Saturday, November 2, 2013

Monday Night: November Pattern Update

Two weeks back I put out this map for November temperature projections..

Based on latest modeling I think this forecast will be accurate. The cold air we have had over the last two days will not last and will clear out by mid week as a very strong upper level ridge develops over the east coast

This will occur in response to a storm system that will be in the middle section of the country. Areas around I-80 will get snow from this system. Although there will be brief shots of cold this warm air will dominate though most of the month with that eastern ridge holding strong. Most of this warmth will be due to a positive North Atlantic Oscillation and Arctic Oscillation as shown in the green areas of low pressure over Greenland. As many of your know who follow this blog that is not a driver of cold weather for our area. 

Another factor to look at is an oscillation called the MJO which is an area of convection in the tropics that has an influence on the jet stream. Based on where this convection moves (1 of 8 phases) dictates precipitation and temperature trends over the US. Right now european model forecasts this oscillation will go from phase 1 into a weak phase 2 by November 18th as shown by green line

Below are temps for each phase..

As you can see the current phase favors warmer conditions over the east and phase 2 favors colder conditions, however it looks like we will be in a very weak phase 2 so the impact will be minimal. This leads me to believe the forecast of slightly warmer than normal (around 58 is normal temp for this time of year) in November will hold. The climate models agree..

I am going to be posting my final Winter 2014 forecast on Friday which will be broken down month by month and there might be some big changes form my preliminary forecast released in Sept. so be sure to check in.

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