12/16-12/17 Godzilla: Final Snow Map & Obsevations

The 00z EURO is moments away from being available. I am not expecting it to budge a whole lot versus where other 00z models landed tonight. We have pretty good consensus in my opinion. Things like where the CCB sets up, who gets dry-slotted, and when/if there is a changeover to sleet/rain will mostly have to be now-casted. However, I took these features into consideration in my final call.



We're looking at a 2-4pm Wednesday start time (from south to north) and 4am-6am Thursday end time (from south to north).

Tomorrow I will compare actual surface and upper air features versus models and see who is leading the way in terms of calling the storm accurately.

Happy tracking!

Some images from tonights EURO.

The SE cut-offs are becoming sharper run to run. Double digit snow amounts to virtually little is just a couple dozen miles apart.

Nice, Frank!! Honest question: What led you to orient your higher snow totals like that instead of more southwest-northeast?

rb924119 wrote:Nice, Frank!! Honest question: What led you to orient your higher snow totals like that instead of more southwest-northeast?

It may just be me trying to be too perfect in predicting the 'jackpot' area, but it's a combination of predicting where the initial WWA/frontogenesis banding stalls then pivots.

00z Euro drops hammer on NYC/LI. I can sleep tight. G’nite all!

Can't wait to track this live tomorrow

I am not sure if I will get any work done (definitely not)

Goodnight all!

Night Frank. I I hope euro is right in nicely in that 15 to 18. But your map seems safe and still good with imo potential for more in some the 8 to 12 area like the euro shows. It's all now cast. Morning SR I guess but great seeing you all.

SoulSingMG wrote:00z Euro drops hammer on NYC/LI. I can sleep tight. G’nite all!

yes very nice bout 12 to 15 for us.

I think a lot of people are overplaying the cold card here and are gonna get burned by it. I think anywhere along and south of a line from Yonkers-Hackettstown-Lehighton-Pottsville-Harrisburg mixes before precip shuts off. Vehemently disagree with people “elsewhere” that NYC sees double-digit totals with this. Models are not colder, in fact 06z NAM is warmer overall with more backed flow aloft which is being misinterpreted by some as being lower heights ahead of it. They’re not “lower” because it is less amplified. They’re “lower” because the trough is more negatively tilted, aka more amplified. Very frustrating to watch this unfold in the weather community in other places.

URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
347 AM EST Wed Dec 16 2020

NYZ078-080-179-162100-
/O.UPG.KOKX.WS.A.0001.201216T1900Z-201217T1800Z/
/O.EXA.KOKX.WS.W.0001.201216T1900Z-201217T1800Z/
Northwestern Suffolk-Southwestern Suffolk-Southern Nassau-
347 AM EST Wed Dec 16 2020

...WINTER STORM WARNING IN EFFECT FROM 2 PM THIS AFTERNOON TO
1 PM EST THURSDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 6 to
13 inches. Winds gusting as high as 50 mph.

* WHERE...Northwestern Suffolk, Southwestern Suffolk and
Southern Nassau Counties.

* WHEN...From 2 PM this afternoon to 1 PM EST Thursday.

* IMPACTS...Travel could be very difficult to impossible. The
hazardous conditions could impact the morning or evening
commute. Gusty winds could bring down tree branches.

* ADDITIONAL INFORMATION...There is still some uncertainty with
how much, if any mixing occurs Wednesday night. Snowfall amounts
could be a bit lower than forecast along south coastal portions
of the region if more mixing occurs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency.

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

Finally!! NWS going with the colder solution for Suffolk county!
products issued by NWS for: Deer Park NY Share|

Winter Storm Warning
URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
347 AM EST Wed Dec 16 2020

NYZ078-080-179-162100-
/O.UPG.KOKX.WS.A.0001.201216T1900Z-201217T1800Z/
/O.EXA.KOKX.WS.W.0001.201216T1900Z-201217T1800Z/
Northwestern Suffolk-Southwestern Suffolk-Southern Nassau-
347 AM EST Wed Dec 16 2020

...WINTER STORM WARNING IN EFFECT FROM 2 PM THIS AFTERNOON TO
1 PM EST THURSDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 6 to
13 inches. Winds gusting as high as 50 mph.

* WHERE...Northwestern Suffolk, Southwestern Suffolk and
Southern Nassau Counties.

* WHEN...From 2 PM this afternoon to 1 PM EST Thursday.

* IMPACTS...Travel could be very difficult to impossible. The
hazardous conditions could impact the morning or evening
commute. Gusty winds could bring down tree branches.

* ADDITIONAL INFORMATION...There is still some uncertainty with
how much, if any mixing occurs Wednesday night. Snowfall amounts
could be a bit lower than forecast along south coastal portions
of the region if more mixing occurs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency.

