9 Regional Weather Terms You May or May Not Know

Is it a hurricane, typhoon, or tropical cyclone? Read on to learn about this and other regionally-inspired weather terms. Image: Wikimedia Commons.
Is it a hurricane, typhoon, or tropical cyclone? Read on to learn about this and other regionally-inspired weather terms. Image: Wikimedia Commons.

In the course of conversations about last week’s polar vortex (or lack thereof), several of us GeekMoms began to discuss some weather terms that are unique to our own cultures. Thanks to those discussions (and some time I’ve spent forecasting in Europe, Asia, and the Middle East) I thought it’d be fun to share some weather terms that are uniquely American…or Canadian…or Korean…or Middle Eastern.

Many of you might look at these terms and be surprised at how regional they actually are.

Sleet/Ice Pellets

Like I did with my polar vortex post, I will be referring to the American Meteorological Society’s online Glossary of Meteorology for most definitions. The glossary does a great job delineating between the American and Commonwealth definitions of “sleet”.

sleet

  1. See ice pellets.
  2. In British terminology, and colloquially in some parts of the United States, precipitation in the form of a mixture of rain and snow.

Wait a second, what’s that? It quickly refers us to the definition of ice pellets. 

ice pellets

A type of precipitation consisting of transparent or translucent pellets of ice, 5 mm or less in diameter.

What you’re seeing is a pure terminology difference. American meteorologists will refer to precipitation that falls as ice pellets as “sleet” while many other nationalities will refer to sleet as a rain/snow mix.

For what it’s worth, there is no official METAR (weather observation) coding for the term “sleet”. Ice pellets are coded “PL” while a rain/snow mix will be “RASN”.

Monsoon

How many people know that a monsoon is a wind? Generally it’s any seasonal wind, wet or dry. Although more often it’s associated with the winds that bring wet weather (I’ll cover the dry seasonal winds next).

A monsoon is not the heavy rain itself! The general public often associates the monsoon with heavy rain merely because the shift in the wind brings the moisture up from the oceans. The media will report on some of the devastation that comes from the monsoon-related heavy rains.

The term “monsoon” itself is regional and most often is associated with the Indian Ocean monsoon that brings heavy rains to India and Bangladesh. In other parts of the world this shift in the wind that brings seasonal rains is called:

  • Korea: Changma
  • China: Meiyu
  • Japan: Bai-u
  • Australia: The Wet
  • Southwestern United States: Summer or Desert Monsoon

Foehn/Chinook

A “foehn” is also a type of wind. Similarly, depending on where you live, that wind will go by different names. First, the definition.

foehn

(Or föhn.) A warm, dry, downslope wind descending the lee side of the Alps as a result of synoptic-scale, cross-barrier flow over the mountain range.

That’s the European term. But here are some other similar downslope winds whose names you might be more familiar.

Humidex/Heat Index

This term was completely new to me, introduced by GeekMom Jules a couple weeks ago as we were discussing other weather terms that are regional in nature. The humidex is similar to—but not the same as—the Heat Index that Americans are more familiar with. The humidex was developed by Canadian meteorologists J.M. Masterton and F.A. Richardson of Canada’s Atmospheric Environment Service in 1979 and is still used as the standard value for demonstrating how hot the weather feels to an average person.

HumidexFormula
Image credit: Wikipedia Commons.

 

The humidex is calculated with a temperature value and a dewpoint. A few variations exist between the Canadian and American calculations, such as how the “base” dewpoint in Canada is 45 degrees F, while in the U.S. it’s 57 degrees F. This is a subjective indication of “comfort” between Americans and Canadians, I’m sure.

Frost Quakes

This is another relatively new term for me, but it did make headlines after early January’s <lobe of a> polar vortex event. Frost quakes, known scientifically as cryoseisms, occur when a quick freeze of ground water triggers cracking of the soil, explosion-like “booms”, and underground vibrations. It happens more often in Canada, but earlier this month was also being reported in Wisconsin, Vermont, and Illinois.

