Dec 22-23 snow/ice threat

[ORH_wxman]

3 minutes ago, STILL N OF PIKE said:

The significant QPF Waits till pm on most guidance, Thou right?

So ice fans need to see that cold really hold till 0z Sunday Or longer.

How does that occur, stronger high, another meso?

You have the sfc reflection track south of the area...the GFS did it...never got the boundary NW of the SE MA. Euro is pretty close too...you see this weakening primary in like central PA trying to track up to BGM/SYR but the whole time there is this big bulge out to the east and another sfc low is trying to track near the Cape and then that low becomes the dominant one in the gulf of maine...in a siggy ice event, you'll see that sig get stronger and it will hold the cold at the sfc even more.

It could trend back warmer too, but my experience has always said watch this very very carefully when you have an arctic high where it is in Quebec.

[Modfan]

10 minutes ago, ORH_wxman said:

You have the sfc reflection track south of the area...the GFS did it...never got the boundary NW of the SE MA. Euro is pretty close too...you see this weakening primary in like central PA trying to track up to BGM/SYR but the whole time there is this big bulge out to the east and another sfc low is trying to track near the Cape and then that low becomes the dominant one in the gulf of maine...in a siggy ice event, you'll see that sig get stronger and it will hold the cold at the sfc even more.

It could trend back warmer too, but my experience has always said watch this very very carefully when you have an arctic high where it is in Quebec.

If I remember in 2008, the icing only made as far south as Oxford Ma; I assume NW RI over to Kevin look to Benin the game with this

[STILL N OF PIKE]

Thanks Will

Would a stronger surface reflection usually also mean less mid level warmth

And potentially a IP issue being more likely than Fzrn 

[tamarack]

57 minutes ago, Damage In Tolland said:

Yeah I didn’t mean SE Mass like the Cape , but TAN could ice for a time . Reminds me of the 1973 icestorm setup 

May be similar for who gets what in SNE, but this looks to be a far less powerful storm.  I lived in BGR then, and we got a quick 4" followed by 2.5" RA as the LP hung a sharp left and the temp shot up to 56.  (While my parents in NNJ had IP and 15.)

This one might offer advisory level snow but with the messies finally getting all the way to the foothills.  Still a net gain for snowpack, and lots better than the inch-plus of 50° RA I was looking at 2 days ago.

[ORH_wxman]

15 minutes ago, STILL N OF PIKE said:

Thanks Will

Would a stronger surface reflection usually also mean less mid level warmth

And potentially a IP issue being more likely than Fzrn 

Yeah I would think so...stronger sfc reflection would prob mean a bit colder so it might increase the thickness of the below freezing layer...so the IP zone could creep south....but we're still a little ways out from trying to pick it apart in that type of detail. Hopefully by tomorrow we are able to hone in on a solution...still have somewhat wide goalposts on this event.  

[HoarfrostHubb]

This doesn't seem like a 2008 redux to me.  Moving a bit faster and flipping a lot quicker.

[ORH_wxman]

3 minutes ago, HoarfrostHubb said:

This doesn't seem like a 2008 redux to me.  Moving a bit faster and flipping a lot quicker.

2008 was an historic event...definitely not the same setup. That one had tropical moisture all the way from the Caribbean feeding into the system as it traversed along the northern Gulf of Mexico. We had like 3 inches of qpf.

 

That said, this one could still be pretty impactful if the ducks line up right. A half inch of ice would be pretty big impact and is within the envelope of reasonable solutions. Hopefully it just ticks colder and there's more IP/SN.

[#NoPoles]

hmmm...will i be 55 and rain or 45 and rain???

[JC-CT]

2 minutes ago, #NoPoles said:

hmmm...will i be 55 and rain or 45 and rain???

I'd go with 43 and rain.

[Damage In Tolland]

8 minutes ago, ORH_wxman said:

2008 was an historic event...definitely not the same setup. That one had tropical moisture all the way from the Caribbean feeding into the system as it traversed along the northern Gulf of Mexico. We had like 3 inches of qpf.

