July 4-5, 2009
Air Temperatures – The following maximum temperatures were recorded across the state of Hawaii Saturday afternoon:
Lihue, Kauai – 84
Honolulu, Oahu – 89
Kaneohe, Oahu – 84
Kahului, Maui – 89
Hilo, Hawaii – 84
Kailua-kona – 86
Air Temperatures ranged between these warmest and coolest spots near sea level – and on the highest mountains…at 4 p.m. Saturday afternoon:
Kailua-kona – 86F
Kaneohe, Oahu – 81
Haleakala Crater – 55 (near 10,000 feet on Maui)
Mauna Kea summit – 46 (near 14,000 feet on the Big Island)
Precipitation Totals – The following numbers represent the largest precipitation totals (inches) during the last 24 hours on each of the major islands, as of Saturday afternoon:
0.24 Mount Waialaele, Kauai
0.38 Oahu Forest NWR, Oahu
0.00 Molokai
0.00 Lanai
0.00 Kahoolawe
0.13 Oheo Gulch, Maui
0.21 Glenwood, Big Island
Marine Winds – Here’s the latest (automatically updated) weather map showing a 1031 millibar high pressure system to the north of the islands. This high pressure cell, with its associated high pressure ridge, will keep the trade winds blowing through this holiday weekend…into the new week ahead.
Satellite and Radar Images: To view the cloud conditions we have here in Hawaii, please use the following satellite links, starting off with this Infrared Satellite Image of the islands to see all the clouds around the state during the day and night. This next image is one that gives close images of the islands only during the daytime hours, and is referred to as a Close-up visible image. This next image shows a larger view of the Pacific…giving perspective to the wider ranging cloud patterns in the Pacific Ocean. Finally, here’s a looping IR satellite image, making viewable the clouds around the islands 24 hours a day. To help you keep track of where any showers may be around the islands, here’s the latest animated radar image.
Hawaii’s Mountains – Here’s a link to the live webcam on the summit of near 14,000 foot Mauna Kea on the Big Island of Hawaii. The tallest peak on the island of Maui is the Haleakala Crater, which is near 10,000 feet in elevation. These two webcams are available during the daylight hours here in the islands…and when there’s a big moon rising just after sunset for an hour or two! Plus, during the nights and early mornings you will be able to see stars, and the sunrise too…depending upon weather conditions.
Aloha Paragraphs
Happy 4th of July!
The trade winds took over nicely today, becoming quite gusty in some places…as is normal for the month of July in the islands. As we move through the remainder of this 4th of July holiday weekend, these trade winds will continue to prevail. As the trade winds increase further during the new work week ahead, we’ll see the return of small craft wind advisories in our coastal waters around Maui and the Big Island at least.
Despite the returning trade winds, our overlying atmosphere remains fairly dry and stable, so that whatever showers that manage to fall…will remain on the light side generally. The leeward beaches will continue to see lots of sunshine beaming down right on through this holiday weekend and beyond. In general, this weekend shouldn’t have all that many showers…with at least the first half of the new work week remaining quite dry as well.
It’s Saturday evening here in Kula, Maui, as I begin writing this last part of today’s narrative. The 4th of July weather today was near perfect. This kept most all of our outdoor activities available. The trade winds were blowing, actually quite strong along most windward areas, lighter in general over on the leeward sides. The trades should be able to ventilate, quite quickly, whatever smoke that we have around…associated with the holiday fireworks this evening.
~~~ I went over to Baldwin Beach today, actually early this afternoon, for a long walk, and at the end…a nice swim. I noticed that the ocean is warming up nicely now, and felt so good! The trade winds were strong enough that there were lots of white caps chalking-up the sea surface. I had planned on doing some putting while I was over there in Spreckelsville, but since I’ve been putting lately on my rug downstairs, into a cup…I forgot my putter at home.
~~~ It’s a bit after 6pm as I write these last words, with the air temperature here in Kula, a warm 71.6F degrees. I noticed that it had went way up to 77.7 degrees when I got home from the beach. It’s cloudy, or at least partly cloudy up here on the slopes of the Haleakala Crater. I don’t have anything going on tonight, so I’ll just stay home and wait for the fireworks to start popping! I hope you have a great Saturday night, on this 4th of July, celebrating the freedom that we American’s have created for ourselves! I’ll be back Sunday morning with your next new weather narrative from paradise. Aloha for now…Glenn.
Interesting: Is it possible that something as insubstantial and transitory as snow could be responsible for large scale vertical movements of Earth’s surface and the excavation of deeply incised gorges? Extensive regions of the southern Rocky Mountains of the Southwestern United States have experienced more than 1.5 km of erosion over the past 10 million years, including the development of deeply incised canyons almost a kilometer deep.
And while climate change has been suspected of having a role in the removal of vast volumes of Earth’s crust, determining the specific processes responsible for the large scale erosion has proved problematic. In this month’s GSA Today article, John Pelletier of the University of Arizona has identified the likely culprit — snow.
Pelletier demonstrates that as the global climate system cooled, the fraction of total river discharge derived from snowmelt increased significantly. The result was a huge increase in the magnitude and frequency of highly erosive floods.
