March 13 - 15 Major Winter Storm Potential

[tdp146]

3 minutes ago, JetsPens87 said:

Watch dual-pol radar tomorrow to get an idea of that.

Was just going to ask if anyone has the link to a good dual-pol radar?

[LongBeachSurfFreak]

12 minutes ago, Ericjcrash said:

Gorgeous 

Gorgeousness! Look at the size of this thing. Also the moisture feed seems to even have a pacific connection!

happy I'm not home on the south shore for this one. It's looking likely there will be a painful period of heavy sleet while the north shore and NYC rips snow followed by rain while those areas sleet. I used to hate hate hate when that happened. 

Right now I think we struggle to a foot in wantagh

18" looks like a good call here 3 miles NW of the park on 120th and broadway 

[BxEngine]

Timeouts incoming. 

[swamplover56]

Just now, bluewave said:

The coastal front really hits a wall on the 18Z RGEM is is nearly identical to the Euro.

 

 

 

 

 

Would love to hear your thoughts on NYC thanks

[Tornadocane]

I may be incorrect (Okay let’s just start out from the position that I am completely incorrect), but I think the best principles to utilize for this storm are the same principles utilized in a Miller B type over-running event, where one low along the Alps decays whilst tracking toward a strong high pressure system in SE Canada, and subsequently, energy transfers to a Coastal Low in a favorable baroclinic area.  This time is special, because everything snow-weenies imagined goes right, and the primary transfered far enough south and the Coastal Low was able steal all the energy from the primary and turn into a Monster that rapidly develops prevents the changeover from snow to mixed/rainy precipitation within the five boroughs and western LI. 

Awesome? I’m not sure.  I’m sort of concerned about the dynamically-driven snowfall cooling the surface in NYC into the lower-20s, while the low brings in warmer, maritime air into Coastal sections by directing midlevel winds from the ESE, E and ENE.  Mid-Level Temps rise above freezing, and a deep layer of cold 22-26 degree temperatures remain at the surface.   What about if the mid-levels in NE NJ and SE NY warm enough to mix?  You don’t have that primary charging into the high pressure or that strong, persistent midlevel wind out of the South and East like normal over-running events.  You have a Surface High that sits in place and continuously feeds cold air into the storm at the surface level. 

My question to the forum… Could we see a period of significant freezing rain along and just south of the I95 corridor if the storm plays out the way I’ve suggested?  Then another wrinkle in the story is the winds gusting 40-50 MPHs with a storm displayed as close as the EPS, NAM and EURO suggest.  What kind of damage is that going to do during the height of this storm?  I have a feeling that a significant power outage potential exists with this storm. 

With that said, I expect the low to pull 50-100 miles east of Monmouth County, and keep NYC all snow with infrequent period of sleet mixed within the snowfall.  These storms are the type I used to pray happen in Paramus, NJ, because the cold air and dynamically-driven snow lowered temperatures into the 10s to Mid-20s, and sleet usually never made it across the Hudson or was sprinkled into the snowfall.  But this is the type of storm that would drop 20-30” across with an enormous deformation zone that forms in Northern NJ and Southern NY that translates to 6-8 hours of 2”-5” an hour snow rates. 

[Violentweatherfan]

12 minutes ago, JetsPens87 said:

Watch dual-pol radar tomorrow to get an idea of that.

can you recommend any good sites

[Paragon]

1 minute ago, bluewave said:

The coastal front really hits a wall on the 18Z RGEM is is nearly identical to the Euro.

 

 

 

 

 

Chris does this remind you somewhat of the second storm in February 1994? It does to me.  That one also trended more west and eventually ended up changing to sleet at JFK but was all snow at NYC, but both places saw around or just over a foot of snow.  EWR had the most with 17" and 31" on the ground because of the back to back storms.

[ag3]

Sref plumes at LGA showed the tight cutoff. LGA was 13.5", JFK was around 9"

[readingaccount1]

The gradients across Middlesex County (nj) are always impressive. I can recall getting significantly more snow in the northern part of the county during some events. Looks like a storm where the northern areas get 20 inches and the southern parts less.

[Drz1111]

The coastal front will be very interesting here.  Granted, once the 700mb low passes overhead, it's not going to save folks from mixing.  But during the height of the storm, in some instances where you have a rapidly intensifying low just off the coast, the ageostrophic flow and the geometry of the coast makes a coastal front want to set up right around JFK up to Port Washingtonish. IIRC that's what happened in 2010.  In those storms there can be a very steep gradient between CPK and LGA and even parts of central Nassau County.   It requires a special set of facts, but this storm might have it.

Of course, there are also plenty of storms where the coastal front blows through most of NYC, with the possible exception of the far N Bronx.  But it should be pretty obvious early on where the coastal front is setting up and folks just to the west of it should have some of the highest totals in the whole region. 

[Paragon]

1 minute ago, ag3 said:

Sref plumes at LGA showed the tight cutoff. LGA was 13.5", JFK was around 9"

that sounds reasonable, but it will probably be a little tighter- something like JFK 10" LGA 13" NYC 15"

[Ericjcrash]

1 minute ago, Violentweatherfan said:

can you recommend any good sites

Buy Radarscope. Good $10 investment. 

[RDRY]

3 minutes ago, bluewave said:

The coastal front really hits a wall on the 18Z RGEM and  is nearly identical to the Euro.

