December 2022 Obs/Disc

[Damage In Tolland]

3 minutes ago, ORH_wxman said:

It looks colder behind the 12/15-16 system....doesn't look downright frigid at the moment, but a generally seasonably cold pattern. When the EPO ridge spikes like that though, there's always a chance we get an arctic shot, even if it's temporary. But right now, my money would be on a bit below normal temps when you have a split flow -PNA/-EPO/weak -NAO.

I’m sure you guys know why I’m asking lol. If it does snow I was thinking about pack . Noyes mentioned another mild stretch late next week

[ORH_wxman]

1 minute ago, Damage In Tolland said:

I’m sure you guys know why I’m asking lol. If it does snow I was thinking about pack . Noyes mentioned another mild stretch late next week

Late next week is the 12/15-16 system....if that tracks to our west, then it will wipe out any pack from 12/12.....but there's a chance we end up with more of a SWFE and in that case, any pack would probably survive at least in the interior.

But lets see what happens for 12/11-12/12 first. That system is going to affect the one behind it. We need a pack to protect first.

[40/70 Benchmark]

I think he was probably basing that off of a presumed unfavorable storm track....just broad-brushing the longer term.

[UnitedWx]

21 minutes ago, 40/70 Benchmark said:

I don't think its done trending. Folks brushed myself and a few others off when we gave some credence to the CMC yesterday (not to that degree), but this is what happens with blocks....you get faster corrections with shorter lead times.

I hope I didn't come across as brushing you off.  My comments about the CMC were aimed at those who would no doubt insist we use it as the standard the rest of the season if it happens to be the one to sniff this out first (George, are you listening? ).  Any piece of guidance can score once in a while and is worth a look...

[40/70 Benchmark]

2 minutes ago, UnitedWx said:

I hope I didn't come across as brushing you off.  My comments about the CMC were aimed at those who would no doubt insist we use it as the standard the rest of the season if it happens to be the one to sniff this out first (George, are you listening? ).  Any piece of guidance can score once in a while and is worth a look...

Not directed at anyone in particular, but I recall a few posts to the effect of "nothing else shows it", blah, blah.....I mean, a 2' blizzard....unlikely, but a plowable snowfall for a portion of the region is a totally viable outcome.

I'm guilty of it a lot, too, but its tough to sometimes not view a solution through a biased lens due to the reputation of the model.....all else equal, its not a huge leap of faith that an exiting coastal trends less progressive in the face of a large block.

[ORH_wxman]

Just now, 40/70 Benchmark said:

Not directed at anyone in particular, but I recall a few posts to the effect of "nothing else shows it", blah, blah.....I mean, a 2' blizzard....unlikely, but a plowable snowfall for a portion of the region is a totally viable outcome.

There's always been a few ensemble members toying with the idea too....again, low probability initially (but now increasing quite a bit), but when you consistently have like 10% of the members showing something at 6+ days out, then you should at least consider it as a real possibility even if you wouldn't actually forecast it on your 7 day outlook.

[Damage In Tolland]

10 minutes ago, ORH_wxman said:

Late next week is the 12/15-16 system....if that tracks to our west, then it will wipe out any pack from 12/12.....but there's a chance we end up with more of a SWFE and in that case, any pack would probably survive at least in the interior.

But lets see what happens for 12/11-12/12 first. That system is going to affect the one behind it. We need a pack to protect first.

Yeah I was putting the cart before the proverbial horse . Was just envisioning a positive outcome in the future and worrying  what might come after . Let’s get Monday to even happen first. 

[DJln491]

Excuse my newbness, still learning the lingo- I keep seeing "SWFE."  What is that acronym? Thanks.

[CoastalWx]

1 minute ago, DJln491 said:

Excuse my newbness, still learning the lingo- I keep seeing "SWFE."  What is that acronym? Thanks.

SouthWest Flow Event. These events are usually characterized by strong warm advection aloft (think 850 and above) on SW winds. At the surface many times you get redevelopment just offshore crossing over SE areas. Typically the airmass ahead of them is fairly cold, so snow or mixed precip occurs before any possible changeover. Typically these favor areas with latitude so the farther north you are, the better the chance of more wintry events. Many of a famous Nina's like 2007 and 2008 had these events. 

[40/70 Benchmark]

2 minutes ago, DJln491 said:

Excuse my newbness, still learning the lingo- I keep seeing "SWFE."  What is that acronym? Thanks.

SouthWest FlowEvent.......its when the storm in the mid levels cuts west, causing winds aloft to scream southwest and advecting warmer air ne. But when when there is confluence and cold air in place, the surface low is forced to redevelop off to the se and the warm air advection causes snowfall. There tends to be a transition to sleet for many spots due to mid level warmth

[ORH_wxman]

4 minutes ago, DJln491 said:

Excuse my newbness, still learning the lingo- I keep seeing "SWFE."  What is that acronym? Thanks.

SouthWest Flow Event. That is describing the flow aloft, not at the surface. Typically those systems where it might snow on the front end as a storm trying to cut to the west hits a strong high to the north....we'll frequently flip to sleet and ZR and maybe even rain in those too, but you never really torch in the warm sector because the storm tries to redevelop and track over the Cape.

