Rain/Thunder and Anafrontal Snow

[WeatherGeek2025]

After Central Park hit earliest 80 degree day ever, and today hitting 70's tomorrow evening we could be talking some heavy snowfall which shouldn't accumulate to much but it'll coming down for a couple of hours! Mostly a car topper but someone could get a surprise 1-2 inches Thursday evening

[NEG NAO]

this should be interesting....

[MJO812]

Coating tomorrow on cold surfaces 

[MJO812]

SREF better

Take some away because it will be less than 10:1

[WeatherGeek2025]

nam just gave us a few inches lol

[MJO812]

25 minutes ago, WeatherGeek2025 said:

nam just gave us a few inches lol

Yes

[WeatherGeek2025]

there's gotta be some severe weather there

[Stormlover74]

37 minutes ago, WeatherGeek2025 said:

there's gotta be some severe weather there

No warnings at this time

[PhiEaglesfan712]

You all know it's really not going to snow. There is a lack of cold air, the ground is way too warm, and the sun angle is too strong.

[NEG NAO]

56 minutes ago, WeatherGeek2025 said:

there's gotta be some severe weather there

elevated

[MJO812]

Heavy thunderstorms here in Brooklyn.  My newborn got scared =(

[MJO812]

12 minutes ago, PhiEaglesfan712 said:

You all know it's really not going to snow. There is a lack of cold air, the ground is way too warm, and the sun angle is too strong.

What does the ground and sun angle have to do with the atmosphere?

All winter you have been on the no snow train. Not working out for you . 

[MJO812]

54 degrees now with thunder and lighting. 

[PhiEaglesfan712]

1 minute ago, NEG NAO said:

 

ignore him he is just trying to create chaos here 

No, I'm not the one creating chaos. You're the ones doing it by causing unnecessary panic by saying there's going to be a snowstorm, when you all know it isn't going to happen. When was the last time you saw snow immediately after 80 degree days? Because I can't think of one of the top of my head. And I'm not young, I was born in 1988 and remember the 1993 snowstorm.

[MJO812]

2 minutes ago, PhiEaglesfan712 said:

No, I'm not the one creating chaos. You're the ones doing it by causing unnecessary panic by saying there's going to be a snowstorm, when you all know it isn't going to happen. When was the last time you saw snow immediately after 80 degree days? Because I can't think of one of the top of my head. And I'm not young, I was born in 1988 and remember the 1993 snowstorm.

No one is saying snowstorm . Its a wave riding along the front as the cold air comes in ( Anafronts)

We have seen plenty of those in the past. No one is saying this will accumulate. I do think it does on colder surfaces if we get good rates but it will most likely be white rain.

[RU848789]

As always, accumulation rate = snowfall rate - melting rate, where based on experience (and some deep knowledge of heat transfer and physical chemistry phase changes) I'd guesstimate the melting rate in mid-March is about 0.2-0.3" per hour during the day (say 10 am to 4 pm) with temps around 32F, so with temps in the mid-30s, I'd expect a melting rate around 0.4-0.5"/hr on the colder surfaces, so we'd need snowfall rates around 0.5"+ per hour (0.05" QPF/hr) to see accumulation and rates just don't look to be that high, which is why I don't expect much accumulation.

On the flip side, if we can get a thump of snow for an hour or so with ~1" per hour rates, that can get us ~1/2" of snow on the ground and not everyone realizes this, but once there is snow on the ground, that snow is by definition at 32F (at most), meaning subsequent snowfall is no longer melting at the rates above, which are due to a combination of elevated surface temps and elevated air temps with indirect sunlight - the elevated surface temps are a bigger factor in melting (just look at how much more snow melts as temperature increases with the same insolation level, like we saw over the past couple of weeks after the blizzard) - so I'd expect those melting rates to come down to maybe 0.1-0.2" per hour once there is accumulated snow on the ground.

I've never seen anyone truly quantify these melting rates (maybe someone in some research paper has done it?), so these are at best educated guesses - would love to know what they are under various surface temp/surface type/air temp/insolation factor (vs time of day), etc. If I had gotten a PhD in meteorology instead of chemical eng'g, I could see wanting to have done research on such a thing.

[psv88]

Nice thunderstorm here!

[RU848789]

45 minutes ago, MJO812 said:

No one is saying snowstorm . Its a wave riding along the front as the cold air comes in ( Anafronts)

We have seen plenty of those in the past. No one is saying this will accumulate. I do think it does on colder surfaces if we get good rates but it will most likely be white rain.

Exactly.  This wouldn't be more than a moderate 2-4" snowstorm even with cold temps in Jan, as there's just not enough precip and with the elevated surface temps and higher sun angle this one will be unlikely to put down more than 1" on grassy surfaces anywhere.  

But temps in the 70s and lower 80s yesterday has nothing to do with whether or not we can have a snowstorm the next day.  If it turns cold enough and there's enough snowfall intensity, it'll accumulate easily even at midday.