Why Such a Warm January? ~ Weather 101 with Al Kaprielian

By: Al Kaprielian – Feb. 2017

With February now here we have one month to go for meteorological winter. January was a mild month with many days having high temperatures running above normal. The month finished with Boston just over six degrees above normal for January 2017.

Manchester New Hampshire also saw a mild January with high temperatures running above normal. The month finished with Manchester around 7.6 degrees above normal for January 2017. Why such a warm January? One reason was the upper level high pressure system off the southeast U.S. coast. This upper level high pressure was strong enough to push the jet stream to our north.

This caused our region to be on the south side which is the warm side of the jet stream. Even though it was a mild January, some areas in New England got snow and sleet during the month. There was a pretty intense coastal storm on January 23rd into the 24th which produced strong damaging winds along the coast with heavy rains. The strong winds caused some power outages due to down trees and power lines.

Cape Cod saw over three inches of rain from this storm. Farther inland a combination of snow and sleet occurred with this storm making for very treacherous travel conditions. With ocean temperatures running warmer than normal, this was a major ingredient in the storm becoming intense.

Now that February is here we can still continue to get powerful coastal storms. Remember, the Blizzard of 1978 occurred in February. How many powerful coastal storms we get this month will depend on the jet stream and how much phasing occurs with the northern and southern branches of the jet stream. If a lot of the storms have the jet streams phasing, we will see an active month. There is no block (high pressure in the north/northwest Atlantic) to slow the storms down causing them to intensify near the east coast.

With no block, the jet stream stays progressive and this makes it difficult for the two jet streams to phase. Storms can still intensify with this progressive upper level flow, however, they intensify too far away from us out in the ocean. This pattern looks to be with us as we start the month of February. It may not be with us the whole month, as blocking high pressure in the North Atlantic can form in February giving us an intense coastal storms and even blizzard. A blizzard occurs when the visibility is a quarter of a mile or less for three or more consecutive hours, also when sustained or winds gusts of 35 miles per hour or greater for at least 3 hours occurs.

During a blizzard with very low visibilities, this can make driving and walking dangerous. The best advice during a blizzard is to stay inside your home and be safe. If walking outside during a blizzard, you can become disorientated and become lost because of the very low visibilities. During the Blizzard of 1978 the intense storm stalled in the Atlantic and this caused it to snow for two plus days. The long duration of falling snow caused very high accumulations of snow.
Time will tell if we see any blizzards this month but it is highly possible if atmospheric conditions are just right. Next month we will examine the weather from February and take a look at what March can bring weather-wise.