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Scott Patterson • April 2nd, 2024.
On April 8th, a total solar eclipse will be visible from northern Mexico to eastern Canada. Unfortunately for millions of people who want to view the eclipse and are directly in its path, there may be a total eclipse of the eclipse, due to weather.
Even though many people will miss seeing the last US eclipse for another almost 20 years, even with cloudy skies, the effects will be felt just like if it was cloudy at night. The sky will darken, just more rapidly and lighten quicker than if it was under clear skies. The temperature will fall and then rise, but less noticeably. It will still be a strange experience, but based on the time of year, it could have been much crazier.
It’s completely normal in the spring for storm systems to move from Texas towards the Great Lakes and into eastern Canada. Unfortunately, that is almost the exact path to be able to view the eclipse.
Solar eclipse viewing path vs a common track for spring storms
in North America.
These types of storms often spread a significant amount of clouds north and east of the storm center, the (L). On the same day as the eclipse, Monday April 8th, a large storm system is projected to be moving out of the western US into the Central Plains. This will include a large swath of cloud cover from Houston to Chicago and scattered high clouds all the way to Montreal. Timing will be everything.
Early look at a storm that will affect viewing of the eclipse
for millions of people from Texas to Canada.
The storm still could move faster and affect the
Great Lakes and Canada more, but for now
consensus puts most clouds further south.
This year’s solar eclipse will only last, at its longest, a little over 4 minutes in Mexico. Most people along the eclipse’s path will experience between 2 to 4 minutes of changes in the environment. It’s been documented that owls may begin to hoot, bees may return to the hive, stars come out, and cows begin to bed down for the night. The short-term effects on weather will be acutely felt by many, especially in the northern US, where temperatures can still run near freezing. When the moon blocks out the sun, the temperature can fall as much as 3 to 10 degrees Fahrenheit (1.5 to 5.5 C). If this had been December, as it was in 1834, Gettysburg, Pennsylvania reported a drop in temperature of 28 degrees F (14.5 C). How could such a large drop occur? Read below to see one extreme example.
When the ground is heated by the sun, the air above the ground is heated and rises as long as it is warmer than the immediate air surrounding it (like a hot air balloon). When the air rises, it leaves a void below it where there is less air. The surrounding air that is cooler, rushes in to fill this void. This is how wind occurs.
Wind is created when warmer air rises and cooler
air moves in to fill the space it left.
In Gettysburg, Pennsylvania in 1834, a region known for apples and cider, a wind from the west would be coming in down slope from the Appalachian Mountains. These mountains are not big like the Rockies, Alps, Andes, or Himalayas, but they can still affect temperatures based on the wind direction. In Gettysburg, a west wind can be warmer, especially on a cold day in December. If the wind switched to blow from the east, it blows in from the freezing Atlantic Ocean inland toward Gettysburg, causing the temperature to drop. The large temperature drop could have been partly due to the reduced sunlight, but also because wind speeds decreased, and possibly even shifted directions.
One possible explanation for how Gettysburg, Pennsylvania
saw temperatures fall 28F (14.5 C) during a solar eclipse in 1834.
Loss of heating causes winds to shift direction, bringing
in colder air east of Gettysburg.
Water warms slower than land. In the spring especially, rivers, lakes, and oceans are still cold from the winter. The land warms up rapidly after sunrise in the spring. This differential heating creates a daily wind system called the lake or sea breeze and the land breeze. Winds flow off the water in the morning, blowing cold air from the water across the land making it feel cold. In the late afternoon and evening, the winds reverse and it may feel warmer.
This specific type of wind system can be found along the shores of the Great Lakes and in an area that is along the eclipse path from Cleveland, Ohio to Buffalo, New York, and worldwide. In April, water temperatures are still in the 30s Fahrenheit (1-4 C). The land on a sunny day can rise into the 60s (15-20 C). This difference leads to lake breezes that bring much cooler air inland. The eclipse may briefly stop the lake breeze winds, and although this may allow temperatures right near the water to rise, overall the loss of the sun will drop temperatures.
Lake or sea breeze depiction where warmer land
and cool water leads to onshore wind. This process
flips in the afternoon and evening.
Most people will not be surprised by the eclipse, but the darkening of the sky in the middle of the day will be an otherworldly experience. Even a few clouds can cause the temperatures to fall 1 degree, so the sky darkening like night could see a big drop in temperature of 10 degrees F or more in some places. When the sun stops shining, often the winds stop blowing, as was the case of Gettysburg, and huge changes can happen suddenly.
The effects of an eclipse can be a microcosm of an entire day, month, or year’s worth of weather. So even as the eclipse encapsulates such a small part of time, similar changes continue to occur at a much larger and longer scale. Make sure you are not caught off guard by the unexpected and reach out to ClimateAi for the latest climate insights in the short and longer term.