Saturday, February 6, 2016

Saturday Afternoon Storm Update: The Preliminary Forecast

*I have decided to postpone the threat map until tomorrow morning due to high model volatility*


Well I think I have seen enough over the last few days in terms of figuring out what will happen early next week.  I am confident that storm 1 stays offshore and  brushes the NYC area with some snow. Up in eastern New England the impacts will be greater (several inches possible). That in itself is going to end up being the problem with Storm 2. I mentioned this week  if Storm 1 was too strong and close to the coast, it would steal energy away from storm 2. That looks like whats going to happen. What we will be left with is the chance for periods of snow on Tuesday as a digging trough tries to redevelop low pressure off the coast. Most areas in the Mid-Atlantic and northeast might see a few inches with the zone of heaviest snow to be determined. A phenomenon called an inverted trough might set up. Where this occurs will dictate where more significant snow amounts are. 

There is no question that this pattern stays active for the foreseeable future. Regardless of what happens early this week, we have another shot at a very large storm towards the end of next weekend. Cold air will be in great supply and I expect this pattern to linger around until 2nd week of march. If we get out of this period unscathed I would be very surprised. 

In Summary:

  • A very strong coastal storm brushes by the area Monday
  • This will give areas in eastern Long Island and New England accumulating snow and cause some snow to fly near coastal sections of NJ (inch or two)
    • Yes there is a chance this trends west more and hits whole area with significant snow. 
    • Not my base case, but we will have to keep a close eye on this
  • Due to the strength of this first storm, Storm 2 will have a hard time intensifying on Tuesday
  • Regardless, everyone should expect periods of snow on Tuesday with a few inches of accumulation possible
  • There is evidence a weather phenomenon called an Inverted Trough can develop on Tuesday and enhance snow amounts for certain areas.
    • If this does occur then those areas can see over 6 inches of snow
    • It is extremely hard to project where this will happen but I show below an area I am targeting.

So here we go. Storm 1 is a near miss for most areas Monday and hits eastern New England with snow. As you can see, this is a massive storm so the precipitation shield will hit most areas. You are looking at the NAM model below and I think it is a little overdone. The best bet for any notable snow is eastern New England. We will see if this trends more and they end up getting a significant storm. 

Notice all the precipitation to the west of this storm. That is the clipper system that will try to redevelop off the coast Tuesday and cause storm 2. This is seen below..

Notice there is a low pressure center shown by the GFS model off the coast and a lot of scattered precipitation around it. It is at this time that we might see that inverted trough develop. This would end up giving much heaver snow amounts to what ever area is in its cross hairs. On this next image valid 12 hours later, you can see the GFS trying to indicate this developing..

Now we are going to have to use higher resolution models as this event gets closer. The NAM model is one of those. You can see it is trying to show enhanced show developing Tuesday night into Wednesday due to this possible inverted trough shown below. 

If this does in fact occur, then some areas could see over 6 inches of snow Tuesday into Wednesday morning. 

If you cant tell already, this is extremely difficult to predict! I am confident though that flakes will fly Tuesday with the heavier amounts remaining to be seen.

Thanks for reading more tomorrow morning!

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