Weather Around The World 8/12/14: Tropics; El Nino; Southern Hemisphere


Home / Weather Around The World 8/12/14: Tropics; El Nino; Southern Hemisphere
Africa weather

The easterly waves off the African coast have a low probability of developing. The large thunderstorm complex in the middle of Africa is the next system to watch. Image courtesy of NOAA

Attention will be riveted on the tropics for the next few weeks, but right now they are relatively quiet after last week’s fireworks.

The probability of an El Niño is still better than even money, but not as high as it was last month. And it’s the dead of winter Down Under. Let’s go around the world.

Tropics Die Down — Temporarily

After last week’s insane activity, most tropical storms are in the rear-view mirror. Still, tropical cyclone climatic maximum is still nearly a month away. Here’s a review of recent storms and a look ahead.

Atlantic Ocean:

Bertha put on a good show, staving off dry air and hostile winds to become the Atlantic season’s second hurricane. Dry Saharan air has become re-established over much of the Atlantic; the only disturbance is given just a 20% chance by the National Hurricane Center (NHC) of becoming a named storm.

Looking further into the future, there is a very active system in the center of Africa, which could become the center of attention next week after it enters the ocean near the Cape Verde Islands.

Eastern Pacific Ocean:

The twin terrors that threatened Hawaii originated in the warm water south and southwest of Mexico. The next cause for concern is a disturbance moving westward over that warm pool. The NHC gives this system a 90% chance to get a name.

Central Pacific Ocean:

Hurricane Iselle was downgraded to a tropical storm just before it made landfall on Hawaii. Flooding and minor damage was widespread, but the second storm, Hurricane Julio, veered off to the north and only caused a few gusts and some sprinkles.

Genevieve was one of the most remarkable storms ever to affect two jurisdictions. After simmering along in the eastern Pacific, waffling among being a tropical storm, a tropical depression, and an open wave, Genevieve suddenly perked up after passing well south of Hawaii, and finally got its act together, becoming a hurricane for a few hours.

Genevieve did not cease being a hurricane because it weakened, but because it crossed the International Date Line,  180° longitude, after which it was officially called a typhoon. Genevieve eventually became a Super-Typhoon, traveling over open ocean before dissipating over the cold waters of the north Pacific.

Western Pacific Ocean

Typhoon Halong was the second former Super-Typhoon to affect Japan this year (the other was Neoguri). Halong was no longer a Super-Typhoon when it made landfall, but winds gusted over 100 miles per hour, and more than three feet of rain fell in mountainous regions. One death and 30 injuries were attributed to Halong, which is now long gone.

Remarkably, there are currently no threatening-looking systems in the western Pacific.

El Nino Update

As of August 7, NOAA has lowered the probability of an El Niño this fall and winter to 65% from 80%. Water temperature anomalies across the Pacific are still positive, but the steady increases have stalled.

El Niño forecast

NOAA’s water temperature forecast for next winter. If it is correct, there will be an El Niño. Image courtesy of NOAA

It is not unusual for an El Niño to come on in fits and starts, so most forecasters are predicting a weak to moderate El Niño in the fall and winter. There has not been a strong El Niño since 1992.

Dead Of Winter In The Southern Hemisphere

August is midwinter below the equator. Since the earth is at aphelion (farthest from the sun) in July, and perihelion (closest to the sun) in January, the northern hemisphere receives more solar radiation during its winter than the southern hemisphere does during its winter. So one might expect the southern hemisphere’s winter to be harsher.

However, the moderating effect of the southern hemisphere’s oceans, which comprise 80% of the surface area as compared to 60% in the northern hemisphere, keeps temperatures comparatively mild.

As an example, Queensland, New Zealand, at 45 degrees south latitude, has an average high temperature of 50° in August; Montreal, Canada, at 45 degrees north latitude, has a high temperature average of 25° in the comparable month of February.

Look At The Weather

You don’t have to travel to far-off places to find fascinating weather. Just look around you. What’s the weather like where you are?


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