Thundersnow

I was intrigued to learn how few people had heard of “thundersnow”. This definition should be intuitive: snow with thunder and lightning. However, one will find that thundersnow is rare. In fact, even well-seasoned-meteorologist Jim Cantore was caught by surprise in Chicago during a February 2011 blizzard.

There’s usually a trigger occurring in the weather system that allows the mechanisms that are similar to thunderstorm development. In other words, an upward “lift” or “force” of some sort is required. Most reports of thundersnow come from the Great Lakes region, where the relatively-warmer lakes can force an unstable atmosphere which in turn causes the electrification of the winter storm. Terrain can also provide this forcing, with thundersnow events happening in the White Mountains of New Hampshire, Rocky Mountains, and Olympic Mountains of Washington state.

Hurricane/Typhoon/Tropical Cyclone

“What? You’ve GOT to be kidding me! Doesn’t everyone know what a hurricane is?”

I learned this pretty early on in my weather geekery, but to most in North America, it might be surprising to learn that the term “hurricane” is exclusive to North America.

From the AMS Glossary of Meteorology:

hurricane

tropical cyclone with 1-min average surface (10 m) winds in excess of 32 m s-1 (64 knots) in the Western Hemisphere (North Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern and central North Pacific east of the date line).

The name is derived from “Juracán,” a Taino and Carib god, or “hunraken,” the Mayan storm god.

In the western Pacific, they’re called “typhoons”.

typhoon

A severe tropical cyclone in the western North Pacific.

The name is derived either from Cantonese t’ai fung (a “great wind”), from Arabic tufan (“smoke”), or from Greek typhon (a “monster”). Aristotle used typhon for a wind-containing cloud (Meteorologica, III, 1).

In the rest of the world, they’re simply “tropical cyclones”, which is what’s taught as the generic term for a cyclone that forms in the tropics.

Shamal/Haboob

Another kind of wind. For readers who have served, or have had loved ones serve, in Iraq, this term will be associated with the dust that is kicked up. However, the term itself actually means the wind, not the dust:

shamal

The northwest wind in the lower valley of the Tigris and Euphrates and the Persian Gulf.

It may set in suddenly at any time, and generally lasts from one to five days, dying down at night and freshening again by day; however, in June and early July it continues almost without cessation (the “great” or “forty-day” shamal). Although the wind rarely exceeds 13 m s-1 (30 mph), it is very hot, dry, and dusty. The sky is cloudless but the haze is often so thick as to obscure the land, making navigation dangerous.

A haboob or shamal in southwest Asia. Photo: Jim Leurck, used with permission.
A haboob or shamal in southwest Asia. Photo: Jim Leurck, used with permission.

There are other terms that also are associated with dust storms, such as haboob, which is the term that’s more familiar to Americans, because of their happening in the desert southwest. “Haboob” is from the Arabic word for “blasting” or “drafting”, and was originally given to duststorms in the Khartoum region of Sudan.

Yellow Wind/Mineral Dust

This is but one of a number of regional terms that are related to desert dust that gets picked up and carried great distances to deposit on different landmasses and/or continents.

I learned about the “yellow wind” while I was stationed in Korea, which in my case referred to Gobi desert dust being carried from western China and eastern former Soviet republics. It would deposit over the Korean peninsula and make things downright filthy for several days in the spring months. It is also called Asian dust, yellow sand, and yellow dust. If conditions are right, yellow wind dust particles have been known to make it all they way to the United States.

Further west, the dust can get carried to the Sahara desert northward into Europe, or westward across the Atlantic. This is called “mineral dust” but is the same thing.

Hopefully you’ve been enlightened today with how weather terms can be as varied by region as “soda”, “pop”, or “Coke”. Can you think of any other regional weather terms?

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Patricia Vollmer is the proud mother of two emerging geek sons, ages 12 & 14. She serves part time as a meteorologist with the Air Force Reserve and is currently assigned to the U.S. Air Force Academy. Patricia blogs about her family's nomadic military life at Ground Control to Major Mom. Home is always where the Air Force sends her family, which for now is in Colorado Springs, Colorado. Hobbies include running, despite no one chasing her, sharing her love for Disney and Star Wars, and exploring the world with her boys. Ask her why the sky is blue at your own risk.