Quiescent Conditions: Doesn't It Seem Calm Around Here Lately?

You've probably noticed that in most years we have severe thunderstorm and tornado warnings and watching nearly constantly scrolling across the screen by late-May in this area. That is because we are in a very severe weather-prone region, with some good southerly moisture flowing in and the stronger cold fronts that dip in with larger-scale systems from the West at this point in the year. That happens because there is still a very strong temperature contrast over us that helps to intensify anything.

You likely notice, then, that by about August things get to be just hot and dry - without as many severe weather outbreaks, and then by September it gets cool and cloudy - with an occasional severe storm.

That is the weather pattern we have been in lately. More of a late-summer/early-fall type of weather pattern. Not much flow in the upper levels of the atmosphere in our neck of the woods - with most of the upper level winds happening over southern Canada and toward the southern United States.

This was a quote from a blog post by Greg Carbin of NOAA (full text here: http://www.norman.noaa.gov/2009/05/1137/) talking about the significance of the change in conditions lately - and this quote was from the 22nd:

If the SPC does not issue a watch today or tomorrow, that would be a substantial “first” for this particular week in May. Since 1970, there has not been another May 17th-23rd period without at least 6 watches issued (either a severe thunderstorm watch or a tornado watch somewhere in the country). The SPC has not issued a watch since Saturday evening, May 16, 2009. Since 1970, there have been about 28 watches issued during this week in May. The greatest number of watches ever issued during this week-long period was 59 (averaging almost 9 a day!), in 1989. It now appears likely that SPC will break the previous minimum number of watches issued for the week, 6 in 1976, by Saturday, achieving a record of 0 watches for the week of May 17th-23rd, 2009. That has not happened before and can be considered quite unusual.

Not only is that unusual - but it's also unusual that we have not only met that no watch level through May 23rd, but it's May 26th as I write this and we *still* haven't seen any!

If you consider my comments from earlier, that makes things significant, and there is another quote by Greg where he puts it much better than I could:

It’s still possible that the overall flow pattern can revert to a more typical and active late May weather pattern, thus resulting in more widespread severe thunderstorms and a greater potential for tornadoes. However, the chances of that happening decrease as the summer months approach and the weather pattern, as established, becomes more typical for the time of year we find ourselves in.

All in all - it's been very unusual. We keep getting ready for severe weather in the KDLT Weather Center, but it just hasn't been happening. Don't let this make you less-prepared for severe weather when the time comes - because we get severe weather around here no matter what time of the season it is.

Have a great night and get ready for more sunshine by tomorrow night!

~KDLT Meteorologist Aaron Shaffer