March 18-20 Storm Discussion

[MJO812]

Upton now has a high of 35 for the area.

[IsentropicLift]

Winter Weather Advisory here. NWS calling for up to 0.20" of freezing rain Monday night and 2" of snow.

[Absolute Humidity]

Kinda surprised I haven't seen this mentioned yet until peeking now at the NAM h75 - 84. There's a little low that pops off NNJ coast with light snows area wide. Took a peek at 18z GFS and sure enough, it has the same feature.

[MJO812]

RGEM has a decent front end thump for the entire area

 

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

[sferic]

Is it still in the realm of possibility that NYC stays frozen for the majority of tomorrow's event or is it locked in stone we change over to all liquid?

[MJO812]

Is it still in the realm of possibility that NYC stays frozen for the majority of tomorrow's event or is it locked in stone we change over to all liquid?

 

Snow to rain for NYC

[MJO812]

0z RGEM snow amounts

[jm1220]

Is it still in the realm of possibility that NYC stays frozen for the majority of tomorrow's event or is it locked in stone we change over to all liquid?

I think very likely it's an hour or two of snow or mix/slop over to rain, which has an equal chance of sticking or not sticking before whatever falls gets washed away. You have to be inland to probably White Plains on north and north into CT as well to have much longer of a period of snow that accumulates, and then there being ice after instead of cold rain. Inland over NJ might hold surface cold a bit better but the mid level warm nose will change many locations there over to sleet sooner than N or NE areas. This isn't our storm, at all if you're looking for more than an hour, two hours max of mood snow that gets us maybe a fast coating to an inch.

[MJO812]

I think very likely it's an hour or two of snow or mix/slop over to rain, which has an equal chance of sticking or not sticking before whatever falls gets washed away. You have to be inland to probably White Plains on north and north into CT as well to have much longer of a period of snow that accumulates, and then there being ice after instead of cold rain. Inland over NJ might hold surface cold a bit better but the mid level warm nose will change many locations there over to sleet sooner than N or NE areas. This isn't our storm, at all if you're looking for more than an hour, two hours max of mood snow that gets us maybe a fast coating to an inch.

 

It's weird seeing the RGEM cold. It's usually a warm biased model. Lets hope it's right.

[jm1220]

It's weird seeing the RGEM cold. It's usually a warm biased model. Lets hope it's right.

If the snow comes in like a wall, I can see it being right. But if it comes in showery or not heavy right away, what falls would likely have a hard time sticking since WAA snow often starts a little earlier than progged and that would be mid-late afternoon, and the mid levels warm up quickly afterward. So I don't see it being a good outcome for the immediate metro. It would take a lot for this to be any kind of real event for us locally.

[killabud]

euro looks  a little better for city on east....1-2 on wunderground maps

[sussexcountyobs]

1200' isn't gonna help you when your 850 temps are above freezing. It will help with surface temps though which will increase your icing threat.. Areas to the north of you may stay below 0 at 850 longer hence more accumulation.. Regardless of elevation

Thanks.I dont know how to forecast, or interpret models. Just tryin to learn.

[Brian5671]

Thanks.I dont know how to forecast, or interpret models. Just tryin to learn.

The issue appears to be how close the storm moves to us.   Since it's hugging the coast. most areas will flip to east winds which will bring the warmth in from the relatively mild Atlantic...  We would need a 50-100 mile shift SE of the storm track to have a better chance...with that said, far inland areas like northern Fairfield Cty, CT, Sussex Cty, NJ and Orange Cty, NY will do better, but will still change over to ice and then rain eventually

[IsentropicLift]

Was surprised to wake up this morning and see Winter Storm Warnings flying out this way. Not for my immediate backyard but for right up the street so to speak. Expecting quite the wintry mix. We got down to 23 here last night. It's currently still in the mid-upper 20's.

[Snow_Miser]

The Euro and the 6z GFS ticked considerably colder for the region. The Euro snowmaps show 3-6 for NYC and 6"+ from SMQ N and W. Very interesting to see these models ticking colder.

[jm1220]

The Euro and the 6z GFS ticked considerably colder for the region. The Euro snowmaps show 3-6 for NYC and 6"+ from SMQ N and W. Very interesting to see these models ticking colder.

I highly doubt that's the case, unless miraculously the snow hits like a wall and we thump for 3 hours or more. That's about the window we have for snow-maybe 2 or 3 hours. That isn't good for having any real accums especially around the city if it's before dark.

[Zelocita Weather]

NAM gives us coating to an inch, we shall see...if I had to guess right now I would say TTN- 0.5", SMQ- 1.2", EWR 1.0", NYC 0.9", MMU 2.0" but possibility for a bust on the upside....

[IsentropicLift]

The Euro and the 6z GFS ticked considerably colder for the region. The Euro snowmaps show 3-6 for NYC and 6"+ from SMQ N and W. Very interesting to see these models ticking colder.

Could be why they went ahead and hoisted WWA and WSW for most of the northern and western burbs.

[IsentropicLift]

I highly doubt that's the case, unless miraculously the snow hits like a wall and we thump for 3 hours or more. That's about the window we have for snow-maybe 2 or 3 hours. That isn't good for having any real accums especially around the city if it's before dark.

