Because of its record-setting size — over 1,000 miles across from tip to bottom — swaths of moisture from Sandy are combining with a Northeastern cold blast dipping into Tennessee to produce a forecast of 1 to 4 inches of snow for the valleys of the Tri-Cities.
“The elevation level is going to be the determining factor for amount of snow,” a forecaster from the National Weather Service in Morristown told the Times-News on Monday.
“As Sandy makes landfall, moisture connected with it is wrapping around and coming across our area. With the cold temperatures coming from the North and Northwest, snowfall continues to be in the forecast.”
Mountainous terrains above 2,500 feet like those on the Great Smoky Mountains, Roan Mountain and the Appalachian Mountain range were to be covered with a 4- to 17-inch coating of snow, according forecast models.
Any ranges above 3,000 feet, including Tennessee’s highest point at Clingman’s Dome at 6,643 feet, were predicted to get blizzards with snowdrifts and blistering winds that were sure to crumple trees and level power lines.
A 2007 report published in the NWS Morristown data section cited the region’s wide range of elevations as a challenge in forecasting snowfall.
“As a result, snowfall patterns are complex and strongly related to elevation and exposure and can create significant forecasting challenges. Mean annual snowfall ranges from only (1 foot) in the valleys to as much as (8 feet) at the highest elevations, where extremely heavy snowfall can occur with major storms,” the report said.
Tri-Cities Regional Airport Director of Marketing and Air Service Development Melissa Thomas said the impact on local air travel to major Southwest hubs would be minimal as of Monday.
“We have a few delays that have crept in as the day has progressed, but Charlotte and Atlanta are still operating,” said Thomas. “Nationally, the airlines canceled flights going into cities that are affected by the hurricane and are waiving change fees for passengers with hurricane-related travel disruptions.
“We are encouraging people to check directly with their airline for more information and to check the arrivals/departures section of TRIflight.com for up-to-date information. Our maintenance crew is prepared for winter operations if we get snow.”
Temperatures in the low 30s at night through Thursday will make it hard for those peaks to shake off their frosty coats, but forecasted highs in the mid-50s by the end of the week should break up and melt any of Sandy’s remnants.
According to NWS data, the Tri-Cities region has received only 1.2 inches of snow so far in 2012, far below its normal 13 inch average.
The record for most snow in a 24-hour period was set on Nov. 21, 1962, when 16.2 inches fell.
Times-News staff writer Hank Hayes contributed to this report.