Potential Snow 11/27 - 11/28

[NEG NAO]

Say what you will, but I think this will likely be a mostly snow event for NYC and much of Long Island. The NAM is, IMO, too warm with the 2m temps. With temps @ 850 mb around -5 C, but more importantly, virtually no wind, it will be very difficult to bring warm air onshore....whatever wind there is, should eventually shift light into the northeast. This is no storm where there is some type of protracted flow off the water...just a weak wave moving through. Saw lots of these in the 1980's where the surface never gets higher than about 33 F. The models also came in wetter at 0z, (NMM was *very* wet), so for now, I'll go for one to four inches of snow on Tuesday for NYC and Long Island.

Agree 100 % - this storm is not strong enough to bring the milder ocean air as far onshore as some of the models are depicting - especially from north of the raritan river through northern middlesex county and northeast NJ

[GD0815]

Agree 100 % - this storm is not strong enough to bring the milder ocean air as far onshore as some of the models are depicting - especially from north of the raritan river through northern middlesex county and northeast NJ

if you want snow, the best thing you could want is a stronger storm, dynamic cooling etc

[Edge Weather]

This is true, but this time we have a colder airmass already in place and no strong storm to bring any warm air in off the ocean. I think that may make the difference.

Here's one of the soundings I was talking about. This verified at the surface like so:

METAR KPHL 072354Z 34014G20KT 8SM -RA SCT012 OVC020 02/01 A2987 RMK AO2 SLP115 P0004 60027 T00220006 10033 20017 50002 $

For those who can't read METAR, that's 36F with light rain, 0.04" of precip in the previous hour. It verified because the precip rate was too low to defeat the warm BL.

[NEG NAO]

if you want snow, the best thing you could want is a stronger storm, dynamic cooling etc

that all depends on the track of the storm - and if you can keep the wind direction N - NE

[ag3]

srefs:

NYC on the edge of the snow also:

[NEG NAO]

srefs:

NYC on the edge of the snow also:

The snow/rain line looks reasonable and what we have seen already in the past on this run - the NAM is too far inland - too far north IMO

[ag3]

NAM is very similar to the srefs. Might come in a little wetter then them.

[NEG NAO]

Gulf seems to be opening up

http://www.accuweather.com/en/us/southeast-region/weather-radar?play=1

[FSUWxMan]

I am flying back from Florida into LaGuardia tomorrow afternoon around 5pm, what kind of delays if any could we be looking at from this?

[Zelocita Weather]

NAM again in the 0.5" range of QPF for most, and 850s plenty cold. We'll see what the boundary layer does tomorrow but it usually responds if precip is coming down decently...

[forkyfork]

this is the wettest nam run yet

[ag3]

this is the wettest nam run yet

Yeah. .50"-.75" for the whole area.

[PB GFI]

Whole argument of not cooling the column ( made here ) would go out the window if .50 - .75 fell .

i would like to see more than 1 model run before i bite .

[ag3]

Whole argument of not cooling the column ( made here ) would go out the window if .50 - .75 fell .

i would like to see more than 1 model run before i bite .

Srefs are pretty solid as well. Wide swath of .25"-.50" areawide.

[weathermedic]

What is the MM5 showing?

[ag3]

Going off black and white maps, the rgem appears to have near .25" for NYC and south with very little north of that. A pretty sharp cutoff.

The precipitation maps are now also showing a mix for the whole event for NYC and west. All previous runs had all rain, so it appears the RGEM is picking up cooler temps.

[Storm At Sea]

Latest SREF's show rain/snow line roughly lining up with I-287. Highest probability of accumulating snow still appears to be E PA and to a lesser extent NW NJ (Warren and Sussex counties). For those that don't have the link, I posted below the PSU Ewall SREF link. Within the 48 HR mark, these are extremely accurate. As you will note, they really make some folks on here look like they are wishcasting. In comparison to the last snow event, SREF in this timeframe showed >90% of 1+ in. and 50% for 4+ in. for Most of CNJ and NNJ.

http://www.meteo.psu.edu/~fxg1/ewallsref.html

Srefs are pretty solid as well. Wide swath of .25"-.50" areawide.

