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

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

Based off trends this morning, it seems I would need to drag the higher snow totals on my map more SW. I’m going to give it a couple of hours before deciding...I need to wake up and look at the current observations. I keep coming back to this thought of dry slotting and fast moving storm which is main reason why I’m lower than what models suggest. However, the cut offs are insane and I don’t think that’s well represented on my map.

Pretty neat map. Shows the change in temperatures from previous run (euro). Look how much colder it got for parts of coastal NJ valid 7am, but the cold likely comes in earlier than that. I still think that area sees mixing and dry slotting issues, but something to watch

What does the HRRR show?. I have been trying to find it.

LI is looking more and more like it is going to be in that 10-15 range...lets hope we get no mixing!

Frank_Wx wrote:Pretty neat map. Shows the change in temperatures from previous run (euro). Look how much colder it got for parts of coastal NJ valid 7am, but the cold likely comes in earlier than that. I still think that area sees mixing and dry slotting issues, but something to watch

The cold air wants to hang tough with this

Joe Snow wrote:What does the HRRR show?. I have been trying to find it.

https://www.tropicaltidbits.com/analysis/models/?model=hrrr®ion=neus&pkg=ref_frzn&runtime=2020121611&fh=17

11z only goes out 18 hours. The 12z will cover the whole duration but it’s not out yet on tidbits

Here are the EPS, and I think this will be close to the final solution. If it is, after thinking back, it actually is a pretty good compromise between the EURO/GFS but I still would weigh it 65% EURO / 35% GFS

Frank_Wx wrote:

Joe Snow wrote:What does the HRRR show?. I have been trying to find it.

https://www.tropicaltidbits.com/analysis/models/?model=hrrr&region=neus&pkg=ref_frzn&runtime=2020121611&fh=17

11z only goes out 18 hours. The 12z will cover the whole duration but it’s not out yet on tidbits

Just saw that, thanks Frank......... Looks like the Island might get a mix/rain at first.
Saw the region map need to correct this. May the snow gods dump on all of us!!!!
I'll wait till the 12z Runs

6z HREF

Frank_Wx wrote:6z HREF

I wish I knew what this meant: lol

sroc4 wrote:

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


 

Great analysis. Absolutely have to look at the soundings on this. 925's 850s may look fine, but it often times it'll be between 700-800 that burns you.

Rooster89 wrote:

Frank_Wx wrote:6z HREF

I wish I knew what this meant: lol

Look at the color chart on the bottom for inches then look at the map if will give you an idea of what the model is predicting

Frank_Wx wrote:Pretty neat map. Shows the change in temperatures from previous run (euro). Look how much colder it got for parts of coastal NJ valid 7am, but the cold likely comes in earlier than that. I still think that area sees mixing and dry slotting issues, but something to watch

At the lower levels of the atmosphere it'll be really hard to push that cold air out especially with a continuous supply of it. It'll be 700-800 that will have to watch on this one. Unfortunately I don't have any sites to see the near real time temps there. Any thoughts?

sroc4 wrote:Looks like 6zgfs came north a fair amount actually.  Most other models tucked in again ever so slightly. The subtle winshsheuld wipers as Bernie would say seem to be in effect.  Slide these lines left or right by 5-10miles and you have the difference between 3-6” SE of yellow. 6”10” between yellow and blue, and 8-12” NW of blue.

Im sticking with this map for LI except I am tipping the lines slightly more ENE than yesterday,

Latest RPM from my friend who is a tv met

Serious CAD (cold air dam)

aiannone wrote:Latest RPM from my friend who is a tv met

I'll take that and quietly walk away LOL

I'm 23.5/8.5 now. That is a seriously nice overrunning surface.

heehaw453 wrote:Serious CAD (cold air dam)

Totally!

Upton’s UP! Just walk outside, guys. What does that airmass feel like to you? When I walked my dog at 2am, I thought, “NOPE. This damming ain’t playing.” Sometimes we’ve just gotta get back to basics; time for good ole obs at this point. City/most of LI is gonna rock n roll with incredible snowfall rates after 4-5pm. Let’s go!

I’ll try to keep my imby ramblings to a minimum here, but SROC, would a stronger, more south hp be able to save this for the Jersey Shore, or nah I’m just cooked on this one? Just 25-50 miles more SE is all I need. Ahhhh!

sroc4 wrote:

heehaw453 wrote:Serious CAD (cold air dam)

Totally!

Oh boy. Just wait till Muggs gets a hold of those pics!

aiannone wrote:Latest RPM from my friend who is a tv met

That is a serious area of 18-24

SENJsnowman wrote:I’ll try to keep my imby ramblings to a minimum here, but SROC, would a stronger, more south hp be able to save this for the Jersey Shore, or nah I’m just cooked on this one? Just 25-50 miles more SE is all I need. Ahhhh!

It might for sure. But Saved needs to be defined. You are pretty far south.

Why do I have to live in belford NJ where every line ever drawn on a snow map has to be? Lol