DISCUSSION: As all eyes turn to a massive storm system eyeing portions of the Mid-Atlantic into the Northeast, arguably the most dangerous feature with this storm will be the extreme cold as the storm exits the region. Above is a snap shot from this morning’s 12Z NAM model (courtesy of WeatherTap) valid Thursday at 1PM which shows the intense low-pressure system, sub 960mb on this model run, off the NJ and LI coast in the Atlantic. This model is forecasting this system to have impressive sustained winds across coastal regions of NJ, all of LI, much of CT and much of coastal New England experiencing sustained winds 25-45 mph with higher gusts as this Nor’easter bombs out. There is a threat for power outages in these locations which is always a risk to safety. This storm will pull down extremely cold air from southeastern Canada elevating the danger of this situation.
The above image is the 12Z NAM (WeatherTap) representation of the actual air temperatures on the morning of Saturday January 6th. These extreme cold temperatures, along with the howling north and northwesterly winds advecting this frigid air into the region will make the temperatures feel well below zero (image below same time frame). This of course is a dangerous situation for any locations that lose power and do not have heat.
A sizable snow pack is forecast by the NWS and the latest model guidance for much of New England. Since snow is a good emitter of infrared radiation, during the nighttime hours more radiation is able to escape out to space much quicker than if there was no snow cover, allowing these temperatures to really drop during the overnight. Such extreme nighttime lows will produce very dangerous wind chills as discussed above.
Just how impactful can a deep snowpack be to low temperatures? The surface analysis above from December 8th 2013 at 12Z is a perfect example. There was over a 20 degree temperature difference in two locations in the Pacific Northwest. Eugene, Oregon, with a few inches of snow cover shown is resting at -9 degrees F and Portland Oregon, with little to no snow cover is sitting at 13 degrees F. This highlights the concern across areas that receive snow and high winds from this system in the Northeast.
A dangerously cold situation will impact the Northeast later this week into the weekend. Be sure to follow GWCC and click here for the latest on this Nor’easter, the snow cover, and the cold air following!
©2018 Forecaster Joseph DeLizio