Iowa weather...

[blabath]

Good morning John,
Folks down here in Iowa have a theroy and I wondered if there's any truth to it. It goes something like this...
Every year we get pretty much the same moisture falling from the sky. If we have a dry summer in the form of rain, we should have a wet winter in the form of rain and or snow. Now nobody here thinks that's a fast and true always happens kind of a thing, just a sorta, kinda rule to go by. Some of the folks thinking then is that we should see more moisture this winter following the drought this summer.
Question... Scientiffically correct or just good old homegrown wisdom?

... or possibly entirely hooey...

Thanks,
Bill Labath

 

[jd]

There is some truth behind what you talk about. If you look at weather anomalies for different lengths of time, the longer you go out, the smaller the anomaly gets. This is because mother nature does like to even the score out over the long term. It is actually one tool that I use to try and help me formulate a seasonal forecast.

However, it is not something that always happens. Sometimes the anomaly can persist through several seasons or even several years. Or sometimes a wet autumn will occur between a dry summer and the following winter and lead to just an average winter. Or, the precip that falls in winter is more rain than snow. So as you can see, there are no certainties and lots of possible outcomes, but still that slight statistical advantage that can come true too.

-John