March 9 Rain/Snow Event (Possibility of a few inches of wet snow for much of the subforum, most likely north and west of NYC)

[jm1220]

25 minutes ago, MJO812 said:

 

We can hope. If the precip comes in like a heavy wall we’ll know the aggressive models were right. If scattered/light the GFS will be right. The heavy wall is how most of us can salvage some decent accums. 

[HVSnowLover]

5 minutes ago, jm1220 said:

We can hope. If the precip comes in like a heavy wall we’ll know the aggressive models were right. If scattered/light the GFS will be right. The heavy wall is how most of us can salvage some decent accums. 

Yea id say we need an inch on the ground by 9 am for this to overperform.    

 

Also precip coming in like a wall would lead to dynamic cooling (NAM has temps at 33, some models are like 36-38).

[winterwx21]

RGEM just came in much warmer than NAM and HRRR. It has quite a bit of rain and rain/snow mix for NYC, and you'd have to go northwest to see accumulations on this run. Probably underdone like NAM is overdone, but can't rule out this possibility either. March storms are unpredictable and it will be interesting to see what happens tomorrow.

[jm1220]

7 minutes ago, winterwx21 said:

RGEM just came in much warmer than NAM and HRRR. It has quite a bit of rain and rain/snow mix for NYC, and you'd have to go northwest to see accumulations on this run. Probably underdone like NAM is overdone, but can't rule out this possibility either. March storms are unpredictable and it will be interesting to see what happens tomorrow.

Haven’t looked at the QPF but I’d assume it’s drier than Nam and therefore not as much dynamic cooling. We can see how tomorrow might take shape already. The city and immediate coast are stuck around 40. Once away from there it’s around freezing. It can get a couple degrees colder from wet bulbing down but the sun will warm it back up without the heavy snow keeping it cool. 

[jm1220]

FWIW the other hi-res models look pretty decent along with the HRRR/RAP. RGEM is a lot drier so it shows less cooling/less snow for near the city. FV3 looks atrocious but I think it's a short range GFS so not surprising.

[HVSnowLover]

9 minutes ago, jm1220 said:

FWIW the other hi-res models look pretty decent along with the HRRR/RAP. RGEM is a lot drier so it shows less cooling/less snow for near the city. FV3 looks atrocious but I think it's a short range GFS so not surprising.

HRRRR looks pretty lousy to me. 

[RU848789]

One thing to keep in mind with accumulations and melting, which we talk about every March, is that it's all about rates, where accumulation = snowfall rate - melting rate.  And once one has a good enough snowfall rate to exceed the melting rate (which is obviously lower on grass than pavement) and accumulation begins, that snow on the ground is now at 32F, so the melting rate for subsequent snow falling on 32F snow goes down significantly, i.e., it's now only a function of melting from above 32F air temps and the impact of the indirect sunlight (where the melting rate due to the warm surface is no longer a factor).  And if the snowfall rate is high enough it can overcome the melting rate even on pavement (the melting rate is probably around 1/2" per hour on pavement).  

[HVSnowLover]

40 minutes ago, jm1220 said:

Haven’t looked at the QPF but I’d assume it’s drier than Nam and therefore not as much dynamic cooling. We can see how tomorrow might take shape already. The city and immediate coast are stuck around 40. Once away from there it’s around freezing. It can get a couple degrees colder from wet bulbing down but the sun will warm it back up without the heavy snow keeping it cool. 

It's only actually around 40 in the 5 boroughs, everywhere else is colder.  

[LibertyBell]

1 hour ago, jm1220 said:

Haven’t looked at the QPF but I’d assume it’s drier than Nam and therefore not as much dynamic cooling. We can see how tomorrow might take shape already. The city and immediate coast are stuck around 40. Once away from there it’s around freezing. It can get a couple degrees colder from wet bulbing down but the sun will warm it back up without the heavy snow keeping it cool. 

I thought this was an arctic airmass, why arent we much colder than this? It's not like this is mid april.

 

[LibertyBell]

1 hour ago, RU848789 said:

One thing to keep in mind with accumulations and melting, which we talk about every March, is that it's all about rates, where accumulation = snowfall rate - melting rate.  And once one has a good enough snowfall rate to exceed the melting rate (which is obviously lower on grass than pavement) and accumulation begins, that snow on the ground is now at 32F, so the melting rate for subsequent snow falling on 32F snow goes down significantly, i.e., it's now only a function of melting from above 32F air temps and the impact of the indirect sunlight (where the melting rate due to the warm surface is no longer a factor).  And if the snowfall rate is high enough it can overcome the melting rate even on pavement (the melting rate is probably around 1/2" per hour on pavement).  

this is what happened in April 2003 and April 2018

 

[snywx]

27/21 here

expecting 2-4” here

[MJO812]

Nam is further north at 6z. Less snow for the city.

[LoboLeader1]

34 here as of 5:30 this AM, under cloudy skies. 

[sussexcountyobs]

31.7/21.9 Snow overhead on radar.

[SnoSki14]

1 hour ago, MJO812 said:

Nam is further north at 6z. Less snow for the city.

Enjoy the cold rain

[lee59]

Snowing here, ground has a coating. 34 degrees

[STORMANLI]

35°

Goose feather flakes

 

[Rjay]

33 and snow

[Snowshack]

Light snow at 34f in Wading River.  Colder surfaces lightly coated.  

[jm1220]

33 here, light snow with a coating. 

[Snowlover11]

very very light drizzle on my way home in yonkers

[Brian5671]

Radar looks like a whiff to the south for northern posters.   Also warm here-35-forecast low was 31

[STORMANLI]

33°

0.3"

Smaller flakes now

[Allsnow]

5 minutes ago, Brian5671 said:

Radar looks like a whiff to the south for northern posters.   Also warm here-35-forecast low was 31

Should fill in late morning into the afternoon 

[Allsnow]

Radar filling in nicely central Pa 

[Brasiluvsnow]

currently 35 degrees in New City and nothing falling last time I looked,,,,,,we can only hope and pray that the Sloatsburg area jackpots out of this as the kids in that area would love to build another snowman 19 

[jm1220]

These models that show rain may also be a little too warm with surface temps. I'm a couple-few degrees colder than those models show. I would think that if we get heavier precip it would be snow. Whether it sticks or not is another question.

[MJO812]

1 hour ago, SnoSki14 said:

Enjoy the cold rain

We live in the worst part of NY for snow

[dmillz25]

Down to 36 with drizzle at the moment 

[bluewave]

36° with light rain here in SW Suffolk.