Glenn James

Hawaii Weather Today
Creator, Author, and Administrator for 30 years

 

The latest update to this website was at 130pm Monday afternoon HST


Here are the latest 24-hour precipitation totals (inches) for each of the island Monday afternoon: 

0.10  N Wailua Ditch, Kauai
0.16  Moanalua RG, Oahu
0.04  Puu Alii, Molokai
0.00  Lanai
0.23  West Wailuaiki, Maui
0.89  Kawainui Stream, Big Island


The following numbers represent the strongest wind gusts (mph) Monday afternoon:

24  Lawai, Kauai – E
28  Honolulu AP, Oahu – NE
27  Makapulapai, Molokai – E 
36  Kealaloloa Rg, Maui – NNE 
39  Kealakomo, Big Island – NW 


Hawaii’s MountainsHere’s a link to the live webcam on the summit of our tallest mountain Mauna Kea (~13,800 feet high) on the Big Island of Hawaii. Here’s the webcam for the (~10,023 feet high) Haleakala Crater on Maui. These webcams are available during the daylight hours here in the islands, and at night whenever there’s a big moon shining down. Also, at night you will be able to see the stars, and the sunrise and sunset too…depending upon weather conditions.


https://weather.gc.ca/data/satellite/goes_gwdisk11_1070_100.jpg

Big Blue…click twice for largest version

 

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Tropical systems remain active in the eastern Pacific…including Tropical Storm Odalys and Tropical Storm Polo 


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Variable low, middle, and high level clouds are present over the island chain

 

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https://radar.weather.gov/ridge/standard/PHKI_loop.gif

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Localized Showers 

 

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Please open this link to see details on any current Watches, Warnings and Advisories noted above




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Hawaii Weather Narrative
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Glenn’s Monday comments:  I’m at home here in upper Kula, Maui, Hawaii

514am, it’s mostly clear with a few high cirrus here at my place. The low temperature here in upper Kula was 55.5 degrees, relative humidity is 76%…with calm winds

930am, the latest update on former TD 15E:

>>> East-southeast of the Hawaiian Islands:

(Former TD 15E)

Satellite-wind data indicate the low-level circulation of the remnants of Tropical Depression 15E has become better defined, located several hundred miles to the east-southeast of the Hawaiian Islands.

Environmental conditions are forecast to become conducive for further development, and a tropical depression is likely to form around midweek while it moves slowly west- northwestward or northwestward.

Interests in the Hawaiian Islands should monitor the progress of this system.

* Formation chance through 48 hours…medium…40 percent
* Formation chance through 7 days…high…90 percent


Hawaii’s Weather Highlights…as of Monday afternoon: Breezy trades weaken slightly during mid-week then restrengthen by late in the week. Potential tropical development threatens to bring heavy rainfall to eastern portions of the state during the latter half of the week, though uncertainty remains higher than usual at this time.

Short Term Update:  Skies were partly to mostly cloudy windward/mauka and mostly sunny to sunny leeward. Radar detected isolated light showers south of Hilo, with dry conditions elsewhere. Trades will continue at moderate to breezy speeds today through tomorrow. The chance of formation of the remnants of TD 15E into Nolo (the next name on the list) are up to 90% now. Model spread remains especially large on the track of this system, and this is not likely to improve until the system actually forms and becomes something that the models can “sink their teeth into”, so to speak. The latest ensembles continue to display a large spread in timing and location of the track.

The general consensus is that the storm will remain south of the islands. However, there is a large spread concerning how far south…from just barely to several hundred miles. The latest Google DeepMind ensemble shows this spread well. The system is being monitored closely, of course, and I will update you as soon as something new comes up. This will be a rapidly evolving situation.

Impacts should start with increased rainfall on Big Island (and perhaps Maui County) as early as Wednesday, if the storm tracks toward the northern side of the ensemble envelope. A track more to the southern side would result in impacts starting late Wednesday night or Thursday. Winds will increase across the eastern end of the state regardless of which track the system ends up taking. How strong the system gets, combined with how far away it is, will determine wind speeds. At this time, the forecast shows gusts over 70 mph on the summits of Big Island (over 60 on Haleakala) late this week, but that is subject to significant change.

Weather Narrative…as of Monday afternoon: Attention going forward is on the time frame spanning Wednesday into the weekend. Uncertainty is running significantly higher than normal as former TD 15E lurks well southeast of the islands, and presents as a disorganized area of showers and thunderstorms. General consensus exists that activity will organize during the first half of this week, and advance in the general direction of the Big Island thereafter.

