March 7th-8th 2018 Storm Potential

Good morning.  Lets begin with a brief discussion on the differences between the March 7th-8th set up vs the most recent set up on March 2nd.  First notice our surface LP is sitting in approx. the same spot but in this upcoming set up it has been stated that there will be more cold air to work with. Why?  





Lets take a look at a few things.  I will try and keep it as simplified as possible.  To do so we will look at the surface and the 850mb(5000ft) set up and compare the prev and the upcoming.  

Simply stated the air mass or source regions for the air that will be pulled into the centers of our low pressure vortex at the various levels of the atmosphere will be vastly different.  In both set ups we will have a surface low in similar positions, and a closed 850mb low, 700mb low, and 500mb low in similar positions just south of LI but the atmosphere surrounding them is what will be diff.  Look at the set up for the surface and 850mb levels.  Images will have the March 2nd set up first followed by the 7th/8th







So as you can clearly see that with this current set up the source region is much more favorable for cold air.  You can see by the close up shot of 850mb I showed above the winds were screaming into the coast in the mid levels right off the ocean just absolutely flooding the air mass with warm ocean air.  While it wont be a direct arctic air mass that we are working with we will have a much colder source region from which to draw from given the position and strength of the surrounding features.  

Now lets shift gears to 500mb set up for the up coming system only.  Below is the evolution using the euro but GFS and other globals are pretty similar with the general progression of the pattern.
 
I have outlined the two 500mb feautures that will come together to generate our storm.  There are two import features to look at ahead of the storm.  First notice the HP in the top right and the ULL in the bottom right of all the images below.  Notice that they do not mov at all.  This is our block, plain and simple and is critical to all of this.  Without it we wouldnt be having this discussion.  Second as we head into Mon/Tues (2nd and 3rd image below) we get a reinforcing shot of cold air in the upper levels.  Again not straight up arctic, but colder than what we had pre March 2nd storm without question.  As we head into the Early Wed time frame notice the two upper level pieces of energy begin to interact and phase.  








To reiterate without the block this storm cuts and we get another rant from Jimmy about how awful this winter is.  BUT because there is a block the surface low again trys to cut into the Ohio valley and Nwestern NY, just like the March 2nd, and is forced to transfer to the coast as it runs into the block (the banana HP(because it looks like a banana) to the north).  Its the shape and position of the HP that is why this system has more cold air to work with in along the boundary and low levels.    





This general set up is pretty much uniform throughout all modeling.  However, there are still minor details to be worked out which is what shapes the IMBY results.  Where, when, or if the 500mb low closes off; where is the exact track of the surface low will all be important.  Again the mid level temps should not be an issue even for the coast, unless the track is over LI or west.  The boundary layer cold although much improved over the last system is still a question mark for the coastal plain.  That said a positive for this storm and boundary layer temps is unlike the prev storm where we got started early in the day and got cranking at the peak of the daylight hrs, this system looks to get started mid-day and peak when sun angle shouldn't play as big or any roll if the heaviest comes in at night.   This is an esp important point for the coastal plain.  Lets see what our trends hold over the next 24hrs.  

We Track!!!!!  

And yes it is Banter and yet also not but its awesome none the less

Great write up Scott.
Billings post should be moved over here as well for his points.
This needs to be more evening and nightfall, timing is crucial IMO for accumulations to stick it is not an arctic air mass as you said.
One thing that needs to be for coastal toastal peeps here. Youb want that LP to not be tucked into the coast and you want it to close off off near the VA CAPES. Then we have a bomb ton work with. Also, the 700mb LP needs to be a bit more NW of the region. If it slides directly overhead then we'll see and possibly hear in NJ Syo rant of "this winter sucks". Coastal plain peeps.need to keep in mind even with a good track you may have mixung issues this time of year, it is not Jan nor Feb so need to keep an eye out for this.
If this storm came in mid Feb as currently progged it would not be more favorable to mixing.
Give it some time and we'll see how KING WINTER WXMODEL NAM has to say LOL!! Minor tweaks and we could all see an area wide warning level storm. All news and NWS outlet will stay with the climo this far out.

