Big pattern change? Maybe not

A significant low pressure system will cross the central and eastern United States at midweek, and some meteorologist speculated a few days ago that the storm might be enough to help change the mild winter pattern we've seen so far.

But the latest evidence indicates that any change won't be a real game-changer ... the kind of change that would leave the Southeast prone to snow next week.

The idea was that as low pressure moves into New England, the counter-clockwise flow around the storm would drag cold air down from Canada. In short, the system might open the flood gates from the north.

Certainly, colder air will follow the storm. High temperatures from Friday into early next week will be held to the upper 40s, although I've seen a few forecasts that take those highs into the 50s over the weekend.

But there is no sign in the next 10 days of a bitterly cold air outbreak, the kind needed for a bout of snow or ice.

Several factors are needed for snow or ice in the Southeast. For starters, cold air is necessary. If high pressure were to build over eastern Alaska, the clockwise flow around the high could send arctic air into the eastern United States. There also would have to be a storm track out of the Southwest, with the center of the storm passing across the Southeast -- not up the Ohio Valley, as has been the case several times this winter (and will be the case with this week's storm).

Clearly, there are signs that a cooling pattern is ticketed for the eastern United States during the latter half of January, but the real question is how far south the really cold air will get. Many of the computer models indicate it won't get cold enough in the Carolinas Piedmont for wintry precipitation in the next 10 to 14 days.

We'll keep an eye on the models over the next few days, to see if that changes.

In the immediate future, we'll have Wednesday's storm system to deal with.

Today's clammy conditions -- light rain and temperatures in the upper 40s -- will be replaced Tuesday by partly sunny skies and highs near 60, as weak high pressure builds into the region. Then showers will move into the Charlotte region before daybreak Wednesday.

At some point Wednesday afternoon or evening, the atmosphere might get unstable enough for thunderstorms. Regardless, a significant rainfall is likely, and we should get another soaker to keep ground water levels from shrinking. It has been quite dry over the last 10 days, and the rain will be appreciated.