FOR IMMEDIATE RELEASE
Contact: Curtis Carey
This week's dramatic weather shifts in
the Northeast and Middle Atlantic States are a sign of things
to come, say NOAA National
Weather Service scientists. The warm and dry winter came
to an abrupt end in the region this week when the jet stream
shifted southward and roared into the eastern U.S. bringing bitter
cold temperatures, strong winds and snow.
During the early part of the winter, the well anticipated La Niña brought typical storminess to the northwest U.S., with a storm track running from southwest to northeast through the Tennessee and Ohio Valleys and the Great Lakes. This storm track kept temperatures in the Northeast near normal or above normal. However, NWS scientists point to a phenomenon known as the North Atlantic Oscillation, or NAO, for the sudden change. When the NAO is in its "positive phase" conditions in the Northeast remain warm and dry during La Niña years. The NAO has recently held the jet stream farther north than normal keeping the polar air north of the Atlantic Coast. This week, however, the NWS weather models forecasted the NAO to turn "negative." This change dipped the jet stream toward the south allowing the rush of bitter cold polar air.
Thanks to La Niña and the North Atlantic Oscillation, NWS scientists say the bumpy ride this winter is expected to continue with rapidly changing weather conditions.
Local National Weather Service forecast offices are providing constant updates over NOAA Weather Radio, the local media and the Internet.