Friday, December 19, 2014

Friday Morning: Who's Dreaming of a Green Christmas???

Good morning everyone. I got a great last min gift idea today. In fact I can guarantee you it will come of great use next week leading up to Christmas.

Put away the scarf and gloves, a raincoat boots and umbrella will be required this Christmas eve. All due to a nice powerful rainstorm hitting our area on the 24th...

Cold air will rush in behind the storm for Christmas day but it will be dry. No snow in the cards this year guys. We will have to wait and see what things look like after xmas as we head towards the new year. Snow lovers I share your frustration. We SHOULD have a pattern that can produce snow but whether it snows or not is always a separate thing. Rest assured, when snow hits my radar you will be the first to know!

Thursday, December 18, 2014

Thursday Morning Weather Discussion

Good morning. There is a lot going on next week in terms of weather. For us folks on the east coast it very well can result in all rain or some snow depending on how things evolve. Right now looking at the models verbatim, some snow showers come through our area late this weekend followed by light rain on Monday night then heavier rain just in time for xmas eve. Yes I know quite the depressing forecast. The heavier rain will be due to a very impressive storm system that is projected to cut to our west..

This would funnel a lot of cold air in for Xmas day but it drys out at that time. Could this be the big storm that changes this pattern to winter? Maybe, really to early to tell at this point. The models in general have a boat load of energy to process from a split flow pattern. Just take a look at all the areas of energy on the field next week below.

Rest assured, this means a lot can change going into next week with how all of these disturbances get sorted out. Quite the computing job ahead for the models. We will have to see how this all gets sorted out over the next few days. I am not ruling out a surprise with possibly some snow effecting the area next week. Yes I know things looked a lot better a few days back. Snow lovers be patient, sometimes its when you give up and let your guard down that a storm will sneak up on you. The weather pattern eventually could produce snow. I just have no idea at this point if it will be before the New Year. All we can do is watch the evolution. 

More tonight when I am back from work. 

Wednesday, December 17, 2014

Now It's Time to Throw in the Towel

I officially announce that the storm threat for late this weekend is over.

I explained in my video last night what ruined this opportunity for snow. We came very close but one factor threw this whole storm off. Some light snow is still possible but its nothing to write home about. 

We now turn our attention to the potential big storm threat around xmas eve. The problem is this could just as well be rain as snow depending on the track. 

As of now, the amplification the jet stream for this period is extremely impressive, but I do not see evidence of a 50/50 low. This makes me worry that we will not have high pressure in the correct spot to steer the storm track along the coast and keep cold air in place for the northeast. In any case we have a potential triple phase of all three jet streams (arctic,polar,subtropical)

Looks confusing but looking above to the right panel, each color represents each jet stream. The red is subtropical the green polar and blue arctic. The white line is the operational model projection for each jet stream. notice how the blue is dipping down over the eastern US. That is always impressive to see. So now we watch this storm threat and see how things change over the next few days. Maybe its a good thing that as of now it has our area in rain considering a lot can change. 

More later. 

Tuesday, December 16, 2014

Tuesday Night Video Update

In the short video below I break down why the models have backed away form a major storm threat this weekend. I am waiting till tomorrow when the energy is sampled properly before throwing in the towel on this. 

Tuesday Morning: Next 36 Hours Should Bring Clarity

Good morning. Quick post today as I am going to be very busy. Overall most of the operational models have not been overly impressive in their last two runs. Including the European they have been showing the storm moving more to the south and off the coast. This would mean a minimal impact on our area. Here is an example of the gfs..

The canadian and European are similar. However, lets take a step back here and look at the ensemble spread for the GFS and Canadian...

The red numbers are low pressure centers for the different ensemble runs and the areas that are in darker shades represent the "spread". The spread is basically saying alot of the individual ensembles members are further to the west of the ensemble mean. Translation, there is a high degree in uncertainty in the track of this storm, and it could trend west.

 I am going to pound the table here and remind everyone that we are 132 hours out from this storm threat! Of course the models can be right in saying this is a weaker and offshore storm but accepting that as the end all be all scenario at this time would be premature.

