Hawaiian Islands Weather Details & Aloha Paragraphs / July 20-21, 2017

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

87 – 75  Lihue, Kauai
87 – 75  Honolulu, Oahu
90 – 77  Molokai
89 – 76  Kahului AP, Maui
85 – 75  Kailua Kona
84 – 70  Hilo AP, Hawaii

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

1.55  Mount Waialeale, Kauai
0.659  Moanalua, Oahu
0.11  Molokai
0.00  Lanai
0.00  Kahoolawe
0.53  West Wailuaiki, Maui
2.20  Saddle Quarry, Big Island

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

30  Port Allen, Kauai
31  Kuaokala, Oahu
29  Molokai
32  Lanai
42  Kahoolawe
36  Kahului AP, Maui
38  Pali 2, 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. This webcam is 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

Tropical Storm Fernanda with Tropical Storm Greg to the east / along with a gale low pressure system well to the west-northwest of the islands

Fernanda spinning…with thunderstorms restricted to the northeast quadrant

Fernanda will weaken further to a remnant low by Saturday morning

 

Fernanda’s weakening cloud swirl…to the right of the islands

Clear to partly cloudy…some cloudy areas locally

Showers mostly windward and mountains…over and around the eastern islands
Looping radar image

Small Craft Advisory…windiest coasts and channel around Maui County and the Big Island

High Surf Advisory…east shores of Maui and the Big Island

Special Weather Statement…Coastal Flooding Possible:

Coastal flooding associated with king tides will be a possibility during the next few days. The greatest potential for coastal flooding impacts will be during the mid to late afternoon hours through Monday, when the highest tides are expected.

Note that east swell energy, which was generated by Tropical Cyclone Fernanda, will produce elevated surf along east facing shores through this weekend. This will likely cause greater wave run-up along some exposed windward coastlines, especially during high tide.

Impacts of the king tides may include flooding of beaches that are normally dry, salt water inundation of typically vulnerable low-lying roads, docks, boat ramps and other coastal infrastructure. The potential threat for coastal flooding will eventually be reduced early next week as the peak daily tides diminish.