Be back tonight, wife b day. HAPPY WIFE IS A HAPPY LIFE!! Hopefully there are 30 pages of maps and discussion by then.

Is this a Tuesday night into Wednesday or a Wednesday night into Thursday scenario?

Great right up Scott!!

What in world happened with 12z cmc no one sees barely anything. And yes great write up Scott here's to hoping coast can see warning level snow.

snowday111 wrote:Is this a Tuesday night into Wednesday or a Wednesday night into Thursday scenario?

We’d to Thursday

Got a chance see the 12z CMC closer now, wow 4 LP from 7th to the 13th, miss us to east including this one, way offshore too, hopefully its not a trend.

jmanley32 wrote:Got a chance see the 12z CMC closer now, wow 4 LP from 7th to the 13th, miss us to east including this one, way offshore too, hopefully its not a trend.

Too much blocking. It won’t be OTS like that.

billg315 wrote:
Three things I continue to like about this:
1. System starts with much colder air in place at surface and aloft than last system. Not as cold as I’d like it but better than Friday which actually still worked out for people just to our N&W. Also snow may continue after dark Wednesday which is a better time for accumulation.
2. I like when surface low develops further south (NC/VA) because it gives it more time to deepen and organize as it moves north toward and past us.
3. Unlike last system models seem consistent in general placement of low and cold air. So while coastal areas have mixing concerns (as they always will with March storms) there is at least a little more consensus away from the coast for snow.
Three things I don’t like:
1. A north and west trend as we’ve had this year could kill us with this one. GFS was already a little too close to coast for my liking and produces mix/rain issues NYC east. Any further west and this could be a slop fest at best;
2. This storm may not be as strong do areas that stay cold enough for snow may not be in heaviest precip.
3. During day Wed. even with colder temps we’re still mostly above freezing so stickage at outset is still as Mike pointed out a concern.

sroc4 wrote:

jmanley32 wrote:Got a chance see the 12z CMC closer now, wow 4 LP from 7th to the 13th, miss us to east including this one, way offshore too, hopefully its not a trend.

Too much blocking. It won’t be OTS like that.

good for nothing cmc lol,

12z UKIE with the crusher. Bomber over benchmark on that run.

SoulSingMG wrote:12z European

Close but no cigar.  Is that an improvement over the last run?

NWS has a low form off the VA capes and then move up inside the BM by about 74-100 miles.  Spits out 2” qpf. On the coast. Probably mostly rain verbatim based on the track if it verifies

Perfect position right now. With the block in place it's going to back west a little

sroc4 wrote:Perfect position right now. With the block in place it's going to back west a little

Agreed. Most storms this winter have trended west once inside 48-72 hours. If anything I'm concerned of a coastal hugger with this event.

sroc4 wrote:Perfect position right now. With the block in place it's going to back west a little

Agree completely. MET Mike Masco out of Philly points out (see his map below) how the Euro "is pulling the storm more east as a linkage it's trying to model between a tiny weakness in the expansive ridge over Greenland." Expect westward correction by 00z tonight or def by 12z Monday.

wouldnt a west shift cause the coast to rain? i would have assumed we want it a bit east. less snow but colder

That is what I thought too so not sure why everyone wants a west shift

Euro was perfect for me. I’m thinking big picture for everyone.

sroc4 wrote:Euro was perfect for me. I’m thinking big picture for everyone.

I trust you buddy. But I also trusted rb and Frank last storm and look what’s happened

aiannone wrote:wouldnt a west shift cause the coast to rain? i would have assumed we want it a bit east. less snow but colder

Depends on how far and what time of day is it.

sroc4 wrote:

aiannone wrote:wouldnt a west shift cause the coast to rain? i would have assumed we want it a bit east. less snow but colder

Depends on how far and what time of day is it.

ahh makes sense. well king nam should be in range this aftn

I dunno sroc euro is east too cut off is CT for warning level snows. We have time but no good.