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

I can not view the map

Everything looking good for us this morning CP.12 to 18 with no mixing issues.Will be watching the radar as this develops today.

It’s interesting because the 6z GFS tracks the Low over South Jersey and the 500mb seems to track over NWNJ/NEPA which is exactly what rb has been pointing out and what logically is not good news for us, but in its surface output stands fast to its 10-15” area-wide snowfall with little mixing. So I don’t know what to think. It does pick up that dry slotting that every model is now showing - and of course the one consistency in this thing is the dry slot is modeled right near or over my backyard.

NWS is sticking with 12-20” for me (which first of all is a pretty big range, can we narrow that? Lol). Based on last nights chat and this dry slot that keeps showing up, as well as the history of mid-level warmth monkey business in this part of the area, I’ll be happy with 8-12” - which is where Frank has me and what I sent out to co-workers as a forecast yesterday afternoon. I’m sticking with that but worried dry slotting could kick me down to a 4-8” eventually.

Just wish the NAM would have the same 850 temps as the Euro and the GFS. I hate that warm air they bring into the Island at 850..

Wasn’t going to do my own snow map for this but haven’t been able to do one in two years so I think I will just for fun. Let’s see if I can remember how. Lol.

Upton upped amounts. Actually removed sleet from my forecast completely on the north shore. Now has 10-16”

Going to be a fun day!! Seeing how it all plays out and where everything sets up! Im hoping we get a little bit more SE shift today! Although happy with Franks map and Uptons. Was a fun time last night on zoom

billg315 wrote:It’s interesting because the 6z GFS tracks the Low over South Jersey and the 500mb seems to track over NWNJ/NEPA which is exactly what rb has been pointing out and what logically is not good news for us, but in its surface output stands fast to its 10-15” area-wide snowfall with little mixing. So I don’t know what to think. It does pick up that dry slotting that every model is now showing - and of course the one consistency in this thing is the dry slot is modeled right near or over my backyard.

There was talk last night on another
chat room from a met that the upper levels should be more stacked than what the models depict and that the upper low should be further south. At this juncture it really doesn’t matter anymore since we’re in now casting.

Frank_Wx wrote:

rb924119 wrote:Nice, Frank!! Honest question: What led you to orient your higher snow totals like that instead of more southwest-northeast?

It may just be me trying to be too perfect in predicting the 'jackpot' area, but it's a combination of predicting where the initial WWA/frontogenesis banding stalls then pivots.

Everything seems to show me in the jackpot zone so for once I will see the big snow. I almost always get screwed on coastals.

Good morning form West Milford NJ!
I bring you Bernie Rayno.

6z Euro

billg315 wrote:It’s interesting because the 6z GFS tracks the Low over South Jersey and the 500mb seems to track over NWNJ/NEPA which is exactly what rb has been pointing out and what logically is not good news for us, but in its surface output stands fast to its 10-15” area-wide snowfall with little mixing. So I don’t know what to think. It does pick up that dry slotting that every model is now showing - and of course the one consistency in this thing is the dry slot is modeled right near or over my backyard.

500mb never closes off at least not until well past us. its 850 and 700mb closed low that you need to follow to see where the warmth and or dry slot will occur. GFS and Euro cont to insist that 850 is just to the south of LI.

This is 850: The positioning on the 6x GFS is such that it keeps the freezing line just south of LI, but as soon as it scoots by temps at this level crash further. The dashed line however is where models like the NAM and CMC have it pass. This would bring the freezing line up into the coastal plain somewhere lending its slef to mixing with sleet, rain and possibly freezing rain depending on where your surface temps are siting.





You really need to look at the sounding though to check all levels of the mid levels for the warm nose.

As you can see first image is a sounding just east of my house. Black horizontal line represents where the atmosphere goes slight above freezing just below the 100mb mark or about 400feet above sea level. whereas the second sounding is one into Nassau county to my west. Temps throughout all are below freezing





Withall due respect to you Ray but I think you may be underplaying the cold air. While others may be reading the results of a model output incorrectly verbatim I think it is well within reason to side with the models that have that subtle shift to the exact local of the mid level lows. Euro and GFS cont to hold steadfast in keeping 850 just south of LI. If true even the NS of LI will get close to if not exceed double digit totals. If nbot then the wam nose sneaks in and mixing holds down totals.

There is no doubt we have officially approached now cast time. I strongly urge people to go to this site today and tonight to monitor real time observations at the various levels. At the top of he page you can hover your mouse over change sector and click on the NE rectangle for a zoomed in version when we get to later this afternoon. Also hover over Upper Air and toggle through the 925, 850, and 700mb levels as we head into tonight to follow where there closed lows actually track. Trust me...if the track south of or just south of LI the coastal plain will stay white or mostly white. If its center is over NYC and LI then totals will be surpressed.

https://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=19