Behind the scenes–forecasting snowstorms
It’s been quite a winter so far. This morning, winter storm warnings blanket New England as the second major tempest–a true blizzard near Boston–in a little over two weeks mounts a furious assault. It’s already dropped 6 to 12 inches on NYC.
Winter storm warnings are also in effect for much of Washington state, northern Idaho and northwest Montana. Wind chill advisories cover the Great Plains and portions of the Midwest. Hard freeze warnings are a dime-a-dozen in the Deep South.
Where I live, near Atlanta, things remain at a virtual standstill after Sunday night’s crippling snowstorm. No mail. No newspaper delivery. No trash pick up. No school. Oh, and two of Atlanta’s eight plows reportedly collided with each other yesterday. At this rate, it may be St. Paddy’s Day before things return to normal here.
A question I’ve been asked is how do we–meaning meteorologists, both working and retired–know these nasty storms are coming? Forecasting snow, especially in Dixie, has always been fraught with peril. And yet this year, the computer models have been able to hone in on these things with laser-like intensity.
There are two global weather forecasting models on which meteorologists rely most heavily: the European Center for Medium-Range Weather Forecasting (ECMWF) model, or “Euro” as we mets call it, and the U.S. model known as the Global Forecast System or GFS. All of us weather guessers, working or not, have access to these models via the Internet.
Both the Euro and GFS have been pretty darned good recently, although the Euro seems to catch on to developing events a little quicker than does the GFS.
Case in point: the chatter by forecasters on Facebook about Sunday night’s impending snow blitz in Atlanta actually began the previous Wednesday. The Euro was the “canary in a coal mine,” raising the specter of a big winter storm for the Deep South. Meteorologists don’t go public with this sort of talk, since we know way too much can “go wrong” so far in advance.
But by Friday, all the models were singing from the same sheet of music. What had begun as a few glowing embers of discussion on Wednesday had exploded into a full-fledged wildfire on the Internet by Friday.
Although much of the public was aware something big was brewing, many people remained oblivious. Here’s a story that illuminates that. At my stepdaughter’s request to keep her apprised of developments, I sent the following email to her at the large law firm where she works in Midtown, thinking it would be for her eyes only:
Looks like this should be the biggest winter storm in ATL since Superstorm ’93. My guess is the metro area will be at a virtual standstill Monday. Still looks like a late afternoon or early evening start Sunday with maybe 3-5 inches of snow and sleet overnight, topped off by a little light icing…. No rapid warmup after this, so the roads will likely remain a mess for much of the coming week.
It turned out the message got much wider dissemination than I ever intended it to have.
My daughter showed it to her boss who thought it was a joke. He even checked on Snopes.com. Lawyers. Anyhow, convinced the forecast was legit, contingency plans were made to deal with Old Man Winter’s shenanigans Monday and beyond. My stepdaughter says I became a “hero” around the office. But the story doesn’t end there.
She forwarded the message to her father who works at a local Walmart, He showed it to his boss who said, “Wow. I hadn’t heard about this. Maybe we’d better lay in some extra bread and milk.”
Ya think?
Anyhow, based on the early red-flag waving of the Euro model, my wife and I gathered our storm supplies on Wednesday and Thursday. “Let’s beat the stampede,” I told her.
So, is there more winter nastiness in store for the Southern states? Beats me. But given what seems to be a persistent pattern and the fact we haven’t even reached mid-January yet, I wouldn’t bet against it.