Monday, May 19, 2008

March Chill & "Shock Egg" Clouds Hover Over the Midwest



Happy Monday! There is a lot to talk about with all these great cloud pictures! Let's begin with Matt's e-mail. I took an extra couple hours today to research it so that is why I took so long to write you today.


Hi Mike,
I'm attaching some photos of lenticular clouds I took along I-80 between Princeton, IL, and I-39 Saturday afternoon at around 3:00 CDT.
I don't ever remember seeing a display quite like this away from mountains.
I'm also attaching soundings from yesterday for Davenport, IA, and Lincoln, IL. I believe that these clouds formed in waves in the moist, very stable, layer at around 3500 m.
Thanks,
Matthew Boehm
Lafayette, IN

These are not UFO clouds even though that is what some folks tend to call them. I went through my hundreds of almanacs at home and these were very tough to find. At first I thought they were a cousin of the lenticular clouds you usually see in the mountains. Maybe they were a type of altocumulus lenticular clouds.



Matthew Boehm sent me a sounding that showed a moist, stable layer at 3,000 to 5,000 feet. This is one of the prerequisites for lenticular clouds but we were still missing the mountains that are needed to form lenticular clouds. Otherwise, the moist, stable air would not have enough lift to form these unusual clouds.


Here is another great shot of what I think are types of clouds related not to lenticular or lens shaped clouds but to contrail clouds. Of course contrails are created by a jet's exhaust that condense usually into ice crystals. In this case these clouds are what are called shock eggs or vapor cones. They are caused by fighter jets that are moving at supersonic speeds or usually faster than the speed of sound. We also see these type of clouds during space shuttle launches and unfortunately they would also form after nuclear tests or blasts. These shock eggs are telling meteorologists that there was a sudden drop in pressure created by a shock wave of some sort. I think it would have to be fighter jets. It seems like fighter jets are creating a lot of havoc these days in the Midwest. We remember the window-rattling we had a couple nights in a row near Logansport and Kokomo before the earthquake hit. Here is exhibit A as to how I came to my conclusion.



These pictures have been on the internet for almost 10 years and were taken by navy pilots, John Gay and Jared Hodge. You can see the shock eggs forming around the shock wave created by the incredible speed of the jets! I am still in awe. They say you learn one thing a day...but this is a doozy! Today we will be in shock not from the clouds but once again our chilly temperatures! We will look and feel like March as the more traditional stratus clouds we normally see in the late winter and early Spring turn the entire sky gray. Stratus clouds will then likely turn into nimbostratus clouds or stratus clouds that produce rain as we head into the afternoon and evening. Since we are on a roll with interesting clouds today, over the weekend we had cumulonimbus clouds that gave us this brilliant lightning display you see below. Luckily, we had only light amounts of rain so our Wabash River will be able to recede below flood stage as we head through this week.


Richard Beedle snapped our beautiful sunset we had on Sunday evening. Unfortunately, the sunshine will only be making brief appearances the next few days. We have one chilly re-inforcing shot after another moving our way in the northwest flow. This creates enough instability in the atmosphere to create plenty of clouds and evening some pop up showers during the afternoon and evenings. But I do think we have a great big silver lining in the clouds by late week and into our Memorial Day weekend. We will talk more about this here on the blog tomorrow and on the newscasts tonight. I will also have your sneak peak race forecast here on the weather blog on Tuesday.


Meanwhile, have a wonderful day and remember this nice bright picture to help you through it.




8 comments:

Anonymous said...

What beautiful photos! And Happy Monday to you as well1

Anonymous said...

What beautiful photos! And Happy Monday to you as well1

Anonymous said...

What beautiful photos! And Happy Monday to you as well1

Anonymous said...

What beautiful photos! And Happy Monday to you as well1

Renee said...

I love the pics..the way the clouds look..nice..i hope race day will be nice out..it will be my first time there.Enjoy your day.

Anonymous said...

From what I seen race day is going to be clear I have never been to the race but I have been to the time trial and that was cool in fact I got Danica Patrick autograph hope you have fun.

Justin in Lafayette

Anonymous said...

That is really cool I new about the jet exhaust and ice crystal
but the shock egg is news to me.

Justin in Lafayette.

Renee said...

Thank you Justin. I am very thankful to have been givin free Indy 500 tickets from them, due to my husband being in Iraq and also to other military families as well.
I just now caught that those clouds are called shock eggs, interesting.