Pattern Changing: Early December threats?

[CoastalWx]

Well get used to it, because that's the way it is when trying to pin down any pattern more than a week out (even that is not always safe).

Even at work, we're saying this going to turn cause people to go bald early..lol. There's just such conflicting signals between the Pacific and the Atlantic right now. It seems like if one signal is even a little more "powerful" than the other, the resulting solution migrates strongly to one end of the spectrum or the other. That's probably why we're seeing these swings. On one run, the GOA troughing is stronger and -pna enhanced which leads to a warmer solution in the east. 12 hours later, it weakens just a little bit, and we have a colder solution in the east. There's no real happy medium.

[Baroclinic Zone]

Even at work, we're saying this going to turn cause people to go bald early..lol. There's just such conflicting signals between the Pacific and the Atlantic right now. It seems like if one signal is even a little more "powerful" than the other, the resulting solution migrates strongly to one end of the spectrum or the other. That's probably why we're seeing these swings. On one run, the GOA troughing is stronger and -pna enhanced which leads to a warmer solution in the east. 12 hours later, it weakens just a little bit, and we have a colder solution in the east. There's no real happy medium.

Hmm... ATL v PAC I wonder how often the ATL wins?

[CoastalWx]

Hmm... ATL v PAC I wonder how often the ATL wins?

Well in this case, I think it's more placement of features. Atlantic can win if certain features are in place, but also a bad PAC is not necessarily detrimental to us, as we've seen in past history. Things are still "adjusting" towards winter, so a pattern like this even 4 weeks from now, may have a different outcome. Fun times ahead when it comes to model watching!

[Tropopause_Fold]

Hmm... ATL v PAC I wonder how often the ATL wins?

depends on where you are though. can definitely win in the NE and lose for other areas.

[Tropopause_Fold]

overall a pretty chilly look to the 12z GEFS.

it has the same hints as the op of a inland runner type of set-up early next week. behind that, it's showing a large trough over much of the nation...with the coldest temps over the upper miss. river valley/western lakes. interestingly, it also has a storm passing E of NE on the 6-8th...somewhat surprising given the time-frame and smoothing of the mean.

nao stays negative out into the 2 week period...in fact heights come back up over the DS region toward the end of the output.

GOA low reappears out toward the end of the run but the result is a dual region of low heights, one in the NW part of canada/alaska/GOA...and another over the NE.

[CoastalWx]

overall a pretty chilly look to the 12z GEFS.

it has the same hints as the op of a inland runner type of set-up early next week. behind that, it's showing a large trough over much of the nation...with the coldest temps over the upper miss. river valley/western lakes. interestingly, it also has a storm passing E of NE on the 6-8th...somewhat surprising given the time-frame and smoothing of the mean.

nao stays negative out into the 2 week period...in fact heights come back up over the DS region toward the end of the output.

GOA low reappears out toward the end of the run but the result is a dual region of low heights, one in the NW part of canada/alaska/GOA...and another over the NE.

It actually trended weaker with the -nao as compared to 00z, but was colder over Canada which eventually spills into the nrn tier of the US. Defintelty some conflicting signals as heights lowered out west, but between all these indices rising and falling, no wonder models are developing a big storm. We can have a -pna, but we just don't want it to dig for oil out west.

[CCPSUSuperstorm2010]

Generally it isn't. It produces a downstream trough in the PNA region of western Canada and PAC NW...which is fairly hostile to KU events. Most of the storms that occur on the east coast in that setup tend to be redevelopers or retrograding storms if you have an NAO block.

However, its not impossible and there are always exceptions, it just depends on the exact orientation of the Aleution ridge and NW trough...especially when there is a severe -NAO block.

So Will, we need the Aleutian ridging further west, over the western Aleutian islands, so that the downstream trough over the GOA is placed further west and a ridge can develop over the PNA region.

[Damage In Tolland]

Sounds like cold then rain then cold in the long term seemingly ignoring the monster block

[CoastalWx]

Sounds like cold then rain then cold in the long term seemingly ignoring the monster block

Not verbatim, but that is always a risk. The bottom line, is to expect big swings in the models. Don't adhere to one model run, unless multiple models have it for a few runs in a row. It's not a classic pattern for sne, like we've been saying....but with the block to our northeast and cold nearby...it very well could deliver. Just be prepared for all sorts of solution.s..from inside runners to benchmark storms. If I had to guess...I think the risk may be for storms to hug the coast..or pass too close by, but that doesn't mean much at this point, nor is it a given.

