Why It’s So Hot This Summer

In case you missed my explainer this past Sunday morning on why it’s been so hot this summer here’s a quick recap…..

Controlling Factors ….

1) Lack of El Nino

2) Moderate to Severe Drought

Back in April I based my summer outlook on the development of the El Nino which is an unusal warming of the tropical waters in the Pacific Ocean off the coast of Peru (South America). Scientists know that this happens roughly every 3 to 5 years, but are still somewhat baffled as to why. Since everything in this wonderful world of weather is interconnected…. the oceans, the atmosphere, solar patterns, etc. when you change the temperature of a large body of water like this, it in turn changes the jetstream pattern (steers storms) around the world. The typical jetstream pattern in the United States during a summer El Nino is to run it right smack dab through the middle of the Great Lakes states and off the coast of the Mid Atlantic bringing cooler than normal temperatures to the Northeast (from the Delmarva to New England) and keeping the blistering heat west through the heartland of the nation.

Back in April when I made the summer prediction, the climate models had the El Nino developing in May.  Meanwhile, three months later here we are in the middle of July and it still hasn’t developed yet. So with the lack of a developing El Nino, obviously the cooler than normal jetstream pattern in the United States hasn’t materialized. By the way, this is also one of the reason why I laugh everytime I hear some big wig scientist talk about how 100 years from now we’re all going to be under water because all of the arctic sea ice is melting and temperatures will warm an incredible 2-4 degrees fahrenheit. Yeah right …. the climate models can’t even get next month right and you expect me to believe they are good enough to get the next 100 years right??? Give me a break! Anyway, that’s an argument for another day.

So the lack of an El Nino is point number one. Point number two is something that has really taken much of the country by surprise because of how quickly it has happened and how severe it has become. That point is the massive drought that has stricken the United States. As of July 17th nearly 60% of the continental lower 48 states is in either a moderate or severe drought. When we include the states of Hawaii and Alaska that number jumps all the way up to an incredible 70%. The US Department of Agriculture has declared 26 states in the heartland of the nation disaster areas now which is overall larger than the dust bowl era of the 1930’s.  This currently makes this year’s drought one of the worst this nation has ever seen.

Why is this a factor in our oppressively hot summer you ask? Well contrary to what many of you might think, the sun doesn’t heat the air. The sun actually heats the ground. The ground in turn heats the air directly above it. It’s a process called conduction. True story, look it up :). Winds then transport that heat around the globe. A process called Advection. This is why when you’re 25,000 feet up in a jet airliner you can touch your window and it’s cold. It’s because the sun’s not heating the air, it’s heating the ground.

When the ground is damp and there’s been recent rains, about half of the energy from the sun actually goes towards evaporating that moisture first, while the other half goes towards heating the ground. So the end result will be the ground will warm, but it will warm at a slower pace. However, when the ground is dry, like it is now, 100% of the energy of the sun is focused soley on heating the ground. This results in the ground heating up very rapidly. Well, that’s what we’ve had to deal with so far this summer. A dry ground can have a huge impact on our temperatures. In most cases it can add an extra 3 to 5 degrees. However, in situations where a drought covers an extended amount of real estate even that becomes enhanced. Take the plains states for example. There temperatures a few weeks ago were nearly 10 degrees warmer than what the models were predicting and that’s a ton! Unfortunately there was no way of knowing something like this would happen since no climate model is armed with the physics to show something like this. Therefore it was like a sneak attack. This is the main reason why I was so adament about how we needed the rain back in March and April. It’s a vicious pattern!

So where do we go from here? Well on a positive, the El Nino is finally starting to develop. Even though it’s three months late and only still in it’s infant stages at least it has finally started developing. The only question I have at this point is… the drought has become so severe across much of the country that I’m honestly not even sure that the developing El Nino will even matter now. I personally think it will make a difference, and I think there’s a strong possibility you will see that difference towards the end of the month and into August, but I can’t say that with much confidence. The forecast models still show quite a few 90 degree days to come this month.

If the El Nino doesn’t do the trick there are two other ways that this pattern can come to an end. The first is through tropical systems. You see, once we get a little rain out there, or at this point a lot of rain out there, the heat pump will pull back west because it naturally wants to go towards the driest and hottest point. That point is the desert southwest. So a couple of tropical systems coming right up the Gulf of Mexico and moving into the Tennessee and Ohio Valleys would put a serious dent in the drought and more than likely bring this oppressive summer weather pattern to an end. The second way to end all of this is with a change of season. A change of season will start up the monsoon out west. It will also change the pattern of the jetstream and bring more rain storms into the country. The problem with this scenario is that it’s still July and the summer season doesn’t officially end until the middle of September. So that’s a long way off.

So let us cheer on the El Nino for now and see if it can do the trick over the next few months!

-CS

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About Chris Sowers

I'm the weekend meteorologist for WPVI-TV, Action News in Philadelphia. I've been forecasting for nearly twelve years now. Some of my stops along the way include Bowling Green, Kentucky and the windy city of Chicago, Illinois. I have an identical twin brother, Gary, and a younger brother Jason. I'm a big sports nut. I watch everything from football to baseball to hockey, even horse racing. Another passion of mine is finance. There's nothing like making money, and lots of it! But most of all I enjoy spending time with my family and friends. I have a little niece, Gabriella, and four year old nephew Hayden. They both mean the world to me. So much so that I've started a little segment on my Action News facebook fan page called "Gabby says". Once a week little Gabriella gives her forecast to the city of "Brotherly Love!" You can catch me Saturday and Sunday mornings from 6-8am, 9-10:30am and then again at noon.
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One Response to Why It’s So Hot This Summer

  1. marcy says:

    Chris thanks so much for this explanation….I am a faithful action news watcher and one of the chatters at 6@4. I watch you on the week-ends and appreciate your professional delivery always!

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