A first look at winter

A real autumn air mass will roll into our region this weekend, and at some point Saturday or Sunday, you'll think about winter.

Hopefully, you won't think too much about winter, because we have a lot of beautiful fall weather ahead before the next season change.

But if the thought crosses your mind about winter 2011-12, here's the answer ... it looks like a mixed bag again this year, much like last winter. And some meteorologists say our upcoming winter could more closely resemble 2008-09, which was among the craziest winters we've experienced in a long time.

First, a review of last winter -- 2 1/2 months of nasty, cold and sometimes wet weather; followed by one month of an early spring.

The same players are here again this year. La Nina has reappeared, after disappearing late in the spring. La Nina is a condition of colder-than-average waters in the eastern Pacific, and it usually translates into dry, mild weather for the southern tier of the United States. It also was blamed in part for the tornado outbreak last spring, but let's focus on winter for now.

If La Nina were the only condition of importance, we'd be looking for a dry and mild winter.

But another key factor, as we learned last year, is the North Atlantic Oscillation, or NAO. That condition describes the overall path of the jet stream in the upper ranges of the Northern Hemisphere. When the NAO is negative, as it was for the first two-thirds of last winter, it means cold air masses and occasional storm systems dive from the arctic into the eastern United States (and also into Great Britain and northern Europe, on the other end of the stream).

Last December and January were very cold months, and there were notable winter storms on Christmas Day and again Jan. 9-10. We had a few other close calls on winter storms, and the Mid-Atlantic got hammered.

Then, like someone flicked a switch, the NAO relaxed around Valentine's Day. La Nina took stronger control, and high pressure built over Texas. We had warm weather and mostly dry conditions from mid-February into much of March.

But what about the winter of 2008-09, which some meteorologists expect in some form this winter? It was wild. Overall, temperatures were around average for the season (see map at upper right). But try these extremes:

-- December was mild. It reached 67 degrees on Christmas.

-- January and February featured wild swings. It dropped to 9 degrees on Jan. 17 but hit 60 or higher six days. Feb. 5's low was 13, but it climbed to 71 degrees just two days later.

-- Then came March. A strong winter storm struck on the 1st. After dumping nearly 2 inches of rain and causing flooding, the precipitation changed to snow that Sunday evening, and we got 4 inches in Charlotte (the only measurable snow of the winter). A foot fell near Shelby. Then, less than a week later, it was 80 degrees. In fact, we had six days of 70 or warmer in the first part of the month.

We'll fine-tune the forecast in weeks to come, but this will give you something to think about as you break out the sweaters and jackets this weekend.

The real Weather Guy

I'd planned to write today about the coming winter's weather, but there'll be another day for that.

Instead, today's topic is a person whose work you had read for years in the Observer, but you never saw his name. I don't know if he considered himself a weather geek, but I did. For true weather geeks, that's not a title we hand anybody. It's earned.

I came to the Observer more than 33 years ago, and a year or two after I arrived, I realized we'd hired a clerk named Joe Sovacool. The term "clerk" doesn't describe everything he did. Basically, Joe managed the Newsroom.

He shuffled phone calls to the right people, answered the phones and received thousands of tips from the public, passed those tips to reporters, and did dozens of other things.

He knew a lot about the Charlotte region and a lot about the journalism business. If a reporter or editor asked him for advice, they'd get a good, sound answer.

Joe also handled the Observer's weather page. A lot of the information we publish on that page comes to us automatically, but it wasn't that way 20 or 25 years ago. We had a weather wire machine, and Joe accumulated and compiled the high and low temperatures, forecasts, tide information and everything else on the page.

Somewhere along the way, I discovered Joe actually enjoyed meteorology.

He understood the peculiarities of Carolinas weather, and he taught me a few things over the years. About a decade ago, when I started writing about the weather, I would run ideas past him. We'd talk about a topic -- an approaching storm, a dry spell, memorable snowfalls.

"Are you gonna write about it?" he'd ask.

Joe cared about that weather page. It was merely one of many things he did, but he took this whole journalism accuracy thing seriously. He knew people looked for temperature information and when high tide was coming.

Back in September 1989, when I was working in our Monroe bureau, I called Joe to talk about Hurricane Hugo, which was then near Puerto Rico. We agreed that Hugo seemed headed for the Carolinas, and we talked about the possibility that it might affect Charlotte.

"Are you gonna write about it?" he asked. I didn't. Back then, I wasn't a weather writer.

Joe died Thursday evening, and all of us at the Observer -- whether we've been there one year or 33 -- will miss his friendship.

To me, he's the Observer's real Weather Guy.

And this time, I'm writing about it.

Storm deflector's turned on

It's like someone sprayed a can of storm repellent on the United States mainland this weekend, and the result for those of us in the Carolinas will be the nicest Saturday-Sunday combination we've had in quite a while.

