What's worse ... sleet or freezing rain?

The winter storm system moving across the Carolinas today is bringing all three types of precipitation -- snow, sleet and freezing rain.

We won't have to worry much about snow, as a "nose" of warm air several thousand feet up in the atmosphere is melting the precipitation as it falls. Some of that is refreezing into sleet, and some is reaching the ground as rain -- then freezing.

Anyways, since we're seeing a little of everything this morning, here's a quick primer on how it forms.  And I'm including my two cents' worth on what's worse ...

SNOW

This requires cold air in all levels of the atmosphere.  The only areas seeing snow today are in the northwest mountains, because the "warm nose" (I'll explain this later) isn't expected to reach as far north as the Boone area.

Power outage impact: Usually none, unless the snow is very heavy.

Road impact: Considerable, although crews usually can manage snow with plows and salt.

SLEET

For sleet to fall, we need a relatively thin column of warm air in the middle levels of the atmosphere. Precipitation starts falling as snow, melts on its way down and forms rain droplets, then freezes back into ice pellets as it moves within a few thousand feet of the surface.

Power outage impact: None.

Road impact: Intense.  Sleet causes big problems on the roads, as it tends to melt when reaching the surface and then freezes immediately.  Also, sleet tends to fall when precipitation is heavier. The overwhelming volume of sleet causes pockets of frozen pebbles to form on roads.

FREEZING RAIN

For freezing rain to fall, we need cold air at the upper levels, and then relatively warmer air all the way to the ground. But the surface levels have to be at or below freezing.

Power outage impact: If ice accumulates 1/4 of an inch, tree limbs can fall onto power lines, and we have trouble. When ice accumulates to 1/2 inch or more, there can be widespread problems.  Accumulations in the Charlotte area from today's system are only predicted to be 1/10 of an inch.

Road impact: Often, the main travel lanes on major roads remain in pretty good shape during freezing rain. Ice tends to form on the curbs -- and, of course, on bridges and overpasses, where the road surface is colder. Sidewalks are especially dangerous.  One other thing -- downhill sections of roads tend to get ice, too.  I'm sure there some explanation for this, but you'd have to ask a Physics teacher.

Farmers' Almanac not shutting down

We interrupt coverage of Friday's potential winter storm system with some really important news.

The editor of the Farmers' Almanac said Wednesday morning that the annual publication, which is 196 years old, will continue to be printed.

That was in some doubt after an announcement earlier this week that the manufacturing facilities at the almanac's headquarters in Lewiston, Maine, will be shutting down. That closure will eliminate about 75 jobs.

Peter Geiger, the Farmers' Almanac editor, says the issues that have been printed at the Maine plant since 1955 had been used for promotional purposes. Geiger, the parent company of the Farmers' Almanac, produced a variety of promotional materials at the plant, Peter Geiger said.

But the Farmers' Almanac that you see on shelves in grocery stores, magazine racks and book stores was printed at another plant, in Wisconsin.

The Farmers' Almanac remains interesting reading. It is loaded with facts -- some obscure, some of real-life value.  It also contains a number of other articles, but its noteworthy appeal is meteorology.

The almanac, of course, contains weather forecasts that are produced far in advance -- more than a year in advance, for some months. The authors say their predictions are based on a number of scientific principles, and considering the inconsistencies of computer models used by the National Weather Service and other meteorologists, it's sometimes tough to criticize the Farmers' Almanac methods.

Geiger says the almanac is "much more than just a physical product. It's a way of life, a belief that you can live life more simply, naturally, and in harmony with the world around you."

By the way, the almanac's forecast for the next few days in Charlotte is "mild with showers."  Oh, well ... you can't get them all right.

Another Friday, another iffy forecast

It would be easy for meteorologists if arctic air was in place across the Carolinas, and a big low pressure system was moving out of the Gulf of Mexico toward the region.

That would mean a big winter storm.

But as was the case last Friday, a storm system expected to affect the region this Friday won't have all the ingredients needed to produce a sure-fire, lock-cinch wintry forecast.

