Glenn James
Hawaii Weather Today
Founder and maintainer for 30 years 

 

The latest update to this website was at 1026am Sunday (HST)

 

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

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

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

06  Port Allen, Kauai – NNE
18  Oahu Forest NWR, Oahu – SE
21  Makapulapai, Molokai – ENE
21  Lanai 1,  Lanai – NE
25  Kealaloloa Rg, Maui – NE
32  Kealakomo, Big Island – NW

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/20260951140-20260951930-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…very few 

 

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 California.

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

 

>>> Highest Temperature Saturday, April 4, 2026 – 96 degrees at La Puerta, TX
>>> Lowest Temperature Sunday, April 5, 2026 – 1 degree at Peter Sinks, UT

 

Hawaii’s Broad Brush Weather Overview…as of 955am 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?

 

Short Term Update…as of 937am Sunday: The forecast remains on track, with moderate trade winds and mostly dry weather expected to continue over the next couple of days. The only exception is that latest satellite imagery does show a few light showers upstream of Oahu and Molokai, so a few windward showers can be expected there today. The main focus of the forecast remains on mid-late week flood potential.

Weather Details for the Hawaiian Islands…as of 304am Sunday: A relatively benign trade wind pattern remains in place across the Hawaiian Islands and is expected to persist into Monday. Moderate easterly trades will continue to focus mainly light showers along windward and mountain slopes, while leeward areas remain dry.

Global guidance remains in good agreement and depicts a notable amplification of the large-scale pattern across the central Pacific by Tuesday. The surface ridge to the north will gradually erode, as an attendant broad surface trough evolves to the west. This will disrupt the typical trade wind flow by Monday night, and allow low-level winds to gradually veer out of the southeast to south Tuesday through Wednesday.

This transition to southerly flow will draw deep tropical moisture northward into the islands beginning Tuesday and especially by Wednesday. Precipitable water values are forecast to climb toward 2 inches or higher, signaling a marked increase in moisture. This increasing moisture combined with daytime heating, sea breezes, and a potent shortwave trough moving through, may even trigger some heavy showers over interior areas on Tuesday.

Confidence is increasing that the second half of the week may present the highest potential for widespread rainfall and flooding impacts across the state. The combination of deep moisture, increasing large-scale forcing for ascent, and gusty southerly winds favors a transition toward a more widespread and organized rainfall event. 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.

Although forecast confidence begins to lower by next weekend due to model differences, the general large-scale pattern could linger. This scenario suggests the potential for rain may persist through next weekend and beyond, for at least parts of the state or where the deep moisture axis anchors.

Regardless of the precise evolution, antecedent conditions remain a significant concern. The islands have 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 heavy rainfall may 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, as additional adjustments to timing, duration, and impact messaging are likely as this change in the pattern evolves.

 

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 304am 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…is located approximately 460 NM west-northwest of Suva, Fiji

https://www.metoc.navy.mil/jtwc/products/31P_050000sair.jpg

 

North Indian Ocean:  There are no active tropical cyclones

 

South Indian Ocean: 

Tropical Cyclone 29S (Indusa)…is located approximately 755 NM east-southeast of Port Louis, Mauritius

https://www.metoc.navy.mil/jtwc/products/29S_041800sair.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.”