If you're headed for any of the festivals in the area (the Greek Festival and the Blues & BBQ event are Charlotte's highlights), you'll have great weather. The same is true for anyone headed to a football game this weekend.

There are three tropical weather systems in the Atlantic/Caribbean basin, but none of them figure to bring us much trouble either.

High pressure will dominate the Carolinas for several days, and the stubborn storm system -- the remnants of Tropical Storm Lee -- that caused serious flooding in parts of the East has moved away. That system spun clouds into the Charlotte region Wednesday and Thursday, but sunshine has taken control today. That will continue into next week.

With more sun, high temperatures will return to the low 80s today, then the mid 80s over the weekend. Morning lows will be near 60.

Folks, it doesn't get much better than that in September.

It looks as if the upper 80s will return by later next week. The computers continue to hint at a real cool down next weekend (think, highs in the mid 70s), followed by a return to 90-degree weather by Sept. 20 or so.

Here's a rundown of the tropical weather systems:

Katia -- This system is losing its tropical characteristics as it moves into cooler water in the North Atlantic. It looks like Katia will plow into Scotland early Sunday with sustained winds of 70 mph and stronger gusts. That'll be a very stormy day in the northern part of the British Isles.

Maria -- It was a weak tropical storm Friday morning, but the National Hurricane Center expects Maria to get stronger over the next two days, possibly reaching low-level hurricane status. Maria will bring strong winds and rain to the northern Antilles (Guadeloupe and St. Martin, for example) and then the Virgin Islands. After that, Maria will do what most other hurricanes have done this year in the Atlantic -- curve away from the U.S. coast.

A strong trough continues to dominate conditions along the East Coast, and it has provided the United States with hurricane insurance this year, with the notable exception of Irene.

High waves and rip currents will be a problem along the Outer Banks, however, due to Maria.

Nate -- This tropical storm is forecast to grow into a hurricane. It's in the Bay of Campeche, in the southern part of the Gulf of Mexico. Hurricane specialists expect it to make landfall in central Mexico later this weekend. It will have no impact on the United States.

Today's topics: Phony autumn, busy tropics

It really seemed like autumn arrived in the Charlotte region today, with the morning low dropping to 59 degrees, and temperatures only recovering into the lower 70s by mid-afternoon.

Cool weather is expected to continue for several days, with highs near 80 and lows in the upper 50s. And it's a dry air mass, not the artificially-cooled situations we sometimes get when the humidity is sky-high and the only reason why temperatures have dropped is because of thick clouds.

No, this really is a taste of autumn, thanks to low pressure over the eastern United States that is dragging Canadian air southward.

But the computers say it won't last. Actually, we didn't need the computers. The calendar and common sense could have told us that.

It's September 7, and history shows there are still some hot days ahead. Sure enough, the latest computer models predict a return of much warmer conditions by next Tuesday. Highs in the middle of next week are predicted to be in the upper 80s to near 90 degrees. The computers show plenty of really warm weather into the last week of September, in fact.

So enjoy the next few days, and pretend that autumn has arrived. But when summer returns next week, you should be prepared.

Busy Tropics: As of 2:30 p.m. Wednesday, we have three systems in the Atlantic/Caribbean basin. Hurricane Katia is bound for the North Atlantic, never to bother a land mass in the Western Hemisphere. It was steered away from the United States by a low pressure trough over the East Coast -- as has been the case, in large part, for about three years.

The other two systems are Tropical Storm Maria, which is in the eastern Atlantic, and Invest 96F, a cluster of thunderstorms in the Bay of Campeche, off the Gulf of Mexico.

The computers haven't agreed on the future track of either system, but their paths might be related -- just as Tropical Storm Lee's northeast push pushed Katia away from the U.S. coast.

If 96F, which is expected to become a tropical storm soon, moves northward into the Gulf Coast, it would deepen the trough along the eastern United States shore and steer Maria away from the coast. That's what some computer models are predicting. By the way, that would leave open the possibility of 96F (which would be named Nate) copying Lee and bringing heavy storms into the western Carolinas.

But that's a long ways down the road.

Now, if 96F should move westward into Mexico (which is what most models forecast), then it leaves the door open for Maria to stay on a westerly track past the Caribbean islands and toward the Florida or Georgia coast.

The overwhelming trend this year -- and in 2008, 2009 and 2010 -- has been for Atlantic hurricanes to curve away from the Southeast coast. And that's probably what will happen with Maria.

But there are some interesting possibilities to watch in coming days.

Katia -- a real headache for forecasters

Hurricane Katia ... oops, Tropical Storm Katia (it's swung back and forth several times in recent days) has proven to be a real mess for the National Hurricane Center's meteorologists.

Both the storm's intensity and track have proven nearly impossible to predict, and the 5 p.m. update from the National Hurricane Center reinforces that.

Meteorologist Daniel Brown said it "cannot be stressed enough that there is considerable uncertainty in the track forecast."

