Jump to content
  • Member Statistics

    17,502
    Total Members
    7,904
    Most Online
    Weathernoob335
    Newest Member
    Weathernoob335
    Joined

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)


HVSnowLover
 Share

Recommended Posts

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).

Link to comment
Share on other sites

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.

  • Haha 1
Link to comment
Share on other sites

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. 

Link to comment
Share on other sites

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).  

  • Like 1
  • Haha 1
Link to comment
Share on other sites

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.  

Link to comment
Share on other sites

  • HVSnowLover changed the title to 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)
  • Rjay pinned this topic
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.

 

Link to comment
Share on other sites

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

 

  • Like 1
Link to comment
Share on other sites

  • Rjay unpinned this topic

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...