Saturday, April 25, 2009

April Storm Data

I've been spending some time this week finding data on storms that occur in Missouri during April. It seems that this month is quite a transitional month with hard freezes, tornadoes, hail, and snow all occuring during the past 9 years.


First, I checked back into my CoCoRaHS data since 4/07. I haven't been keeping track of days with thunder until this year, so my data consists of comparisons with my comments and those of other observers in Callaway and Boone counties.

Days with Thunder -- At MO-CW-1

- 2007: 4
- 2008: 7
- 2009: 1 (so far)

It is easy to see that 2008 was an active year. I don't remember it being especially stormy, but apparently it was compared to this year. I've only heard thunder once this month so far, and it was from a small cell that passed to our north one night a couple of weeks ago.

2007 was the year of the damaging freeze through the nation's mid-section, and Missouri was not spared from it. The National Weather Service compiled a comprehensive study into the meteorological conditions, and agricultural and horticultural impacts. If you've got some time to read the 52 page study, brew some coffee, sit down and enjoy.


I was interested to find any data on severe weather events in Missouri that normally occur in April. That prompted me to dig into the NWS site for data, and I am amazed by the amount of information that they provide for the public. I seem to find something new every time I look around their site. All data comes from the Storm Prediction Center.

Number of Severe Weather Reports in Missouri (Tornado, High Wind, Hail)

For more information, including locations and divisions of each severe weather event, click on the links provided.

- 2000: 165
- 2001:
- 2002:
- 2003:
- 2004:
- 2005:
- 2006:
- 2007:
- 2008:
- 2009:

What an amazing contrast between 2004 and 2006! The predominant severe weather report seems to be hail. It should be noted that the hail criteria has changed this year to 1", in contrast with the previous size of .75". This will cause this year's severe hail reports to decline somewhat, but it seems as April, 2009 looks to be similar to 2004 with the reports predominantly located in southern Missouri. Of course, history shows us that one severe outbreak can increase this year's number, even double it!


OSNW3 said...

WxWatcher, I agree that the amount of information the NWS provides is astounding. As it should be.

We saw our first lightning bolt last night and heard our first thunder this April. This entry has given me the nudge to seek out recorded thunderstorms here at OSNW3. The only way I will be able to accumulate the data is also by the daily descriptions (comments), so the data will be spotty at best.

I am seven pages into the 2007 Freeze study... :) And it would seem the reports of hail will decrease regardless of the amount of events with the hail criteria changing to a larger specimen. No?!

WxWatcher said...

It looks like you all got some good rain, too. I saw on WeatherScout's entry yesterday that he got nearly an inch.

Glad you got some thunder! I too wish I had kept better record of storms in the area. Living in the midwest, it seems we get a lot of storms...but it would be nice to have some quantitative data.

Great report on the freeze, isn't it? I got through the first 12 pages last night. I knew it was a bad event, but 2 billion dollars? Quite amazing.

Chris said...

Nice post! That 56 page article sounds interesting. Some day......some day.....

OSNW3 said...

I done did it.

Quickly though, as I searched the comments for a string, "-s". The reason because mostly I write "t-storm" or "t-shower". Ha. Anyways.

2007 - 6
2008 - 16
2009 - 2

I know I diligently tried to include a mention of a t-storm each time one happened. I'll go through the data line for line some other time.

WxWatcher said...

Great job OSNW3! You know, I am somewhat surprised by your data. I wouldn't think Wisconsin would have that many storms in April.

...that makes me wonder...what would you say is your "stormiest" month?

OSNW3 said...

WxWatcher, wait one second. That is for the entire year! Not just April! My bad. :)

As for April ONLY...

2007 - 1
2008 - 3
2009 - 2

The "stormiest" months are the transition months in my mind. I'll put more thought into this as I'll have plenty of time in the evenings this week.

BTW, sorry for the confusion. :)

WxWatcher said...

Aaahhhh...that does make more sense. :o) Thanks for the clarification.

And thanks for the data!