Communities along the coasts of all the world’s oceans are at risk from tsunamis. Tsunamis are one of nature’s most powerful and destructive forces. Although they occur relatively infrequently, and most are small and nondestructive, tsunamis are a serious threat to life and property. Since 1850, tsunamis have claimed hundreds of thousands of lives and…

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A moonbow, also known as a lunar rainbow, is a rainbow produced by moonlight rather than direct sunlight. Other than the difference in the light source, its formation is the same as for a solar rainbow. It is caused by the refraction of light in many water droplets, such as a rain shower or a…

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Mammatus clouds, meaning “mammary cloud”, is a cellular pattern of pouches hanging underneath the base of a cloud.  They are most often associated with cumulonimbus clouds and severe thunderstorms, although they may be attached to other classes of parent clouds. The name mammatus is derived from the Latin mamma, which means “udder” or “breast”. They are formed by cold…

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The practice of naming tropical storms and hurricanes dates back decades. The first known meteorologist to assign names to tropical cyclones was Clement Wragge, an Australian meteorologist, who began giving women’s names to storms before the end of the 19th century. In 1953, the United States abandoned a confusing two-year old plan to name storms…

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As August arrives, here’s a breakdown of the 30 year climatology and some of the official records for Pittsburgh. Climatology *Average High is 81 degrees *Average Low is 61 degrees *Average Rainfall is 3.48″ We will lose 70 minutes of daylight from August 1st until the 31st. Records *Hottest Daily High – 103 on 8/6/1918…

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Dog in the Pool - Frank Skrajny

The “Dog Days” of summer last from July 3 to August 11. What are the Dog Days, exactly? Here is the explanation according to the Old Farmer’s Almanac. The term “Dog Days” traditionally refers to a period of particularly hot and humid weather occurring during the summer months of July and August in the Northern Hemisphere. In ancient Greece…

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Erie Sunset -- Lynda Sabo

According to climatology, July is the warmest month of the year with an average daytime high of 83 and an average nighttime low of 63 degrees. Over the 31 days, the typical rainfall total is 3.83″ and, perhaps, the worst stat of all, we will lose 41 minutes of daylight by August 1st. July is…

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Moraine State Park #3 -- Chris Condello

You may have noticed that meteorologists and climatologists define seasons differently from “regular” or astronomical spring, summer, fall, and winter. So, why do meteorological and astronomical seasons begin and end at different times? In short, it’s because the astronomical seasons are based on the position of Earth in relation to the sun, whereas the meteorological…

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May in Western Pennsylvania certainly had it’s fair share of up and downs. As you may recall the first two weeks of the month were more winter-like than springtime. It truly was a tale of two seasons. The first 13 days the average high temps was 57, the last 18 days the average high was…

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Blocks in meteorology are large scale patterns in atmospheric pressure fields (high and low pressure), which are nearly stationary, and as a result there is little or no movement of weather systems.  These “blocks” can remain in place for several days (or longer) producing the repeating weather pattern. On such block is known as, the…

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Super Moon -- Dan Kotouch

April was an interesting month in and around Pittsburgh. Spring was trying to gain a foothold, but had limited success. Overall, the month included more chilly days than warm days and more wet days than dry. Here’s a look at the official numbers for April 2020. TEMPERATURE *Average high for the month was 57.8 degrees,…

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Ring around the moon means rain soon — sometimes. It’s not uncommon to see circles of light around the sun or moon, and halos have fueled superstition for centuries. But there’s nothing unnatural about how these ghostly rings form. Though you might see them in a clear sky, the culprit are wispy clouds tens of…

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It’s exactly what it sounds like. On a clear day, you can see the edges of Earth’s shadow at twilight creeping up or down the horizon. It’s a dark bluish band that appears opposite to the rising or setting sun. The Earth is really big and curved, and its shadow is the same way. In…

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Perhaps when you have visited the beach a thunderstorm has rolled in off the water. These are spectacular sights, which sometimes produce region specific weather events… like waterspouts! They appear as tornadoes of water, waterspouts are an eye-catching small-scale phenomena. They can simply be tornadoes that moved from land to bodies of water, but oftentimes…

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Virga

Virga is ghostly precipitation that never makes it to the ground. When the air beneath a cloud is very dry, precipitation falling through it evaporates before reaching Earth’s surface. What’s left are feathery streaks extending from the cloud’s base, capturing the path the rain or ice took before becoming water vapor. The evaporation process takes…

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What is lightning? Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges builds up enough, this…

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Last night we had a line of strong storms that moved across the area. The heavy rain, thunder, lightning and strong winds came together in a well defined line across a large area. In the world of weather, this is called a squall line! Thunderstorms can come in all sorts of forms. Sometimes they arrive…

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Sometimes you’ll find yourself bathed in a spotlight of sunlight, streaming out of the clouds at slanted angles. Those alternating bands of light and shadow are crepuscular rays; their name comes from the Latin word for twilight, when they are most easy to see. The effect comes depends on having a lot of particles in…

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In most years, as April arrives you can expect spring weather to take hold full time. Temperatures start to consistently warm, flowers begin to bloom (etc. etc.). However, there are always years when things just aren’t “normal”. Here is some insight on what a normal April should be (according to climatology) as well as some…

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