Hawaiian Islands Weather Details & Aloha Paragraphs / April 6-7, 2018

Air Temperatures – The following high temperatures (F) were recorded across the state of Hawaii Friday…along with the low temperatures Friday:

76 – 70  Lihue, Kauai
84 – 73  Honolulu, Oahu
80 – 71   Molokai AP
80 – 73  Kahului AP, Maui
86 – 74  Kailua Kona
85 – 74  Hilo AP, Hawaii

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

0.76  N Wailua Ditch, Kauai
0.87  Moanalua RG, Oahu
0.67  Molokai
0.61  Lanai
0.35  Kahoolawe
2.71  Kahakuloa, Maui
1.86  Puu Mali, Big Island

The following numbers represent the strongest wind gusts (mph) Friday evening:

18  Port Allen, Kauai
37  Kuaokala, Oahu
28  Molokai
29  Lanai
35  Kahoolawe
28  Kapalua, Maui
36  Kohala Ranch, Big Island

Hawaii’s Mountains – Here’s a link to the live webcam on the summit of our tallest mountain Mauna Kea (nearly 13,800 feet high) on the Big Island of Hawaii. Here’s the webcam for the 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.

Aloha Paragraphs

A cold front has slipped into the state

A southwest to northeast oriented cloud band is over parts of the state

Clear to partly cloudy…cloudy areas

Showers locally…especially over and around the Big Island
Looping image

 

~~~ Hawaii Weather Narrative ~~~

 

Flash Flood Watch…all islands this weekend

 

Broad Brush Overview: Showers will remain in the forecast through the weekend, with even a few possible thunderstorms…as a cold front stalls near the Big Island. A return of the trade winds has occurred, which will focus clouds and showers over the windward sides…although not exclusively. Improving conditions with a drying trend is likely Sunday night through early next week, especially over the Kauai side of the island chain.

Details: Satellite imagery shows a cold front having slowed to a stop near the Big Island. Radar showed showers developing along this boundary over parts of Maui County and the Big Island. Moderate to breezy northerly winds have filled in over Kauai and Oahu. This new weather change will continue…as the front stalls near the Big Island.

The slightly cooler northerly winds over the western end of the state, will veer northeast in the wake of the front. A return of trades, along with lingering moisture, will keep off and on showers active, especially over windward sides of Maui County and the Big Island. An approaching trough will enhance these showers to some degree Saturday and Sunday…statewide.

Looking Ahead:  Sunday night through early next week, breezy trades and a gradual drying trend will become a possibility. The lingering moisture however, will keep the rain chances alive over the eastern end of the state into next week. In sum, with the return of our trade winds, we’ll face periodic bouts of passing showers along our windward sides…although the leeward sides will get into the act at times too.

Here’s a wind profile of the Pacific Ocean – Closer view of the islands / Here’s the vog forecast animation / Here’s the latest weather map

Marine environment details: The trades will be here through at least next week. They will become breezier on Monday, as a strong surface high settles in northwest of the islands. A small Craft Advisory (SCA) will likely be issued Monday for these strengthening winds.

A series of northwest swells will be rolling in throughout this forecast period. The first of the series is slated for tonight, at near advisory level for the north facing shores. The surf will gradually lower late Saturday into Sunday. Then a series of overlapping northwest swells arrives early Monday morning…with advisory level surf for along the north and west facing shores of most islands. A smaller pulse from the northwest is due to arrive Thursday.

Surf along east facing shores may rise slightly over the weekend but especially by the middle of next week with the breezy trades. Waters will become rather rough and choppy due to this trade wind swell.

Surf along south facing shores will remain small with very little activity shown within Hawaii’s swell window over the south Pacific over the next few days.

 

The long absent trade winds are returning

World-wide Tropical Cyclone activity

Here’s the latest Pacific Disaster Center (PDC) Weather Wall Presentation covering a tropical disturbance being referred to as Invest 91P near Vanuatu

>>> Atlantic Ocean:

>>> Caribbean Sea:

>>> Gulf of Mexico:

Here’s a satellite image of the Caribbean Sea…and the Gulf of Mexico

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

>>> Eastern Pacific:

Here’s a wide satellite image that covers the entire area between Mexico, out through the central Pacific…to the International Dateline.

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

>>> Central Pacific:

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

>>> Northwest Pacific Ocean: No active tropical cyclones

>>> North and South Indian Oceans / Arabian Sea: No active tropical cyclones

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


Interesting: NASA Hopes Supersonic X Plane Will Deliver Less Bang For The Buck – NASA is building a new X plane with the goal of deadening the loud thunderclap that jets make when they travel faster than sound.

Those noisy sonic booms are one of the reasons supersonic planes aren’t used commercially today.

The Low-Boom Flight Demonstration program will build the new experimental aircraft and then fly it over cities to see if it’s quiet enough to satisfy residents and regulators.

The reason supersonic aircraft generate sonic booms is complicated, but there’s a simple way to think about it: “A sonic boom happens because the air doesn’t know the airplane is coming,” says Peter Coen, manager for the Commercial Supersonic Technology Project in NASA’s aeronautics mission directorate.

When a plane travels toward you at speeds below the speed of sound, you can hear it coming because the sound wave is moving faster than the plane. But when the plane breaks the sound barrier, it slams into the air without any warning. This creates multiple shockwaves.

Those shockwaves converge as they travel to the ground, causing what sounds like a bang. But by making small adjustments in the shape of the nose or canopy or wings, you can smear out that shockwave, “so instead of a bang, you just hear a thump,” he says.

The main feature of this new, supersonic test plane will be a long pointy nose. “Supersonic aircraft tend to be long and slender,” says Coen. “Low boom supersonic aircraft is that to an extreme.”

Designers are also thinking about the environment the new plane will fly in. Aeronautical engineer Douglas Hunsaker of Utah State University uses computers to estimate how supersonic shockwaves move through the air. He says weather can be a big factor in the size of a boom. “In fact humidity affects it a lot,” he says.

Hunsaker says his colleagues at Texas A & M University are testing metal alloys that would allow a plane to change shape in the air that would mitigate the sonic boom depending on changing weather conditions. That work is separate from the NASA project announced this week.

The new X plane is the first experimental jet built by NASA in more than a decade.

“The thing that I’m most excited about is that NASA is moving back to this X plane concept,” says Bobby Braun, dean of engineering at the University of Colorado in Boulder. He says experimental planes have been crucial to advancing aviation.

There’s been no commercial supersonic travel since the European-built Concorde passenger aircraft was retired in 2003. But Braun believes it may make a comeback.”It wouldn’t surprise me at all, if say 10 years from now, starting with supersonic business jets, and then moving into larger commercial aircraft that we’re back flying supersonically,” says Braun.

NASA has signed a $247.5 million contract with Lockheed Martin Aeronautics Company of Palmdale, California to build the new X plane. The agency expects delivery by the end of 2021.