Winter 2016 - 17 is more than a month away and questions are already flowing across the country regarding its severity. NOAA (National Oceanic and Atmospheric Administration) has issued its winter forecast for the US and it gives the Mid-Atlantic an “EC Winter” or equal chance. This means that Maryland will have an equal chance of seeing an average, below or above normal winter. The goal of this outlook is to break down the potential impact for Maryland.
Putting together a seasonal forecast is tough. The science and concepts surrounding them is still pretty young. Therefore, research & forecasting techniques are playing "catch up" to other meteorological advances like precipitation forecasting. In other words, the meteorological community is still trying to perfect the 7 Day forecasts, so a 90 day forecast will have its limitations.
What We Look For?
If you live in a four season latitude you can always expect winter to be winter. The cold, dry air masses and wintry precipitation will always be anticipated. Seasonal outlooks make an attempt at forecasting the severity of the season. We look for clues, research and trends to make a forecast on how patterns may hold up. Listed below is our winter forecast for Maryland and some forecast factors we’ve given the weight too.
Siberian Snow Cover:
The ABC 2 Weather Team is a fan of the research done by Dr. Judah Cohen of (AER) Atmospheric and Environmental Research. His research found a correlation between snow cover in Siberia and cold and snow for Europe and the United States. This year the snow cover is off to a fast start, which could support a colder than normal winter for the Eastern United States.
Arctic Oscillation (AO)
The AO refers to opposing pressure patterns in the middle and high latitudes of the Northern Hemisphere. The AO plays a role in weather patterns as it affects the track of storms, and the location of cold air. When the AO index is negative, there tends to be high pressure at the pole and weaker zonal winds, so more cold air is able to drop down into the mid-latitudes.
This winter we’re expecting the AO to play a role in our weather later in the season. If it trends negative as models suggest this would support below average temps for the heart of winter and creating several opportunities for weak snow storms like Alberta Clippers, which can intensify along the coast turning into Nor'Easters.
Last winter was greatly influenced by a really strong El-Nino - leading to above normal temperatures while ironically fueling the Mid-Atlantic’s largest snow storm ever. This upcoming winter is expected to be different since that strong El-Nino has reverted to a neutral or weak La Nina phase, which usually has a different impact on the Mid-Atlantic’s weather - leading to a drier pattern.
**The strength of La Nina is in question leading into 2017. Right now it appears it will remain close to a neutral or weak phase for the majority of winter. If La Nina strengthens, it could impact the winter outlook and the severity of the season.**
Our Winter Forecast:
We are expecting a slow start to winter but an overall colder than normal season. The factors suggesting this winter will be colder than normal will not have a strong El-Nino influence to counter act this year.