Weather Around The World: Tropical And Extra-Tropical Weather Collide

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The weather map for early Tuesday shows the remains of Hurricane Gonzalo north of Scotland. To the south, a non-tropical low is near the Canary Islands. Analysis courtesy of NOAA

The weather map for early Tuesday shows the remains of Hurricane Gonzalo north of Scotland. To the south, a non-tropical low is near the Canary Islands. Analysis courtesy of NOAA.

Fall is the time when the tropics and the mid-latitudes interact the most — weatherwise. This week there are four systems that could be considered hybrids.

They’re found in the Atlantic Ocean, Gulf of Mexico, and Pacific Ocean.

There will also be the first nor’easter on the Atlantic coast; hail fell in Australia; and of course, the forecast for the World Series. Let’s go Around The World.

How The Atmosphere Works

The atmosphere is a giant heat engine. Heat is constantly being transferred from the equator to the poles (otherwise the planet would be unlivable except in a narrow strip in mid latitudes). The two most prominent transfer mechanisms both rely on a lowering of potential energy:

  • In the mid-latitudes, storms redistribute the heat so that warm air lies on top of cold, which releases the potential energy of warm air next to cold.
  • In the tropics, water vapor molecules condense into water droplets, releasing the latent heat of condensation.

In both cases, prevailing winds transport heat energy poleward. The atmosphere doesn’t seem to care which way it accomplishes the goal of heat transfer, so storm systems can do one or the other — or both.

Hurricane Gonzalo Beats Up Bermuda Then Wallops Wales

Gonzalo was the sixth hurricane of the Atlantic season and the second major hurricane (winds over 115 miles per hour). Gonzalo scored a direct hit on Bermuda, with category three winds of 120 miles per hour, then raced past the tip of Newfoundland, whirled across the Atlantic, all the while transitioning to an extra-tropical cyclone.

Gonzalo Gone Wild is currently whipping much of the still-United Kingdom, especially northern Wales, with gale force winds. Exposed coastal areas could experience gusts to near hurricane force.

Hurricane Ana Douses Hawaii With Record Rain

Tropical Storm Ana has passed the Hawaiian Islands. Eventually it will hit the western US and Canada as an extra-tropical cyclone. Forecast courtesy of US Navy

Tropical Storm Ana has passed the Hawaiian Islands. Eventually it will hit the western US and Canada as an extra-tropical cyclone. Forecast courtesy of US Navy.

This has been the busiest tropical storm season for Hawaii since meteorologists began keeping records; Ana was the third tropical system to affect the island chain.

Though Ana veered south of its original forecast track, the storm produced torrential rain in many locations, often doubling the daily records and the monthly averages.

Ana was downgraded to a tropical storm as it passed south of Honolulu, but forecasters expect it to remain a strong tropical storm  as it turns north. When the jet stream picks up Ana, it will undergo a transition to an extra-tropical cyclone and head for the west coast of North America.

Invest 93-L, A.K.A. Tropical Storm Trudy

Occasionally a tropical system crosses from one jurisdiction to another. The remnants of Tropical Storm Trudy — which formed last week in this year’s breeding ground for tropical systems south of Mexico and hit the coast with flooding rains — crossed into the Gulf of Mexico.

Trudy is now Invest 93-L, which means it is worth investigating, and if it becomes strong enough to warrant a name, there is the question of whether that name should be Trudy, or the next name on the Atlantic list — Hanna.

Whatever the name, the system is likely to merge with a frontal boundary located in the eastern Gulf of Mexico. Eventually the storm could impact the east coast of the United States as an extra-tropical cyclone, but current forecasts take it across Cuba and into the Caribbean.

Invest 92-L Dumps Heavy Rain On The Canary islands

The process of transition can go both ways. A large non-tropical low pressure system currently located near the Canary Islands could become tropical, or at least acquire some tropical characteristics, as it drifts westward over warm water. Storms like this are unusual, and there is no consensus on how or whether it will develop. The Canary Islands have already received record-breaking amounts of precipitation.

World Series Weather In Kansas City And San Francisco

Let’s get to the important stuff. What will the weather be as my Kansas City Royals face the San Francisco Giants in the World Series, which begins tonight in Kansas City? It appears that Major League Baseball will luck out; no rainouts are in the forecast. In fact, good baseball weather is now predicted for all games. Go Royals!

Golf-Ball-Size Hail Down Under

Perth, Australia experienced a rare hailstorm on Saturday. It was just a reminder that even in the summer the weather at this latitude can get nasty. A thousand miles out in the Indian Ocean, where seas are often turbulent, those searching for missing airliner MH370 are hoping for some (relatively) tranquil weather.

First East Coast Nor’easter Likely Thursday And Friday

The east coast of the United States is famous for its storms. The name, nor’easter, even sounds fierce. The name derives from the direction of the prevailing wind , which can reach hurricane force, as the storm travels up the coast.

A nor'easter is forecast to affect New England on Thursday. Forecast courtesy of NOAA

A nor’easter is forecast to affect New England on Thursday. Forecast courtesy of NOAA.

Currently  the forecast calls for a slow-moving storm to hit the mid-Atlantic on Wednesday, reach southern New England on Thursday, and only slowly exit the coastal waters on Friday night. Winds could gust to tropical storm force (39 miles per hour).

This storm comes at the time of the new moon, which means elevated ‘spring’ tides. (Spring tides occur at the time of new and full moon when the gravitational forces of the sun and moon align.) Flooding is likely along the coast, especially in areas exposed to a long northeast fetch: from Boston to Plymouth and on Outer Cape Cod.

But coastal residents should count their blessings. The full moon tides are much higher right now because the moon is closer to earth in its elliptical orbit at the time of the full moon.

This storm will be the first real meteorological omen of winter in the east. What signs do you see that winter is approaching in your neighborhood?

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