The GFS model is an interesting beast. Its known error bias is to keep things too flat and out to sea. In most cases when you see the GFS out to sea with other major model guidance a hit, it tends to correct back west. However, this is not the first time it scored a big win. Every so often it does pick up on something the other models do not see and what can be mistaken has some merit in it. This usually is apparent when within 72 hours it keeps holding its ground. That appears to be the case this time and some of us are left holding the bag.
So here is a quick summary:
- Storm mainly stays offshore this weekend with limited impacts over the tri-state
- expect some snow to break out Sunday with 1 to 2 inches of possible accumulation.
- There should be no travel impacts
- Up in eastern New England especially eastern Mass, impacts will be greater
- 3 to 6 inches can fall in those areas
Here is updated map. I threw a bone to some areas with the light blue. 1 to 2 is possible but do not get your hopes up.
The image below shows the storm just skirting by our area tomorrow..
This then could intensify close enough to shore to give the Boston area a notable snow event..
The weather is and always will be a chaotic phenomenon. There is no one perfect model. When I look back on this last season we saw every model have its highs and lows. Think of the NAM model which nailed the Blizzard but usually is always wrong in every other case. Or the UKMET model which was nailing those inland runner rainstorms but completely whiffed this time. To try to combat this, they develop ensemble forecast systems to take these main models and adjust their input values to account for possible errors. You then get up to 51 reruns of the main model and can see where each member is leaning. Probability tables are developed and statistically it sounds like we have a great handle on a situation. Well, not so fast. The mighty European ensemble really failed this time. For the most powerful forecasting tool in the world (just upgraded too) take a look at what it was suggesting just the other day..
You can see each ensemble members listed by the low pressure centers. Notice the strong signal that this storm would trend west as seen by the clustering of those members. If you averaged it all out you got a snow map that looked like this..
This obviously ended up being completely wrong despite the fact the probability of 6+ inches of snow over NJ was over 60%! Get used to it guys it happens all the time! This is why the weather will always have my interest. As humans even in the year 2016 our most powerful computer modeling can completely miss as close as 72 hours away. This is what will always keep my hobby alive.
Thanks for reading guys. It just was not our year.You will find that in other years it will simply just want to snow. This year it did not want to snow. That brings me to the old saying "it snows where it wants to snow" Sometimes simple tag lines like that make a lot of sense when you look back at a season.
Will have a few updates later and tomorrow as this storm approaches.