Old Man Winter Wakes Up

It finally feels like winter today here in North Texas for the first time since early December. This is the first winter I can remember where my coat has rarely been required. Most of January, although bone dry, felt more like April. Mother nature however, like cats, abhors a vacuum. ;-)

To retaliate against a prolonged Indian Summer, the atmosphere is undergoing a major alteration in the upper air pattern. A rather large upper vortex has developed over the NE US and will reorganize/retrograde westward to the northern Rockies. The models of course are having difficulty in formulating a final solution on how this will all play out in 5-10 days.

However, it is certain that a very large and bitterly cold arctic airmass will build over most of Canada and begin to invade the US next week. With strong westerly and even south-westerly flow aloft, it will be quite a headache in trying to determine how far south it will move, how quickly and more importantly how much it modifies.

Right now, there isn't any snow pack between Texas and the Canadian border. That will tend towards more modification. However, the cold air will continue to be reinforced as the upper cyclone hangs tough. Normally, we get a big glob of arctic air that blasts into the US and then that's it. Not this time. In short, the north pole shifts southward. Depending on how long this upper cyclone remains in place, we could be in for a pretty prolonged period of very cold weather here in the plains.

In my experience, what ends up happening in this pattern is that the density of the airmass ends up oozing southward under the prevailing upper flow resulting in a shallow but very cold arctic airmass reaching into Texas. It usually accelerates too because of the damming effects of the Rockies and higher terrain out west. The result is that these shallow arctic airmasses often come in faster and stronger than model progs and forecasts.

To complicate matters, the orientation of the upper cyclone and overhead jets are a typical pattern resulting in numerous impulses moving across the area. The 850-700mb winds override the shallow arctic airmass producing additional lift as well as necessary moisture. What we usually get down here as a result is freezing rain. It's also known as the North Texas ice capades on the roads where most people's ignorance of basic science (like water freezes at 32F; rubber provides no traction on ice; etc.) are exposed to the world much to the chagrin of insurance companies.

There is of course alot of uncertainty as far as amount/type of precipitation because too many necessary details can't be resolved this far out. But, it is certainly my opinion that old man winter is coming back to stay for awhile....and he could be pretty cranky because his wife, Mother Nature, is booting him out of the comfort of his home within the arctic circle. :-)

Stay tuned.....it's going to be pretty interesting next week.