Initially, uncertainty in system movement likely stems from the current lack of organization, and typical uncertainty related to the cyclone`s development sequence. However, by the end of the week, considerable differences arise among the models regarding the evolution of governing mid-latitude troughing, as it approaches the state from the north. This will be the key to determining placement of the convergent moisture plume wrapping around the periphery of a potential tropical cyclone.

Broadly speaking, there is consensus that a trough will pivot toward the area and spur a low northwest of Kauai. The remaining portion of the trough then quickly advances southeast through the islands and, at some point, forces any tropical system to the south and away from our area. How quickly this unfolds is dependent upon the amplitude and forward motion of the trough. Some models show a well-defined low forming early, shunts the tropical system to the south much more quickly, and suggests a rather brief/24-hr window for flash flooding potential centered around Thursday.

On the other hand, the ECMWF model keeps the trough intact longer and results in considerable delay forcing the system southward. This makes all the difference as modeled rainfall totals run the gamut, from being measured in inches over a day or so, to measured in feet over several days. Accordingly, there is concern that the heavy rainfall in the case of a closer brush with this system, will occur over the same areas impacted by Hurricane Lala, though this remains far from certain. AI guidance have been equally unhelpful, as they too demonstrate considerable spread given the rather short lead time.

Summing up the current modeling situation, hints strongly at high end rain potential over much/all of the Big Island Thursday, Friday, and Saturday with consensus at this time tending to focus on the Hilo District and portions of the Puna District. The official forecast is guided by this information but additional revision to the magnitude and location of the heaviest rainfall is likely during the next couple of days. There could be isolated thunder in the forecast during this period, and the chance for heavy rain over the Big Island for the second half of the week.

A Flood Watch the Big Island and possibly Maui could be possible for future forecast packages. Strong trades likely worthy of wind headlines will also develop late this week into the weekend.

Fire Weather: Breezy trades continue through the week, likely strengthening this weekend. However, dewpoints and subsequent relative humidity values will remain elevated throughout this time. The inversion hovers around 6,000 feet but will rise over the eastern end of the state, as deeper moisture entrained in the trades works into the area.

 

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Here’s a near real-time Wind Profile of the Pacific Ocean – along with a Closer View of the islands / Here’s the latest Weather MapLooping Surface Precipitation…through the next 8-days / Vog Map

 

Marine Conditions…as of Monday morning: Fresh to locally strong trade winds expected through tonight, before decreasing slightly through mid-week. A Small Craft Advisory is in effect for the typical windy waters of Maui County and the Big Island through Tuesday evening. Wind speeds will restrengthen during the latter half of the week, as a trough or potential tropical disturbance moves near the islands. Shower coverage will also increase, along with the potential for isolated thunderstorms, particularly across the eastern waters.

Surf along south facing shores will remain above average over the next couple of days, as a long period SSW swell holds relatively steady. This swell will then gradually fade heading into mid-week. A slightly smaller, long-period south-southwesterly swell will fill in late this week into next weekend, generated by a series of lows near New Zealand. West facing shores will experience a bit of the southerly wrap through most of the week.

Breezy trade winds will maintain moderate surf along east facing shores for the next several days. Surf along north facing shores will remain flat to tiny, but will see a slight rise Tuesday into Wednesday as a small, medium-period northwest swell fills in from an Aleutian low. Then a small, long-period west-northwest swell generated by Tropical Storm Dujuan as it curves northeast near Japan and potentially strengthens into a hurricane, will build locally Friday into next weekend, increasing surf along north and west facing shores.

 

>>> Highest Temperature Sunday, September 20, 2026 – 108 degrees near Tecopa, CA


>>>
Lowest Temperature Sunday, September 20, 2026 – 22 degrees at Austin, NV

 

The scenic keauhou bay. These views always impresses. even in the midst of a storm watch! Hawaii nice!


