Monday Morning Long Range Weather Discussion: Enjoy Warmth this Week, Cold Winter Like Pattern to Set In

Good morning everyone, there is a lot to talk about in today's weather discussion. After this week all signs point to a cold pattern dominating the central and eastern USA. In fact, it is that exact pattern that I expect for this winter. What does that mean? Well remember it is November so a winter like pattern does not mean sub-zero temperatures, but it does mean a big chill will be in the air. This along with a very active polar and sub-tropical jet stream means we need to be on high alert for storm development. I know the question in everyone's mind is will it snow? The answer is yes for very interior mountain sections of the east coast and not out of the question for areas near the coast. I am still holding on my my thoughts that most areas see their first snow in the 1st week of December,however, but it would not surprise me if this upcoming pattern beat me to it. 

Let's take a look at the factors. I will try to be as simple as possible. For those of you who read my winter forecast you remember that I mentioned we have a very weak sun right now. A weak sun results in more ozone building up in the highest levels of the atmosphere. This ozone buildup causes the upper atmosphere to heat up. Hot air expands which compresses the troposphere below it. When you compress air it gets colder. 

Here is the current ozone build up..

Notice the high areas of ozone around northwestern Canada, the North Pacific and Eastern Asia. This is a HUGE factor in predicting colder weather 2-3 weeks away as it normally results in something called stratospheric warming. Or in simple terms warming of the upper atmosphere, above where our weather is.

Consequently, here are projected stratospheric temps..

Notice how the warmer colors are exactly where the ozone build up is. Normally a winter can see big episodes of stratospheric warming. This ends up disrupting the polar vortex which allows big shots of cold air to funnel down into the USA. In this case, we are seeing this warming go on very early. Based on all the factors I looked at for this winter in my outlook, this does not surprise me.

So we know the stratosphere is warming, now lets see what models project for the jet stream pattern 7-12 days from today..

A very cold pattern for the central and eastern USA. Notice the deep trough south of the islands off Alaska. This trough pumps up a big ridge of high pressure over the west coast into Canada. This then allows the jet stream to buckle south into the central and eastern USA pulling all the cold air down with it.  Remember the jet stream acts as a barrier between warm and cold air so when it sinks, the cold air from Canada comes with it. Those high stratospheric temperatures over the North Pacific are a big driver of this, especially with the aid of developing that trough south of the islands off Alaska. Right now all major modeling is showing the pattern you see above will hold for most of the Month!

So what about storms, are they likely? From what I see yes. Let's take a look at a few reasons why.

The image above shows moisture coming off of the pacific ocean from the south. I drew an arrow to demonstrate the sub tropical jet stream. Think of this as a fire hose that shoots moist air into the southern zones of the country. If conditions are just right, this moist air can combine with cold polar air to produce big storms. Focusing your attention back to our image of the jet stream you can see how this sub tropical moisture along with the big trough over the east can cause some mischief. I will say again it is still November so thing really need to fall in line perfectly, but the wintry threat is there. 

This next image shows the two jet streams potentially combining..

Expect this to be a common theme this winter. 

So now that we know a cold active pattern is on its way after this week, Do I see any storm threats on the horizon. Here's what I am looking at. Another storm will effect the east coast this weekend, but with rain in most areas. However, this storm will do one important thing which is pull down cold air in its wake. I show this below..

Grey colors basically represent cold air. As our weekend storm departs, I see potential for those two jet streams to combine but do so further south. With more cold air to work with it means we need to be on alert for a potential storm system early next week. The models are hinting at this..

This is just one run, so we cant just say wow look at that storm. Things will keep changing day to day \and again it still is very early to be thinking all snow. The important thing is to focus on the pattern I am breaking down. This pattern can produce storms like this. If not next week, then multiple more chances will arise given the pattern holds. 

If we didn't have enough already for active weather take a look at this..

That circle out in the pacific represents a typhoon that is developing. That typhoon is forecasted to recurve past Japan later this week. That will also have big implications in support for our pattern. When typhoons recurve out to sea off the coast of Japan, they tend to lead to big troughs (cold air) over the eastern USA 6-10 days later. In many cases we see storms.

Similar to the typhoon rule we also have to now focus on the Bering Sea. A massive storm is possible in the Berring Sea later this week as well..

Looking above the berring sea is bacially the water between Alaska and Russia. Look at the size of that storm! Its a 925mb low pressure system which is as powerful as I have seen. A lot of reasearch has shons that big storms in the Bering Sea can result in deep throughs (cold air) developing over the east coast 2.5-3 weeks later. This also increases the chances for big storms to develop along with those troughs.

So in summary you can see there is a lot to get excited about if you love the weather over the next several weeks. We have the warming of the strasophere which is causing a cold weather pattern to lock in. This cold weather pattern will develop along side an active sub tropical jet stream. The combination of the sub tropical jet stream and polar jet stream's can cause big storms. The first threat looks to be early next week. Past that period, we have a a lot of support from the Berring Sea and a Typhoon recurving off Japan that mid-late November looks a very active as well. Of course none of this in guaranteed, but in any event this blog should be very busy over the next few weeks and into the Winter!

More to come this week as I watch this pattern evolve. Stay tuned!