A near-miss for us this time

After getting clobbered with arctic air masses and winter storms the past month, the Charlotte region will miss the worst of what's coming in the next five to seven days -- apparently.

A storm system is tracking eastward today, delivering a belt of snow and freezing rain.

Since mid-December, the storm track frequently has been across the Southeast, with the Charlotte area on the north (cold) side of the system. The result: sleet on Dec. 17; snow on Dec. 25 and 26; and then snow, sleet and freezing rain last Monday.

This time, the storm's path is north of our area. That puts us on the milder side of the system, and it means any precipitation that falls today and Tuesday will be in the form of rain -- except perhaps in the higher mountain altitudes.

Instead, it looks like freezing rain could be a problem in places like Washington, Baltimore, Philadelphia and maybe the New York City area.

Then there's the matter of the next arctic blast, headed for the continental United States this weekend.

Originally, the computer models indicated the very cold air would push well into Georgia and South Carolina, much like the air masses have done in recent weeks. That would mean another round of far-below-average temperatures from Saturday into the early part of next week.

But now it looks as if the cold air will sweep over the Upper Midwest, Great Lakes and Northeast. In the Carolinas, we'll be at the edge of the cold air mass. Our temperatures will turn chillier again this weekend, with highs in the low 40s. But we won't be looking at a string of days with 35-degree highs --hopefully.

Some of the advance forecasts show a trend of near-average temperatures for the next 10 days or so.

Given the history of this winter, I doubt that. There's still too much cold air in place over Alaska and Canada. But we'll take every day of "average" we can get.

Stick a fork in that La Nina forecast

I spent more than a few sentences in late autumn describing what a mild and dry winter we would have in the Carolinas.

Talk about making a mistake!

Most long-range meteorologists predicted the Southeast would slide through winter with few if any problems. Those forecasts were based on the emergence of La Nina, the Pacific Ocean condition that tends to keep the South mild in winter while sending the nasty weather into the Northwest.

I remember seeing a comment posted under one of my blog entries from someone who took exception with the forecast, saying there are other conditions at work, including the North Atlantic Oscillation (NAO). That guy, whomever he was, hit the nail on the head.

I noticed an article last week on Accu-Weather's website on this topic. The point of their article: this will be a bitterly cold month in much of the United States, and their long-range specialist, Joe Bastardi, had reversed his earlier forecast of mild conditions in January and February. Their article noted that making long-range weather predictions is still tricky business, because meteorologists are still learning how all the different variables work together.

So far, this winter has been brutal in the Carolinas. December 2010 was the second-coldest in Charlotte history, and while January so far isn't among the coldest, it's well below average -- about 5 degrees below average so far.

The reason for all this cold weather is the negative NAO. Basically, that means high pressure over Greenland has created a ripple in the atmosphere that sends arctic or polar air masses racing southward into the eastern United States. On the other side of the high, the same thing is happening in Europe.

There are signs of another big blast of arctic air moving south, toward the end of next week. We'll deal with this in our next post, but it appears as if very cold air will sweep into the eastern U.S. sometime around Jan. 22 or 23. It's possible the Carolinas will miss the worst of that, but it's a sign that the negative NAO remains locked in place, at least for now.

So I'm ready to stick a fork in the forecast for a mild winter in the Southeast, because it doesn't appear as if a trend back toward less-harsh conditions will take place anytime before the beginning of February ... if it happens then.

For the record, this will be our second straight cold winter -- and the third consecutive winter with significant snowfall.

Remember that when we have three or four straight winters with no snow.

Storm's headaches: School closings, travel woes

The likelihood of heavy snow Monday in the Carolinas is grabbing the headlines, but this storm will be a headache for a number of other reasons.

Three potential problems I see arising:

1. An ice storm across parts of the South, possibly causing thousands (or tens of thousands) of power outages.

2. Travel problems, including air travel.

3. School closing decisions, due to the timing of the snow's arrival in Charlotte.

ICE STORM WOES

Ice storm warnings are posted this morning for central and parts of southern Mississippi, and you can expect those warnings to be expanded eastward later today.

It looks as if southern Alabama (although not on the Gulf coast), south-central Georgia and parts of South Carolina's Midlands are most likely to see enough freezing rain to bring down tree limbs and power lines.

In the Charlotte region, the heaviest ice accumulations are forecast, naturally, to the south. Chester County is expected to get a little less than 1/10 of an inch of ice. Typically, anything less than 1/10 of an inch does not cause power outage problems. Normally, it takes 1/4 inch or more for tree and power line troubles.