He wasn't talking about the coast. Inland areas probably won't change over until the early morning hours when the secondary makes its closest approach.

[ag3]

He wasn't talking about the coast. Inland areas probably won't change over until the early morning hours when the secondary makes its closest approach.

Yes he is.

The 0z euro has .35"+ of precip for the city with 850s below zero and surface temps of 33-34 degrees.

And .35" is a conservative number. Looking at soundings, it could be close to .50".

[IsentropicLift]

NAM gives us coating to an inch, we shall see...if I had to guess right now I would say TTN- 0.5", SMQ- 1.2", EWR 1.0", NYC 0.9", MMU 2.0" but possibility for a bust on the upside....

If the 6z NAM is correct it will be pouring rain here tomorrow morning. One interesting note is that the snow totals on the 00z NAM and 06z NAM were nearly identical for our region. Hard to go against the Euro though when it matches the GFS. We shall see what the 12z NAM shows shortly.

[Kaner587]

For areas on the north shore of LI and northern NYC it is way more than 2-3 hours jm ( more like 6 hours). For your location I agree you may thump for an hr or 2 before changing over and getting an inch of two. But there is certainly the possibility at least based on the euro that areas on the north shore and places like the Bronx and northern manhattan northern queens could see 3-4 before changing over. I happen to doubt it but its possible and this cold air means business so I think well have to watch it unfold

[IsentropicLift]

Yes he is.

The 0z euro has .35"+ of precip for the city with 850s below zero and surface temps of 33-34 degrees.

And .35" is a conservative number. Looking at soundings, it could be close to .50".

You're right, I miss read his post. The Euro does give the city a good shot of frozen and gives inland areas a borderline warning criteria event.

[MikeS]

I highly doubt that's the case, unless miraculously the snow hits like a wall and we thump for 3 hours or more. That's about the window we have for snow-maybe 2 or 3 hours. That isn't good for having any real accums especially around the city if it's before dark.

 

I agree. During the heaviest precip, the 6z 4km NAM has the majority of the area as rain or a sloppy mix.

 

[StatenWx]

I think right now as it stands a c-2" is likely in NYC and its close burbs.

[IsentropicLift]

For areas on the north shore of LI and northern NYC it is way more than 2-3 hours jm ( more like 6 hours). For your location I agree you may thump for an hr or 2 before changing over and getting an inch of two. But there is certainly the possibility at least based on the euro that areas on the north shore and places like the Bronx and northern manhattan northern queens could see 3-4 before changing over. I happen to doubt it but its possible and this cold air means business so I think well have to watch it unfold

The thing that worries me is that with WAA events we tend to warm in the mid-levels faster than forecasted. That could be an ugly IP/ZR situation for inland areas. Hence the forecast of 0.10-0.20"+ of ZR by the NWS.

 

 

[jm1220]

For areas on the north shore of LI and northern NYC it is way more than 2-3 hours jm ( more like 6 hours). For your location I agree you may thump for an hr or 2 before changing over and getting an inch of two. But there is certainly the possibility at least based on the euro that areas on the north shore and places like the Bronx and northern manhattan northern queens could see 3-4 before changing over. I happen to doubt it but its possible and this cold air means business so I think well have to watch it unfold

Hopefully you guys are right but the Euro has been a little cold on some events this year (2/8 it was all snow for most of us and instead many of us had to deal with lots of sleet/rain). But I agree that this airmass is pretty tenacious. The further north and east you are, the better. I would still expect maybe a sloppy 1-2" for areas near the city and more like 2-5" once you get to places like Paramus up to White Plains. Some of the usual suspects out over northern Suffolk and Nassau might eek out more than 2".

[jm1220]

The thing that worries me is that with WAA events we tend to warm in the mid-levels faster than forecasted. That could be an ugly IP/ZR situation for inland areas. Hence the forecast of 0.10-0.20"+ of ZR by the NWS.

 

 

A lot of times the mid levels warm quicker than forecasted as you mentioned, but the ground is also colder and doesn't warm up as fast as models show. So a zone of freezing rain is a definite possibility, along with a good amount of sleet. But oftentimes the snow changes to sleet faster in these type of events, unfortunately.

[IsentropicLift]

Hopefully you guys are right but the Euro has been a little cold on some events this year (2/8 it was all snow for most of us and instead many of us had to deal with lots of sleet/rain). But I agree that this airmass is pretty tenacious. The further north and east you are, the better. I would still expect maybe a sloppy 1-2" for areas near the city and more like 2-5" once you get to places like Paramus up to White Plains. Some of the usual suspects out over northern Suffolk and Nassau might eek out more than 2".

I don't think anyone should be expecting more than a low end advisory snow/icing event outside of the far NW burbs and portions of Orange/Rockland/Weschester Counties and up into SW CT, hence the advisories and warnings that are currently in place.

[IsentropicLift]

A lot of times the mid levels warm quicker than forecasted as you mentioned, but the ground is also colder and doesn't warm up as fast as models show. So a zone of freezing rain is a definite possibility, along with a good amount of sleet. But oftentimes the snow changes to sleet faster in these type of events, unfortunately.

Yeah I agree, it could be a very ugly commute for some tomorrow morning. The radar doesn't look particularly impressive this morning either. I gather we'll have several hours of virga until the stuff out in Central PA can make it out this way.