8 to 14 Day Forecast: September 18-24 to Feature Broad Eastern US Trough - NECN
Weather New England

Weather New England

Meteorologists' Observations on the Weather

8 to 14 Day Forecast: September 18-24 to Feature Broad Eastern US Trough



    8_TO_14_DAY_TEMPSThe combination of Tropical Storm Leslie and Hurricane Michael moving north from the Atlantic to a position north of Iceland will mean a substantial infusion of energy into the jet stream.  This will lead a number of connected responses called "teleconnections" in the atmosphere.  Most immediately, the absorption of these tropical cyclones into the jet steram will cause a surge of warmth into the Arctic Circle, furthering the already accelerated Arctic sea ice melt of this season.  In response, intense, cold energy will dig south across the skies of Alaska, prompting strong storm development just a week after 130 mph winds were observed near Anchorage.  The response to this large storm and associated jet stream trough in Alaska will be to ripple the jet stream farther downstream, across the Lower 48, resulting in a ridge over the Western U.S., and a broad Eastern U.S. trough.  This trough will allow cool fall air to drop into the Great Lakes, Midwest and Ohio Valley, while warmth will continue beneath the ridge in the Western U.S.  New England should stay just removed from the surge of cool air, which would promote near normal temperatures.

    8_TO_14_DAY_PRECIPWith a sizeable trough in the Great Lakes, strong, energetic disturbances will drop south around the base of the trough, and at least one of these is likely to pick up Gulf of Mexico moisture as it rounds the base of the trough, resulting in surface low pressure development near the Tennessee River Valley, then ejecting northeast to pass off the Mid-Atlantic and near Southern New England, which is the reason I've outlined above normal precipitation for the Eastern U.S.