Thursday, January 5, 2017

Thursday Morning: Light Snow Tonight, Wide Right This Weekend with a Suprise

Good morning. The arctic front has arrived and much colder temperatures have come along with it this morning. This cold air will hold for at least the next 5 days with temperatures only reaching the upper 20's to low 30's for highs and teens for lows. Bundle up!


  • Light snow moves in late tonight for most areas
    • 1-2 inches with the higher amounts closer to the coast
    • Locally 3 near Long Island and Boston
    • Snow ends by day break south to north
  • Weekend storm misses to our east and scrapes the coast with light snow
    • Areas near Boston need to watch out for enhanced snowfall Saturday night due to something called an inverted trough
  • Still a little room for the weekend storm to trend west but not enough for major impacts inland

Light snow moves in later tonight as a wave develops along this arctic front. Snow should start a few hours before midnight in many areas..

By day break it is moving out and focusing on the Boston area..

Since it will be very cold there will be high snow ratios. This means only a 10th of an inch of liquid can produce 1.5" of snow. 

Right now I like this ratio adjusted snow projection for amounts...

General 1-2 inches with locally 3 near the coastal areas especially near the cape.

There should be some travel impacts due to the timing of this system.

We then move on to my whiff of a weekend storm. Believe it or not, the models have trended back west a little due to enhanced blocking but it is too little too late. However, an interesting situation is developing where something called an inverted trough can develop as this time passes by. This means a small area of heavy snow mostly likely near Boston. Lets take a look..

As is most major models now show a close miss for Saturday..

This can still trend about 50 miles west so coastal areas and the southern Mid Atlantic say around DE, VA, E MD, and NC need to keep an eye on this.

Heres where things get interesting. As this storm scrapes by with light snow in coastal areas an inverted trough can develop somewhere near Boston shown below..

Inverted troughs are small scale features that can produce a small localized area of heavy precipitation or snow. They are extremely hard to predict but models have been hinting on this feature to develop somewhere in that red circle on late Saturday night. If this occurs there will be moderate snowfall amounts associated with it. 

For example look at the GFS snowfall projections because of this inverted trough..

We are going to have to watch this closely due to the difficult nature of nailing this feature down. Just know its possible. 

Thats all for now, I will have an update on the light snow and the weekend situation later tonight around 8pm.

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