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Wintercast Extra: What goes into the Wintercast?

Chief Meteorologist shares a few of the maps that help him decide the wintercast.
Here are some of the things that I look at for controls of our winter weather.

ENSO (El Nino/La Nina)

El Nino and La Nina both influence the weather and the jet stream flow from the Pacific to North America. There are direct correlations of each to weather across parts of the United State, but the correlation to our winter weather is actually smaller than other places. It doesn't matter though as temperatures are running close to average across the tropical Pacific Ocean. We have nicknamed this condition as La Nada. You can see in the diagram below that the temperatures are pretty close to average across the equatorial Pacific.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstweek_c.gif
This neutral La Nada leaves us to look at other signs for what can control our winter weather.


Temperatures in the Gulf of Alaska

I have found that the temperatures in the Gulf of Alaska can help determine if cold air wants to push more into the western United States. If it's cold in the west, then it would be warmer in the east. This year as you can see in the map below, temperatures are slightly below average.
http://www.ospo.noaa.gov/data/sst/anomaly/2013/anomnight.11.7.2013.gif

Below average temperatures tend to promote more cold from the west and milder air for the southeastern United States. This signal is week and is weakening more. I do think cold shots in the early winter are going to be more focused for the western United States but I think all bets are off for the middle and latter part of the winter.



Snowcover

It's not just how much snowfall is in the Northern Hemisphere at the time of the wintercast, but how fast it grew through October and into early November. This year, the snowfall grew at a rapid pace and is still above average for parts of Asia and Canada. The bluish colors here are areas that have snow that usually don't by this date. The red is where there is no snowcover where there usually for this date. The white area near the arctic represents areas that have snow and normally does at this date.

Snow growing at a faster pace increases the albedo, or reflectivity of the sun's energy when it strikes the surface of the earth. This sets the stage for colder air to build earlier in the season across the northern land areas, especially Siberia. While this cold does not always translate to our area, it does increase the chance  of some severe cold outbreaks.


Water Temperatures off of the Atlantic

I have found that the water temperatures off of the East Coast have a small correlation to the amount of storminess near the coastline. Warmer than average temperatures fuel Nor'easters more while colder water right near the coast help to diminish the storms.

When I wrote the wintercast, temperatures right near the coast are a little below average with warmer waters off of the New England coastline. This told me that the storms may not develop as much until past our area.

http://www.ospo.noaa.gov/data/sst/anomaly/2013/anomw.10.28.2013.gif



Though since the original map, these temperatures have ended up near average so this leaves us with a weak signal.

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