Last Friday, the powerful low pressure system was lacking cold air. It got cold enough, briefly, for a few bursts of snow. But for the most part, that was a serious rain-maker.

This week, arctic air will be in place. The questions surround the storm's path and the amount of precipitation.

The cold air arrived early Tuesday and won't really leave this week, although it will become slightly modified across the Southeast. By Thursday, high temperatures might be in the range of 45 to 48 degrees in Charlotte.

The low pressure system hasn't formed yet. It will develop off a larger storm in the Pacific, then will follow a path into the western United States, across the Midwest, and then eventually into the Southeast or Mid-Atlantic.

The computer models have been evolving over the last 24 hours, and that probably will continue to happen for another 24 to 48 hours.  Monday at this time, the Friday event looked like nothing for the Carolinas. It appeared as if low pressure would track along the Ohio Valley and bring some major snowfall to places like Ohio, Pennsylvania, New York, and New England.

But some of the computer models have begun forecasting the low will dive a bit, into the Southeast.

Precipitation amounts still look light, but with arctic air in place when something starts falling from the clouds Friday morning, it wouldn't take much to cause problems.

Temperatures could be in the upper 20s and low 30s when something -- snow, sleet or rain -- begins falling. If it's rain, the precipitation will freeze on surfaces (especially bridges, overpasses, tree limbs and wires). That's the working definition of freezing rain.

Right now, there is nothing pointing toward a major freezing rain event for the Charlotte area. But there is enough input from computer models to show a few hours of light freezing rain, and that would be enough to bring some big business to auto body shops.

Farther to the north -- let's say, along the I-40 corridor -- the precipitation would be more likely to start as snow before changing over to sleet or freezing rain. Some of the computer models show Hickory and Statesville remaining below freezing for much, if not all, of Friday.

There's a long way to go yet.  If the models shift the storm back to the north, we could be looking at a bit of sleet or freezing drizzle Friday, but nothing else.

As WCNC-TV chief meteorologist Brad Panovich notes, "This one bears watching."

Inauguration -- today's near-miss, and some history

Today's inauguration ceremonies for President Obama will take place under fairly nice conditions for this time of year.

Temperatures reached 60 degrees Sunday in Washington, and although it'll be quite a bit cooler today, the weather still will be better than what you'd expect in the nation's capital for Jan. 21.

If the ceremony were taking place eight hours later, or 24 hours later, it would be a lot different -- and not nearly so nice.

And in looking at history, you get even more appreciation for today's mild conditions. Some past U.S. Presidents have been inaugurated in horrible conditions.

For the official swearing-in ceremony at noon today, the forecast is for partly sunny skies and temperatures in the mid 40s. The average high for Jan. 21 in Washington is 43 degrees, and the temperatures might reach the upper 40s during Monday afternoon's inaugural parade.

A strong cold front, accompanied by a weak low pressure system, will cross the Mid-Atlantic later Monday. Snow could break out by late afternoon, temperatures definitely will be tumbling. All this will be accompanied by a stiff northwest breeze.  It's possible that an inch of snow could accumulate this evening.

Tuesday's high temperatures in Washington won't get out of the 20s, so it's a good thing the calendar has placed the inauguration today.

But as I said earlier, it could be worse.

The National Weather Service's office in Baltimore-Washington has produced a nice feature article, complete with photos, on the history of weather for the inauguration.

Anyone of my era probably remembers the inauguration of John F. Kennedy in 1961. The event already was historic, because Kennedy came into office as part of a new era in politics, as a fresh political face. He also came into office a day after an 8-inch snowstorm buried Washington.

Old video of the swearing-in ceremonies and subsequent parade make it look as if the inauguration took place in Duluth, not D.C.

Some other interesting tidbits from history ...

First, you'll remember that until Franklin D. Roosevelt's second inauguration in 1937, the event took place March 4.  In 1909, William Howard Taft's events were moved indoors because of an early-March snowstorm, with 10 inches of the white stuff. Winds knocked down trees and power poles.

