Major Nor’Easter Likely – Local Impact Still Unclear

If there’s one thing that has become more certain today it’s that a powerful coastal low will develop off the Mid Atlantic coast Friday and Saturday. The question is how quickly does the storm develop and where it tracks after it forms. The best bet at this time frame is to look at our “ensemble models” which show a range of possible solutions rather than one deterministic solution. I’ll start here with the GFS ensemble (GEFS) members which show a range in possible outcomes.

gefs_ptype_ens_ma_22

You can see a tremendous range of outcomes – from miss to big hit to everything in between. We can look specifically in Hartford to try and visualize each of these 20 GEFS members in a different way. Each line here represents a precipitation forecast in Hartford. There are several “blockbuster” members showing over 1.5″ of liquid (read: big snowstorm), many with a moderate hit (around 0.8″ of liquid – which is the mean) and some members showing a miss or little precipitation at all. This is a lot of spread!Screen Shot 2016-01-18 at 8.21.18 PM

The European model has ensembles too. We can take all 51 (yes, 51 different ensemble members!!) and plot their outcomes in terms of probability of any given grid point exceeding a certain amount of precipitation. The European ensembles show a 50%-70% across Connecticut chance of exceeding 0.5″ of liquid which equates to about 5″ or 6″ of snow.

eps_qpf_0.5_ma_27

So here’s where we stand. It’s reasonable to think there’s a >60% chance of seeing at least a plowable snowfall of 3″. For a 5 day forecast – those are pretty good odds!

Based on current modeling the most likely area for “jackpot” snows would be in the Mid Atlantic. To get over a foot of snow you generally want to be just north and west of a storm when it is undergoing the most rapid strengthening. A good way of looking at this is looking at the track and intensity of the 700mb low pressure. Getting a 700mb low to track nearby while the low is undergoing rapid deepening is a great place to be for “jackpot” snows. This is what happened in February 2013 and February 2006.

This storm reminds me quite a bit of the Blizzard of 96 with its evolution as currently modeled. Note: this doesn’t mean I’m forecasting a repeat! The ’96 storm was associated with a large and deep circulation that reached its peak intensity over the Mid Atlantic. Below is the NARR reanalysis for the 1996 storm and today’s “Happy Hour” GFS run. You can see the similarities.

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NARR Reanalysis for the “Blizzard of ’96”
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GFS Forecast valid Saturday Evening

So what are some of the things we should be watching for in the coming days?

  • How quickly does the form intensify and occlude to our south. Too early and the heaviest snow will remain well south of us.
  • How far north does the entire storm make it? A storm that winds up a bit farther south could effectively shut New England out. The high pressure system over northern New England and Quebec continues to be modeled stronger and stronger over the last couple days.
  • Better consensus/less spread in our ensemble output. While consensus is high that there will be a nor’easter the impacts on the northern fringe are uncertain.

Keep the faith snow lovers – the January 1996 storm was mighty kind to us here in Connecticut. We’ll see how this one plays out over the coming days!

Exceptional Damage Following Historic Freak October Snow

The northwestern half of Connecticut will be picking up the pieces for days and even weeks following a spectacular and historic October snowstorm that has not just broken, but shattered, every long-standing weather record.

Even with temperatures at or above freezing (in fact in some areas the entire storm occurred at 34 degrees) snow had no problem accumulating in many areas. Snowfall totals exceeded expectations or wound up on the high end of my ranges in many towns because getting snow to accumulate at some marginal temperatures is just remarkable.

Instead of starting as rain in the greater Hartford area the storm began as snow around 2 p.m. With an inch of snow the power began to flash by 4 p.m. and by just before 5 p.m. we switched to generator power for the duration of the storm (in fact I’m writing this on generator power, 15 hours later).

Studio Lights Go Dark as Engineers Switch to Generator Power

Remarkable damage occurred after dark and in many areas the full extent of damage won’t be known until later today. What sounded like shotgun blasts through the night was trees snapping in half. The night sky lit up with flashes from both lightning and transformers exploding.

The first 6″ of the storm in most towns was a heavy, water-logged paste. The second (or third, in some cases) 6″ was more fluffy. Here’s a look at the front of our building around midnight. Take a look at the poor saplings in the background.

NBC Connecticut Around Midnight

It’s been a marathon here at the station no doubt. From the morning show on Saturday to coverage all day and night yesterday the NBC Connecticut gym turned into my personal bedroom for the night.

The Sailboat Blanket is Soft!

Here are 2 tweets that stand out this morning:

@CTLightandPower Unprecedented damage from this storm. Please prepare for worst case scenario – a week or more without power. Call 211 for shelter info.

@bobmaxon 25 years of weather forecast/coverage….I’ve never seen anything like this. On the heels of Irene, this is unreal

I’m ready for a drink. And a nap.