I've seen forecasts for up to 1/2 inch of ice accumulating in parts of Georgia, Alabama and Mississippi.

We can be happy that problem is expected to remain to our south and southwest.

TRAVEL TROUBLES

Obviously, highway travel will be a precarious matter through Tuesday in the South and Southeast. This storm will affect these interstate highways: 20, 22, 24, 26, 30, 40, 55, 75, 77, and 85.

But there probably will be air travel problems, too. Some major airports, including hubs such as Atlanta, Memphis and Charlotte, figure to have delays and cancellations, especially on Monday. Some of the smaller airports also will be affected -- Little Rock, Birmingham, Jackson, Columbia, Greenville-Spartanburg.

By Monday, these cancellations could have a ripple effect that causes problems across the eastern United States, even in cities not directly impacted by the storm.

If you're planning to fly later today or Monday, have a backup plan.

SCHOOL CLOSINGS.

Pity the school superintendents who probably will have to decide on canceling classes early Monday -- before the snow ever arrives.

If the storm system continues to behave the way it's predicted to do, the decision on whether or not to close school Monday should be easy. Having 3 to 5 inches of snow fall on highways in the Carolinas means there's no school. But it's a lot easier to make that call when the snow already has arrived.

Incidentally, should this storm produce the snow and sleet that is predicted, there probably will be a lot of school closings Tuesday, too. And the delayed openings could extend into Wednesday.

Temperatures will only reach 32 to 35 degrees Tuesday, so little melting will take place. And with lows in the mid 20s Wednesday morning, the slush would re-freeze.

We might "escape" with heavy snow

Many people might look at the forecast of 4 to 6 inches of snow Monday in Charlotte as a big problem, and it will be.

But we might be getting off easy from the storm system expected to move across the South on Sunday and Monday.

A corridor farther to our south stands to get hammered by an ice storm that could knock out power to tens of thousands of customers. That area will stretch from northern Louisiana, across central Mississippi, central and southern Alabama, and southern Georgia.

Heavy snow could fall from northern Mississippi, across northern Alabama, northern Georgia and the western Carolinas.

We'll watch the development of this storm over the next few days, but it looks now (Saturday morning) as if the cities that could get the worst of the freezing rain and power outages would include Shreveport, La.; Jackson, Miss.; Montgomery, Ala.; Macon, Ga.; and possibly Columbia. Other big cities in the South -- Birmingham, Atlanta, Charlotte and Raleigh -- are more in the zone of heavy snow, rather than ice.

All this can change. Stay tuned.

8 inches, or 2 inches plus ice?

The computer models and meteorologists are in rare agreement that a storm system will turn the start of the work week Monday into a first-class mess in the Carolinas.

If you're of the belief that a 100 percent lock-sure forecast of snow or ice means it won't happen, suit yourself.

The rest of you might want to plan ahead for a messy Monday.

All of the computer models -- the GFS, European, and so on -- predict a low pressure system developing this weekend in the western Gulf of Mexico. That system is expected to track across the northern Gulf and then either head off the Carolinas coast and curve up the coast.

Either way, the Carolinas, especially the Piedmont, figure to be in the crosshair of the frozen precipitation. And once it falls, the frozen stuff might not disappear for a while (we'll deal with that issue later).

First, the customary caution ... the storm system responsible for this mess hasn't actually formed yet. So forecasts can change dramatically over the next few days. But the current thinking is that precipitation will move into the Charlotte area sometime shortly after midnight Sunday, probably in the form of snow.

And it will be around Monday evening or maybe early Tuesday before it ends.

Anthony Sturey, of the National Weather Service office in Greer, S.C., has produced a graphic that shows the heaviest snow and sleet accumulations in a band from Gaffney, S.C., over to western Union County. It includes the Charlotte area, and we're talking about 7 1/2 to 8 1/2 inches.

Relax! Sturey says that Armageddon-like forecast is preliminary. "these are very preliminary snow estimates," he says.

I've seen other forecasts from private meteorologists of 2 to 4 inches, with quite a bit of sleet and freezing rain on top. They think the precipitation will start as snow, then change to sleet and freezing rain by Monday afternoon.

It probably will be Sunday morning before we have a really good idea on the timing and the totals. But it's also important to mention that this storm will precede another blast of very cold air later next week.

We could be looking at single-digit morning temperatures next Friday and Saturday in the Charlotte region, with daytime highs not climbing above the mid 30s. The cold air next week will delay the melting of whatever falls Monday and will present black ice and re-freezing problems Tuesday and Wednesday mornings.

More to come ...

