Wednesday, October 17, 2012

Warmer Trend Next Week. Remember Last Year? Mild December Ahead?

Using the various teleconnections as a guide for future weather pattern can be a crap shoot considering all of the random processes that occur in the atmosphere. Now consider that we are into late October--a transition month--which by itself offers a bunch of other forecasting obstacles. Forecasts can be very tricky to say the least.

I frequently post some of these workups on my Facebook Fanpage as single images.

Taking all of this into account, let's look back to last year at this time to see how the pattern was evolving in late October and November. Remember that last winter was one of the mildest EVER in northeastern Ohio.

By late October, the upper level pattern showed typical autumnal characteristics. Strong ridging and strong troughs which equated to rain and milder periods followed by cooler periods.

By early November, the trough in the east was starting to break down allowing for longer periods of milder air.

By Thanksgiving, the high pressure ridge responsible for the milder winter was almost in place.

Throughout December, the ridge south of Alaska and the ridge in the east prevented cooler outbreaks.

So temperatures across NE Ohio and eastern US were well above normal.

Notice how late October is shaping up. The projections are establishing a ridge in the east with a warmer than normal trend all next week.

Will this translate to a milder than normal pattern similar to last year? I am somewhat skeptical for two reasons: 1) Last year we were in a La Nina. This winter will be a weak El Nino at best. 2) The water temperatures in northern Atlantic close to the Canadian shoreline are VERY warm. This seems to be displacing the Greenland high so as to make the NAO (North Atlantic Oscillation) more favorable for colder air outbreaks.

While next week will be a nice break from our frequent rains and cooler/windier pattern recently, I don't think this Indian Summer next week will last into early winter.