. The west sides will be gradually lowering into Tuesday…although still have nice breaking waves. Surf along the east shores will remain rough and choppy Monday and Tuesday…as the trade winds continue. South shores will be very small to flat through Tuesday.
North shores – Small to lower medium northwest swells will keep waves breaking through most of this new week…choppy ocean conditions continuing, especially Wednesday and Thursday.
West shores – The northwest swell will keep these beaches active, although smaller than the north shores as usual.
South shores – Surf will remain very small to flat on these leeward shores
East shores– Wind swell remaining rough and choppy