March 8, 2013
Weather Investigation: The Mid-Atlantic Non-Snowstorm
The hype was high for a big storm along the Mid-Atlantic Coast this week, so high that cities were shutting down. But what happened? Why didn’t it work out as forecast?
There are quite a few things that can be looked at to explain this. The first is one experience I had this week with this forecast. On March 3, I wrote a storm blog depicting what I thought the outcome of the storm would be. When I was looking at the weather models, I noticed that there was a lot of uncertainty in what was going on with this storm. So this quickly put me into “Weather Dynamics Mode”, which means that I started using my past experience and education to look further into the forecast. So, as I looked at the ocean waters along the East Coast, I knew they were going to play a key role in this forecast. The next thing I looked at was the location of the low pressure system; it was moving in from the Dakota’s and Minnesota, which means it was not going to be your typically East Coast storm. The third thing I watched was the 850mb approx. 5,000ft above the ground. I examined the temperatures at this level. The reason this was so important was that all of this cold snow from above was going to have to fall through this layer to make it to the ground. Now, on to the solution and what I decided.
Knowing that this storm was coming in from the northwest, and not the typical south track, made me take into consideration that a warm layer would develop ahead of the warm front at that said 5,000ft level; the only thing was where would it setup. This storm it setup right over the coastline of Maryland. If this storm was coming in from the south, this would have been no issue as that warm pocket would have been over the Atlantic Ocean; but for this storm it was a key element. So, this warm pocket developed over the region and eventually spread even further south into the DC area. With this warm pocket in place, it meant only one thing; this storm was bound to underachieve in the snowfall amounts.
The second thing was the ocean temperatures; they are still fairly warm as the Gulf Stream flows right past this area. This meant the surface temperatures over the land were going to be warmer because of this. But the big thing was how much warmer would it make the land. Well, the final result was that the southeast flow setup ahead of the warm front for these places and these southeast winds pushed warmer air into the region. A simple weather dynamics solution tells you that with warm air in place it likes to rise; this only meant more fuel for that 850mb warm air region. Now the low pressure itself it was moving in from the northwest, the cold air would not be in place right away and this would create more troubles trying to get that cold air in place. So as the night of March 5th started to take shape, I remember seeing all of this unfold before my eyes, knowing that these snow totals were going to be off for the cities of DC and Baltimore. Knowing the basic dynamics behind a storm system makes our job a lot easier, because of this case and point right here.
So, seeing all of this unfold before my eyes made me feel good that weather dynamics had out done the weather models again. We, as meteorologists, sometimes rely too heavily on weather models for the job at hand. This can back fire just like we saw today. The good news is that hopefully it sheds light on the word “Weather Dynamics” again across the weather community and how important it is to understand the basic concepts of weather before getting wrapped around any storm and the potential impacts it may have.
Feel free to stop by my Storm Blog for March 3-6 if you want to see what Weather Dynamics can do to a forecast three days in advance.