[Damage In Tolland]

Not verbatim, but that is always a risk. The bottom line, is to expect big swings in the models. Don't adhere to one model run, unless multiple models have it for a few runs in a row. It's not a classic pattern for sne, like we've been saying....but with the block to our northeast and cold nearby...it very well could deliver. Just be prepared for all sorts of solution.s..from inside runners to benchmark storms. If I had to guess...I think the risk may be for storms to hug the coast..or pass too close by, but that doesn't mean much at this point, nor is it a given.

I was just hopeful of waves riding south of us with light to mod snows. That's the pattern I was envisioning

[CoastalWx]

I also wouldn't be shocked if the rest of the guidance looks more "wintry" again at 12z. It was a big change at 00z, so while it may not revert back to showing 2 KU's, it very well may do what the 12z GFS did. We'll see in a few hours.

[Tropopause_Fold]

It actually trended weaker with the -nao as compared to 00z, but was colder over Canada which eventually spills into the nrn tier of the US. Defintelty some conflicting signals as heights lowered out west, but between all these indices rising and falling, no wonder models are developing a big storm. We can have a -pna, but we just don't want it to dig for oil out west.

yeah i actually hadn't looked at 00z on a global scale...only NE type of stuff. it's actually quite a bit weaker. still there, but certainly not as emphatic.

[CoastalWx]

I was just hopeful of waves riding south of us with light to mod snows. That's the pattern I was envisioning

I'm not sure if this pattern supports weak clipper type storms. If we get more ridging out west, we could see that because that's the pattern that supports clippers, but with a -pna trough and block to the northeast, it's probably gonna open the door for more stronger storms. I didn't mean that every low would be a monster, but the pattern def supports larger lows, probably more in the moderate category of intensity.

[cpickett79]

well at least wednesday's cold is LOCKED in. that is consistent and on the gfs, nam , euro again at 12z

euro has -8c 850 at mid morning wednesday so .....

yesterday i tried to temper my euro enthusiasm b/c it was still 5 or so days out.....i think this run is more crutial than many for the fri-sun period but so is tonite's and tommorrow's will lock it in.

FRI now shows 1c 850's by mike and pete with 2-3 c 850's for most of sne cept warmer S coast and toward NYC......so no torch friday on this run.

[CCPSUSuperstorm2010]

So Coastalwx, a +PNA is more conducive or favorable for miller B cyclones/clipper systems, then say large storm systems like miller As and other type of storms?

[powderfreak]

Sounds like cold then rain then cold in the long term seemingly ignoring the monster block

That's always the most frustrating pattern, hands down. Several days of cold/dry, then one day of 40s and rain, then several days of cold/dry.

Its enough to drive most weenies crazy.

[OKpowdah]

Too much ridging between the departing Friday storm and the incoming Dec 1-2 storm. We need the DS ridging to retrograde a little more, trapping the Friday system from moving too far NE.

[CCPSUSuperstorm2010]

Too much ridging between the departing Friday storm and the incoming Dec 1-2 storm. We need the DS ridging to retrograde a little more, trapping the Friday system from moving too far NE.

Sam is there a way I can see the historical records of a snowstorm such as the March 2-5 1960 snowstorm? I know about Plymouth State Weather Center, but is there another way?

[OKpowdah]

Sam is there a way I can see the historical records of a snowstorm such as the March 2-5 1960 snowstorm? I know about Plymouth State Weather Center, but is there another way?

Here's another pretty good reanalysis site:

http://facstaff.unca.edu/cgodfrey/reanalysis/reanalysis.shtml

In terms of specifically for that storm, I'm sure somebody here has a good site for it.

[CoastalWx]

So Coastalwx, a +PNA is more conducive or favorable for miller B cyclones/clipper systems, then say large storm systems like miller As and other type of storms?

Well +PNA are favorable for both. I think Miller As are more favorable with split flow out west. This type of flow is more likely when we have a strong srn stream..like in an El-Nino year. But remember, the "classic" patterns don't happen all that frequently, so don't worry about seeing a "classic" pattern on the models. All you really need is one favorable feature, like a -nao or some sort of ridge out west, whether it be +pna or -epo. The reason why it's nice to have ridging out west, is because this general pattern shoves the cold farther east. It's not common to have a +pna and -nao all at once for a prolonged period of time, but it's nice to have one of these features in a favorable state, when the other is not. This time around we have the -nao, but we are sort of at the mercy of the Pacific. I do like seeing ridging poking into the N-Pole from Kamchatka. It holds the cold on this side of the Pole, but it also sometimes leads to GOA lows.

