Saturday, December 1, 2012

Why I Was Wrong In Writing Off December

I don't like to flip-flop on forecasts because I generally don't trust meteorologists that do such a feat. However, this time around, I have to tell you all that last night's post on December is likely partially incorrect, and I'm here to explain why.

In last night's post (click here), I told of how the strong Bering Sea High Pressure (HP) anomalies would move north, but into North Asia. This movement could provoke a polar vortex strengthening over Greenland, which would not be good at all for the East US' prospects for cold and snow. However, in a crucial error, I did not look at the long range forecast for the North Hemisphere height anomalies, as pictured above.

This forecast shows that our North Asia HP system has moved into North Europe, where it has combined with Greenland to produce a negative NAO. This negative NAO would then make a disturbance form in the East US.

Additionally, the ensembles project a disturbance to form in the Bering Sea. This disturbance would then force a ridge of high pressure to form in the Gulf of Alaska (GOA) and the West Coast. In response to that ridging (which is a positive PNA), a stormier pattern is encouraged to form in the East US.

So, in conclusion, I did make the crucial error of not looking at the long range forecast and instead kept my eyes on the short range. While this is still a far way out, the GFS has been trending with a general pattern change as of late, which would arrive in Mid December. I apologize for this sudden change of my forecast- I never want to flip on my forecast, I find it one of the worst things a forecaster can do.

Watch for mid-December to see a colder, stormier pattern to emerge. Siberia is still working against a cooler idea, so be wary of such an idea.

Andrew

5 comments:

wvmountainboy said...

Eh, the way I look at it it takes a bigger man that me to admit you might've got part of it wrong! LOL! Thanks again for it all!

Anonymous said...

Andrew, you are doing a fine job of explaining what the weather is likely to do rather then stating the obvious like other forecasters have a tendency of doing.

mike paulocsak said...

Like I said before,and I'll say it again!Your the only site I can trust to see what the weather has in store for us!Cannot wait until the first BIG storm for you to track.You can trust I'll check this site often for updates.

ERN WX said...

Dec will be back and forth. Mostly west/Mw for snow and cold. I do see E snow and cold though. Nao goes - mid month, Ao neg, and PNA pos that is a lot of help. Its coming. Andrew, great work.

Anonymous said...

Its fine Andrew! I like this sight because it goes in depth about forecast and has scientific methods and models to back it up. Better to admit you were wrong about a forecast than it would be to just leave ot hanging and be PROVEN wrong.

Thanks again!