New Year, New Pattern.

Before I get into the long range, some of us in the coverage area will have to deal with a Wintry Mix Monday Night, before a change over to rain. 48 hours ago, models were trending colder, suggesting that many of us, even York/Lancaster counties, would see at least a moderate impact from snow, sleet, and freezing rain. Reason being was the location of the High Pressure system sitting in Canada, was originally modeled to be a few hundred miles southwest, and much slower to leave the Northeast. With a clock-wise motion, this helps funnel in the cold air into our area from Canada.

I drew up a quick image to represent what I am talking about. "X" marks the spot. The "X" is where the high pressure was originally modeled to be. The "H" you see stands for High Pressure, which is where the HP is now modeled to be.

Pretty substantial difference as you can see. This leads to a more wet scenario than white. To be honest, as a snow lover myself, this is a great thing. Because let me tell you, this would NOT of been a snowstorm for the Lower Susquehanna Valley even if the HP was located where it was originally modeled. Instead, it would of been a significant sleet and freezing rain storm..two types of precipitation you do not want to mess with.

Here is a zoomed in look over our region during the onset of the storm.

Notice the oranges and pinks...our area might not escape all of the sleet/freezing rain. But look how quick the transition is from pinks/oranges to green. Green being rain obviously. It still is possible that as far south as Northern York, may start off as a period of Sleet... AT THE ONSET. But, within a half hour it will turn into a cold rain for everyone south of I-80.

Areas north of I-80, may hang onto the sleet/freezing rain a little longer. Enough that Winter Weather Advisories may be posted for those areas. But, even these areas will transition to a cold rain.

LONG TERM UPDATE:

As the New Year approaches, our weather pattern will be changing. Take a look at the current temperature anomalies.

Hard to miss the warm pool of temperatures across the Eastern half of the US. This storm that will impact us Monday Night into Tuesday Morning will take a track right along the temperature gradient, or where the above normal temps, meet the below normal temps. I guess you can call that your lesson for the day. Many storms follow where the temperature gradient sets up. Alright back on track. Take a look at Western Canada. Notice the below average temps located there where I have the "X". This would indicate a trough over the western half of the US, and a ridge in the East. Typically, whatever happens in regards to temperatures in Western Canada, the opposite occurs over the Eastern US. This whole month of December we have been under that Southeast Ridge. This is why our temps are record breaking warm.

But...looking ahead after the New Year, we have a whole different pattern setting up.

Notice the warm pool of air in Western Canada. This is a huge difference than what we saw for the entire month of December. This leads to a more seasonal/colder look for the Eastern US.

Not only does that pool indicate warm temps in Western Canada, it also promotes ridging in the West and a trough in the East. Although, I would like to see that warm pool of air slide further south into the Western US, to receive our bigger storms, this pattern would still support clippers that burst out of Canada and impact our region with light to moderate snowfall events. Now do not worry snow lovers. The chance for big storms will increase as we head later into January. But, for the first week of January. we are looking at a "clipper pattern" with colder temperatures in the East.

-Chris