Glenn James
Hawaii Weather Today
Founder and maintainer for 30 years 

 

The latest update to this website was at 520pm Sunday (HST)

 

Here are the latest 24-hour precipitation totals (inches) for each of the islands as of Sunday evening:

0.02  Lihue AP, Kauai
0.04  Kahana, Oahu
0.03  Honolimaloo, Molokai
0.00  Lanai
0.04  Honolua, Maui
0.04  Kaiholena, Big Island

The following numbers represent the strongest wind gusts (mph) as of Sunday evening:

22  Port Allen, Kauai – ENE
27  Kuaokala, Oahu – NE
23  Makapulapai, Molokai – ENE
22  Lanai 1,  Lanai – NE
28  Maalaea Bay, Maui – NNE
32  Kawaihae Rd, Big Island – NNE

Hawaii’s Mountains – Here’s a link to the live webcams on the summit of our tallest mountain Mauna Kea (~13,800 feet high) on the Big Island of Hawaii, and atop the Haleakala Crater (~10,023 feet) 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

 

https://cdn.star.nesdis.noaa.gov/GOES18/ABI/SECTOR/tpw/13/GOES18-TPW-13-900x540.gif

A cold front northwest

 

https://cdn.star.nesdis.noaa.gov/GOES18/ABI/SECTOR/hi/GEOCOLOR/20260951500-20260952250-GOES18-ABI-HI-GEOCOLOR-600x600.gif

Low clouds arriving along the windward sides / higher level clouds moving by to the southeast

 

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

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

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

  Showers locally 

 

