Saturday, February 13, 2016

Saturday Morning Storm Update: Model Spread Continues, Sticking With Preliminary Forecast

Good morning everyone. Although we are starting to get a little more clarity on the situation for Monday night into Tuesday a lot of uncertainty remains. I am sticking with my preliminary forecast below..

  • The dark blue zone should expect a significant snowstorm.
  •  The pink zone will feature a front end thump of snow Monday night, changing to ice,  then eventually some rain
    • I am concerned that the ice will be a big issue for this area Tuesday morning
  • The green zone will start as snow but quickly change to ice then rain
    • There will still be impacts early Tuesday morning. 

I will update this tomorrow. At this time we have two ends of the spectrum. The European model is still the warmest and farthest west with this storm..

The Canadian and GFS models remain further east. I will add that we have had some very good consistency in the Canadian model last few days. Below you can see what it is projecting. Notice the snow changing to ice and remaining ice just to the NW of I-95. This is a big concern of mine. 

The GFS is not far off from this. As I showed yesterday, the differences in the models more west vs east is how strong they are modeling the lead shortwave ahead of this storm. The GFS and Canadian are stronger with lead shortwave and weaker with the southern shortwave. The result is a colder storm. Here is an updated image showing this below..

European is left Canadian is right. Might be hard to see but on the Canadian the lead feature (top circle) is stronger. This holds cold air in a little longer and causes the storm to develop more to the south and east. 

So we have a lot t track here guys and I am sure more things will change. I do feel really good about what I have out right now however. Stay tuned for more details to come!

Friday, February 12, 2016

Friday Morning Storm Outlook: Releasing My Preliminary Impact Map for Tuesday

Good morning everyone. As we have been discussing, we are tracking a storm that will impact the area Monday night into Tuesday. So many details need to be worked out as usual (as they all say), but I want to try my best to keep you guys ahead of the situation and give you my best thinking. First lets take a updated look at model projections for Sunday mornings temps!

Yes that's sub zero in many spots! Highs all weekend will only be in the teens for many areas. This is the result of the polar vortex coming to town..

Ok back to early next week.

 Here is my first projection on what can happen Tuesday..

We do not currently have the proper set up for a big east coast storm (big cities). This is due to the bitter cold air we will experience this weekend (sub zero in spots) exiting the area ahead of this storm. HOWEVER, in this pink zone the cold air should put up a fight. I expect things to start off as snow Monday night (few inches possible) then transition to ice then finally rain. There is a big risk here cold air can hold on near the surface  especially in the western areas of the pink zone. This means freezing rain and a potential horrible commute Tuesday morning. Rain should eventually take over but not until some impacts are made. 

For the green zone, things should start frozen but I expect a much quicker transition to rain and limited impacts at this time.

The jackpot looks to be the dark blue zone where significant snow accumulations are possible. I will note there is some model guidance that is west of my map which would result in even the dark blue zone getting liquid. At this time, I am trying to show you guys what I think will happen as opposed to just copying a model projection. 

This map will be updated twice over the next 4 days. I will eventually have a snowfall map then tweak it to a final forecast as event approaches.

So now that you have a general idea of what I am thinking, lets take a look at the maps. We have a wide range of solutions here as the models are still struggling to get a handle on this. The image below is my best way of showing whats influencing this storm. The European model is on the left and the Canadian on the right (click to make bigger)..

Looking above a few things to note. Notice how the European model has that southern feature stronger. Also compare it to the Canadian which has a weaker southern feature and more evidence of a stronger lead short wave ahead of this storm. Here lies our forecasting issue folks. The key to the track of this storm depends on what feature ends up being modeled correctly. If the lead short wave as seen on the right image ends up being stronger like the Canadian shows then it will help hold in the cold air longer and also develop a low closer to the coast. If this does not happen as the European shows, we have a warmer solution. This is what we are going to have to track over the next few days.

My forecast map is basically a blend of these two with some input from the GFS model. I also am trying to look at similar storms from history. At the surface here are some model projections for Tuesday morning..



As you can see much different outcomes and it all comes down to the features I discussed above!

More later. 

Thursday, February 11, 2016

Thursday Morning Update

I want to take a quick updated look at next week this morning. A lot of details need to be sorted out but based on this pattern we can start to get a general idea of what can happen.

Before we get there, I mentioned yesterday that the coldest air of the season comes in this weekend. Temps will be in the teens for highs and possibly go below zero at night for some areas. You can see the details on yesterdays write up. 

I am tracking a storm in the wake of this cold outbreak. The track is a big question mark right now, but I am finally starting to see come consistency in the models. At this time it looks to be like an event that could start as snow but quickly change to ice then some rain for the big cities. Further inland NW of I-95 the snow and ice could hold on longer before a transition to liquid. This could be a big issue if it verifies. Remember we have bitter arctic air in place that tries to move out ahead of this storm. Cold dense arctic air doesn't move easily, and usually means ice when you have an approaching storm trying to bring in warm air. 

Why do i think this is not mostly snow for the big cities?  Yes the cold air is in place ahead of the storm, BUT there is nothing to keep it in place (blocking). This means a storm track that is even just a tad too far inland results in ice to rain.

The massive area of high pressure that brings in the bitter cold air for the weekend slides offshore as you can see in the image above. This means we need perfect timing of disturbances to stay in the cold area of the storm.

