November Weather Discussion

[CoastalWx]

Yeah I can't say I totally hate the progression right now. We obviously feel a little uneasy with the precarious AO situation and always the potential that it could decide to plant a vortex over the EPO region...but that Aleutian ridge for now seems to want to hold its ground enough to not allow for the big blowtorch pattern into Canada...southern Canada may torch for a time post-11/15, but the source region looks good right now north of that.

 

I also agree about a sneaky cold shot that could be fairly potent around 11/12-13. Good trajectory on the Scooter Canadian praries high oozing eastward and draining cold from the north.

 

I think right now I care more about the Pacific because it's not like we are screwed with the +NAO like you mention. If I had to WAG something..maybe we see it rebuild heading into December, but I'd like to flush the GOAK trough out or at least change the orientation of it. That would be ugly I think. Something like a Dec 2007 or 2008 look is more ideal. Dec 2008 even more ideal.

[Tropopause_Fold]

Yeah I can't say I totally hate the progression right now. We obviously feel a little uneasy with the precarious AO situation and always the potential that it could decide to plant a vortex over the EPO region...but that Aleutian ridge for now seems to want to hold its ground enough to not allow for the big blowtorch pattern into Canada...southern Canada may torch for a time post-11/15, but the source region looks good right now north of that.

 

I also agree about a sneaky cold shot that could be fairly potent around 11/12-13. Good trajectory on the Scooter Canadian praries high oozing eastward and draining cold from the north.

[CoastalWx]

 

Your name should be included too since we both look at it the same way.   Need the cold for the coast.

[toronto blizzard]

Maybe...I don't see any definitive signs yet of whether December will be warm or cold across our area. I'm slightly leaning warm, but that could definitely change...if Aleutian ridge is poleward with a -PNA...then we'd likely get a gradient pattern that keeps Canada cold and potentially the northern tier of the central/eastern U.S. depending on other nuances.

However, if the Aleutian ridge is more flat and we don't compensate elsewhere, then we would blowtorch.

Very similar to dec 2007 which had a +NAO, - PNA but a poleward Aleutian ridge. Of course I don't have to say how that month went

[Tropopause_Fold]

Your name should be included too since we both look at it the same way.   Need the cold for the coast.

yep...give me HP or give me rain. lol. 

[ORH_wxman]

This is the type of pattern we can get away with in December if we are forced to deal with a +AO/+NAO/-PNA....it has to be this configuration

 

 

 

 

The key is the Aleutian ridge is poleward enough to keep the lower heights east of the EPO region...the source of that air is the Arctic ocean and Siberia versus the Gulf of Alaska.

[jamesnichols1989]

If we get a combo of -NAO/-AO but with -PNA the PNA could be compensated for, with Aleutian ridging, however if we don't get a -NAO/-AO during a -PNA then we have to wait on the PNA to go positive and the EPO to go negative.  This is all a work in progress given the state of the current pattern we are in, so I imagine that this pattern will change, but it's a matter of when it does occur.  Is it early December?  Mid to late November or later than the first week of December?

 

Anyways 00z euro and GFS both showed a more amplified pattern setting up for our day 6 disturbance going into day five.

[CT Rain]

Good stuff in this thread. Definitely a wait and see situation that really hinges on the Pacific. Given AO signal I think a lean warm is good for December for now. Can't get more specific yet.

[powderfreak]

A quick recap of the two days of below normal across New England and eastern New York...

 

ID   SUN-03 MON-04 AVERAGE
---  ------ ------ -------
MPV    -13    -15    -14
MVL    -11    -13    -12
1V4    -11    -12    -12
BTV    -11    -12    -12
DDH    -10    -13    -12
CON    - 9    -13    -11
ALB    - 8    -13    -11
GFL    - 9    -12    -11
PBG    - 8    -11    -10
PSF    - 8    -11    -10
BDL    - 6    -12    - 9
VSF    - 8    -10    - 9
BGR    - 7    -10    - 9
LGA    - 5    -12    - 9
ORH    - 6    -11    - 9
POU    - 6    -11    - 9
GYX    - 6    -10    - 8
NYC    - 6    -10    - 8
BDR    - 5    -10    - 8
BOS    - 4    -11    - 8
HUL    - 6    - 9    - 8
PVD    - 4    -11    - 8
PWM    - 4    -11    - 8
FVE    - 6    - 7    - 7
CAR    - 6    - 6    - 6
ISP    - 4    - 8    - 6
MLT    - 5    - 7    - 6

 

Awesome!  Never thought I'd see the day when we were at the top of a negative departure list, lol.

