No early spring....(2-22-13)
We are quickly approaching the end of February and even though this winter hasn’t been particularly brutal, central New Yorkers are starting to think (or hope) that spring is right around the corner. Some of our longer range computer guidance now peeks into early March and with a couple of days of agreement from the models I’m going to let you know what we are seeing.Here is a couple maps, one from the European ensemble means and one from the GFS ensembles that shows the jet stream flow 8 to 10 days in the future.
The maps you see above are an average for next Friday, Saturday and Sunday (the first 3 days of March) This is certainly not a very spring like jet stream pattern for us here in central New York. While there are some subtle differences between each model, they are in pretty good agreement on the major features: Blocking high pressure arcing over the North Atlantic into eastern Canada, a trough of low pressure in the eastern United States and a ridge of high pressure over the Rockies.Just to back up with our models, here is what the Arctic Oscillation (AO) is forecast to do during the first part of March. The fact that it goes strongly negative is a also a sign of blocking taking place in the atmosphere over us.
This graph shows 10 days out. I haven’t included it, but the 14 forecast of the AO is still negative.While I expect our temperatures to average below normal our temperatures during early March it shouldn’t be brutally cold. With the ridge over Canada, it will be hard (if not impossible) to tap into any true arctic air. Instead, it looks like a cloudy and stormy period with rain or snow. While the clouds would keep our high temperatures below normal, they would also serve to keep overnight lows up, probably above normal. Although we don’t know all the details late next week, with temperatures not too far below normal elevation may playa role when we are forecasting precipitation type (rain vs. snow).So it look like "Punxsutawney Phil" may have been a bit premature when he forecast an early Spring 3 weeks ago. Central New Yorkers will have to use their typical March patience when dealing with the late winter weather
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