 

 

 

 

 

Great maps. Though I'd imagine that snowfall rates wouldn't be too good until you get at 20 miles northwest of the changeover line.

[NortheastPAWx]

You have to remember that there's a warm layer somewhere because sleet is still being shown even with H85 temps <0 in NYC.

[Paragon]

Just now, Drz1111 said:

The coastal front will be very interesting here.  Granted, once the 700mb low passes overhead, it's not going to save folks from mixing.  But during the height of the storm, in some instances where you have a rapidly intensifying low just off the coast, the ageostrophic flow and the geometry of the coast makes a coastal front want to set up right around JFK up to Port Washingtonish. IIRC that's what happened in 2010.  In those storms there can be a very steep gradient between CPK and LGA and even parts of central Nassau County.   It requires a special set of facts, but this storm might have it.

Of course, there are also plenty of storms where the coastal front blows through most of NYC, with the possible exception of the far N Bronx.  But it should be pretty obvious early on where the coastal front is setting up and folks just to the west of it should have some of the highest totals in the whole region. 

The difference with the last storm in Feb 2010 was we went from rain to heavy snow- which is much easier to handle than going from snow to rain lol.

We actually had similar totals to the city for the other storms that season (or more- for example in 12/09 we had 18" while the city barely had 10")

 

[Drz1111]

1 minute ago, RDRY said:

Great maps. Though I'd imagine that snowfall rates wouldn't be too good until you get at 20 miles northwest of the changeover line.

No - actually the exact opposite.  Best rates are right at the changeover line and then there's a subsidence zone and then another good band sets up NW of the subsidence zone.  The worst place to be is around 20 miles in from the changeover line (one of the reasons why CPK received less snow than most surrounding stations in 1996).

[NortheastPAWx]

Subway guide for reference with all elevated service suspended. Also cuts into more lines - B, C, M, W, 5 all totally axed.

http://newqa.mta.info/sites/default/files/mta/2017_winterguide_subway_map_b_with_2_av_subway_1-26-17.pdf

[Paragon]

1 minute ago, Drz1111 said:

No - actually the exact opposite.  Best rates are right at the changeover line and then there's a subsidence zone and then another good band sets up NW of the subsidence zone.  The worst place to be is around 20 miles in from the changeover line (one of the reasons why CPK received less snow than most surrounding stations in 1996).

I remember Dec 2003 when the changeover line was 5 miles south of us and we got the best rates

[Drz1111]

3 minutes ago, Paragon said:

The difference with the last storm in Feb 2010 was we went from rain to heavy snow- which is much easier to handle than going from snow to rain lol.

We actually had similar totals to the city for the other storms that season (or more- for example in 12/09 we had 18" while the city barely had 10")

 

Yeah, it's not a common scenario.  We used to see it more back in the 80s and 90s when there were more coastal huggers and warmer storms generally.   The youngins probably don't remember. 

[Paragon]

Just now, Drz1111 said:

Yeah, it's not a common scenario.  We used to see it more back in the 80s and 90s when there were most coastal huggers and warmer storms generally.   The youngins probably don't remember. 

yes that was during the snow drought era when people to our south, north, west and east all got more snow than we did   

[Rtd208]

State of Emergency now declared for NY as well.

[RDRY]

2 minutes ago, Drz1111 said:

No - actually the exact opposite.  Best rates are right at the changeover line and then there's a subsidence zone and then another good band sets up NW of the subsidence zone.  The worst place to be is around 20 miles in from the changeover line (one of the reasons why CPK received less snow than most surrounding stations in 1996).

Thought I saw a met post saying that the immediate vicinity of the changeover line could see lousy snowgrowth, riming and graupel.

[Rittenhouse]

How accurate is the RAP at this range?

The latest shows NYC with 1.7" qpf before mixing.

[weatherlogix]

5 minutes ago, bluewave said:

Root for the colder Euro which only has a brief period of sleet around 18z.

 

 

That is a great cross section view

[BrooklynSno]

Look at the latest HRRR.  It looks like the low center is going to go east of Virginia Beach.  As JB said this morning west of VA Beach would have been a bad sign for staying mostly snow in NYC

[Drz1111]

Just now, RDRY said:

Thought I saw a met post saying that the immediate vicinity of the changeover line could see lousy snowgrowth, riming and graupel.

Generally, that's not true in big nor'easters.  There's a discussion of this in the K&U book.  I actually don't know the physics of why it occurs; it might just be that the highest vertical velocities are associate with the zone right in front of the warm nose. 

[NortheastPAWx]

Just now, BrooklynSno said:

Look at the latest HRRR.  It looks like the low center is going to go east of Virginia Beach.  As JB said this morning west of VA Beach would have been a bad sign for staying mostly snow in NYC

It's not reliable at this range.

[bluewave]

Just now, weatherlogix said:

That is a great cross section view

On the higher res it looks like the warm pocket and sleet sneaks in around 15Z. You can see that sneaky warm layer showing up above the 850 charts.

 

 

[BrooklynSno]

Disagree Northeast PAWX, it may not be great for precip and type but it generally doses decent about the track of the low pressure area.  It has also been trending east when you look at it in the Virginia maps on wxbell.

[nesussxwx]

Just now, BrooklynSno said:

Disagree Northeast PAWX, it may not be great for precip and type but it generally doses decent about the track of the low pressure area.  It has also been trending east when you look at it in the Virginia maps on wxbell.

it's been flip flopping the low pressure each run back and forth... too early to use it for LP.