WINTER WEATHER ADVISORY TONIGHT, Messy Commute Likely Tuesday 12/17

Keeping an eye on the precipitation Monday night 12/16 into Tuesday. Precipitation probably will not be heavy...I would hesitate to call this a storm....but the temperature profile is concerning. Very uncertain forecast right now, but there is a possibility of sleet or freezing rain for an extended period. As of now the timing would have this occurring overnight, but the timing could shift a few hours either way.


There was a time, when I thought you were one of the good guys!


tomcat said:

There was a time, when I thought you were one of the good guys!

 I don't make the news, I just report the news.


Sunday morning update for overnight Monday 12/16 precipitation.

This one is still giving us problems, with disagreements in timing and precipitation type between all three of the major models. As of now, we could have light snow falling during the afternoon rush Monday, with changeover to sleet and rain Monday night. Fingers crossed this could still be a non-event for us, but a shift in the track or timing could bring freezing rain sometime during the window from Monday early evening to (more likely) early Tuesday morning. It is still a low potential for a full-blown ice storm as there is not enough water in the system, but it could still drop enough ice to affect the commute Tuesday morning.


Not enough water in the system? Drop enough ice?


So a very quick update on tomorrow. A cursory look (I’ll dig a little deeper tomorrow morning) shows the chance for some wintry mix/maybe some ice tomorrow afternoon/evening/overnight. I don’t expect much snow with this system, but a flake or two is possible. 


WxNut2.0 said:

So a very quick update on tomorrow. A cursory look (I’ll dig a little deeper tomorrow morning) shows the chance for some wintry mix/maybe some ice tomorrow afternoon/evening/overnight. I don’t expect much snow with this system, but a flake or two is possible. 

 And no sooner do I write this do the models come in with a pretty impressive environment for snow tomorrow. Sub-freezing temperatures from the ground up along with favorable profiles for heavy snow could lead to a couple of pretty intense snow bands. I'm weary of saying we're going to see substantial accumulations --  much like last week the ground is warm -- but I'm not sure we can't rule out at least a couple of inches *if* these model solutions come to fruition. For now I'm still thinking a wintry mix with maybe a decent burst of snow or two, but that could very well be underselling the real potential here. Something to definitely keep an eye on in the hours leading up to the start of the precipitation. Let's start the bidding at a dusting to two inches with some ice mixed in and see where the evening takes us.


Becoming cautiously optimistic as the forecast for tomorrow Monday 12/16 and Tuesday comes comes into better focus.

Fairly confident that daytime snow Monday will be minimal, flurries if anything in the late afternoon.

Overnight Monday into Tuesday could still see some sleet and snow mixing in with the rain and possible complicating the commute Tuesday 12/17 morning.


Monday, 12/16

The main concern remains tomorrow morning, 12/17.

For today, while there may be some light snow this afternoon, snow is likely to change over to rain or a wintery mix tonight.

Precipitation type and timing is unclear at any point overnight, but there is a possibility of freezing rain, sleet, or plain rain. There is enough variation in the models as to both ground temperature and mid-level temperature that we cannot be certain.

Tuesday morning commute could be messy, with rain, sleet, or freezing rain. This uncertainty may continue through tonight's forecast.


Where do you see ground temperature variation?


WxNut2.0 said:

Where do you see ground temperature variation?

 GFS warmer than NAM and Euro.  Also this from disco:

The biggest challenge will be the ptype 
as warm air begins to move in aloft creating 
a warm nose. If the warm nose is large and/or 
the sub- freezing air near the surface is 
very shallow, we could end up with more 
freezing rain than sleet. It is that precip 
type will vary at times overnight as moderate 
or heavy precipitation will cool the column 
sufficiently changing the precip to sleet 
or snow at times.

Looking esp from midnight to early morning rush


max_weisenfeld said:

WxNut2.0 said:

Where do you see ground temperature variation?

 GFS warmer than NAM and Euro.  Also this from disco:

The biggest challenge will be the ptype 
as warm air begins to move in aloft creating 
a warm nose. If the warm nose is large and/or 
the sub- freezing air near the surface is 
very shallow, we could end up with more 
freezing rain than sleet. It is that precip 
type will vary at times overnight as moderate 
or heavy precipitation will cool the column 
sufficiently changing the precip to sleet 
or snow at times.

