Monday, June 4, 2007

Ready or Not, Our Wildest Week Since April is on the Way

It has been way too quiet by Indiana standards for the past couple months. So far this year we have had only 1 very weak tornado. This compares to last year when we had 10 tornadoes across our viewing area. It is important not to get complacent. I cannot emphasize this enough especially after looking at the latest weather maps. This week's 7 day forecast really makes the point.

Remember the peak of our severe weather season runs from mid-May through June. Today we have an upper-level low pressure that will pinwheel our way. It has had a history of producing a type of tornado called a cold-air funnel in Minnesota and Wisconsin. The good news is these funnels are more closely related to dust-devils than typical tornadoes. The bad news is these funnels can prompt tornado warnings and if they do reach the ground they can cause damage. Here is a look at a cold air funnels that have been spotted in our viewing area in recent years.

Here is a picture of the cold air funnel that was spotted near the new 231 bridge in Tippecanoe County on June 12, 2003. I still remember the tornado sirens blaring that day. The good news is that it caused no damage. There were reports of it touching down knocking over a tree, but our weather team found no visual evidence.

This is a cold air funnel that was spotted in Monticello on July 24, 2003. Once again as is typical with these funnels, no damage was reported across the area.

Cold air funnels usually form under cold core low pressure systems. This causes an unusually quick drop in temperatures from the ground up to 40,000 feet. This steep lapse rate causes low level moisture to rise rapidly. Add a little sunshine to the mix and it causes towering cumulus clouds to quickly develop which can cause spin in the atmosphere. Many times no thunder is associated with cold air funnels.

They may look scary but rarely reach the ground. When these weak circulations do reach the ground they have been known to cause minor damage. Most wind speeds with cold air funnels are close to 60 mph while typical tornadoes in Indiana produce wind speeds close to 100 mph. But remember if these funnels are spotted, tornado warnings are issued, no matter how weak or strong they become.

Today we need to keep an eye out for these cousins of the dust devil and water spout. I still think our biggest threat with today's storms will be hail, but do not be surprised to see a cold air funnel. No matter what nature decides to throw at us, I will cut-in to programming as necessary.

This will only be the beginning of a wild weather ride. Late in the week and this weekend our first heat wave of the season is likely. We will have a better chance for more widespread severe weather across our area. The Storm Prediction Center has already outlined us in a risk area. I will have more on this here on the blog as we get closer. One thing is for sure, and that is we will have to be prepared. Nature looks like it is making up for some lost time.

I do not want to be all doom and gloom. To make sure I get your Monday off to a good start, I have a great picture to share of a double rainbow sent in from Flora, Indiana.

Courtesy of Jim Franklin

You are looking east from Flora toward Carroll High School. The forecast this weekend was for more rain than rainbows and it certainly worked out that way. We did get some needed rain as well with .36" of an inch at WLFI to .75" in Flora. Frankfort had .70" in about 30 minutes. More cloud bursts and rainbows are on the way for today. Have a great day and thanks for reading. I look forward to seeing you tonight. I will have the latest on Live Doppler 18.

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