The Northeast is in the news once again, but it isn’t about snow this time. It’s about the cold air, which has entered the Northeast, but will reach its coldest Saturday night. The highest difference in temperatures is forecast to be in Islip, New York, on Long Island, where the temperatures is forecast to drop to around 1 degree. The record low temperature for that day is 7 so a difference of 6 degrees is forecast. Two of the lowest temperatures are forecast to be around -12 degrees in Albany, New York and Worcester, Massachusetts. Worcester has actually gotten down to -11 before as a low temperature on February 14th before while Albany has reached -10 on this date before so it certainly is in their climatology to reach very cold temperatures this time of year. As such, numerous wind chill advisories have been issued across the Northeast through Sunday midday as record cold temperatures pair with windy conditions. Wind gusts may approach 30 miles per hour at times, especially during the day.
So what is the cause of this record cold? In order to understand this, a general climatology of temperature within the bottom two layers of the atmosphere must be given as a framework. At the bottom of the atmosphere, the earth’s surface is warm because the earth’s surface absorbs the sun’s energy the best. Then there’s a decline in temperature from the lowest point in the lowest layer on the earth, called the troposphere, to the highest point within the troposphere, called the tropopause. The temperature slightly rises from the bottom of the stratosphere to the top of the stratosphere as a result of ozone absorbing the sun’s energy. Then a slight lowering in the temperature occurs in the mesosphere and a slight rise in the temperature occurs in the thermosphere.
This is important because this shows that what happens in the troposphere (the lowest atmospheric layer) has huge implications on what the weather does. It also shows that the stratosphere also has an impact on the earth’s weather, for example, the height of tropopause (the top of the troposphere) can indicate how cold the surface will be. We already know that record temperatures are swinging through Saturday and early Sunday morning. This is also the time that the tropopause drops to its lowest height. Another indication of the cold temperatures would be to have temperatures in the upper levels that are above normal because that would mean below normal temperatures in the lower levels based on our atmospheric structure. Temperatures in the layer that the jet stream normally occurs are 2 to 3 degrees above normal. Admittedly, this temperature is certainly not as cold as it could be and could be warmer according to the NAEFS model situational awareness table, which has these jet stream level temperatures being about average.
This air mass should leave the Northeast especially by Monday as another low pressuresystem approaches bringing warmth from the south and the precipitation type changes from snow to rain or freezing rain overnight.