Saturday, November 17, 2012

End of Warm Pattern in Sight?

A side-by-side comparison of the long range ECMWF (left) and GFS (right) forecasts shows that the ECMWF believes the stormy pattern will break down in the NE Pacific, bringing an end to the warm pattern that has been covering up much of the nation.

These two models are forecasting an average of 500mb height anomalies between Hour 168 and Hour 240- also known as between 8 and 10 days away. Let's take a look at a few key points to help us see if this really is the end of the stormy northeast Pacific pattern.

1. The ECMWF is on board.
The ECMWF model is widely regarded as the best model currently in service, with a verification score higher than the GFS. The ECMWF has been known to catch significant events before other models. For example, the ECMWF forecasted a Northeast landfall by Hurricane Sandy while the GFS was way out to sea. If it were a battle between these two models, I would favor the ECMWF.

2. Both models show a location change in this stormy pattern.
Putting aside the difference in how good one model is over the other, both models are showing a change in where this stormy pattern is. The ECMWF eliminates the stormy trend altogether, while the GFS moves it onshore into southwest Canada. While the GFS change may not seem like much, this slight shift east paves the way for a positive PNA pattern to come back- something that cannot happen when the stormy pattern is prevalent in the NE Pacific.

It will take some more time to investigate this potential, but it is appearing possible that this warm pattern that has (and still is) affecting much of the nation may collapse in the next week to 10 days.

Andrew

February 2013 Forecast

Brutal is the best way to describe it. Siberia and NAO correlations go all out on a cold and stormy pattern for the East US in this final month of winter. Bone-chilling temperatures are likely to reach as far south as the southeastern states like Georgia and Alabama, possibly flirting with the fragile Southeast winter agriculture economy. Farmers should prepare now for a deep chill nationwide. Northern Plains residents will bear a huge brunt as February delivers several punches to the gut of pure cold. The Northeast continues with its -NAO pattern, and the cold only enhances any snow potentials.

NOTE: Confidence is lowered in the forecast for the Plains and Midwest.
Short questions can be asked below.

Andrew

January 2013 Forecast


Winter comes in with a bang. Continued indications from Siberia show moderation in temperatures and a continued negative NAO pattern. This negative NAO pattern would most likely intensify in response to a 3-year lag correlation, which means we could see NAO values similar to those seen in 2009-2010 (I know, crazy, right?). Temperature moderation ends in mid-late January as a deep freeze begins to take over.


Short questions can be asked below.

Andrew

December 2012 Forecast

December will most likely be pretty warm. A persistent stormy pattern in the northeast Pacific, combined with indications from Siberia in October lead me to believe that much of the East will get a little warm in terms of temperatures. However, the North Atlantic Oscillation is likely to be negative during the month of December, if not averaging out neutral for the month. This means several opportunities for snow may arise in the Northeast during this month, and this region would most likely get one of the coolest temperatures for the month of December.

Short questions can be asked below.

Andrew