That tearing sound you hear is the sound of forecasters' watches and warnings being rent asunder. Mother Nature has used one of the more complex and unusual winter storms in memory to humble the meteorologists and their high-speed computers. It is a pitiless science.

Although the storm is still getting cranked up this (Thursday) morning, and light snow was falling early this morning on the Eastern Shore, Central Maryland has obviously escaped the 1 to 3 inches meteorologists had expected to fall overnight. Temperatures were too mild, and the storm dragged too much dry air into the region to allow much to fall.

There was some snow at BWI-Thurgood Marshall Airport, and it arrived pretty much on schedule in the wee hours after a few hours of light rain. But it never amounted to anything.

Forecasters cancelled their Winter Weather Advisories for much of the region, although they left the Winter Storm Watch up across Carroll, Baltimore and Harford counties - including the city. That's in anticipation of the storm's third act, which could pull cold air and snow out of the northwest as the big low loiters over New York late today and tomorrow.

UPDATE: Those Winter Storm Watches have been downgraded to Winter Weather Advisories, with just 1 to 2 inches of snow likely late today, and perhaps the same amount again overnight. And Anne Arundel County has been added to the advisory zone.

But forecasters out in Sterling don't sound real certain about any of this. (Edits are mine, for clarity):

"METRO BALTIMORE NEAREST CENTERPOINT [OF THE STORM]...AND STANDS BEST CHANCE AT
RECEIVING ACCUMULATING SNOWFALL. MAIN QUESTION THEN BECOMES WHAT TO DO WITH THE
WINTER STORM WATCH CURRENTLY POSTED ACROSS NORTHEAST MD.

"[PRECIPITATION AMOUNTS] WILL BE THE PRIMARY FACTOR. UNFORTUNATELY...DUE TO THE COMPLEXITY OF THE SITUATION...DONT HAVE BEST COMFORT THAT [COMPUTER] GUIDANCE [IS]  ADDRESSING THE NUANCES...ESPECIALLY IN REGARDS TO THE RETROGRADING SURFACE LOW [THE MOVEMENT OF THE STORM'S CENTER].

"SO DONT REALLY WISH TO GO WITH DETERMINISTIC QFP [A DEFINITIVE PREDICTION ON PRECIPITATION]. ... SATURATION IN SNOW GROWTH REGION NOT ALL THAT STELLAR... [SNOW] TOTALS WILL END UP BELOW WARNING [5 INCHES] ...BUT IT COULD BE VERY CLOSE. GIVEN THESE UNCERTAINTIES... WILL LEAVE WATCH STAND THIS CYCLE."

Eric the Red, a professional meteorologist in Baltimore, bailed on the snow forecast late Wednesday evening:

"It is fizzlin' big time. Obviously, snow won't stick when it's 40 degrees. That was courtesy of late-arriving clouds and a strong late-February sun. Next up, the coastal low is gonna stay offshore, so we'll miss the big snow. Finally, the low will travel farther north before getting stopped and turned around by the block, so our wrap-around snow for Thurs night will be less.  As luck would have it, we probably won't miss out on the winds.  Oh joy.

"At this point, maybe an inch or two in northern MD.  For everyone else... nada.  I'm guessing folks won't be too disappointed.  I should point out that we have at least one of these 'It's coming!  Oh, Nevermind...' storms a year, and this is the one for 2009-10."

The student forecasters at FootsForecast.org have a very informative spread on all this on their site this morning, including the serious winds still predicted for the region late today and tomorrow. Their snow map (above) shows us in a kind of protective bubble.

This is still a very big, very powerful storm. We just get to sit on the sidelines for most of it this time and watch others cope.