Trade winds increasing in strength through the weekend into early next week, passing showers along our windward sides, occasionally on the leeward sides on the smaller islands…rough surf along our north and west facing beaches.
Hawaiian Weather Synopsis: The three main things that will most influence us today through the weekend will be:
Strengthening trade winds – The trade winds are already on the rise, and will become quite strong and gusty through the weekend, and into the middle of the new week ahead. This weather chart shows high pressure systems to the north and northeast of our islands, which will be the source for these increasingly strong trades. We also see a cold front to the north of Kauai, which extends southwest from a gale low pressure far to the northeast of Hawaii. As this frontal boundary weakens, which it is expected to do, it will allow these stronger trade winds to arrive into our area. The NWS office in Honolulu has a small craft wind advisory up for almost all of the state now through 6pm Saturday evening.
Passing showers – Showers are few and far between this afternoon, with the most concentrated area along the windward side of the Big Island at the time of this writing. This satellite image shows this, with high and middle level clouds offshore over the ocean to the east and southeast. At the same time, we can see some heavy showers offshore to the northeast of both Kauai and Oahu. Meanwhile, we can also see the fairly non-threatening cold frontal cloud band not far north of Kauai too. Skies were mostly clear from Kauai down through Maui County, with just a thin strip of clouds along east Maui’s Haleakala slopes. As far as rainfall goes, most of it was associated with an area of lower clouds directly east and southeast of the Big Island…as shown here. Showers should be increasing some along our windward sides as we move into the weekend.
Large rough surf along our north and west shores – A mid-latitude storm earlier this week generated a large swell train of waves. This swell is causing larger than normal surf to break along our north and west shores this afternoon. It began earlier in the day along Kauai and Oahu, then reached Maui County early this afternoon. The NWS has a high surf advisory active from Kauai down through Maui County. The surf is expected to reach 18-22 feet (wave faces) along the north shores, while the west facing beaches will find 12-18 footers breaking. The Big Island remains outside of this high surf advisory zone at the moment. This surf is expected to peak during the day, and then gradually lower in height through the upcoming weekend.
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 near 1031 millibar high pressure system located far to the northeast, and another to the north-northwest of the Hawaiian Islands Friday afternoon. These high pressure cells have ridges that run east and west from their centers, to the north of the state. A weak and dissipating cold front breaks through their ridges to the north of Hawaii. The trade winds will gradually become stronger from the trade wind direction later today into Saturday.
The following numbers represent the strongest wind gusts (mph), along with directions Friday afternoon:
21 Port Allen, Kauai – ESE
18 Bellows, Oahu – NE
21 Molokai – NE
21 Kapalua, Maui – NE
28 Lanai – NE
23 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 Friday afternoon. Looking at this NOAA satellite picture we find that the high and middle level clouds remain well to the southeast and east of the Big Island…over the ocean. We can use this looping satellite image to see this high level moisture streaming up from the southwest…which continues to shift gradually eastward, along with a cold front not too far north of Kauai…that seems to be losing steam quickly. Otherwise, skies are mostly clear to partly cloudy elsewhere. Checking out this looping radar image we see just a few showers over the ocean, most of which are in the light to moderately heavy category, most concentrated over the ocean to the southeast of the Big Island.
Here are the 24-hour precipitation totals (inches) for each of the islands as of late Friday morning:
0.51 North Wailua Ditch, Kauai
0.97 Manoa Lyon Arboretum, Oahu
0.23 Puu Kukui, Maui
1.18 Pahoa, Big Island
Here is the latest NWS rainfall forecast
Here are the latest available satellite images:
SURF OUTLOOK: The north shores will be large Friday…from a new northwest swell train of waves, remaining large into Saturday. The west sides will be larger than normal Friday into Saturday as well. Surf along the east shores will remain active Friday and Saturday…larger Saturday. South shores will be very small to flat through Saturday.
North shores – A northwest swell will keep large waves breaking Friday, lasting into the weekend…very slowly lowering through Sunday. A second NW swell will arrive right after the weekend, keeping the surf up for several more days.
West shores – The northwest swell will keep these beaches very active too, although smaller than what we’ll find along our north shores into Sunday…with a second northwest swell arriving after the weekend.
South shores – Surf will remain very small to flat on these leeward shores
East shores – As the trade winds increase Friday into the weekend, so will the wind swell into early next week.