Cover Story: Predicting winter weather

By Jeff Atkinson - bio l email

CHARLOTTE, NC (WBTV) - This might seem like a strange time to talk about balloons when snow is falling from the sky, but balloons play an integral role in forecasting storms like we had this week.

For almost a week now, we've been trying to pin our meteorologists down for the details of Tuesday night's storm.  Until Monday they said "the models are conflicting."

What does that mean and how to balloons fit in?  It's those balloons and the data they bring in that allow meteorologists to make the most accurate forecast.

But how do you make an educated decision when you're getting mixed messages?

When the snow came down in Charlotte mid-morning on Tuesday.. you could almost hear a sigh of relief go up.

There in black and white in the morning newspaper:  "Rain, snow or slush?  Forecasters not sure."

A meteorologist with the National Weather Service said pinpointing this forecast is "almost like nailing jello to a wall."

Even WBTV senior meteorologist Eric Thomas was hedging his bets.  He said Monday night, "It still could go either way. This is one of the trickiest ones I've had to deal with."

What made this one so tricky? Why the uncertainty about whether it was going to be snow or rain?

"Until the snow actually started to fall and you could see the whites of its eyes we weren't 100-percent sure which way this was going to go," says WBTV meteorologist Al Conklin.

You could blame the balloons.  Radiosondes (their official name) are launched all over the globe at the same time twice a day to give us a snapshot of atmospheric conditions.

Data's entered into a computer and using different formulas various model are developed of how weather will behave going forward.

In this case the models didn't agree.

"We look at generally about 4, 5, 6 models. As we get closer to a storm typically they start to converge on one final solution. That didn't really happen here."

At the time of the storm hitting us, some models pinpointed the air at the surface (about a-thousand feet from the ground up.. the critical area) would be cold.. below freezing-- bringing us snow.

Other models showed the surface air temperature would be above freezing.. which would lead to rain.

You know which one won out.

Meteorologist Al Conklin says forecasting in the Carolinas in the winter can be tricky because the surface air here can change.

We're not like a Buffalo where it stays cold and any winter precip is snow.  Or a Tampa where winter precip is generally rain.

Did you know an inch of rain is equal to about a foot of snow?

Say they forecast an inch of rain and we get a half-inch.. usually not a big deal.. no one even knows.

But the same moisture difference with SNOW ... Could be six or more inches!

Says Conklin, "And you go out and say we're going to get one to three inches of snow and in reality we get seven inches of snow. Everybody goes crazy. What happened to the forecast? It was so wrong. You're only off by about that much."

Snow is an emotional forecast in Charlotte.. we only average about 7 inches of snow a winter.  And for some reason it likes March 2nd.

Of the top 10 March snows in Charlotte, four of them have happened on guess when.. March 2nd.

And of course it was 50 years ago Tuesday.. a big snow on March 2nd..

It was a Wednesday and that year it snowed on three consecutive Wednesdays.

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