World-wide Tropical Cyclone Activity

 



>>>
Here’s a link to the latest Pacific Disaster Center’s
Weather Wall




Atlantic Ocean:

Tropical cyclone 06L (Fay) is located about 405 miles southwest of the Azores

FAY MOVING SLOWLY SOUTHWARD

According to the NHC advisory number 9

Fay is moving toward the south near 5 mph. A gradual turn toward the southwest and west-southwest is expected over the next few days. Maximum sustained winds have decreased to near 50 mph with higher gusts. Continued weakening is forecast, and Fay could degenerate to a post-tropical remnant low in a couple of days. Tropical-storm-force winds extend outward up to 80 miles from the center. The estimated minimum central pressure is 1000 mb (29.53 inches).

cone graphic

 

 Caribbean Sea: There are no active tropical cyclones


Gulf of America:
There are no active tropical cyclones

 

Northeast Pacific:

Tropical cyclone 16E (Odalys) is located about 1415 miles west-southwest of the southern tip of Baja California

 

ODALYS LIKELY TO REMAIN OVER OPEN WATERS DURING THE NEXT SEVERAL DAYS

According to the NHC advisory number 6

Odalys is moving toward the northwest near 12 mph, and this motion is expected to continue through tonight. An eastward turn is forecast on Tuesday, followed by a gradual turn toward the east-northeast by midweek, and toward the northeast by the end of the week. Maximum sustained winds are near 45 mph with higher gusts. Gradual strengthening is expected, and Odalys is forecast to become a hurricane by mid-week. Tropical-storm-force winds extend outward up to 80 miles from the center. The estimated minimum central pressure is 1003 mb (29.62 inches).

cone graphic

 

Tropical cyclone 17E (Polo) is located about 255 miles south-southeast of Manzanillo, Mexico

POLO RAPIDLY INTENSIFYING OFFSHORE OF MEXICO

According to the NHC advisory number 4

Polo is moving toward the east near 5 mph. A slow eastward or southeastward motion is expected through tonight. However, a sharp turn toward the west-northwest or northwest is expected by late Tuesday. On the forecast track, the core of Polo is expected to be near the coast of southwestern Mexico during the next few days. Maximum sustained winds have increased to near 65 mph with higher gusts. Polo is expected to continue to rapidly intensify, becoming a hurricane by this afternoon and a major hurricane on Tuesday, with further intensification likely though midweek. Tropical-storm-force winds extend outward up to 70 miles from the center. The estimated minimum central pressure is 997 mb (29.44 inches).

https://www.nhc.noaa.gov/storm_graphics/EP17/EP172026_5day_cone.png

 

Central North Pacific: There are no active tropical cyclones

>>> East-southeast of the Hawaiian Islands:

(Former TD 15E)

Satellite-wind data indicate the low-level circulation of the remnants of Tropical Depression 15E has become better defined, located several hundred miles to the east-southeast of the Hawaiian Islands. Environmental conditions are forecast to become conducive for further development, and a tropical depression is likely to form around midweek while it moves slowly west- northwestward or northwestward. Interests in the Hawaiian Islands should monitor the progress of this system.

* Formation chance through 48 hours…medium…40 percent
* Formation chance through 7 days…high…90 percent 

 

>>> South of the Gulf of Tehuantepec:

An area of low pressure could form in a few days to the south of the Gulf of Tehuantepec.

Thereafter, environmental conditions appear favorable for gradual development, and a tropical depression could form late this week or this weekend while the system moves slowly west-northwestward to northwestward, parallel to the coast of southern and southwestern Mexico.

* Formation chance through 48 hours…low…near 0 percent
* Formation chance through 7 days…medium…40 percent

 

Northwest Pacific Ocean:

Tropical Cyclone 24W (Dujuan)…is located approximately 106 NM east-southeast of Yokosuka, Japan

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Southwest Pacific Ocean: There are no active tropical cyclones

North and South Indian Oceans / Arabian Sea: There are no active tropical cyclones

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Here’s the link to the Joint Typhoon Warning Center (JTWC)



Interesting: 
Study Confirms Permanent Loss of Canada’s Last Arctic Epishelf Lake

Canada’s last epishelf lake drained into the Arctic Ocean following the 2020 breakup of the Milne Ice Shelf and will not recover, a new study confirms.

Epishelf lakes form when an ice shelf acts as a dam, trapping a layer of freshwater floating above seawater connected to the ocean. The Milne Fiord epishelf lake, located on northern Ellesmere Island in Nunavut, supported freshwater microorganisms near the surface and marine species below.

In July 2020, the Milne Ice Shelf broke apart, losing 45 per cent of its area and removing the barrier that held the freshwater in place.

Read More: University of British Columbia

A former channel beneath the Milne Ice Shelf, exposed after the ice broke apart. The channel carried freshwater from the epishelf lake to the Arctic Ocean.