 No, not just because I want it to snow, but I really like this pattern for the reasons I discussed over the last week. Also, we all know that until the energy comes onto the field tomorrow the models really do not have a handle on how this situation will evolve. The ensembles above are telling us that! We need more clarity on how and if the northern stream will be amplified enough and phase with the southern stream. Some of our best storms are the ones that trend at the last second from minimal events to major threats. Will that happen this time? I have no idea but I think the smart thing to do here is see the trend over the next day and a half. Once we get to tomorrow afternoon I believe we can determine if its worth throwing in the towel or getting excited.

Stay tuned, I will update on twitter today if I can. 

Monday, December 15, 2014

Monday Morning: An Updated look at the Ingredients Behind Potential Big Storm Sunday

Good morning, as promised I wanted to give an update on the threat of a winter storm late this upcoming weekend. In my post last week, I mentioned how we needed to keep a close eye on this threat because it was showing hints at the upper air signature required for major storm development. A few days have gone by and those hints are still there and starting to produce a few plausible scenarios for this storm. This is the first time this season that we will have colder air to work with ahead of the storm. This is a big change from all the other storm threats we have received this season. The big question mark now is will the cold air be the saving grace or will it be too strong and sheer the storm out to sea. Let's take a look at the drivers.

The image above is the GFS models projection of energy in the upper atmosphere 48 hours before this potential storm. Lets review the updated ingredients we are working with.

  • A western ridge in the jet stream.
    • this supports a trough to develop down stream and increases the chances that a northern jet stream component will dive down into the flow. A very essential ingredient to an east coast storm
  • Energy on the field!
    • Looking at the two red circles you can see we have disturbances or energy in the jet stream. The circle on the bottom represents the southern branch jet stream energy and the circle to the north is the northern jet stream energy. All big storms usualy phase the two. You can see in this image that they are both heading on the right path. 
    • This is basically a split flow in the jet stream
  • Looking to the top right corner of this image we have a very critical ingredient which is a low pressure system over eastern Canada.
    • This is one of the most important factors in my opinion because it is the key to where the high pressure system ahead of the storm is placed. The reason is its placement over eastern Canada results in something called a confluence zone to its west. In a confluence zone you tend to see high pressure develop at the surface.
    • This high pressure system supply the cold air for the storm! 
    • With out this 50/50 low any high pressure area will be allowed to just slide off short and the cold air leaves
    • You can see I labeled the high pressure system to the 50/50 low's west. The placement of this low stops the cold high from sliding offshore too quickly.
  • Along with a 50/50 low we usually have a negative NAO to go with it. Models are hinting that this could happen as well. 
    • A negative NAO is high pressure over Greenland. This high pressure helps buckle the jet stream south and aids in the supply of cold air. 
So you can see the many factors we look for in a major east coast storm are present. However, its never that easy. Getting a major storm requires all these ingredients to come together perfectly. For example, if that high pressure center is too strong due to the confluence zone being too far south it suppresses the storm out to sea similar to what the Canadian model is showing.

This is certainly a possibility, but I think the Canadian is a little too extreme with this suppressed scenario. 

The european model is more agressive with placing all these ingredients in a more favorable position. The result is a low pressure center that is closer to the coast and results in heavy snow for many areas including near the coast..

Turning to the GFS, it is similar to the european but not as strong with the storm..

So all these models will now start to flip flop with their surface projections of this storm. The important thing that I will be studying is the evolution of those factors way up in the atmosphere which produce the surface outcomes. Right now its a matter of do we get a major storm or do we get a suppressed non-storm scenario. I know I have a bias to want snow but I think this storm occurs. The reason is I think once all the energy is sampled properly by the models, we wills see a more aggressive upper air setup in particular a more stronger northern disturbance than what is modeled.  Regardless, whether this pans out or not we have a lot of potential right behind it for Xmas week. We look to be in for a while ride!

Stay tuned I will keep you guys updated daily on this threat via this blog and twitter.