 

 

You are the man. Lol the irony of PFs area jackpotting with cold after all his postal meltdowns about a lack of such.

 

That back to back negative double digit departures is the most impressive cold shot relative to normal in a very long time.  I'm impressed.

 

However, we are still only at normal only 5 days into the month at the main climo site of BTV, lol.  +20 at BTV the first day of the month is at least erased now.  Its pullin' teeth Ginxy to get below normal in the means...pullin' teeth I'm tellin' ya!  I'm impressed its been so cold for 2-3 days now, and BTV is only two-tenths of a degree from normal.

[powderfreak]

This is actually probably one of the more notable early November cold shots in a very long time.  Multiple record lows and back-to-back negative double digit departures.  After seeing those numbers I'm blown away...the atmosphere still has it in it.  right now.

[CoastalWx]

That image would work perfectly with lower heights in western Canada. That's a -PNA that will work. But, shift that west 500-1,000 miles and no good. Lets hope for the former. Obviously it's a function of the latitude gained with the Aleutian ridging.

[CoastalWx]

This is actually probably one of the more notable early November cold shots in a very long time.  Multiple record lows and back-to-back negative double digit departures.  After seeing those numbers I'm blown away...the atmosphere still has it in it.  right now.

 

I may have missed it, but who broke a record? BTV and MVL?

 

Edit, I see it now.

[CoastalWx]

Well, well. Sneaky Scooter high leading too sneaky cold next week.  Two reasons it seems. A little wave breaking ridge pealing ESE from nrn Alberta at hr 192 and and the bigger picture is a anomalous >590decameter ridge over Eastern Aleutians.

[icebreaker5221]

Great discussion here guys!  Just thought I'd add:

 

A big time +EPO with neutral PNA usually means a big time ridge parked over New England into SE Canada.  Sneaky cutoff lows can occasionally slide under the ridge, and in the right airmass (usually Jan-Feb) produce snow for the mid-Atlantic or southeast.

 

On the other hand, a big time -PNA but neutral EPO more often translates to a southeast ridge centered over GA/NC/SC, generally prohibiting snows in the southeast / mid-Atlantic but can allow for southwest flow and gradient snows for New England. 

 

So yes, certainly for this subforum I agree with Will that the EPO is more the one to watch. 

[ORH_wxman]

That's pretty cold stuff on the GFS for next week...that cold shot we were discussing upthread. That's a bit more impressive than this past cold shot.

[toronto blizzard]

GFS looking interesting with that wave around 192

[ORH_wxman]

That image would work perfectly with lower heights in western Canada. That's a -PNA that will work. But, shift that west 500-1,000 miles and no good. Lets hope for the former. Obviously it's a function of the latitude gained with the Aleutian ridging.

 

Yes...the composite temperature anomly for those Decembers showhow precarious it is...not far from breaking out the banana hammocks

 

 

 

 

 

 

This pattern really seems to work best in December...in January it seems like the wavelengths get enough off kilter that we torch more in a -PNA.

[HoarfrostHubb]

Your name should be included too since we both look at it the same way.   Need the cold for the coast.

It's bad enough you get the moisture... you want the cold, too?

[IsentropicLift]

12z GFS clown maps show several inches of snow for interior upstate NY, northern VT/NH and western Maine days 8-10.

[HoarfrostHubb]

Yesterday's -11 at ORH basically wiped out the torch, today will flip to negative (maybe) then back above Weds, Thurs

 

Yo yo

[CoastalWx]

Yes...the composite temperature anomly for those Decembers showhow precarious it is...not far from breaking out the banana hammocks

 

 

 

 

 

 

This pattern really seems to work best in December...in January it seems like the wavelengths get enough off kilter that we torch more in a -PNA.

 

I meant shift those anomalies west from western Canada by 500-1,000 miles...I wasn't clear on that but regardless..that's a toaster tight rope.

 

Sometimes you have to walk the line to really get the goods and take advantage of baroclinic boundaries.  Storminess.

[CoastalWx]

Looks like Ginxy tried to run the GFS op in his basement.

[CoastalWx]

And I'm pretty sure that Aleutian ridge is record breaking as progged by the op runs.

[ORH_wxman]

I meant shift those anomalies west from western Canada by 500-1,000 miles...I wasn't clear on that but regardless..that's a toaster tight rope.

 

Sometimes you have to walk the line to really get the goods and take advantage of baroclinic boundaries.  Storminess.

 

 

Well yes....you can see if you shifted everything west, then those warm anomalies in the SE would probably run right up our fanny. Everything would get tilted more N...cold retreats well NW and everyone blowtorches.