 

That said, this one could still be pretty impactful if the ducks line up right. A half inch of ice would be pretty big impact and is within the envelope of reasonable solutions. Hopefully it just ticks colder and there's more IP/SN.

Was 73 a coastal or more of an overrunning?

[ORH_wxman]

Just now, Damage In Tolland said:

Was 73 a coastal or more of an overrunning?

'73 was actually a pretty strong coastal. This won't be like that.

[Damage In Tolland]

6 minutes ago, ORH_wxman said:

'73 was actually a pretty strong coastal. This won't be like that.

I was just reading up on it. 3-5” of rain in SE Mass. 

[Whineminster]

27 minutes ago, ORH_wxman said:

2008 was an historic event...definitely not the same setup. That one had tropical moisture all the way from the Caribbean feeding into the system as it traversed along the northern Gulf of Mexico. We had like 3 inches of qpf.

 

That said, this one could still be pretty impactful if the ducks line up right. A half inch of ice would be pretty big impact and is within the envelope of reasonable solutions. Hopefully it just ticks colder and there's more IP/SN.

Did you guys see 2008 coming from a ways out? I feel like the Boston news didn't hit on it until the night before the storm.  Granted the event occurred outside the Boston metro and anyone in Mass knows that anything outside 495 might as well be New York.  I just remember coming into work in Marlborough and wondering why the heck people from north and west of Worcester were all absent. 

[ORH_wxman]

8 minutes ago, Whineminster said:

Did you guys see 2008 coming from a ways out? I feel like the Boston news didn't hit on it until the night before the storm.  Granted the event occurred outside the Boston metro and anyone in Mass knows that anything outside 495 might as well be New York.  I just remember coming into work in Marlborough and wondering why the heck people from north and west of Worcester were all absent. 

We saw 2008 about 48-60 hours out. Too bad Easternuswx isn't still available online for archive purposes...we had an excellent thread over there on it.

[Ginx snewx]

14 minutes ago, ORH_wxman said:

We saw 2008 about 48-60 hours out. Too bad Easternuswx isn't still available online for archive purposes...we had an excellent thread over there on it.

whats date was that?

[ORH_wxman]

8 minutes ago, Ginx snewx said:

whats date was that?

Dec 11-12, 2008 was the ice storm.

[40/70 Benchmark]

1 minute ago, ORH_wxman said:

Dec 11-12, 2008 was the ice storm.

I haven't been able to look...does it still torch Saturday on the Euro?

[ORH_wxman]

1 minute ago, 40/70 Benchmark said:

I haven't been able to look...does it still torch Saturday on the Euro?

No...at least for most of us...prob SE MA and S RI...those types of areas.

[Damage In Tolland]

1 minute ago, 40/70 Benchmark said:

I haven't been able to look...does it still torch Saturday on the Euro?

Nope

 

[40/70 Benchmark]

Just now, ORH_wxman said:

No...at least for most of us...prob SE MA and S RI...those types of areas.

Awesome.

Hopefully that holds

[OceanStWx]

4 hours ago, ORH_wxman said:

Time to start a thread for this one. The high in Quebec is trending more stout and the wave is trending flatter...that equals a more wintry solution than the torching cutter being shown just a few model cycles ago.

 

There could be a significant icing scenario for interior southern New England as well...most guidance shows a cold tuck behind a mesolow that develops near the Cape and travels into the Gulf of Maine while at the same time, more moisture begins to stream in from the southwest and mid-level temps creep above zero....see GFS for below example. Note the streamlines over eastern SNE come from SE NH and S ME....that is classic icing signal...ignore the verbatim temps, they'd likely be much colder:

That's pretty much it right there. Fuzzy clustering backs up this analysis perfectly. 

I'm pretty sure I can't share the images, because it's behind a password, but I'll try and describe the process. All ensemble members are grouped into five clusters based on similarity (CMC, GEFS, and EPS included) relative to the two highest probability MSLP variance patterns (PCs). From there you can map the means of different variables of each cluster, rather than the whole ensemble suite, to see what in the pattern is causing certain clusters to do what they are doing.