So you might get this type of progression for weather:

1. Snow on the front end...temp in the 20s (maybe 2-5" of accumulation)

2. flipping to sleet, temps still in the 20s but creeping up to near 30F

3. flips to freezing rain for a few hours as temps continue to clibm near freezing

4. Temp finally inches above 32F and you get cold 33-37F rain for a bit before dryslotting.....then temps eventually cool back below freezing behind the storm.

 

Some SWFEs are colder than others...and sometime we can stay mostly or all snow. But the above is probably the most classic representation of how the weather plays out in SNE during them.

[40/70 Benchmark]

Triple ninja

[40/70 Benchmark]

Main difference I see is that the low near NF is a bit further away on the GEM, which maybe allows for faster amplification of coastal.

[ORH_wxman]

Many times, SWFEs were at some point cutters on the models and then they trended colder. That is one reason you don't want to freak out every time you see a cutter out in la-la land on the models....esp if there is some cold hanging around to our north.

[Damage In Tolland]

4 minutes ago, ORH_wxman said:

SouthWest Flow Event. That is describing the flow aloft, not at the surface. Typically those systems where it might snow on the front end as a storm trying to cut to the west hits a strong high to the north....we'll frequently flip to sleet and ZR and maybe even rain in those too, but you never really torch in the warm sector because the storm tries to redevelop and track over the Cape.

So you might get this type of progression for weather:

1. Snow on the front end...temp in the 20s (maybe 2-5" of accumulation)

2. flipping to sleet, temps still in the 20s but creeping up to near 30F

3. flips to freezing rain for a few hours as temps continue to clibm near freezing

4. Temp finally inches above 32F and you get cold 33-37F rain for a bit before dryslotting.....then temps eventually cool back below freezing behind the storm.

 

Some SWFEs are colder than others...and sometime we can stay mostly or all snow. But the above is probably the most classic representation of how the weather plays out in SNE during them.

A good portion of them rip SE areas of SNE into warm sectors of 40’s and 50’s.. even if fairly brief. I can think of many where Ginx south and east hit 45-55 and it stays in mid -upper 30’s NW of that line . 

[40/70 Benchmark]

We may end up with an inverted trough on Monday, too (yay)

[ORH_wxman]

Just now, Damage In Tolland said:

A good portion of them rip SE areas of SNE in warm sectors of 40’s and 50’s.. even if fairly brief. I can think of many where Ginx south and east hit 45-55 and it stays in mid -upper 30’s NW of that line . 

Yes that can happen for sure. There's different flavors of SWFEs. The ones where the secondary tracks over SE MA/RI can warm up those southeast coastal regions pretty good. There's also ones like 12/13/07 which stay mostly snow even in SE areas.

[CoastalWx]

Just now, Damage In Tolland said:

A good portion of them rip SE areas of SNE in warm sectors of 40’s and 50’s.. even if fairly brief. I can think of many where Ginx south and east hit 45-55 and it stays in mid -upper 30’s NW of that line . 

There's always variations. The classic ones keep you below 32 until the "cold front" passes when you briefly mix the torched air aloft. Over here I may tickle 40ish with east winds but hopefully 6" of man snow is down prior.

[CoastalWx]

Lets not forget the dumbfounded variations. 

[ORH_wxman]

Just now, CoastalWx said:

Lets not forget the dumbfounded variations. 

[MJO812]

Rgem is amped up

[ineedsnow]

12Z ICON trending

[40/70 Benchmark]

1 minute ago, CoastalWx said:

Lets not forget the dumbfounded variations. 

I love 33 and snow in Chatham and 19 and IP in Tolland

[Damage In Tolland]

2 minutes ago, CoastalWx said:

There's always variations. The classic ones keep you below 32 until the "cold front" passes when you briefly mix the torched air aloft. Over here I may tickle 40ish with east winds but hopefully 6" of man snow is down prior.

I always get so nervous in those.. when I see IJD to Ginx at like 46 with dews and fog eating wind thinking about losing snowcover . Typically the warmest ones get to 38 here and then drop back to near 32 until west wind fropa 

[CoastalWx]

2 minutes ago, 40/70 Benchmark said:

I love 33 and snow in Chatham and 19 and IP in Tolland

The best.

[Damage In Tolland]

4 minutes ago, CoastalWx said:

Lets not forget the dumbfounded variations. 

I love 24-36” in ORH to Tewksbury and 14” in Metheun 

[40/70 Benchmark]

Just now, Damage In Tolland said:

I love 24-36” in ORH to Tewksbury and 14” in Metheun 

You know my weak spots hahahaha That would eat my soul away in short order

[CoastalWx]

ICON is kind of interesting. 

[ariof]

We should probably start a glossary of terms used in this thread so n00bs can read a sentence like "it looked like a SWFE but then we got Leoned" and make some sense of it. (This might already exist.)

[TalcottWx]

5 minutes ago, Damage In Tolland said:

I love 24-36” in ORH to Tewksbury and 14” in Metheun 

I was thinking 36" tolland to Talcott to ORH. Maybe 12" Methuen. Wet rain S Weymo