Why the LRC doesn’t make sense to winter forecasting
I am the last one who should be criticizing any other meteorologist. Until I get the perfect forecast, which will never happen, far be it from me to chastise others. Weather forecasting is a difficult endeavor, something that most people don’t understand. And how could you? You don’t see the variables we see in the atmosphere when we put together a forecast. The atmosphere is dynamic, constantly changing, and forces on one side of the planet can effect the atmospheric flow on the other side.
With this in mind, I can never understand seasonal forecasts, and I have blogged about this in the past. (Read more HERE and HERE.) In my opinion, there are simply too many complicated variables that prevent somebody from making a forecast for three or four months in the future.
One of the local Milwaukee television stations puts out a seasonal forecast at the beginning of winter based on Lezak’s Recurring Cycle (LRC). It is a theory from Kansas City meteorologist Gary Lezak. I’ve never met Gary but I have read his LRC blog. As I understand it, the LRC seasonal forecast is based on recognizing a pattern in the 500 mb (approx. 18,000 feet above the ground) flow during the month of October and the first week or so of November and determining when this pattern will repeat itself during the months ahead. Supposedly this allows the forecaster to determine when certain storm tracks will occur that could produce large snowfalls.
I have never seen quantitative research regarding the LRC, and as far as I know there are no peer reviewed papers regarding the theory behind the LRC. Gary explains his cycle HERE. It seems to be empirical. However, from what I know about the general circulation of the atmosphere, I don’t understand how an upper air pattern in October and early November has anything to do with repeating itself throughout the winter.
The local Milwaukee television station, using the LRC, makes a winter forecast on the last night of the November TV ratings period. It’s a wonderful way to drive viewers to watch their station. In the weeks following their broadcast, I receive many questions from viewers regarding their winter forecast. One such question came in the form of a phone call asking “how can that station make such an accurate winter forecast and you can’t?” I asked the caller how they knew the forecast was accurate and they replied “because the TV station said it was accurate.” Ah yes, the importance of marketing and promotion.
The LRC forecast for this winter has not worked out well so far. Many of you were awaiting a major winter storm around Christmas, according to the LRC. Seasonal snowfall for Milwaukee was projected to be 55″ to 65″, according to the LRC and the local TV station.
We still have a long way to go before winter stats are in the books, so we’ll see what happens. But so far the main influence on our mild and low-snowfall winter has been a positive North Atlantic Oscillation (NAO). You can watch my explanation of how the NAO has influenced our winter so far by watching one of my YouTube videos HERE. The NAO is based on atmospheric circulation principles. It is the wildcard in making any winter seasonal forecast.
If forecasters want to use and rely on the LRC in making seasonal outlooks, that is a decision each meteorologist needs to make. I can only speak personally, but I don’t believe the LRC is meteorologically valid. However, forecasting is equal parts art and science, and I think the LRC, along with other theories people may have, is just another way to look at our changing atmosphere. It just doesn’t make sense to me.