Winter storm could strike area Monday

There might not be anything pretty about the winter storm system predicted to affect the Charlotte area at the beginning of next week.

In fact, we might be dealing with the much-dreaded mixed bag of precipitation that includes ice on Monday.

A huge dome of polar air that dropped temperatures to near minus-80 degrees Fahrenheit last week in Siberia is expected to send a piece of that system crashing into Canada and the United States over the next few days.

Over the next two weeks, additional pieces of that incredibly cold air are forecast to move into the United States.

With cold air in place early next week, a low pressure system is predicted to form in the western Gulf of Mexico, move along the Gulf Coast, and then swing up the East Coast early next week. The Charlotte area would be on the cold side of that system, which means wintry precipitation.

The last time, temperatures in Charlotte were above freezing when the storm arrived, so the precipitation fell as rain for a few hours on Christmas Day, until the atmosphere cooled sufficiently and the rain changed to snow.

It's still four days from the arrival of the storm system, but meteorologists say the computer models are indicating layers of air that are above and below freezing. Specifically, some of the models (including the 6Z GFS) show a layer of warm air above a layer of freezing temperatures near the ground. That would support sleet or freezing rain.

People disagree about snow. Some folks like it, some don't.

There's no disagreement about sleet and freezing rain. Everyone hates it. Sleet turns roads into ice rinks. Freezing rain knocks out power.

Mike Dross, a meteorologist who used to work for Duke Energy and now puts his forecasting skills to use with the energy industry in Houston, says he sees a scenario where some parts of the Charlotte area receive 1/4 inch of ice. That's enough for power outages.

"This will probably change with future (computer model) runs," Dross says, but he adds that the freezing rain-sleet forecast is what the computers are projecting now.

And this might be just the start of a stretch of bad weather. Temperatures seem likely to remain below average for a week or more, so if any other low pressure systems develop in the Gulf, they could bring more trouble to the Charlotte area.

The big news of 2010

We've got the coldest air in possibly two decades headed our way next week, so let me get some unfinished business out of the way -- and then we'll start thinking about the frigid air mass headed our way.

First, let's put a wrap on 2010, and the big weather stories in the Charlotte region:

1. A non-story ... the lack of hurricanes.

The National Hurricane Center and just about every other long-range meteorologist predicted a busy year for tropical storms and hurricanes in the Atlantic basin, and they were correct. There were 19 named storms this year, compared to an average of 11.

But nearly all the storms veered away from the U.S. mainland. A few of the meteorologists who make hurricane season predictions had forecast landfall of a major storm on the Southeast coast, but a powerful high pressure system sat over our part of the country through much of July, August and September.

That kept storms from the U.S. coast. It was good news for vacationers, those who own beachfront property, and all of us who didn't have to pay $6 a gallon for gasoline (no storms affected the petroleum industry).

2. The summer heat.

There were only two days above 100 degrees, both in July, and that's not terribly out of the ordinary. But Charlotte came within an eyelash of breaking the record for 90-degree days.

There were 87 days of 90 degrees or hotter in Charlotte, barely falling short of the record of 88, set in the miserably hot summer of 1954. Summer got off to a hot start, with 18 straight 90-degree days in June, and the heat kept going through Sept. 25, when it hit 95 degrees.

On Sept. 26, the high was only 75, and that marked an end to a very hot summer.

3. Christmas snow (or Dec. 26 snow).

Whether 2010 produced a white Christmas or not is something meteorologists can argue about. The National Weather Service says official snowfall measurements are taken at 7 a.m., but there was accumulated snow in Charlotte before midnight on Christmas. So for most of us, it was a white Christmas.

While the snowfall -- and all the speculation leading up to the snow -- was something of a curiosity piece for the Charlotte area, the storm system was a serious problem farther up the East Coast, where it turned into a raging blizzard. The storm wrecked the airline flight schedule for several days and turned the Christmas holiday into a first-class mess for many travelers.

4. October 26 tornadoes.

A half-dozen tornadoes touched down in Cleveland, Catawba and Iredell counties, as a powerful low pressure system moving along a stalled cold front spread stormy weather across much of the western Carolinas.

The next day, additional severe thunderstorm activity broke out across the area, before the cold front finally sagged into South Carolina.

5. March 28 tornadoes.

A low pressure system moving across the Carolinas set off severe weather on a Sunday evening, including a tornado in Belmont and thunderstorms with damaging wind gusts in western Mecklenburg County. The same system also triggered a tornado in the northern Rowan County town of Spencer. Fortunately, there were no serious injuries.