The latest guidance (from 00z) is showing group 5 (not important the number but it's made up of some EPS and GEFS, no CMC) are clustered at 0 PC2 and +PC1. When you map the group 5 mean 546 dm contour it is the most amplified. Conversely, group 3 is clustered at 0 PC2 and -PC1 and is the flattest 546 dm contour. 

So what is the PC1 pattern (since these examples don't have a strong PC2 signal)? PC1 is a deeper low centered north of MSS. So a +PC1 matches that stronger low near MSS, a -PC1 pattern would be the opposite (and what we're looking for if we want a more wintry scenario).

So what does that long winded explanation mean? We want the flow to match group 3 if we want more wintry conditions, which is the flattest 500 mb flow of the ensemble clusters.

[Sugarloaf1989]

My NWS p/c has rain and 51F for Saturday, which is above freezing the last time I checked. 

[WintersComing]

2 minutes ago, Sugarloaf1989 said:

My NWS p/c has rain and 51F for Saturday, which is above freezing the last time I checked. 

And that surprises you?

 

[Whineminster]

A half inch of ice isn't that big a deal really. Once you push beyond 3/4" then you have to start worrying.  Most of the weak limbs were thinned out in 2008 and Snowtober in 2011. Plus the power companies have been way more proactive in trimming which would help.  At least in this area. 

[CoastalWx]

11 minutes ago, OceanStWx said:

That's pretty much it right there. Fuzzy clustering backs up this analysis perfectly. 

I'm pretty sure I can't share the images, because it's behind a password, but I'll try and describe the process. All ensemble members are grouped into five clusters based on similarity (CMC, GEFS, and EPS included) relative to the two highest probability MSLP variance patterns (PCs). From there you can map the means of different variables of each cluster, rather than the whole ensemble suite, to see what in the pattern is causing certain clusters to do what they are doing.

The latest guidance (from 00z) is showing group 5 (not important the number but it's made up of some EPS and GEFS, no CMC) are clustered at 0 PC2 and +PC1. When you map the group 5 mean 546 dm contour it is the most amplified. Conversely, group 3 is clustered at 0 PC2 and -PC1 and is the flattest 546 dm contour. 

So what is the PC1 pattern (since these examples don't have a strong PC2 signal)? PC1 is a deeper low centered north of MSS. So a +PC1 matches that stronger low near MSS, a -PC1 pattern would be the opposite (and what we're looking for if we want a more wintry scenario).

So what does that long winded explanation mean? We want the flow to match group 3 if we want more wintry conditions, which is the flattest 500 mb flow of the ensemble clusters.

You can see it at 500 too. The flow in Canada is trying to keep it flat. We also do not want that s/w causing the low to develop in the Plains, to dig for oil. 

[Sugarloaf1989]

5 minutes ago, WintersComing said:

And that surprises you?

 

See above 

[CoastalWx]

1 minute ago, Whineminster said:

A half inch of ice isn't that big a deal really. Once you push beyond 3/4" then you have to start worrying.  Most of the weak limbs were thinned out in 2008 and Snowtober in 2011. Plus the power companies have been way more proactive in trimming which would help.  At least in this area. 

Half inch is bad. That will cause lots of tree damage and outages.

[RUNNAWAYICEBERG]

3 minutes ago, Whineminster said:

A half inch of ice isn't that big a deal really. Once you push beyond 3/4" then you have to start worrying.  Most of the weak limbs were thinned out in 2008 and Snowtober in 2011. Plus the power companies have been way more proactive in trimming which would help.  At least in this area. 

I pretty sure 1/2” starts causing sizeable damage.... trees down, widespread power outages...that type of stuff. 

[A Moonlit Sky]

What does the flatness of the wave refer to and why does it matter?

[40/70 Benchmark]

3 minutes ago, CoastalWx said:

You can see it at 500 too. The flow in Canada is trying to keep it flat. We also do not want that s/w causing the low to develop in the Plains, to dig for oil. 

Yea, if that SW decides to dig in the midwest, nothing will stop it....but hopefully the confluence provide just enough inhibition.