Winter Forecast 2017-18

Each year everyone wonders what the winter season will bring. For the past few years, I have been giving my winter forecast, keeping data on my webpage and then asking 7A kids to grade those predictions at the end of the season. While difficult, my forecasts, at times, have been spot on and at other times a disaster. It is a mixture of science, experience and you guessed, it dumb luck… but there are a few factors to look at. By examining the North Atlantic Oscillation, El Nina/La Nina, the Jet Stream and a few old traditionals (like the Woolly Bear Caterpillar and the faithful Old Farmer’s Almanac to name a few) this year’s forecast will be interesting to say the least when looking at the ingredients that goes into predicting the upcoming winter.

First, the North Atlantic Oscillation (NAO) is a measurement of atmospheric pressure at sea level between the Azores High and the Icelandic Low (more commonly known as the Subtropical high and Polar low in the Atlantic Ocean). This phenomenon is one of a few predictors used to create our winter forecast. When the NAO is in a positive phase, we usually see warmer than normal temperatures and conversely when it is in the negative phase, we see cooler than normal temperatures. Over the last month it has been trending negative but recently it is moving towards the positive.

(To find out more about the NAO, click on the hyper link above or for a more in depth look at the NAO click here.)

Next, El Nino/La Nina or El Nino- Southern Oscillation (ENSO) is the warming or cooling of the equatorial Pacific Ocean and depending on either phase, can greatly impact our weather here on the east coast. An El Nino Winter trend means the equatorial pacific is warmer than normal while a La Nina Winter is just the opposite causing a colder Pacific Ocean where both impact the jet stream differently as it arrives on our Pacific coast. The trend right now is a weak La Nina season.

(Check out the link for a cool 1:53 video showing both)

Our third impact is the Jet Stream which is a fast moving current of air near the tropopause (about 5-11 miles above the earth’s surface) that meanders across the US depending on cool or warm air masses that impact it at any given time. The Jet Stream can travel up to 250 miles an hour yet on average will travel at about 110 miles an hour on any given day. Depending on the strength of the air masses acting on it, the Jet Stream is what brings systems into and out of our area West to East. I like to think that the Jet stream is what drives all systems across the country and depending on its path can bring very different weather conditions throughout the winter.

(The hyperlink above is the best live Jet Stream map I could find so check it out)

The final ingredient that is put into the forecast are a few old reliable traditions that generations have looked towards to predict the winter. Among them include the Wooley Bear Caterpillar and the Farmer’s Almanac (Check these two links out for more details). The color combos of the Caterpillar and the reliability of the Farmer’s Almanac make for some interesting conversations as we try to prepare for the winter season.