A cold rain fell in 1841, when William Henry Harrison was sworn in. He caught pneumonia and died a month later.

In 1937, for the first Jan. 20 inauguration, a nor'easter moved up the East Coast. Temperatures were in the mid 30s, and more than 1 3/4 inches of rain fell in Washington. FDR insisted on riding in the inaugural parade in an open car.

Ronald Reagan's two inaugurations made history -- in different ways. In 1981, it was 55 degrees when he took the oath of office at noon. That's the warmest ever for a Jan. 20-21 inauguration.

But four years later, at his second inaugural, the parade was canceled in the wake of the worst arctic outbreak in the eastern United States in decades.  That was the outbreak that produced a low temperature of minus-5 degrees in Charlotte.  It was 7 degrees at noon that day in Washington, with wind chills of 20 to 25 degrees below zero.

Check out the Weather Service's article here http://www.erh.noaa.gov/lwx/Historic_Events/Inauguration/Inauguration.html

That was one crazy weather week!

The week has not ended, but it appears as if our wild weather has, fortunately.

We've gone from late spring, to fall, to winter -- all in a span of five days. We've tied or broken records for warm temperatures and rainfall. We've had thundersnow, regular snow, and flooding.

A blast of cold air -- the coldest we've seen in probably two years -- is coming early next week. But we'll have time to discuss that later.

In the meantime, let's take a look at some of the amazing weather of our past week in the Charlotte region and the rest of the Carolinas, in no particular order:

-- Charlotte's high temperature last Sunday was 75 degrees, which tied a record for the date and was about 25 degrees above the average high for that time of year. That came a day after we had a 73-degree high.

-- The weather turned cooler in Charlotte late in the week, but not to the south of us. On Thursday, while Charlotte dealt with a cold rain and temperatures in the upper 40s, it was nearly 80 degrees as close as Columbia and Florence (about 90 to 100 miles away).  Get in the car, drive 90 minutes, and switch from overcoat to shorts and T-shirts.

-- The warm front that divided winter and late spring on Thursday pushed south late in the afternoon. Temperatures fell from 78 degrees in Columbia to 50 degrees in three hours.

-- Mountain rainfall was excessive, and it certainly put a dent in drought conditions. Some totals I saw this morning included (for the past seven days): 12.18 inches at Wallace Gap, in Macon County in the western mountains; 9.33 inches at Highlands; 8.57 inches at Sylva; 7.39 inches at Elkville, in Wilkes County; 6.49 inches at Ararat, in Surry County; 4.99 inches at Healing Springs, in Davidson County; and 4.81 inches at Jacobs Fork, in Burke County.

-- Rainfall on Thursday from the strong low pressure system was 2.38 inches at Charlotte's airport. That set a record for the date.

-- Thursday's rain in Charlotte was the most since May 8 (2.41 inches). And Thursday's rain was 3 1/2 times the total for the entire month of November.

-- Shelby recorded 3.1 inches of rain Thursday. That was the most for the day anywhere in the United States.

-- There were numerous reports Thursday night in the area of thundersnow.  WCNC's Brad Panovich did a nice job in an Observer chat Thursday of explaining the phenomena. You need about 60 degrees' difference from ground temperature to the top of the cloud for a thunderstorm to form. That's not hard to find in summer. It is in winter. But on Thursday night, with air temperatures around 35 degrees, the extremely cold tops of clouds in the strong low pressure system were around minus-30 degrees.

What will next week bring?

Thundersnow from a potent little storm

The low pressure system that will be responsible for heavy rain and snow today and tonight across the Charlotte region is not your typical winter storm.

This is an unusual system that has fascinated weather fanatics and meteorologists -- the kind of storm we don't see very often.

It is expected to produce thundersnow, and precipitation falling at extremely heavy rates.

Any other winter system that crossed our region with snow, ground temperatures around 50 degrees, and air temperatures around freezing wouldn't be a threat to drop accumulating snow. It would melt on its way to the ground, or quickly when it touched ground.

But this storm is different.

It is very strong, not very big, and will be moving quickly.  It is strong enough to create its old cold weather, actually.

As I've written before, this column is not aimed at meteorologists, but at people who are fascinated by weather. So I won't go into deep detail. But suffice to say there will be a lot of vertical lift in the clouds.

As WCNC-TV meteorologist Brad Panovich noted earlier today, it takes a difference of about 60 degrees between ground and upper level of clouds for a thunderstorm. That's not hard to get in summer, but it's unusual in winter. Ground temperatures will be near 35 degrees, but the very cold air aloft in this strong system will have readings about 20 to 30 degrees below zero.

When that happens, precipitation falls at very rapid rates.

Heavy rain is likely this afternoon and early this evening across the area. And as the center of the system crosses the area, temperatures will tumble, and the very cold air at the top of the cloud columns will be sent to the ground. That will help saturate the air with cold temperatures, enabling snow to reach the ground.

If the snow falls heavily enough, it will overcome the relatively warm ground temperatures and accumulate. Obviously, the process will be helped in places where ground temperatures are cooler (such as the mountains). But if it snows really hard in the Piedmont, those places could get a quick 2, 3 or even 4 inches of snow.

A similar storm hit the area March 1-2, 2009. Heavy rain fell that Sunday afternoon in Charlotte, and the rain changed to snow about 7 p.m. that day. Between 1 and 2 inches accumulated.

But a deformation zone -- one of those areas of heaviest precipitation -- formed in a corridor from Gaffney, S.C., to west of Gastonia. Strangely, that zone was right along Interstate 85. Snow fell at a rate of 2 to 3 inches an hour, and between 8 and 12 inches accumulated. Cars and trucks were stranded on the interstate highway overnight.

Will that happen again tonight?  Possibly, somewhere.

Either way, this is an interesting storm to watch.

Something I forgot ... There are some absolutely amazing temperature contrasts today in the Carolinas.  While we're talking about a snowstorm in North Carolina, on the other side of a warm front stretched across South Carolina, it's like April.

Can you believe that the 3 p.m. temperature in Columbia, just 90 minutes away, is 78 degrees! And it's 81 degrees in Kingstree, S.C., about halfway between Columbia and the coast. Or try 78 degrees in Florence.

Waiting for cold air? It's coming next week

The mountains are likely to get a full dose of wintry weather Thursday afternoon and evening, with heavy snow expected to fall for several hours.

That's great news for the ski resort operators and their customers, as the 3 to 6 inches of snow will set the stage for a fun weekend. It's certainly welcome news to those folks, especially after last weekend's spring-like conditions.

Lower elevations, such as Charlotte, will get rain from Thursday's storm, although we'll be seeing a brief shot of winter-like weather next week.

After the storm passes Thursday, it looks like we'll have generally dry and seasonal conditions Friday through Sunday, with highs in the upper 40s Friday and the mid 50s Saturday and Sunday. But a pair of cold fronts will cross the region late Sunday and Monday, and when all that has been completed, an arctic air mass will be the controlling factor in our weather.

Despite full sunshine, we'll be lucky to reach 40 degrees Tuesday afternoon in Charlotte. Morning lows Tuesday might be in the teens.

It'll be cold (mid 40s) again Wednesday, but it appears as if the cold air will be a short-lived event.  High temperatures are forecast to be back in the mid 50s Thursday and Friday.

Meteorologists have been talking for weeks about sudden stratospheric warming at the north polar region, and the eventual displacement of bitterly cold air into Canada and the United States. Some of that very cold air has arrived in the United States, but it's been bottled in the northern part of the country.

When the cold air has tried to poke into the Southeast, it's been short-lived.  Looking ahead into early February, it looks like that pattern will continue.  That doesn't mean we can't get snow, sleet or freezing rain. The storm responsible for mountain snow Thursday will be working with only marginally cold air. But the short-lived cold air intrusions are good news to those who don't like winter.