 

~~~ Hawaii Weather Narrative ~~~

 

Broad Brush Overview: High pressure to our north will keep gusty trades active through Friday. These trades will soften some this weekend as this broad area of high pressure weakens. A band of moisture riding in on the trades will move through this morning, with drier conditions then expected this afternoon through Friday. Tropical moisture will overspread the islands this weekend, leading to increased humidity…and increasing showers locally. The weather early next week depends on what happens with the remnants of Fernanda, expected to pass not far north of the islands Monday. Fernanda will likely weaken our winds, and bring very muggy conditions for a couple of days.

Details: The weather details this weekend hinge on the track of Fernanda’s remnants, which the models show tracking by to the north of the island chain. The trade winds will trend down Friday night through the weekend, as high pressure north of the state weakens, and the remnants of Fernanda approach from the east. Deep moisture from the east will move across the islands Friday night, with humid, tropical conditions remaining in place through the weekend. As a result, we should see an increase in showers primarily over windward areas, as the trades continue to hold on marginally. There will also likely be some leeward shower development during the afternoons…into the evening hours through the weekend.

Looking Ahead: As the remnants of Fernanda pass by to the north of the islands Sunday night through next Tuesday morning, our trades will weaken further, allowing for sea breeze development in most areas. These light winds may continue into Tuesday, before the remnants of Fernanda pass away northwest of the islands…and high pressure strengthens north of the state. This will allow for a return of moderate trade winds by the middle of next week. The models show moisture associated with Fernanda passing by to the north of the islands, although with the humid conditions and light winds in place, afternoon and evening upcountry showers are expected during the first couple of days of next week. Drier, less humid, and more stable conditions are then expected to return by Wednesday.

Tropical Storm Fernanda will continue moving west through the central Pacific, and as a result…the Hawaiian Islands will need to keep an eye on it. Fernanda will be losing strength quickly as it moves closer. It’s still too early to know exactly what influence this storm could have on the islands, as it moves into the area northeast of the state later this weekend, although high surf generated from this storm will be breaking along our east shores will continue. Whatever is left of Fernanda [the current strong winds will be long gone], may bring clouds and showers, some of which may be locally heavy. As Fernanda moves to the northeast and then north of Hawaii, it should cut off our trade winds…bringing very sultry conditions into the state for a day or two.

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: A surface ridge of high pressure north of the state will maintain moderate to locally strong trade winds through Friday night. The trades will continue to produce Small Craft Advisory (SCA) conditions through tonight across the Oahu leeward waters, the waters surrounding Maui County, and the Kaiwi Channel, in addition to the typically windy waters adjacent to the Big Island. The SCA is expected to remain in effect at least through Friday night for the typically windy waters of Maui County and the Big Island. The latest forecast for Tropical Storm Fernanda continues to indicate it will weaken to a post-tropical remnant low, that will pass north of the islands early next week. As this area of low pressure approaches the area, expect the trade winds to weaken this weekend. The flow will likely become much lighter early next week, depending on the exact track the remnant low takes as it passes by.

An east swell generated by Fernanda when it was a major hurricane this past weekend, is evident at all of the near shore buoys with an east exposure in the Hawaiian Islands. A High Surf Advisory has been issued for elevated surf along east facing shores of the Big Island and Maui through this afternoon. The smaller islands west of the Big Island and Maui will likely be shadowed from most of this east swell energy. The model guidance continues to indicate reinforcing east swell energy arriving along east facing shores of the Big Island starting Friday. This east swell will continue to build and spread across the remainder of the state through this weekend. As a result, surf will likely reach the High Surf Advisory criteria again initially along the east facing shores of Maui and the Big Island starting late Friday or early Saturday. Ultimately, most east facing shores of the state will likely be in the High surf Advisory from some time this weekend into Monday.

The largest high tides of the month (king tides) will occur each afternoon during the next several days. Note that these abnormally high tides, combined with wave run up due to the east swell produced by Fernanda may result in coastal flooding in some areas…especially from Friday into Monday.

Elsewhere, no significant swells are expected. Small south swells will continue to produce small surf along south facing shores into next week.

 
Larger surf east shores…generated by Fernanda

>>> Southern California Weather Brief: Expect night through morning low clouds to persist across most coastal areas and possibly into portions of coastal valleys at times. High pressure will continue to dominate the weather pattern with slightly higher than normal temperatures for inland areas through Saturday. A weak upper trough will move close to the forecat area allowing some modest cooling through early next week with the possibilty of monsoonal moisture affecting the local mountains and deserts. A warming trend expected by mid week.

Mostly clear inland…low clouds offshore

 

>>> San Francisco Bay area weather brief:  A building ridge of high pressure will lead to warmer temperatures into the weekend…cooling is then expected early next week.

Low clouds offshore…locally inland

World-wide tropical cyclone activity

>>> Atlantic Ocean: No active tropical cyclone

No tropical cyclones are expected during the next 5-days

>>> Caribbean: No active tropical cyclone

No tropical cyclones are expected during the next 5-days

>>> Gulf of Mexico: No active tropical cyclones

No tropical cyclones are expected during the next 5-days

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:

Tropical Storm Greg remains active, here’s a graphical track map, a satellite image…and what the computer models are showing

1.) A broad area of low pressure centered several hundred miles south of the southern tip of the Baja California peninsula is producing disorganized showers and thunderstorms. Environmental conditions are forecast to be conducive for the formation of a tropical depression during the next couple of days before upper-level winds become unfavorable for development. This system is forecast to move westward to west-northwestward at around 10 mph through early next week.

This disturbance is being referred to as Invest 99E, here’s a satellite image…and what the computer models are showing

* Formation chance through 48 hours…high…70 percent
* Formation chance through 5 days…high…80 percent

2.) Showers and thunderstorms have become better organized in association with a tropical wave over the far eastern Pacific southwest of Central America. Environmental conditions are forecast to become increasingly favorable for development, and a tropical depression is likely to form later today or tomorrow while the system moves west-northwestward at 10 to 15 mph.

This disturbance is being referred to as Invest 90E, here’s a satellite image…and what the computer models are showing

* Formation chance through 48 hours…high…70 percent
* Formation chance through 5 days…high…90 percent

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: 

Tropical Storm Fernanda remains active, here’s the  track map, a satellite image…and what the computer models are showing.

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

>>> Northwest Pacific Ocean:  

Tropical Storm 07W (Noru) is active, here’s a graphical track map, a satellite image…and what the computer models are showing.

Tropical Depression 08W is active, here’s a graphical track map, a satellite image…and what the computer models are showing.

Tropical Storm 09W (Kulap) is active, here’s a graphical track map, a satellite image…and what the computer models are showing.