Looking esp from midnight to early morning rush

 What you’re seeing here isn’t ground temperature though, it’s near-surface air temperature. There’s a subtle yet important distinction to be made; ground temp will largely impact accumulation whereas air temp will impact precip type, maybe save for freezing rain where they’re both important. Ground temp is parameterized in models and is difficult to find on the publicly available websites. It is usually an average temperature of the ground from the surface down to some depth. It will change slowly compared to the air temp, hence why last week we got heavy snow that didn’t stick. 


Also should add — in these situations, the temperature profile is the ONLY modulator of precip type (rain vs. snow vs. ice). There is no dependence on moisture content in that regard, aside from very minimal evaporative effects. 


WxNut2.0 said:

Also should add — in these situations, the temperature profile is the ONLY modulator of precip type (rain vs. snow vs. ice). There is no dependence on moisture content in that regard, aside from very minimal evaporative effects. 

 Yes, I was unclear about this.  Moisture content in my post referred to amount of accumulation, so the impact on the ground.  Although a heavy precipt can drop lower atmosphere temps and then have a knock-on effect on p-type, that's indirect.  It is still the temp profile that matters.


WxNut2.0 said:

max_weisenfeld said:

WxNut2.0 said:

Where do you see ground temperature variation?

 GFS warmer than NAM and Euro.  Also this from disco:

The biggest challenge will be the ptype 
as warm air begins to move in aloft creating 
a warm nose. If the warm nose is large and/or 
the sub- freezing air near the surface is 
very shallow, we could end up with more 
freezing rain than sleet. It is that precip 
type will vary at times overnight as moderate 
or heavy precipitation will cool the column 
sufficiently changing the precip to sleet 
or snow at times.

Looking esp from midnight to early morning rush

 What you’re seeing here isn’t ground temperature though, it’s near-surface air temperature. There’s a subtle yet important distinction to be made; ground temp will largely impact accumulation whereas air temp will impact precip type, maybe save for freezing rain where they’re both important. Ground temp is parameterized in models and is difficult to find on the publicly available websites. It is usually an average temperature of the ground from the surface down to some depth. It will change slowly compared to the air temp, hence why last week we got heavy snow that didn’t stick. 

Of course you are right -- the models very specifically show 2 meter temps, not ground temps.  I try to use layman's language, though, and frankly I try to be succint.  I'll try to remember to say "near the ground"  more often rather than just "ground" unless "surface" is a good alternative?  Thoughts?

max_weisenfeld said:

 and frankly I try to be succint.  I Thoughts?

 Succinct means, "Its gonna snow. Its not gonna snow."


The Max weather thread has been my go to weather source for a while now. I'm bummed that it has become more of a debate between two sources in recent times, especially with a contrarian back and forth. I can get that from traditional sources.


vdfam said:

The Max weather thread has been my go to weather source for a while now. I'm bummed that it has become more of a debate between two sources in recent times, especially with a contrarian back and forth. I can get that from traditional sources.

That’s not what I see going on at all. I see two informed sources both trying to bring us clarity who occasionally, and generously, offer to clarify each other (while allowing the rest of us to eavesdrop and maybe pick up some knowledge along the way).


DaveSchmidt said:

vdfam said:

The Max weather thread has been my go to weather source for a while now. I'm bummed that it has become more of a debate between two sources in recent times, especially with a contrarian back and forth. I can get that from traditional sources.

That’s not what I see going on at all. I see two informed sources both trying to bring us clarity who occasionally, and generously, offer to clarify each other (while allowing the rest of us to eavesdrop and maybe pick up some knowledge along the way).

 Same here. These tend to be the best and most informative threads on MOL, IMHO.


vdfam said:

The Max weather thread has been my go to weather source for a while now. I'm bummed that it has become more of a debate between two sources in recent times, especially with a contrarian back and forth. I can get that from traditional sources.

 The weather isn’t cut and dry. The prediction of the weather is open to interpretation and is the result of the analysis of multiple data sources. I am a professional meteorologist and take pride in that fact. If I see something I disagree with, I will call it out based upon my experience and education. My goal is certainly not to be contrarian, but rather interpret the data as I see it. This is what meteorology — and science — is.  


max_weisenfeld said:

WxNut2.0 said:

max_weisenfeld said:

WxNut2.0 said:

Where do you see ground temperature variation?

 GFS warmer than NAM and Euro.  Also this from disco:

The biggest challenge will be the ptype 
as warm air begins to move in aloft creating 
a warm nose. If the warm nose is large and/or 
the sub- freezing air near the surface is 
very shallow, we could end up with more 
freezing rain than sleet. It is that precip 
type will vary at times overnight as moderate 
or heavy precipitation will cool the column 
sufficiently changing the precip to sleet 
or snow at times.

