Friday, February 6, 2015

Upcoming Pattern Very Favorable for East Coast Snowstorms

The upcoming pattern appears to be very favorable for snowstorms along the East Coast.

Tropical Tidbits
The above image shows the 500mb geopotential height anomaly field over North America, forecasted by the GFS Ensembles from February 11th to February 16th. In this graphic, we see a strong upper level low dipping down over the Bering Sea, forcing a strong ridge to blossom along the Western US. A Rex Block then forms in the Southwest, as an upper level low slides under the ridge. Usually, a Rex Block upstream creates zonal flow downstream, but instead of rather calm weather in the East US, we see a deep upper level low pushing its way into the Northeast. This looks to be the pattern for the next 2 weeks or so.

In this sort of pattern, sustained northwest flow (winds from the northwest) often leads to a 'clipper train', where a multitude of Alberta Clippers slides southeast-ward into the Central US. These clippers can then move east off the coast, and can intensify to produce heavy accumulating snow for the East US. I believe that this is a possibility, and could happen more than once in the next couple of weeks.

A look at sea surface temperatures shows how potent this environment is. For now, we'll focus on the East Coast. Notice all the oranges and reds immediately along the coastline, extending a bit east. Those are very warm waters, with well-above normal anomalies being detected. Consequentially, any clippers that move off the coast and threaten the East will have unusually warm waters to work with, which could very well enhance snowfall totals.

To summarize:

- The upcoming pattern is favorable for accumulating snowfall in the East US.
- This pattern may support more than one event of plowable snow.
- Extreme cold may affect the Northeast, at times.