Could Climate Change Reduce the Frequency of Tracks Like Hurricane Sandy's? — Dr. Jeff Masters

Every so often, a trough in the jet stream bends back on itself when encountering a ridge of high pressure stuck in place ahead of it--a so-called "blocking high". According to NOAA's Climate Prediction Center, a "blocking high" near the longitude of Greenland (50°W) only occurs about 2% of the time in the fall, and can cause winds that flow from southeast to northwest over the Northeast U.S.  It is this sort of unusual flow that sucked Sandy into New Jersey and allowed the hurricane to take the most perpendicular track into this section of coast of any tropical cyclone in the historical record.

Dr. Jennifer Francis, who has authored several studies linking Arctic sea ice loss to unusual jet stream patterns, noted ... "One of the strongest pieces of evidence for the study’s main conclusion is that easterly winds are projected to decrease in a large zone north of Newfoundland.  The location of the strongest decreases, however, is north of the location of the block during Sandy, exactly in the region where stronger west winds would occur when blocks like this existed.  This suggests that the pattern may actually cause an increase in unusually high pressures in the same location of the Sandy blocking high."

Also the researchers conclude that "tropical cyclones will increase the probability of present-day extreme events over the North Sea and the Gulf of Biscay with a factor of 5 and 25 respectively, with far reaching consequences, especially for coastal safety."

Could Climate Change Reduce the Frequency of Tracks Like Hurricane Sandy's? — Dr. Jeff Masters