Gradually strengthening trade winds, windward biased showers for the most part…larger surf along our north and west facing beaches Thursday.
Hawaiian Weather Synopsis: The trade winds have begun their strengthening process today, with some gusts reaching the mid 30 mph mark, on both Lanai and Oahu at the time of this writing. These winds are being generated by a strong high pressure system far to the northeast of the state. The forecast calls for these gusty winds to continue blowing through the end of this week. The latest computer forecast models are showing that the trade winds may increase further as we get into the first part of next week. All this air in a hurry will make our local coasts and channel waters rough and choppy well into the future. Early December isn’t particularly known for such consistent trade winds, as the trade blow on average only 57% of the time during this last month of the year.
Speaking of rough ocean conditions, we’ll be seeing a new northwest swell arriving late today, and then peaking Thursday and Friday…before gradually lowering in size this weekend. High surf advisories will go up along our north and west facing beaches, in response to this larger than normal swell. The strengthening trade winds will add to this gnarly ocean surface, bringing its countless white caps into the mix. In contrast to these large waves, the south facing leeward sides of our islands will be much more user friendly…as is often the case during our autumn and winter months. This of course is due to the summer season in the southern hemisphere now, where our south swells are generated during their winter season.
The rainfall pattern here in the islands continues to be fairly typical for such a trade wind weather pattern. It almost goes without saying, that we’ll see the common passing windward biased showers falling here and there…from time to time. This straight forward reality will continue through the rest of this work week. As we get into the weekend, perhaps even more likely later in the weekend, we’ll find some increase in showers along our windward sides. If however, the trade winds are blowing briskly then, as expected, some of these showers will fly over into the leeward sides on the smaller islands at times. Not all of the forecast models are handling this increase in shower idea, although some are very generous in their potential offering of showers…with heavy showers not out of the question into early next week. The Big Island and Maui look to have the best placement for these potential showers.
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 find a strong 1038 millibar high pressure system located far to the northeast of the Hawaiian Islands Wednesday afternoon. This high pressure cell remains well offshore from the Columbia River mouth, between the Oregon and Washington borders. Meanwhile, we see a weaker 1024 millibar high to the north of the islands. The high pressure cell to the northeast has an elongated ridge of high pressure extending from its center…to the north and northeast of the islands.
The following numbers represent the strongest wind gusts (mph), along with directions early Wednesday afternoon:
23 Port Allen, Kauai – NE
35 Kahuku Training, Oahu – NE
31 Molokai – NE
33 Kahoolawe – E
30 Kahului, Maui – NE
38 Lanai – NE
30 PTA Keamuku, 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 Wednesday afternoon. Looking at this NOAA satellite picture we find that high and middle level cloudiness are located over the ocean to the southeast, along with some thunderstorms. We can use this looping satellite image to see low clouds being carried over the islands on the trade wind flow here and there…although skies were mostly clear in most areas today. Checking out this looping radar image we see showers over the ocean, most of which are in the light to moderately heavy category. The most active precipitation areas are coming into the windward sides..especially on Oahu, Maui, and to the southeast of the Big Island.
Here are the 24-hour precipitation totals (inches) for each of the islands as of late Wednesday morning:
0.75 Mount Waialeale, Kauai
0.61 Palisades, Oahu
1.16 Puu Kukui, Maui
0.77 Waiakea Uka, Big Island
Here is the latest NWS rainfall forecast
Here are the latest available satellite images:
SURF OUTLOOK: Surf along the east shores will remain active, rough and choppy Wednesday and Thursday…generally on the small side or a little larger. The north shores will gradually lower during the day Wednesday, rising Thursday. The west sides will be lowering slowly Wednesday, then coming back up again Thursday. South shores will be very small to flat through Thursday.
North shores – The current northwest swell will gradually lower during the day Wednesday. The next larger northwest swell will arrive early Thursday, remaining active for several days…gradually lowering through the weekend. The largest surf late Wednesday in those best aligned spots will be 4-6 feet.
West shores – The current northwest swell will lower Wednesday…with another larger northwest swell Thursday into Friday, gradually lowering Saturday and Sunday. The largest surf Wednesday in those best aligned spots will be 2-4 feet.
South shores – Surf will remain small on these leeward shores
East shores – Surf gradually rising Wednesday into the weekend…as the strengthening trade winds bring choppy and rough conditions.