December 4th-5th, 2020 Nor'easter

[donsutherland1]

A quick video clip from East Lyme, CT:

 

[psv88]

45 minutes ago, donsutherland1 said:

It was east of there. I believe there was mixed precipitation near Melville.

Most of Suffolk mixed with snow for a time, lots of white rain

[LibertyBell]

1 hour ago, donsutherland1 said:

It was east of there. I believe there was mixed precipitation near Melville.

Thanks I heard there were some mangled flakes as close as Lynbrook

[donsutherland1]

4 minutes ago, LibertyBell said:

Thanks I heard there were some mangled flakes as close as Lynbrook

There could have been. I didn’t go back to MPING to see what was happening afterward.

[LibertyBell]

Just now, donsutherland1 said:

There could have been. I didn’t go back to MPING to see what was happening afterward.

but no all snow reports or anything on the ground south of CT from what I can surmise?

 

[wdrag]

Looking back: Original post Tue... too slow by 12 hours and no freezing rain.  Rest OK.  Had general 0.3-0.9" rainfall se NYS, ~1/2"extreme nw NJ otherwise widespread 1-2" there in NJ, also LI and  CT. Will post complete CoCoRAHS summary qpf and snowfall tomorrow, around 1PM. 

This morning's expectations (my own): Wind gusts were 5 knots less than expected,  no Thunder occurred.  

ECMWF Kuchera and all 10 to 1 ratios I think in general were too high especially valleys.  I think snow ratios need to be taken into account when thinking of amounts.   Accordingly power outages not as high as expected from combined snow and wind or wind alone. 

None of these elevation snows are easy: Other than the one day of extreme west modeling solutions, the overall modeling guided the main impact areas pretty good... For our NYC forum..a routine event, with knowledge that this is the fourth decent storm in the past 3 weeks (Nov 11-15, Nov 30, Dec 5).  759P/5

[Rjay]

1 hour ago, psv88 said:

Most of Suffolk mixed with snow for a time, lots of white rain

Islip reported rain the entire time but there was a bunch of white rain.  

[jm1220]

2 minutes ago, Rjay said:

Islip reported rain the entire time but there was a bunch of white rain.  

It was a fight back and forth in the meat of that CCB but there was a point where it was mostly snow here but obviously no accum. Elevation probably helped somewhat here for whatever that was worth today. 

[donsutherland1]

46 minutes ago, LibertyBell said:

but no all snow reports or anything on the ground south of CT from what I can surmise?

 

That appears to be the case. I didn’t see any snow on the ground until I was near Guilford in CT. Some areas were dusted around there.

From the latest PNS:

000
NOUS41 KOKX 052253
PNSOKX
CTZ005>012-NJZ002-004-006-103>108-NYZ067>075-078>081-176>179-061053-

Public Information Statement
Spotter Reports
National Weather Service New York NY
553 PM EST Sat Dec 05 2020

The following are unofficial observations taken during the past 8
hours for the storm that has been affecting our region. Appreciation
is extended to highway departments, cooperative observers, Skywarn
spotters and media for these reports. This summary also is available
on our home page at weather.gov/nyc

********************STORM TOTAL SNOWFALL********************

LOCATION          STORM TOTAL     TIME/DATE   COMMENTS
                     SNOWFALL           OF
                     /INCHES/   MEASUREMENT

CONNECTICUT

...Middlesex County...
   East Hampton           2.0   215 PM 12/05  Broadcast Media

...New Haven County...
   Wolcott                3.5   130 PM 12/05  Broadcast Media
   2 W Rockland           1.8   245 PM 12/05  Broadcast Media
   1 ESE Platts Mills     0.8   200 PM 12/05  Trained Spotter

 

[Intensewind002]

8 hours ago, psv88 said:

Where’s your anemometer? You seem to record solid wind gusts. 

I have it on the roof of my aunt and uncles house, I was originally gonna put on the roof of my parents but my house is only 20 ft tall. Her house is about to 30 ft tall or so so it's closer to the official height the nws recommends. As for the good measurements, I thought maybe it's because they live by the water. It definitely helps with southerly winds. They also don't have a lot of trees on their block that obstruct the measurements (another reason I asked if i could place it there). I also thought there might be a chance it over estimates the wind a little but idk.

[uofmiami]

7 hours ago, Intensewind002 said:

I have it on the roof of my aunt and uncles house, I was originally gonna put on the roof of my parents but my house is only 20 ft tall. Her house is about to 30 ft tall or so so it's closer to the official height the nws recommends. As for the good measurements, I thought maybe it's because they live by the water. It definitely helps with southerly winds. They also don't have a lot of trees on their block that obstruct the measurements (another reason I asked if i could place it there). I also thought there might be a chance it over estimates the wind a little but idk.

Sounds like an ideal location, all things considered.  Below are my two station’s anemometer locations on the house.  My parent’s roof I’m not a fan of going on.

Here’s my parent’s house, probably around 40’  No trees nearby & get good readings due to it.

My house around 32’.  Trees to my NE hinder good readings when leaves are out.

[forkyfork]

model snow maps are dumb part 854

[wdrag]

Hello... my own version of the wrap.  QPF from 2 days of Co CoRAHS,  CoCoRAHS snowfall,  and LSR'd snowfall.  The NOHRSC is above. Closest lightning was quite far away per the added lightning archive. 

This to compare with modeled qpf/snowfall and topic intent of coverage.  

While one can argue on the use of models and models vs pattern recognition, one difficulty continues over the years... use of 10 to 1 snow ratios. We need to be careful about this. NWS has a blended snow ratio tool (every 6 hours or less which can be interpolated). Overall model intent was good (except the one day of  a very westward set of solutions) but snowfall was way overdone on amounts Southern NH southward on some of the models that did the phase change reasonably well.  The over forecast was due to the occurrence of wet snow during 33-34F air temp, non frozen ground and much of it during daylight hours. My guess (there may be some verification out there?) was a 6 to 1 snow water ratio.  

[LibertyBell]

On 12/6/2020 at 11:27 AM, forkyfork said:

model snow maps are dumb part 854

I'm telling ya it was obvious that coastal SNE wouldn't get much snow and they didn't  This was an interior SNE and CNE/NNE snowstorm.