Let me start off by showing you what the official government outlook is currently predicting for Winter, courtesy of the fine folks at the Climate Prediction Center. You'll see that the temperatures are forecast to be normal for us. So whatever the typical temperatures are for the given month we are in...that's what they are forecasting that we will see. Precipitation however is forecast to be considerably above normal. In fact, they have drawn a bullseye of precipitation right on top of Kentucky in their maps. Take a look and then we'll talk about why the maps look like they do.
One of the contributing factors to our weather last Winter was La Nina. This typically causes the jet stream to hang out in the midwest section of the nation, and that in turn steers a lot of storm systems into the Ohio Valley. That's one reason we had lots of frequent snows last year. La Nina is predicted to redevelop this Winter, and the last charts I saw indicated that it could become a fairly strong La Nina pattern. So most climatologists myself included believe that the jet stream will once again spend a lot of time dividing the nation through it's heart, rather than staying south of us like we typically see. For this reason, temperatures are expected to stay seasonable through the Ozarks and into the Ohio Valley. "Seasonable" for Kentucky still means cold...just not abnormally cold for extended periods of time.
With precipitation the position of the jet comes into play once again. Just as last year brought frequent weather systems, this year is expected to be similar. With the average position of the jet expected to be in the nation's mid section, a lot of moisture should be able to pool into the Ohio Valley on southerly winds. As weather systems fly in on the atmospheric flow from the west and run into this feature, precipitation should be common here in Kentucky. One fear is that with the war zone between warm southerly air to our south and cold polar air to our north being parked over the Ohio Valley with this jet stream, we could end up in the zone of "wintry mix" type weather. Therefore, this Winter will have an increased risk of ice storms here.
The overall weather experienced for us in a nutshell should be normal in terms of temperatures, but perhaps not quite as many cloudy depressing days as we usually see thanks to the jet keeping systems moving through in the flow. But with that will also come some heavy rains, and possibly heavy snows or ice storms from time to time. I don't think it'll be a boring Winter by any means. Cold snaps to go along with warm spells, and sunshine to go along with clouds, snow, and rain. I'll take that deal, as I really hate the Winters that keep us cloudy all the time.
Just to jog your memory, last year October was nice in terms of temps and rainfall. Very similar to what we are seeing this month. By November, we were seeing wild swings in the weather. And by December the bottom fell completely out. We finished December 2010 with a monthly average of 26 degrees in Lawrenceburg, which is well below where we should have been and set records. So it can go downhill quickly. Don't let this month's nice weather fool you.
Now, here is the fly in the ointment. Since February, every single month in 2011 has been wet in Lawrenceburg with above normal rainfall. I am a firm believer that nature always keeps a balance, and some drier than normal months are coming ahead. There is no question about that. The question is when? Will these dry months show up this Winter or will we see a continuation of this active pattern until late Spring or Summer turns into a drought? I suppose time will tell. I think that regardless, the coming Winter is going to be a fun one.
By Thanksgiving, I will update this outlook with the latest model data and we'll try to nail down what Winter will hold for us this season. Have a good one...
-Shawn