[ag3]

Latest SREF's show rain/snow line roughly lining up with I-287. Highest probability of accumulating snow still appears to be E PA and to a lesser extent NW NJ (Warren and Sussex counties). For those that don't have the link, I posted below the PSU Ewall SREF link. Within the 48 HR mark, these are extremely accurate. As you will note, they really make some folks on here look like they are wishcasting. In comparison to the last snow event, SREF in this timeframe showed >90% of 1+ in. and 50% for 4+ in. for Most of CNJ and NNJ.

http://www.meteo.psu.../ewallsref.html

The post of mine you quoted makes no mention of snow or accumulations. All I said is that they show a solid swath of .25" - .50" of precipitation.

Nothing else.

[Storm At Sea]

Your plants must really need the rain then.

The post of mine you quoted makes no mention of snow or accumulations. All I said is that they show a solid swath of .25" - .50" of precipitation.

Nothing else.

[IsentropicLift]

12Z NAM FOR KMMU - NO ACCUMULATIONS

121127/1200Z 24 VRB02KT 35.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.013 0:1| 0.0|| 0.00|| 0.00|| 0.01 46| 0| 54

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

121127/1300Z 25 VRB01KT 33.2F SNOW 11:1| 0.0|| 0.00|| 0.00|| 0.043 0:1| 0.0|| 0.00|| 0.00|| 0.06 81| 0| 19

121127/1400Z 26 VRB02KT 33.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.043 0:1| 0.0|| 0.00|| 0.00|| 0.10 71| 0| 29

121127/1500Z 27 05003KT 34.1F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.024 0:1| 0.0|| 0.00|| 0.00|| 0.12 62| 0| 38

121127/1600Z 28 04005KT 34.6F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.021 0:1| 0.0|| 0.00|| 0.00|| 0.14 64| 0| 36

121127/1700Z 29 03005KT 34.4F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.032 0:1| 0.0|| 0.00|| 0.00|| 0.18 65| 0| 35

121127/1800Z 30 02005KT 33.5F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.054 0:1| 0.0|| 0.00|| 0.00|| 0.23 76| 0| 24

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

121127/1900Z 31 01005KT 33.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.062 0:1| 0.0|| 0.00|| 0.00|| 0.29 78| 0| 22

121127/2000Z 32 02007KT 33.2F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.061 0:1| 0.0|| 0.00|| 0.00|| 0.35 75| 0| 25

121127/2100Z 33 01007KT 33.5F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.045 0:1| 0.0|| 0.00|| 0.00|| 0.40 69| 0| 31

121127/2200Z 34 01007KT 33.5F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.041 0:1| 0.0|| 0.00|| 0.00|| 0.44 69| 0| 31

121127/2300Z 35 01008KT 33.9F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.025 0:1| 0.0|| 0.00|| 0.00|| 0.46 61| 0| 39

121128/0000Z 36 01008KT 34.4F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.013 0:1| 0.0|| 0.00|| 0.00|| 0.48 50| 0| 50

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

121128/0100Z 37 36008KT 34.6F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.010 0:1| 0.0|| 0.00|| 0.00|| 0.49 46| 0| 54

121128/0200Z 38 36007KT 35.0F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.003 0:1| 0.0|| 0.00|| 0.00|| 0.49 43| 0| 57

[Analog96]

12Z NAM FOR KMMU - NO ACCUMULATIONS

121127/1200Z 24 VRB02KT 35.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.013 0:1| 0.0|| 0.00|| 0.00|| 0.01 46| 0| 54

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

121127/1300Z 25 VRB01KT 33.2F SNOW 11:1| 0.0|| 0.00|| 0.00|| 0.043 0:1| 0.0|| 0.00|| 0.00|| 0.06 81| 0| 19

121127/1400Z 26 VRB02KT 33.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.043 0:1| 0.0|| 0.00|| 0.00|| 0.10 71| 0| 29

121127/1500Z 27 05003KT 34.1F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.024 0:1| 0.0|| 0.00|| 0.00|| 0.12 62| 0| 38

121127/1600Z 28 04005KT 34.6F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.021 0:1| 0.0|| 0.00|| 0.00|| 0.14 64| 0| 36

121127/1700Z 29 03005KT 34.4F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.032 0:1| 0.0|| 0.00|| 0.00|| 0.18 65| 0| 35

121127/1800Z 30 02005KT 33.5F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.054 0:1| 0.0|| 0.00|| 0.00|| 0.23 76| 0| 24