Brown noted -- as have other meteorologists -- that the evolution and future path of Tropical Storm Lee will have a great deal to do with whether Katia curves away from the U.S. coast or plows into the mainland later next week. For days, computer models have predicted the storm would curve into the open Atlantic.

But the models also have waffled on the forecast. Some models that once predicted a recurve are now hinting that Katia -- currently heading northwest and far from any land mass -- might switch to a westerly track in several days, making a beeline for the U.S. coast. And some models that initially brought the storm close to shore have switched to a recurve solution.

If Tropical Storm Lee moves northeast in the next few days, as predicted, it will serve to "catch" Hurricane Katia and curve it northward, away from the U.S. coast.

But the winds steering Lee are extremely light, and forecasters aren't certain when it will move.

And if all that isn't enough, the National Hurricane Center has struck out in trying to predict Katia's intensity. Forecasters predicted a couple days ago that Katia would be a major hurricane by now. Instead, its top sustained winds were only 70 mph Saturday evening.

It's a mess, and it will be another few days before we can say with certainty that the East Coast is safe.

Katia's future? Look to Japan

Hurricane Katia will make this a very nerve-wracking and interesting weekend for amateur and professional meteorologists -- and for authorities along the East Coast of the United States.

For days, the computer models insisted that Katia would become a major hurricane and curve northward, never coming close to the United States. If any land mass would be threatened, it would be Bermuda.

That has changed considerably over the past 24 or 36 hours.

And Jeff Masters, a really outstanding meteorologist with plenty of tropical forecasting experience, says Katia's future might depend a lot on a tropical storm predicted to hit Japan this weekend.

Here's the set-up:

Many of the computer models show a slow-moving but strong Hurricane Katia moving northwest for a few days, but then veering westward toward the Carolinas coast. That westward turn depends on the strength of a trough (low pressure) along the U.S. East Coast.

A deep trough would recurve Katia away from the United States. A not-so-weak trough would allow high pressure in the Atlantic to strengthen. And the clockwise flow around the high would push Katia into the East Coast.

So what about the Japanese storm?

Tropical Storm Talas is expected to move into Japan on Saturday morning, then convert to a non-tropical storm -- and a very strong one -- in the Gulf of Alaska.

That Gulf of Alaska storm is predicted to have a ripple effect on smaller storm systems downstream -- across Canada and into the United States, including the trough in the East. If Talas becomes a very strong storm, the thinking is that it will deepen the trough in the East and push Katia away from the United States.

A weaker Alaskan low, and Katia could push toward the United States.

You can read Masters' blog at http://bit.ly/qyN9qh.

Katia wouldn't threaten land until the end of next week. But its waves and rip currents could be felt along the Outer Banks and possibly the Grand Strand by Labor Day.

As we said, this will be an interesting weekend. The last thing that anyone on the Outer Banks wants is another visit from a hurricane.

Tropical trouble for someone

The tropics are certainly back in business for meteorologists, with a hurricane moving westward in the Atlantic and another system trying to form in the Gulf of Mexico.

The next several days will be extremely interesting for meteorologists and other weather-watchers, because the computer models can't figure out what to make of the situation.

There is a chance that the Charlotte region could be affected by either -- or neither -- of the two systems.

Hurricane Katia is out there -- way out there -- in the Atlantic. The coordinates at midday Wednesday were 15.5 degrees North and 47.5 degrees West, and the storm was moving westward at 18 mph with 75 mph winds. Don't look for much strengthening in the next day or two, because the storm is encountering dry air and some shear. But Katia is forecast to intensify by late Friday or Saturday and eventually become a major hurricane.

The other system is a cluster of showers and thunderstorms in the Gulf of Mexico, south of Louisiana. Most computer models predict it will become Lee (probably as a tropical storm, not a hurricane), but the computers take the storm all over the place -- westward to near Brownsville, Texas; north into Texas or Louisiana; or even eastward into Alabama or western Florida.

The Gulf low could bring heavy rain to the Charlotte area, perhaps as early as Labor Day but probably later next week. To do that, it would have to come ashore and link with an approaching cold front. That looked likely in yesterday's computer model runs, but less so today (Wednesday).

As for Katia ... who knows?

For several days, the computers predicted the hurricane would curve northward, becoming a threat to Bermuda.

But in the last 24 hours, the computers are predicting that a trough (low pressure) forecast to drop into the eastern United States will be weaker than first expected. That trough -- located between high pressure over Texas and another system in the Atlantic -- was expected to allow Katia to curve northward.

But if the trough is weak, the Atlantic high pressure system could steer Katia toward the U.S. coast.

And to make things even more complicated, the Gulf storm system also could have an impact on Katia's track, by helping steer it northward -- if the Gulf low becomes strong enough, and if it moves eastward.

I think the Gulf system will have more of an impact on our lives, but we'll have to keep watching closely over the next few days.