NOAA released its national winter season outlook this week from the Center for Weather and Climate Prediction in College Park, Maryland.
NOAA acknowledges it's a "low confidence" forecast thanks to the wavering El Niño. El Niño plays an important role in the winter weather across the nation. A couple months ago it looked like we were headed straight into an El Niño, then Mother Nature put on the brakes, and put it in reverse the past few weeks. Ending up in the neutral phase of the ENSO cycle right now. There's still a chance we can go full blown El Niño, but that is looking less likely.
Even with that data, NOAA's forecast for Dec-Feb is similar to an El Niño year. Wet and cooler in the south. Dry and warmer in the west. El Niño years usually bring the jet stream farther south, which means storm systems that follow the jet stream can dump more rain and severe weather in the South.
With the systems farther south, that leaves drought-like conditions in the Midwest and West.
For the specifics on South Florida, The National Weather Service in Miami released it's Dry Season Outlook Friday, and it somewhat contradicts the national forecast. The Miami NWS office is calling for a slightly warmer and slightly drier dry season as a whole, but breaks it down month to month.
Their forecast calls for a cooler and wetter start... Nov-Dec, then gradually becoming warmer and drier at the end to the dry season. This would enhance the chance for wildfires in late April and May or next year. They look at past years with similar weather patterns, our local atmospheric conditions, and also the global phenomenon like El Niño. Their forecast too, is very "low confidence."
The cog in the wheel will be the North Atlantic Oscillation, also called the NOA, and the Pacific/North American Pattern or PNA. These two features can override any El Niño pattern that may develop. The NAO has more to do with our winter weather pattern than anything else. All it is is the difference in pressure between Iceland and the Azores in the North Atlantic.
Studies have shown that when the difference is greater(positive NAO) Arctic cold air travels quickly eastward, without dropping south. When the difference is less, (negative NAO) a pattern sets up that blocks the cold air from going straight east. It has to go somewhere so it buckles south, pushing frigid air far south and setting the stage for cold snowy conditions along the East Coast of the U.S. Check on the NAO here.
For instance, The record breaking winter of 2010/2011 the NAO was strongly negative most of the winter. Last year, 2011/2012 winter was very mild, and the NAO was…you guessed it, mostly positive.
So why not look at that for our winter outlook? Well, the problem is… we do not have the ability to forecast it beyond two weeks. With such a short forecast period, it is useless predicting what the long range patterns will be months in advance.
There are other things that may affect the winter, like the loss of Arctic sea ice, and the sunspot cycles…but there isn't enough known about the relation to these phenomenon and our weather to make an accurate guess.
One thing both agencies are more confident about is it should be cooler than last year, but that's not saying much as last year was one of the top 20 warmest winters across the country.
Let's not forget, it doesn't have to be cooler or warmer than normal, Mother Nature can throw us a curve ball, straight down the middle.
Until then, the summer is behind us, the blistering heat and humidity is relaxing, and the winter season is here! South Florida's weather is always better than the rest of the country, so enjoy!
For more on NOAA's forecast click here
For more on the NWS in Miami's forecast click here.