Average day with BIG Changes next week

Good Wednesday morning!

What a difference 24 hours makes! All the rain from yesterday morning is now well off the coast and cooler air is firmly in place. This cool spell won't last long as we begin a warming trend tomorrow that extends into the New Year. We're watching the first part of next week closely as I'll detail later in the post.

Today:
Morning lows will fall into the upper 30s, meaning we won't get near the freezing mark. That's pretty significant considering we haven't seen temperatures at or below freezing since December 1st. Just a random statistic for ya this morning. A clear sky will allow abundant sunshine to reach the ground. This warms us into the mid 50s, which is average for the end of December. This will be the last average day, high temperature-wise, for the year as we begin a warm up tomorrow.

Sun in the forecast for the rest of 2011:
High pressure will settle in from the Ozarks later this evening. With calm winds and a clear sky, we will be in the mid 30s, with a few low 30s sprinkled in, tomorrow morning. The high then moves to our southeast which gives us a southerly wind flow; warming us a few degrees each day through New Year's Eve. A few high clouds are possible Thursday and Friday in response to a few weak disturbances riding through, but they won't contain any rain.

Cold start to 2012:
I've been talking about the first few days of the New Year being on the chilly side. The Euro has been consistent in bringing a deep trough into the eastern half of the country. The GFS continues to bring the trough through the northeast and isn't nearly as deep as the Euro. Which model will win out? It's tough to say at this time but there's a growing consensus that it will be closer to the Euro's solution. Here's a look at what the models are depicting for Monday morning, the time frame I've been using the past few days:

00Z GFS:

00Z Euro:

Comparing the GFS to its previous 00Z run shows it's a bit deeper and farther west. The ridge over the Rockies is a good deal sharper this run which sets the stage for a deeper trough to develop than is shown currently. It also shows a dry frontal passage late Sunday/early Monday. After the front passes we'll cool off a good deal to the low 50s. That's the GFS. The Euro is much stronger with the trough although it is slightly weaker this run. The main culprit is the slightly weaker ridge out west. This rounds the trough more for the east coast. It's also a bit more east this run compared to yesterday's which decreases the amount of rain its giving us in the same time frame as the GFS. The Euro then has the trough digging in right over the top of us which would give us a cold Tuesday and Wednesday. When I say cold, I mean cold! The model is painting highs in the low to mid 30s with overnight lows in the teens. The GFS is showing the trough getting deep in the western Atlantic, which puts us in a northwest flow aloft. That will draw down some cool air but not as cold as the Euro.

Alright, now that the comparison of the models is done let's get to what I think will happen next week. First of all, the models are picking up on a pattern change. This usually causes chaos in the models and is more than likely the reason why we are seeing such a discrepancy between the GFS and Euro. The PNA, described in previous posts, goes positive for a brief period of time. The AO, Arctic Oscillation, goes less positive which means a cooler east coast generally. The NAO, North Atlantic Oscillation, doesn't go negative, which also gives us cold air in the east coast, but goes close to neutral. All of those combined leads to a greater confidence in the cold snap depicted by the Euro and CMC, another reliable model. In the end, I'm siding more with the Euro this morning as it's not as extreme as yesterday. I'm not expecting highs in the 30s, yet, but mid 40s are likely next Tuesday and Wednesday.

For my friends in North Carolina, your snow that the Euro gave you yesterday was taken away today. That's because the Euro is a bit more east with the trough and shoves the surface low out into the Atlantic. This is the likely scenario as the UKMet and CMC agree with the Euro. The only hope for snow will be in the mountains.

Disclaimer: This is way into the model runs and should be taken with a grain of salt.
Now that I have the next 7 days out of the way, I'll talk about what the models are showing for late next week. All models are in fair agreement with a secondary piece of energy riding down the back side of the trough. The EURO and GFS both show it. In fact, this secondary piece of energy is the reason why the GFS gets us cold late next week with the northwesterly flow aloft. The Euro has the second piece of energy diving WAY south into Alabama which would give hope for those in the southeast for some wintry precipitation. It's NOT a given, just giving you an analysis of the models this morning! If, and that's a big IF, we can keep the positive PNA with some high latitude blocking then we can start talking about winter mischief. Until then, enjoy, or prepare, for the cold snap in store next week.