Hype meter rising on potential weekend storm: What’s the deal?

ECMWF Forecast Model showing a very strong storm system off the East Coast early next week. It is one of a few models showing the potential system in the long range (beyond 6 days).

The meteorological community is buzzing in regards to the potential for a major storm system this weekend, which could affect much of the Eastern United States. Local media has caught on to the potential and is beginning to hype up the potential storm system — as are several weather forecast outlets in the area. However, it is important to remember that the system is still floating around in what meteorologists like to call “Fantasy land” on forecast models. The range where, especially in a high amplitude pattern, models are prone to wild and wacky solutions. In this case, we’re seeing some of the wildest solutions in recent memory — and it’s causing the meteorological community to hype up the potential for a major storm. That being said, taking a look at some of the pieces of the pattern can offer us clues as to where the potential actually lies — aside from the wild model guidance images floating around the internet. We’ll try to answer some of the questions we’ve had emailed/tweeted/facebooked at us throughout the day today.

Why is there a storm threat, where is it developing? One of the major causes behind the threat for a significant storm is the development of a tropical system (Tropical Depression 18) and a large trough over the Central United States, which is then forecast to surge south and east and phase with the tropical system. A phase occurs when two or more pieces of the jet stream interact with one another. In this case, the Central US (northern stream) trough could surge south and east to phase with the tropical entity by next weekend.

Keep reading for a full discussion on the potential and hype…

What are the chances that this “phase” will actually happen? The chances remain very low, but could arguably be a bit higher than normal. One of the main reasons for this slightly higher-percentage chance is the fact that strong blocking exists over the Atlantic Ocean. This blocking (which we discussed in our previous post) keeps a ridge over the North Atlantic and Upper Level Low over the North-Central Atlantic, and could essentially force the Tropical System to remain in the Western Atlantic Ocean, near the coast, and phase with the Central US energy.

What are some of the variables that could change? Anything and everything. Which is exactly why it’s not smart to hype up a big storm at this range. Forecast models are subject to great variability at this range. If the trough over the Central US is not as strong, the phase could occur later or not occur at all. If the ridge over the Atlantic is weaker than models think, the tropical system could drift east and out to sea. Not to mention, tropical systems are unpredictable as it is. The system could track farther east or west than models think it will — changing the forecast completely.

What could some of the impacts be if the storm were to happen? Should all of the pieces come together perfectly, as some of the extreme forecast guidance solutions are showing, we could experience copious amounts of rain and very strong winds. The timing, intensity, etc would have to be analyzed as the storm gets closer.

What should we watch for over the next few days? Just keep it tuned to our Twitter and Facebook as well as the main website right here. We’ll provide you with as many updates as possible (and as many as are reasonable) as the week unfolds. Look — forecast models are for guidance. And at this range, 7 to 8 days away, are generally used to get a broad brush idea of the pattern. In this case, the specific details are extremely uncertain – and confidence in any situation, including the storm forming at all, is very low.