 

But yeah, tis even a little more complicated than that...as Canada itself would probably have less cold available than in the pattern shown.

[Typhoon Tip]

Yes ... the EPO is the primary cold load that sets the stage for availability to the N/A middle latitudes... We've discussed this for years.

 

It's funny how it seems every so-often we go through this complete re-iteration thing, and it almost seems like it's taken as this big revelation -- wow, yeah!  The EPO ... fascinating. 

 

Any minute now, someone is going to post about Heather Archembault, and how cold season PNA phase changes are correlated to enhanced probability for eastern N/A precipitation events.  Really?   whoa.  Stop the train!    AND, sometimes with the NAO, too.   

 

j/k. I suppose for new members of the forum-sphere...  

 

Also, not to discredit Archembault in any way, shape, or form, I find the statistical science to really be quite obvious.  If you have a large domain space that is in a static pattern regime, and then ... disrupt that regime, yeah ... things are going to happen.  To me, the conclusion in a sense sort of proceeded the science in that case.  But it's good to have nailed it down, I suppose.  If it's -NAO for 2 weeks, and there was cold available, then the PNA changes and throws perturbation into the mix, it is quite intuitive that storminess of some sort will result.  And, it is like that all over the planet.      

[Typhoon Tip]

And I'm pretty sure that Aleutian ridge is record breaking as progged by the op runs.

 

 

This is an interesting sort of "west-based" -EPO ...  I mentioned this last night, it is allowing outside sliders off the west coast.  The wave spacing is rather anomalously short during the period, such that those troughs digging along 140 W are popping some ridging over the Rockies ... That is sort of countering the +NAO flow by lowering heights in the E.  It's an interesting, albeit unstable regime, but one that still pays homage to the -EPO controlling things (I think). 

[ORH_wxman]

Yes ... the EPO is the primary cold load that sets the stage for availability to the N/A middle latitudes... We've discussed this for years.

 

It's funny how it seems every so-often we go through this complete re-iteration thing, and it almost seems like it's taken as this big revelation -- wow, yeah!  The EPO ... fascinating. 

 

Any minute now, someone is going to post about Heather Archembault, and how cold season PNA phase changes are correlated to enhanced probability for eastern N/A precipitation events.  Really?   whoa.  Stop the train!    AND, sometimes with the NAO, too.   

 

j/k. I suppose for new members of the forum-sphere...  

 

Also, not to discredit Archembault in any way, shape, or form, I find the statistical science to really be quite obvious.  If you have a large domain space that is in a static pattern regime, and then ... disrupt that regime, yeah ... things are going to happen.  To me, the conclusion in a sense sort of proceeded the science in that case.  But it's good to have nailed it down, I suppose.  If it's -NAO for 2 weeks, and there was cold available, then the PNA changes and throws perturbation into the mix, it is quite intuitive that storminess of some sort will result.  And, it is like that all over the planet.      

 

 

I think the main point of the EPO discussion was to show how you can still get cold in our region despite other ugly teleconnector indices being unfavorable...such as a +AO/+NAO and -PNA....that composite I showed has that combination of all 3 (+AO/+NAO/-PNA) which normally would lead many to believe that we will torch our way through a month....but obviously not the case if you have enough poleward ridging from the Aleutians.

 

 

Sometimes its important to reiterate points....especially when we see graphs of the AO, NAO, PNA, etc posted all the time. Just an alternative way of thinking rather than blindly following the index numbers...if that makes sense.

[Typhoon Tip]

Yeah, that D9 GFS ... that would probably result in one helluva ice storm

[CoastalWx]

Well yes....you can see if you shifted everything west, then those warm anomalies in the SE would probably run right up our fanny. Everything would get tilted more N...cold retreats well NW and everyone blowtorches.

 

But yeah, tis even a little more complicated than that...as Canada itself would probably have less cold available than in the pattern shown.

 

My mind is wondering how this pattern would materialize a month from now. Something tells me it would be an interesting 10 days or so if this were mid December.  You'd have a huge cold dump from Canada heading south through what would be snow covered ground.

[CoastalWx]

This is an interesting sort of "west-based" -EPO ...  I mentioned this last night, it is allowing outside sliders off the west coast.  The wave spacing is rather anomalously short during the period, such that those troughs digging along 140 W are popping some ridging over the Rockies ... That is sort of countering the +NAO flow by lowering heights in the E.  It's an interesting, albeit unstable regime, but one that still pays homage to the -EPO controlling things (I think). 

 

The GEFS do try to pop a weak Rocky Mtn ridge which may be ok in Dec or Jan I suppose. I think it does owe to the wavelengths like you mention.