Why the flawed forecast?

National-Weather-Service-LOGO

TUPELO – After days of on-again, off-again forecasts of snow and ice in Northeast Mississippi, the National Weather Service in Memphis on Wednesday afternoon canceled the region’s winter storm warning but extended a downgraded statement for several hours.

Light snow was reported during daylight hours Wednesday in places as disparate as Oxford, Itawamba County and Columbus.

“Everything should be shifting east of here,” said Weather Service meteorologist Jonathan Howell. He urged continuing caution on roads until temperatures are well above freezing this morning.

“There may some icy patches on roadways that cause problems,” he said. Temperatures today are expected to reach the upper 40s.

The forecasts and warning/watch conditions have changed frequently over the past several days, with predictions of as much as four inches of snow in parts of Northeast Mississippi and as much as a half-inch of ice in others. Through Wednesday evening, snow was mostly a no-show – even though most schools and several colleges had closed in anticipation of it – and a thin glaze of ice on most bridges and some roadways on Tuesday seemed to be the worst of the storm in this region.

In the nation’s south and east, however, the forecasts were tragically accurate. By early Wednesday evening, more than 5,500 flights had been canceled and an estimated half-million customers were without power across several states.

“Climatologically speaking, snow in the South is a rare phenomenon, so it’s always a difficult situation to predict significant snowfall,” said Jonathan Howell, a meteorologist with the National Weather Service in Memphis. “We can generally predict fairly accurately where the most significant winter weather will occur. Occasionally some differences across the area cause us to have to make updates to the forecast.”

Howell said snow in the South often comes in a narrow band because of the required mix of an Arctic air mass and a breeze bringing in Gulf moisture over the top of it.

“Depending on how deep that cold air mass is determines the type of precipitation it is,” Howell said. “Much of the time the warmer, moister air overwhelms the cold, and you have freezing rain or just rain.”

For those who feel the Weather Service may have cried “Wolf!” a little too often with its recent near-misses, Howell urges them not to take forecasts for granted as tornado season approaches.

“Severe weather is more common in the South compared to winter weather,” he said. “This part of the country is more prone to that type of weather compared to winter weather. It just happens more often.”

Today, the forecast moves in a more pleasant direction with a warm-up that will reach nearly 60 degrees by Sunday.

errol.castens@journalinc.com

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