Wednesday, March 21, 2012

What's Causing All the Warm Weather?


Photo by G�nay Mutlu of photos.com
By Jillian MacMath, AccuWeather.com Staff Writer
Mar 21, 2012; 6:37 PM ET
First, the warm winter. Now, an unbelievably warm March. The question on everyone's mind lately seems to be, "What's going on?"
Though the warm weather has given many the opportunity to get outdoors, tend to their gardens, and get a jump-start on their summer work-out regimens, others are concerned about what's causing this strange pattern and what implications it might have down the road.
Though it is undeniable that temperatures are far above average in many areas, the debate rages on between meteorologists as to what exactly is causing it.
Many non-meteorologists are deducing that global warming, a theory that has gained that substantial media attention over the past few decades, is to blame for the bizarre weather patterns. But meteorologists are keeping their distance from this assumption.
"You need more data to prove global warming," AccuWeather senior Meteorologist Brett Anderson said. "In only one season, you really can't link it."
Temperatures in the West during this past winter have averaged near to slightly below normal. December through February, temperatures in Seattle were 1.5 degrees below average. March 1 through March 12, temperatures averaged 4 degrees below normal.
However, temperatures so far this year have been off the charts in much of the central and eastern U.S., especially last week. Fort Wayne, Ind., experienced record highs for seven straight days, reaching as high as 84 degrees.
Chicago experienced another anomaly, hitting highs that were 15 degrees above normal for the city 10 days in a row. On March 20, the normal high of 48 was shattered when the mercury soared to 85 degrees F.
"It's certainly not hyperbole to call this a historic weather event," AccuWeather Meteorologist Jim Andrews said. But he's not jumping on the global warming bandwagon just yet.
"If the proposition is that Earth's climate is changing - and most people say warming - this is how it might manifest," he said. But he believes the unusual weather may be caused by a sort of "perfect storm coincidence" related to North Atlantic oscillation, Atlantic oscillation, the Pacific/North American pattern, El Nina and La Nina.
"What happens in the oceans is undoubtedly very important to what happens on land," Andrews said. "It may well be that the state of the ocean water temperature surrounding North America is just in an ideal arrangement to maximize warmth over North America."
Expert Senior Meteorologist Alex Sosnowski believes it's a culmination of causes.
"What we're seeing is probably an overlap of several parameters occurring simultaneously. Because of what happened over the winter, you have warm lakes, lack of snow cover. You have a carry-over effect, too," Sosnowski said.
"The biggest thing in my opinion would be Arctic oscillation. It trapped most of the arctic air in the far north and allowed milder air to sweep across Canada and much of the U.S."
Other theories diverge completely from global warming, pattern change and oscillation theories, including that of Expert Senior Meteorologist Henry Margusity.
Margusity blogged that there may be a correlation between the Pacific Ocean's temperature anomalies and the debris field from the tsunami that hit Japan last March. According to Margusity, the two match up almost perfectly.
"The theory is that the debris floating in the Pacific caused a large area of warm water in the north Pacific. Understanding that the ocean and atmosphere are coupled, if one changes the other changes; i.e. La Nina and El Nino patterns are perfect examples," Margusity said.
"So, if that area of the Pacific is warmed, it will cause a natural boundary for storms to develop along. The last 90-day storm tracks show many of the Pacific storms developed right along that zone."
Whatever the reason for this year's unseasonable conditions, it doesn't appear a consensus is on the horizon.

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