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

~~~ Hawaii Weather Narrative ~~~

 

Glenn’s Sunday comments:  I’m here in Bend, Oregon on a working vacation.

406am Hawaii time, I’m here at my friend Bob’s house. It’s clear with high cirrus clouds, with a 34 degree low. BTW, when I say Hawaii time, it is 3-hours later here in Oregon.

1021am Hawaii time, It’s sunny day here in Bend, with lots of high cirrus clouds.

135pm Hawaii time, it’s an unusually warm day here in eastern Oregon, with still some of those streaky high clouds, and a slight breeze. Bob’s boss at the college here in Bend has invited us over for dinner this evening, which will be fun. His boss has a PhD in Geology, while Bob has as Masters Degree in Geographer, and I’m, well, you know what I am. His wife and a few other friends will be joining the group, and who knows what they do for a living.

 

>>> Highest Temperature Sunday, April 5, 2026 – 98 degrees near Winterhaven, CA
>>> Lowest Temperature Sunday, April 5, 2026 – 1 degree at Peter Sinks, UT

 

Hawaii’s Broad Brush Weather Overview…as of 417pm Sunday:  Mostly dry and pleasant trade wind weather will continue into Monday, with brief passing showers favoring windward and mountain areas. A significant pattern change is then expected by Tuesday, as an upper disturbance and surface low pressure evolve northwest of the islands. This system is expected to draw deep tropical moisture northward over the state, leading to an extended period of southerly winds, increasing chances for widespread rainfall, and renewed flooding concerns from Tuesday through next weekend.

 

>>> Please note:  HEAVY RAIN AND FLOODING POTENTIAL EXPECTED LATE TUESDAY INTO NEXT WEEKEND…

A significant pattern change is expected to begin early this week as an upper disturbance and surface low pressure system evolve northwest of the islands. This system is expected to draw deep tropical moisture northward over the state, leading to an extended period of moderate to breezy southerly winds, increasing chances for widespread rainfall, and renewed flooding concerns from late Tuesday through next weekend.

Now is a good time to prepare for possible flooding impacts: – Clear gutters, storm drains, culverts, and drainage areas of debris to improve water flow – Move valuable items out of low-lying or flood-prone areas

– Check pumps, generators, and emergency equipment to ensure they are operational

– Take stock of emergency supplies, including food, water, medications, flashlights, and backup power sources

– Review family emergency plans and check on neighbors and family, especially those in flood-prone locations

Residents living near streams, rivers, gulches, valleys, ravines, and flood-prone areas should remain especially alert and be prepared to move to higher ground if flash flooding develops.

 

>>> Interesting Web blog: Mauka Showers…Is El Niño on Our Summer Bingo Card?

 

Weather Details for the Hawaiian Islands…as of 417pm Sunday: Relatively quiet weather continues across the islands, with only a few light showers embedded within moderate trade winds noted in regional satellite and radar imagery. In addition, the typical daytime increase in cloud cover has occurred over the Kona slopes of the Big Island, though little to no shower activity has been observed there. Moderate easterly trade winds will continue to focus mainly light showers along windward and mountain slopes, while leeward areas remain mostly dry through Monday.

By Monday night, trade wind flow will be disrupted as the surface ridge to the north erodes, and a broad surface trough develops northwest of the islands. As a result, weaker surface winds will begin to veer out of the southeast to south Tuesday through Wednesday. Guidance indicates that this also will mark the beginning of a series of troughs, that are expected to dig southeastward towards the Hawaiian Islands, in what will be a notable amplification and shift in the large scale pattern across the Central Pacific for the rest of the week.

As the wind flow becomes more southerly, models remain in good agreement that deep tropical moisture will be drawn northward once again over the islands, as early as Tuesday but especially by Wednesday. This increasing moisture combined with daytime heating, sea breezes, and a potent trough moving through, may even trigger some heavy showers over interior areas on Tuesday afternoon. From Wednesday through the end of the week, potential for more widespread rainfall and flooding will return.

Upper-level forcing is expected to strengthen as a strong shortwave rounds the base of the trough, potentially enhancing lift over the region, while low pressure organizes west of the islands. The combination of deep moisture, increasing large-scale forcing for ascent, and southerly winds (which could be gusty at times) all point towards yet another widespread and organized rainfall event for the state. In addition to the rainfall concerns during this period, some strong to severe thunderstorms along with gusty downsloping winds for north and windward sides of the islands can`t be ruled out.

There remain some differences among global models by next weekend, but the general consensus is that the active pattern could linger, with the potential for rain across at least portions of the state persisting through the weekend and beyond, where the deep moisture axis anchors. As previous discussions have mentioned, one important consideration with this week`s rainfall is antecedent conditions. The islands experienced significant flash flood events in recent weeks, and despite several days of drier trade wind weather, soils remain vulnerable in many areas.

As a result, any period of high rainfall rates could quickly lead to enhanced runoff, renewed rises in streams and reservoirs, and localized flash flooding concerns. This system will continue to be monitored closely over the coming days, and additional adjustments to timing, duration, and impact messaging are possible as details become more clear.

 