Looking esp from midnight to early morning rush

 What you’re seeing here isn’t ground temperature though, it’s near-surface air temperature. There’s a subtle yet important distinction to be made; ground temp will largely impact accumulation whereas air temp will impact precip type, maybe save for freezing rain where they’re both important. Ground temp is parameterized in models and is difficult to find on the publicly available websites. It is usually an average temperature of the ground from the surface down to some depth. It will change slowly compared to the air temp, hence why last week we got heavy snow that didn’t stick. 

Of course you are right -- the models very specifically show 2 meter temps, not ground temps.  I try to use layman's language, though, and frankly I try to be succint.  I'll try to remember to say "near the ground"  more often rather than just "ground" unless "surface" is a good alternative?  Thoughts?

 I’m not trying to be a jerk by calling this out, but rather help in that succinctness. In this case, I felt there was important enough a difference in the terminology to make the point. That said, yes, surface temperature is kind of the standard here. 


1)   wxnut is right.  Remember, he is the meterologist, not me.  It would be pretty arrogant of me to get defensive, especially in cases like this where I got a bit sloppy.

2)  I learn from and value these conversations, too.  I don't feel threatened or confronted at all.

max_weisenfeld said:

1)   wxnut is right.  Remember, he is the meterologist, not me.  It would be pretty arrogant of me to get defensive, especially in cases like this where I got a bit sloppy.

2)  I learn from and value these conversations, too.  I don't feel threatened or confronted at all.

 My goal here is not to undermine Max either. I respect what he does and how he communicates it. 


Thank you for your responses. I will work on being more chill and less bummed. Carry on!

btw, even with my bummedness, I agree with ridski that "These tend to be the best and most informative threads on MOL, IMHO."


Max and Wx have made me a snowstorm superstar at my company!  The subtle analysis of tricky weather patterns--which seem to be getting trickier as the climate changes--has helped me make the call for bringing in reserves to take care of sidewalks well before others are making that call.  And sometimes I have been able to hold off longer than others because of the debate over which model is better for a give storm, which has saved my clients money and my staff wear and tear.

I do tell my bosses that I have some true weather-weenie friends who parse this stuff at a wonderful level.  But I will not tell them it comes from MOL, because then I would lose my exclusive source!

I really love these weather discussions, especially when you guys start getting into the dynamics of how the systems are working.  I understand perhaps 1/3 of what you say, but it sounds good to me.


snowflakes spotted in WO


conandrob still missing though


As bad as this system is up here, be glad (unless you’re me and miss chasing these) we’re not in the south: Big Louisiana Tornado


Winter Weather Advisory

URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
317 PM EST Mon Dec 16 2019

CTZ009>012-NJZ004-104>108-NYZ071-170900-
/O.CON.KOKX.WW.Y.0015.191217T0200Z-191217T1500Z/
Southern Fairfield-Southern New Haven-Southern Middlesex-
Southern New London-Eastern Passaic-Eastern Bergen-Western Essex-
Eastern Essex-Western Union-Eastern Union-Southern Westchester-
317 PM EST Mon Dec 16 2019

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 9 PM THIS
EVENING TO 10 AM EST TUESDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations of
  1 to 2 inches and ice accumulations of up to one tenth of an
  inch.

* WHERE...Portions of northeast New Jersey, southern Connecticut
  and southeast New York.

* WHEN...From 9 PM this evening to 10 AM EST Tuesday.

* IMPACTS...Plan on slippery road conditions. The hazardous
  conditions could impact the morning commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

Check local Department of Transportation information services for
the latest road conditions.

As of Monday evening, 12/16.

Some snow flurries observed to day, as forecast.

For tonight, the NWS has issued a Winter Weather Advisory starting at 9:00 pm and lasting until Tuesday 12/17 at 10:00 am for snow and ice.

In the MAPSO area, the most likely overnight weather will be a mix of some snow before midnight, then rain, sleet, and freezing rain until morning. May change over to all rain during the morning commute, but I would not count on it. By mid morning, should be all rain but with temps only rising into the mid 30s, it will still be a yucky day. Rain should taper off by the evening rush.


In order to add a comment – you must Join this community – Click here to do so.

Real Estate Listings

Sponsored Business

Find Business

Advertise here!