What is usually Missouri’s rainiest month of the year, May, was anything but, and a state climatologist says that tends to be a bad sign for the rest of the summer.
Pat Guinan says, “When you have a dry May, generally the pattern that we see the following summer, at least historically, is for the summer season to be hotter and drier than normal. There are exceptions to that but the overall trend is for a hotter and drier summer to emerge when we have a very dry May.”
Guinan says May 2012 ranks as the 8th dryest on record. Even after storms yesterday, some parts of the state are still more than five inches off the average rainfall total since May 1.
Guinan says the long-term outlook for the summer is unclear, partly because forecasters have no warming or cooling of the Pacific Ocean, commonly called El Nino or La Nina, influencing the forecast. A La Nina that had lasted through the winter ended about a month ago.
“At least according to what the Climate Prediction Center is saying, they are forecasting for most of Missouri, the summertime temperatures to be above normal, but when it came to the precipitation category they actually gave equal chances for above, below and near normal precipitation.”
Of Monday’s storms, that brought one to two inches of rain to some parts of Missouri, Guinan says, “It’s a step in the right direction, but we have a long way to go to make up a deficit that we’ve accumulated over several weeks this spring. We need a really good two inch soaker across the entire state. The topsoil is very dry and it’s going to take a significant amount of moisture to percolate through and moisten it up.”