From One Extreme to the Next

Last week we were all complaining that we were sick of the cool, wet weather and wanted the sunshine back. Well, it’s back now and out in full force really heating things up. It is downright HOT outside! A big part of the reason behind this is because of the location of the jetstream. It is troughing over the Pacific Northwest presently and we are experiencing an upper level ridge over the Midwest. This is allowing the warm, moist Gulf air to advect from the South.

These conditions have actually been the reason that we have been unable to rule out a pop up shower or thunderstorm the past few days. This has created a fairly unstable airmass across the area with the daytime heating that has been occuring. As you may have noticed last night, there were a few thunderstorms that popped up across our viewing area. One in particular was moving in a rather unusual direction.

A storm cell that developed down around the Memphis area ended up in Gasconade county last night. One may notice that this would mean the direction of the storm cell moved Southeast to Northwest. Usually we see systems move West to East with a Southwestly to Northeastly component. The storm cell last night never became severe however there were a handful of reports of trees knocked over in Gasconade last evening. Why is that? If there was enough power in a storm to knock over trees, one would assume that it was a severe storm..

Well here is the science behind why that is. Trees and other things in nature build up a tolerance on the West side because that is where we usually see the storms and the winds associated move from. When you disrupt this pattern and have a storm move the opposite direction, the strong storms and winds are now blowing on the weaker side of the tree. This tends to cause trees to fall over and in some cases be uprooted. Now while we didn’t see extreme widespread damage in the event last night, these unusual East to West storms tend to do much more damage than storms that move West to East.

One of the most extreme cases of this I can recall in recent past was in St. Louis on July 19, 2006. You can read more about that particular storm here: http://www.crh.noaa.gov/lsx/?n=july_2006 I was actually downtown when this storm system hit. It moved from Illinois into Missouri and did some of the worst damage I have ever seen. Large trees that were decades upon decades old uprooted all over downtown, with power outtages all over due to down trees. Lucky for us, last nights particular storm cell was not severe otherwise the damage could have been a lot worse. We continue to roll on with severe weather season, but beware of the storms that move the opposite direction.