Snowmelt descending down from heights of 1.5 to 3.0 km swept across the Inter-montane basins, removing kilometers of rock and cutting deep gorges into the large, flat-lying basins, while the surrounding mountain peaks were left largely intact.
Pelletier’s research, demonstrating that something as fragile as snowflakes could be responsible for the chasms that slice through the Bighorn and adjacent basins, highlights the challenges involved in understanding our finely balanced Earth system.
Interesting2: Two Australian researchers have defined a newly recognized kind of explosive eruption, termed "neptunian," that is restricted to seafloor volcanoes. Sharon R. Allen and Jocelyn McPhie, of the School of Earth Sciences and Centre of Excellence in Ore Deposits, at the University of Tasmania in Hobart, Tasmania, describe their work in a new article published in the journal Geology.
These eruptions are sustained and driven by gas exsolved from magma. The explosions inject large volumes of hot pumice clasts into the seawater above the vent. The hot pumice clasts rapidly absorb water and sink, forming density currents that flow across the seafloor.
Vast areas of the modern seafloor are covered by these pumice-rich neptunian deposits. Neptunian eruptions differ dramatically from magmatic-gas-driven explosive eruptions on land, reflecting the important influence of confining pressure and the higher heat capacity, density, and viscosity of water compared to air.
Interesting3: Swine flu is running wild in the Southern Hemisphere and is spreading rapidly through Europe, with Britain projected to reach 100,000 daily cases by the end of August. The virus is even showing signs of rebounding in Mexico. World Health Organization Director-General Dr. Margaret Chan and health ministers from around the globe huddled Thursday in Cancun for a two-day summit to design strategies for battling the pandemic.
Nations attending include the United States, Canada, China, Britain and Brazil. "As we see today, with well over 100 countries reporting cases, once a fully fit pandemic virus emerges, its further international spread is unstoppable," Chan said during opening remarks.
Mexican officials wanted the meeting held in the Caribbean resort city of Cancun — where tourism has plunged — to highlight the country’s success in controlling its epidemic with a five-day national shutdown of schools and businesses in May.
The measures were applauded by the U.S. Centers for Disease Control and international health officials. "Our presence here is an expression of confidence," Chan said. "Mexico is a safe, as well as a beautiful and warmly gracious, place to visit."
But Mexico is starting to see an increase in swine flu cases in isolated areas. In southern Chiapas state and the state of Yucatan — adjacent to Quintana Roo state, where Cancun is located — cases have jumped more than 50 percent in a worrying sign that the country may see a resurgence, especially when its winter flu season begins in November.
In the space of a week ending Tuesday, the number of cases in Yucatan state jumped from 683 to 1,362, and in Chiapas from 492 to 1,079, Mexico’s Health Department said. During the same week, Quintana Roo reported 102 new cases. Yucatan and Chiapas officials blamed the spike on outbreaks in schools, which they closed a few weeks early for summer break.
Interesting4: "June is busting out all over," as the song says, and with it, U.S. residents along the Atlantic and Gulf coasts begin to gaze warily toward the ocean, aware that the hurricane season is revving up. In the decade since NASA’s QuikScat satellite and its SeaWinds scatterometer launched in June 1999, the satellite has measured the wind speed and wind direction of these powerful storms, providing data that are increasingly used by the National Oceanic and Atmospheric Administration’s (NOAA) National Hurricane Center and other world forecasting agencies. The data help scientists detect these storms, understand their wind fields, estimate their intensity and track their movement.
But tropical cyclones aren’t the only storms that generate hurricane-force winds. Among others that do is a type of storm that dominates the weather in parts of the United States and other non-tropical regions every fall, winter and into spring: extratropical cyclones. Scientists have long known that extratropical cyclones (also known as mid-latitude or baroclinic storms) sometimes produce hurricane-force winds.
But before QuikScat, hurricane-force extratropical cyclones were thought to be relatively rare. Thanks to QuikScat, we now know that such storms occur much more frequently than previously believed, and the satellite has given forecasters an effective tool for routinely and consistently detecting and forecasting them.
These storms, which occur near busy trans-oceanic shipping lanes, pose a significant threat to life and property for those on the high seas, generating high winds and waves up to 30 meters (100 feet) high. When they make landfall, in areas like Alaska, the Pacific Northwest, New England and the U.S. mid-Atlantic coast, they produce strong winds, high surf, coastal flooding, heavy rains, river flooding and even blizzard conditions.
Take the "Hanukkah Eve" extratropical cyclone of Dec. 14-15, 2006, for example. That storm viciously raked the U.S. Pacific Northwest and British Columbia with torrential rainfall and hurricane-force winds exceeding 87 knots (100 miles per hour) in spots. Dozens of people were injured and 18 people lost their lives, while thousands of trees were downed, power was knocked out for more than 1.5 million residents and structural damage topped $350 million.
NOAA defines an extratropical cyclone as "a storm system that primarily gets its energy from the horizontal temperature contrasts that exist in the atmosphere." These low pressure systems have associated cold fronts, warm fronts and occluded fronts. Tropical cyclones, in contrast, don’t usually vary much in temperature at Earth’s surface, and their winds are generated by the energy released as clouds and rain form in warm, moist, tropical air.