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

121127/1900Z 31 01005KT 33.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.062 0:1| 0.0|| 0.00|| 0.00|| 0.29 78| 0| 22

121127/2000Z 32 02007KT 33.2F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.061 0:1| 0.0|| 0.00|| 0.00|| 0.35 75| 0| 25

121127/2100Z 33 01007KT 33.5F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.045 0:1| 0.0|| 0.00|| 0.00|| 0.40 69| 0| 31

121127/2200Z 34 01007KT 33.5F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.041 0:1| 0.0|| 0.00|| 0.00|| 0.44 69| 0| 31

121127/2300Z 35 01008KT 33.9F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.025 0:1| 0.0|| 0.00|| 0.00|| 0.46 61| 0| 39

121128/0000Z 36 01008KT 34.4F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.013 0:1| 0.0|| 0.00|| 0.00|| 0.48 50| 0| 50

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

121128/0100Z 37 36008KT 34.6F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.010 0:1| 0.0|| 0.00|| 0.00|| 0.49 46| 0| 54

121128/0200Z 38 36007KT 35.0F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.003 0:1| 0.0|| 0.00|| 0.00|| 0.49 43| 0| 57

Well, technically, there would be half an inch on that sounding, because of that one period where it goes to all snow, but that isn't much.

[Storm At Sea]

I suspect that it will be a cold, raw day with mostly rain during much of the day. At the height of the event, rain will change to a mix. May be pretty for a time, but no accumulations.

Well, technically, there would be half an inch on that sounding, because of that one period where it goes to all snow, but that isn't much.

[bluewave]

The GFS is hinting that there may be enough moisture around tomorrow night for the city and coast

to end as some wet snow as colder air filters down behind the low.

[IsentropicLift]

Well, technically, there would be half an inch on that sounding, because of that one period where it goes to all snow, but that isn't much.

True, but I picked KMMU for a reason, it's pretty far west and inland and even that location doesn't get much of anything.

[eduggs]

As currently modeled, I think most places away from the immediate shoreline would see primarily falling snow (low freezing levels, thicknesses, and wetbulb temps). But accumulations would be confined to elevated areas and/or places where moderate precipiation sets up. The NAM depiction would likely result in some light accumulations north and esp just west of the City (regardless of what text output seems to suggest).

[earthlight]

As currently modeled, I think most places away from the immediate shoreline would see primarily falling snow (low freezing levels, thicknesses, and wetbulb temps). But accumulations would be confined to elevated areas and/or places where moderate precipiation sets up. The NAM depiction would likely result in some light accumulations north and esp just west of the City (regardless of what text output seems to suggest).

Agree. The NAM is trying to pick up on localized/mesoscale dynamics over Southeast PA...and is producing a local precipitation max there. So it's not surprising to see 4-6" on the snow algorithms from MDT to the Delaware River. But it only has 1-2" through most of NJ because that band wanes by the time it gets here. The boundary layer won't support accumulating snow, even in the suburbs, unless we get some good lift and heavy snow.

[earthlight]

The RGEM has the same area of moderate precipitation over Southeast PA which eventually makes its way into parts of Western NJ...but weakens before it gets to NYC. You can also see the RGEm picking up on the SN/RN mix a few miles from the coast...and mostly rain at the coast and in the city.

[ag3]

The RGEM has the same area of moderate precipitation over Southeast PA which eventually makes its way into parts of Western NJ...but weakens before it gets to NYC. You can also see the RGEm picking up on the SN/RN mix a few miles from the coast...and mostly rain at the coast and in the city.

A better image of the 12z RGEM:

And Total Snow:

[eduggs]

Looking over the charts, it would be so easy for this to turn into a moderate snowstorm. The mid-level centers are slow to develop and the surface response is extremely weak. Even so, the NAM prints out roughly .5 inch liquid into a marginal atmosphere. If the s/w moving into the midwest were just a bit stronger, it might initiate stronger cyclogenesis. The upper levels look supportive. You wouldn't need too much more positive vorticity advection into the area of baroclinicity along the coast to get better mid-level development. The problem is, PVA is very weak on the charts.

Unfortunately, there's nothing in the ensemble modeling or recent model runs to suggest such a possibility. And I would divide the NAM model QPF in half to make a forecast estimate. I will be watching carefully for any last minute corrections today, but the large corrections don't happen as often as they did 10 years ago.

[ag3]

Total Precipitation from 12z rgem: