In Coming Days

In the coming days we will be seeing a variety of things. One of them will be seeing the ridge of high pressure in the West dissipate and instead be replaced with areas of below average temperatures close to the West Coast. This may be indicative of some storm systems washing shore that would not be able to pump temperatures up. Another big factor that will enhance this dissipating ridge is the potential for another ridge of high pressure to form offshore the US and move towards Alaska. This ridge would therefore defeat the Aleutian semi-permament Low and would have potential to flip things around. This ridge would most likely lead to a trough in the West and a possible ridge in the East if that's how the atmosphere wants to play its games. 

Winter 2011-2012 Update

Winter has not been slow to arrive, even if you think it has. The reason you probably think winter is starting slow is because of the October snowstorm in the Northeast. Let me remind you how that storm was a VERY VERY LUCKY break for the Northeast and has a very low chance of happening anytime soon under normal conditions.

Anyways, this is a briefing on how winter is moving along.
To be honest, it hasn't been starting slow. We  recorded last year O'Hare Airport, Chicago's first snowfall came on December 12th, and they ended up with a historic snowstorm. Just a little bit to tell you.

The La Nina has recently been rumored to be unusually weaker than last year. Well of course it's weaker- it was always expected to be weaker than last year, so the effects will not be just as strong. This leaves more space for other variables to intervene, which they have been doing at the snow lover's disadvantage. At this point in time, we are seeing how some indices will be moving towards better waters:

(Green text is good for snow lovers, red text is bad, yellow text could go either way.)

The PNA will be moving towards positive territory. 
The NAO will be moving towards more neutral territory rather than positive territory.
The EPO will be dipping into negative territory, then staying around neutral territory.
The AO will be sliding towards neutral territory, but then rebounding into positive territory.
The La Nina should sustain itself or move slightly more negative over the winter.


The big question, of course, is when will winter start to act like winter??
We have gotten some indications that the Arctic Oscillation (AO) will be tanking at some point. We cannot independently confirm this, but we are looking for the certain indices that may be looking at this potential.
Recently, the ECMWF received an upgrade that some have indicated are showing signs of improvement in the model. Again, we cannot independently confirm this, but the long range ECMWF does show the Aleutian Low in Alaska breaking down (see what that does by clicking here), which may give the US  a little taste of winter. The teleconnections are changing, so winter may be on its way!

Long Range ECMWF Projects Aleutian Low Breaking Down; May Lead To Cold Air in US

Aleutian Low Example
(The Low Pressure system in Alaska is the Aleutian Low)

12z ECMWF Hour 240

In the top image, you can see the strong low pressure system located just around Alaska. This is called the Aleutian Low. This low pressure system is semi-permanent, meaning it can stay in that area for long periods of time and comes back frequently. When this happens, a consequence is that a ridge (high pressure system) forms in the West US, usually leading to some warmer air over the country. However, if this Aleutian Low breaks and dissipates, a high pressure can form over Alaska and lead to a low pressure forming over the West US, which can lead into colder weather for the country.
Are we saying this will happen? No. Are we saying it could be an indicator that the weather pattern may be changing soon? Possibly. We will have to wait and see at this point.

Thanksgiving Looks to be Quiet Across US

This Thanksgiving looks to be a quiet one across the country. Sunny skies are widely expected across the Eastern US, while some more humid air may provoke some showers and clouds as moisture from Tropical Storm Kenneth enters the country. A system will be moving onshore the Northwest region, so it can be expected some showers will be present as the day goes on. The Central US will likely have sunny skies.
Temperatures are expected to be above normal for the country.

Have a happy Thanksgiving from The Weather Centre!

GFS Hints at Mississippi, Alabama Snow After Thanksgiving

Projected Snow Depth on November 29

The GFS is hinting that Mississippi, Alabama, Louisiana could be in for some snow going into the November 29th timeframe. This does have potential to play out, but it may be slim. For instance, check out the factor that will be inducing snow below

GFS 6z forecast (Anything inside red circle may be snow)

The GFS says a cold pool of air will swirl around a cutoff low (low pressure that has been cut off from the jet stream and sits nearly motionless) and provide snow for the Southern US. It is entirely possible that this does not happen, and I am not too optimistic about it. We will have more information soon.