[powderfreak]

As a decades long resident of the East Slope I feel worrying about whether/when it will snow is like worrying about the sun coming up. Is there any where else in SNE that you'd rather live being a snow lover. Not I. Even the truly spectacularly bad years still feture a good amount of snow. We are on the cusp of Winter now. The models only give us a glimpse of what is possible. They do not afford us clairvoyance. I'll rely on the climo of our region to provide and provide it will. The old saying "A watched pot never boils." comes to mind. I've been so busy lately that I am only able keep loose tabs on the model progs. What I do know is that we've stepped down in temps through the Autumn about as one would expect. We've recieved measurable snow in both Oct and November (the plows were out the last time). Now we're still a week+ away from Dec 1st and the threat of significant snows looms larger. We will recieve snow and likely within the next 10-14 days. As climo would suggest. Let the models oscillate as they will. In the end Ullr pays no heed. Soon he will cast his unifying blanket over God's country, as sure as the sun will rise. FEAR NOT.

I love your faith in Ullr. I am with you on the fact that at some point it will snow... we've also had a few measurable snow/ice events so far and like you, I'm not too worried about snow given my location close to the Green Mountain Spine. With that said, the models have been frustrating lately and even though elevation/location/latitude/climo may tell a different story... you can't just make it snow with H85's of +5C and a low over Lake Erie.

Hopefully we still see some snowy solutions mixed in with the warmer ones in the model runs. 12z GFS would be good snows across the interior Dec 1-2 with a KU on Dec 7th. As long as these types of solutions keep showing up, then we are all set.

I really don't like seeing the warm-ups that pop into the medium range guidance though... like Thanksgiving weekend was looking very cold relative to average and now it looks to warm up again for a couple days at the end of the month.

[powderfreak]

Does this not look like La Nina or what? This is what I remember from 2007-2008... strong primary lows tracking into the Lakes or St Lawrence River Valley, followed by redevelopment somewhere in the mid-Atlantic, SNE, or coastal area... with a high off to the NE.

This is the type of pattern that makes people in places like State College, PA and central NY tip their chairs over, while here to the east we at least have the chance of redevelopment locking in the cold.

This just screams La Nina to me though... and I bet we get another winter of a lot of this primaries tracking W with redevelopment to the SE. Then we get to play the "how soon does it transfer" game...

[OKpowdah]

By the end of the run, the Euro also has replaced our -NAO with a north Atlantic ridge

[Tropopause_Fold]

By the end of the run, the Euro also has replaced our -NAO with a north Atlantic ridge

it's not the best run of all time.

all sorts of stuff going on. it really plows that plains ridge east into the eastern 1/3rd of the country next week.

[powderfreak]

12z EURO doesn't look too good leading up to the Dec 1-2 system. Not good to see it already closed off over Colorado heading for Texas... check out that ridging ahead of the system, wow we'd get warm ahead of that sucker.

[Damage In Tolland]

More 60s almost all of next week. There goes our below normal month. F this

[Tropopause_Fold]

12z EURO doesn't look too good leading up to the Dec 1-2 system. Not good to see it already closed off over Colorado heading for Texas... check out that ridging ahead of the system, wow we'd get warm ahead of that sucker.

verbatim it's very warm middle of next week. like 50s all the way to the vt/canada border and litchfieldlibations prancing in his thong along the CT shore in fairfield.

we'll see what happens. it'll do what it wants to do.

[wokeupthisam]

Does this not look like La Nina or what? This is what I remember from 2007-2008... strong primary lows tracking into the Lakes or St Lawrence River Valley, followed by redevelopment somewhere in the mid-Atlantic, SNE, or coastal area... with a high off to the NE.

This is the type of pattern that makes people in places like State College, PA and central NY tip their chairs over, while here to the east we at least have the chance of redevelopment locking in the cold.

This just screams La Nina to me though... and I bet we get another winter of a lot of this primaries tracking W with redevelopment to the SE. Then we get to play the "how soon does it transfer" game...

For CNE/NNE, those types of winters aren't bad. As MRG said, once we get into Dec-Jan-Feb, climo says snow up this way. We can get some big accums from those transfers to the coast and the transfer-timing game brings snow here more than years when the main storm track is off the coast and the game becomes one of 50 mile swings in stormtrack meaning the difference between flurries and meaningful snow. If the NAO helps out, I'll take my chances in the transfer game.

[Tropopause_Fold]

More 60s almost all of next week. There goes our below normal month. F this

for like a day. it's no big deal. LOL.

[CT Rain]

More 60s almost all of next week. There goes our below normal month. F this

Imagine all the fun we'll have with no -NAO block and a even crappier pattern beyond Dec 15 through Jan and Feb!!!