While a tropical cyclone’s strongest winds are near Earth’s surface, the strongest winds in extratropical cyclones are about 12 kilometers (8 miles) up, in the tropopause. Tropical cyclones can become extratropical, and vice versa. Extratropical cyclones occur in both the North Atlantic and North Pacific year-round. Those with hurricane-force winds have been observed from September through May.
Their frequency typically begins to increase in October, peaks in December and January, and tapers off sharply after March. They can range from less than 100 kilometers (62 miles) in diameter to more than 4,000 kilometers (nearly 2,500 miles) across. They typically last about five days, but their hurricane-force winds are usually short-lived–just 24 hours or less. Because they can intensify rapidly, they’re often referred to as meteorological "bombs."
Wind speeds in extratropical cyclones can vary from just 10 or 20 knots (12 to 23 miles per hour) to hurricane-force (greater than 63 knots, or 74 miles per hour). During their development, they can trek along at more than 30 knots (35 miles per hour), but they slow down as they mature. At their seasonal peak, up to eight such storms of varying intensity have been observed at once in both the North Atlantic and North Pacific.
Early work by scientists at NASA, NOAA and other organizations demonstrated the effectiveness of using scatterometers for detecting these powerful and destructive winds. Scatterometers work by sending radar signals to the ocean surface and measuring the strength of the radar signals that bounce back. The higher the wind speed, the more the ocean surface is disturbed, and the stronger the reflection that is bounced back to the satellite.
Interesting5: Besides the obvious benefits they bring, it looks like we owe our very existence to plants, which helped prevent the Earth from freezing over during the past 25 million years. About 50 million years ago, Earth was a hothouse —: the poles were ice free, and crocodiles lived in the Arctic. Then, the concentration of carbon dioxide in the atmosphere started dropping from around 1000-1500 parts per million (ppm), and the Earth began to cool.
By about 24 million years ago, the uplift of the Himalayan and Andes mountain ranges led to large-scale weathering of rocks, a process that removes massive amounts of CO2 from the atmosphere. This reduced the greenhouse effect and cooled the planet. But something kept the CO2 levels from dropping beyond a certain point, preventing Earth from turning into an icehouse.
Now, Mark Pagani of Yale University in New Haven, Connecticut, and colleagues have identified our saviours: plants. Trees play an important role in the sequestration of atmospheric CO2 in magnesium and calcium carbonate rocks. As mountains grow, rocks break down and become transported to the foothills, where trees hold them in place in the soil and break them down into minerals.
These then combine with CO2 to form, for example, limestone. The team used computer models to simulate the sensitivity of vegetation to atmospheric CO2 and climate, and found that as the CO2 concentration dropped to about 200 parts per million, the plants started starving and suffocating.
This caused a negative feedback, preventing weathered rocks from turning into carbonates, thus putting a natural brake on the sequestration process and letting CO2 levels rise again. "The carbon dioxide level came down and banged up against this lower limit, and has more or less been banging up against this lower limit for the last 20 odd million years," says team member Ken Caldeira, of the Carnegie Institution of Washington in Stanford, California. "Plants [played] a critical role in preventing the Earth from going into a deep freeze."
Interesting6: Research funded by the National Science Foundation, National Oceanic and Atmospheric Administration and the University of Washington indicates that the rain band near the equator that determines the supply of freshwater to nearly a billion people throughout the tropics and subtropics has been creeping north for more than 300 years, probably because of a warmer world, according to research published in the July issue of Nature Geoscience. If the band continues to migrate at just less than a mile a year, which is the average for all the years it has been moving north, then some Pacific islands near the equator — even those that currently enjoy abundant rainfall — may be drier within decades and starved of freshwater by midcentury or sooner.
The prospect of additional warming because of greenhouse gases means that situation could happen even sooner. The new article presents surprising evidence that the inter-tropical convergence zone hugged the equator some 3 ½ centuries ago during Earth’s little ice age, which lasted from 1400 to 1850. The authors analyzed the record of rainfall in lake and lagoon sediments from four Pacific islands at or near the equator.
One of the islands they studied, Washington Island, is about 5 degrees north of the equator. Today it is at the southern edge of the inter-tropical convergence zone and receives nearly 10 feet of rain a year. But cores reveal a very different Washington Island in the past: It was arid, especially during the little ice age. Among other things, the scientists looked for evidence in sediment cores of salt-tolerant microbes.
On Washington Island they found that evidence in 400- to 1,000-year-old sediment underlying what is now a freshwater lake. Such organisms could only have thrived if rainfall was much reduced from today’s high levels on the island. Additional evidence for changes in rainfall, were provided by ratios of hydrogen isotopes of material in the sediments that can only be explained by large changes in precipitation.
"If the inter-tropical convergence zone was 550 kilometers, or 5 degrees, south of its present position as recently as 1630, it must have migrated north at an average rate of 1.4 kilometers — just less than a mile — a year," Sachs says. "Were that rate to continue, the inter-tropical convergence zone will be 126 kilometers — or more than 75 miles — north of its current position by the latter part of this century."
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