Here’s a near real-time Wind Profile of the Pacific Ocean – Zoom Earth – along with a Closer View of the islands / Vog map animation / 8-Day Precipitation model

https://www.weather.gov/images/hfo/graphics/npac.gif

 

Hawaii’s Marine Environment…as of 417pm Sunday: Moderate to locally fresh trades will persist during the next couple days as high pressure north of the islands moves slowly eastward. Winds will ease and shift southeasterly Monday night through Wednesday, as a front stalls and merges with a trough just west of the islands. The winds will turn more southerly and increase to moderate and strong levels on Thursday, as a storm system develops along the trough west of the state.

A series of overlapping small northwest swells will keep some small surf in place along north facing shores through Monday. A new long-period, northwest swell will fill in Monday night and Tuesday, giving a more noticeable boost to north shore surf late Tuesday through Wednesday, followed by a gradual decline Thursday into next weekend.

Overlapping southerly swells will keep some small surf in place along south facing shores through Monday. A new long duration, and slightly larger long-period south swell, will fill in Monday night. This swell will give a more noticeable boost to south shore surf Tuesday into next weekend. Strengthening southerly winds could lead to choppy conditions by late next week.

East shore surf will remain small and below climatological levels during the next 7 days, due to a lack of strong trade winds over and upstream of the islands.

 



World-wide Tropical Cyclone Activity

 

Atlantic Ocean:  There are no active tropical cyclones

Caribbean Sea:  There are no active tropical cyclones

Gulf of America:  There are no active tropical cyclones

Here’s the link to the National Hurricane Center (NHC)

 

Northeastern Pacific:  There are no active tropical cyclones

Here’s the link to the National Hurricane Center (NHC)

North Central Pacific: There are no active tropical cyclones

Here’s the link to the Central Pacific Hurricane Center (CPHC)

 

Northwest Pacific Ocean: There are no active tropical cyclones

 

Southwest Pacific Ocean: 

Tropical Cyclone 30P…is located approximately 687 NM northeast of Cairns, Australia

https://www.metoc.navy.mil/jtwc/products/30P_051200sair.jpg

 

Tropical Cyclone 31P (Vaianu)…is located approximately 290 NM northeast of Port Vila, Vanuatu

https://www.metoc.navy.mil/jtwc/products/31P_051200sair.jpg

 

North Indian Ocean:  There are no active tropical cyclones

 

South Indian Ocean: 

Tropical Cyclone 29S (Indusa)…is located approximately 1109 NM southeast of Port Louis, Mauritius – Final Warning

https://www.metoc.navy.mil/jtwc/products/29S_051800sair.jpg

 

Arabian Sea:  There are no active tropical cyclones

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

 

>>> Here’s a link to the Pacific Disaster Center’s (PDC Global) Weather Wall website

 

Interesting: Tennis courts serve up an unexpected climate solution

Tennis courts serve up a climate solution

It’s probably not what most tennis players are thinking about as they focus on the ball whizzing over the net towards them, but the court they are playing tennis on could be playing a role in combating climate change.

A new study has found that tennis courts made of green clay are able to absorb large amounts of carbon dioxide via a process called enhanced rock weathering. In the US alone, green clay courts sequester more than 25,000 metric tons of CO2 per year. And 80% of green clay courts generate net negative emissions within 10 years, according to the study published in the journal Applied Geochemistry.

Enhanced rock weathering (ERW) is an emerging strategy to address climate change. It is based on a geological process by which silicate rocks such as basalt react with CO2 and store it as carbonate minerals. That natural rock weathering happens over millions of years.

To speed up this process, ERW involves spreading crushed silicate rocks on agricultural and other land so they can react with CO2 in rainfall. Recent studies have shown that EWR has the potential to lock away many gigatons of CO2.

Turns out, green clay tennis courts in the US are made of metabasalt, known as greenstone. It is a type of rock with properties to basalt in terms of their reaction with CO2. So oceanographer Frank Pavia of the University of Washington and earth scientist Jonathan Lambert at the New York University decided to analyze just how much CO2 green clay courts sequester.

There are 698,034 tennis courts in the world, according to the International Tennis Federation. Over 91% of those are outdoor courts; over 55% are hard concrete courts, which are topped with acrylic paint, while almost 26% are clay courts.

From a database of courts in the US, the researchers analyzed data for 17,178 green clay courts. They modeled carbon removal by these courts by factoring the type of basalt used, grain size of the rocks, the court temperature, and chemical composition.

They took into account carbon emissions during mining and processing, transportation of materials to court locations, court construction, and maintenance. They also used similar models to estimate the emissions from hard courts. Clay courts have substantially lower emissions even during construction than hard courts, before you even consider EWR benefits.

According to the calculations, not only do clay courts remove about 25,000 metric tons of CO2 per year, the median time for a green clay court to become net negative for emissions is approximately 3.5 years.

Replacing existing hard courts with green clay courts could be a promising way to sequester additional CO2. “For new court construction, building a green clay court appears to have less climate impact than a hard court,” Lambert said in a press release. “This provides a great opportunity to organizations and facilities that want to reduce their emissions.”