Wednesday, March 16, 2016

Wednesday Morning Update: Offshore is the Latest Consensus For Now

Good morning everyone. Lets dive into latest trends on our storm threat for late this weekend. I discussed yesterday how there were more progressive or offshore trends emerging with this storm. This meant that the chance of an inland runner where diminishing rapidly. Today is more of the same. Most model guidance is just offshore with this system and way too close for comfort. 

There are two clear scenarios here. Scenario 1 is a storm that stays out to sea and scenario 2 is a storm that comes up the coast effecting areas I-95 north and west with winter weather. At this time its a 50/50 shot either way.  By tomorrow morning we will know a lot more.

So lets take a look at what is going on. Most models at this time look something like this..

The reason the storm is offshore is due to the interaction of energy on the models.

Looking above you can see the northern stream and southern stream which are circled. This storm all comes down to how they interact. As stands most models are a little too flat with the amplitude of the northern stream. This sheers out the energy a little bit and causes a late interaction between the two. A lot of this has to do with weaker blocking then originally projected. Over the next 36 hours we will see if this trend holds. IF we get this to sharpen more then we get a big storm closer to the coast. An example of what that would look like is below..

Notice on this image how the southern feature is stronger and the northern feature is sharper or not as flat. This causes a storm that would be closer to the coast as seen below..

This is the DGEX model which is basically the NAM model extended. Its not too reliable but it shows you guys what the other scenario would look like. 

One major factor that we know will be in place is cold air ahead of this. A fresh arctic injection comes in this weekend ahead of this storm (seen below). This means if this storm trends back west then we will be dealing with widespread winter weather..

We have 4+ days of model data to go and things will change here. The difference between both scenarios is just a small interaction at 18k feet in the atmosphere between the northern and southern stream I have shown. 

We have had two days now of more progressive or offshore trends. That doesn't mean too much YET, but one more day of these trends and I would lean more towards the offshore solution. I can not write this off due to the fact all the players are on the field to bring this up the coast.

Lets see what happens today and I will then put out a preliminary outlook. 

More late tonight. 


  1. Hey Willy, how many coastal lows have we seen since last December getting spun off down south from progressive troughs? I've lost count. Almost all have gone too far out to sea, while a few were inland runners. Only one found the right set-up. As to the one for Sunday and Monday . . . temps look favorable, and the NAO probably won't be strong either way (about the same as it was on Jan. 23). But today's runs just don't have the set-up coming together. The Euro is back to kicking it out into the ocean, while the CMC and GFS take it a little further west, grazing us with maybe an inch or two. The west-east flow has just been so strong this winter, hasn't seemed to have given much chance for the 50 50 low and Nova Scotia high to be where you want them. But hey, 4 more days, things could change. I've already bought most of my gardening stuff, but I wouldn't mind one last winter encore before it's time to start getting my hands dirty. On the really long-range end, I've read that most of the Pacific models look for the big Nino to end soon and maybe a Nina developing during the next winter. But supposedly some models suggest a Nino come-back late in the year. However, that would probably be on the weak side. And IIRC, weak Nino's can help fuel high snowfalls in the northeast. Well, there's a long way to go on that. For now, I have some plants to grow. Jim G

    1. Many storms is the answer lol. NAO in transition which is always a good clue, temps look great with fresh injection ahead of storm Now it will all come down to can we get the energy consolidated enough along the east. Big west trends today but will they hold? Things will move back and forth but when it is all said and done I think we are in play here! Wouldn't it be nice if we got a nice send off from the bipolar winter of 2016. Tomorrow will be fun to track.

  2. The Rubik's Cube effect of combinations that cause it not to snow in areas where little to no snow has fallen cannot be defeated. It has beaten all weather forecast's, maps, models, prognostications, Meteorologists, Weather personnel, and novices.

    1. Maybe so, if that ends up happening again I will give you a shout-out.