What we should be left with is something similar to this..

Do not take this image verbatim.I actually do think areas of NW NJ have a shot at seeing more frozen than liquid with this. However, I am trying to show the point that this is not a set up for the big cities. 

How could this change? Two things we will have to monitor. The strength of the ridge out west and how the departing polar vortex of cold air sets up.

I circled those two features on the image above. Ideally you would want to see this ridge pump up more behind the storm and the vortex of low pressure be be to the south and east around coordinates 50/50. This would result in a storm that develops further south and runs in to sustainable cold air. That does not like it will be the case this time. Things can still change however. We are 5 days out. 

Pattern stays active through early March. We need one more significant storm to make this winter worthwhile. Up in the ski areas, a lot of ground needs to be covered. We will see how things turn out over the next 5 weeks.  I do not buy the ideas of any sustainable warm ups for the foreseeable future. Any periods of warmth will last a few days and cold should keep returning. 

More updates to come. 

Wednesday, February 10, 2016

Wednesday Morning Weather Discussion: Coldest Air of Season This Weekend, Storm to Follow?

Good morning everyone. Now that we have gotten past the snow event that wasn't, lets turn our focus on the next leg of this winter pattern we are currently in. When you walk outside you door this weekend it will feel like you are up in the arctic circle, not the eastern USA. This is all due to air that originates from that region delivered by our friend the polar vortex..

How cold will it get? I will put it to you this way, Friday will be the warmest day with temps in the 20's. By the time we get to Saturday and Sunday temps will not even hit 20 in many areas for highs! Sunday will be the coldest day with early morning temps potentially going below zero seen below...

Highs on Sunday will be in the low to upper teens. Welcome to winter!

In the wake of this massive cold surge, I have my eye on potential storm development on the heals of this arctic out break. I am not ready to jump on this yet, but anytime I see storms trying to develop on the back of a major arctic outbreak it sparks my attention. 

I try to show how this can develop in image above. We have our vortex of cold air starting to move out of the area early next week. Directly behind it we have energy that will try to dig down into the region and develop a storm. The major question is where does this energy want to consolidate. If it starts to amplify too early then we have a storm that tracks inland with snow to ice to rain. On the other hand if we get this energy to consolidate a little later then we have a storm that moves right off the coast. 

The models are still split on what scenario occurs. You can see the spread of different low pressure centers below for the middle of next week..

Now I do think we see a storm I just am not ready to speculate on if the tri state sees major impact yet. Most major models do agree this energy consolidates and the trough goes into a negative tilt. A negative tilt indicates a storm is able to intensify..

The issue is does this consolidate too early like I mentioned before. That would cause the inland running scenario which would be a snow to ice to rain scenerio. We need to wait a few days to sort this out.

In any event, I find it hard to believe we see just a big rainstorm when you have such powerful arctic air in front of this storm as you see below...

More on this in the days to come. 

Tuesday, February 9, 2016

Tuesday Night Comment: Busted Forecast

Quick note tonight. I will have much more detail tomorrow morning on the long range. Things will stay very active through Valentines Day and I have my eye on a potential storm threat early next week.

But for now, this forecast today was a bust. Doesn't bother me too much due to the fact it is so hard to predict inverted troughs. But in any event this sums it up...

Some local areas will do well with over 3 inches. Most others will see an inch or two from this. Thank. On the bright side, I did a very decent job with Storm 1 on Monday up in eastern New England. I will show the verification map once that is available.

More in the morning. 

Morning Update: Snow Works It's Way North This Afternoon

Good morning. We got flakes flying in our southern zones currently..

This will work its way northeast as the day goes on. Here is the projected radar for this afternoon around 4pm..

By 9 pm it will be here..

Overall impacts will be very limited in the northern zones today. Later tonight those areas might see some deterioration in road conditions. Regardless, I do not expect big impacts for areas in the NYC metro.

More detail from my post from last night. Tomorrow we will turn our attention to early next week where more mischief can arise. 

Will have a quick update tonight.  

Here is NWS's latest forecast. Not too far off from mine. Notice the much lighter amounts north. Balt/Wash is cut off in this image (different forecast office). 

Monday, February 8, 2016

Monday Night Update: Final Forecast For Tomorrow's Winter Storm

Good evening, below is my final forecast for tomorrow. Here is a summary of impacts:

  • A moderate winter storm effects southern zones tomorrow morning into the evening
    • Hardest hit areas can see 3-6 inches
  • To the north impacts will be less over NNJ into southern New England
  • Snow should start to break late tonight/ early tomorrow morning in MD and Del and slowly work its way into the Philadelphia/Central NJ area by afternoon.
  • Snow will become most intense late morning into the afternoon for the hardest hit areas as an inverted trough of low pressure develops off the coast
  • Northern areas of NJ will see snow develop in the afternoon as this low pressure center drifts northeast off the coast
  • There is a chance this low pressure could track closer to the coast than expected causing more impacts to northern zones than projected
  • Snow ends for southern areas in the evening and northern areas just after midnight 

This storm will be a tricky little system due to the fact it involves something called an inverted trough of low pressure. Inverted troughs are notorious for throwing surprises thus making them very hard to predict. My map below is my best estimate of what impacts will be:

A breakdown of this storm can be found in the 2 min video below, enjoy!