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Medium Range-Long Range thread


NaoPos

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Are you thinking that the ssw will run its course by the end of the month?  It seems that the tropospheric response with this one is shorter or maybe it just feels that way because everyone has been talking about it.  On the other hand, the Roundy guidance almost seems too slow with the progression to P3?  I guess we will see what the EC thinks later today although the week 3 & 4 have seemed noisier than last winter.  

I'm thinking that there is a lot more uncertainty in the robustness of the MJO wave, therefore there is a lot more uncertainty as to where the mean H5 trough (and therefore colder temps) set up. I suspect we'll be -AO through early Feb, but if we go back to -PNA/SE ridge, it's the Rockies and Plains that will cash in.

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The SSW is going to cause significant modeling errors during late Jan-early Feb. This will be a period when circulations between the upper and lower stratosphere will be out of phase and the warming will continue to dismantle the vortex on our side. The ozone rich fetch into eastern Canada will "go with the ride" as pieces of the dying vortex stretch out into the North Atlantic. Initially, this will keep the NAO in check but I suspect the -AO anomaly could build into the west-center NAO regions in early Feb.

 

During this time, the forcing should be predominately in the IO. How quickly the IO starts firing up remains a big question this morning but this will touch off some sort of MT-->PNA response in Feb, despite the increasing -PNA trend late Jan. What possibly will happen is new lows will carve out a trough in the west-central states over time but one may dig west enough to temporarily pump up a ridge in Feb, possibily around the 5th.

 

Now, keep in mind, we did this back in December. This same type of MJO-strat thing gave us a response for Dec 5th at this range if it were November 14th. But this time, it seems like Arctic Air will be available. If the PV continues to remain in this out of phase / weak state but not fully break down or rebuild into March, then there will likely be no "Morch" this year.

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Interesting. If we do skip over into P2/P3, that's still a cold signal for the eastern half of the country. We don't start torching until P4 in February.

 

Yeah I don't think we see any unfavorable forcing into early Feb but I think the PNA will become subject to the retrograding Pacific, resistence from the stable walker/hadley cell in the NE PAC-C PAC and weekly torque/AAM exchanges. Now, I will admit I was dead wrong with how the AAM will progress this week and what that would mean (the response was weaker than I thought and the squeeze play will not lead to a midwest system...gee just like in Dec). But, they will have other opportunities in late Jan and I did indicate their snow wasn't going to come from 1 powerful storm.

 

Feb 20-25 could be another time of MJO "pushing" into the C PAC.

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yes but it was dominated by a -epo. What people don't realize that a -epo i think leads to a lot of our historic cold outbrealks. The -nao is meant for the KU type storms not necessarily cold. 

 

 

 

There was a confluence of events that occurred that winter.  The reason the -epo/+nao combo worked so well was that there were a number of snowpacking events north of our cwa through December.  As of today snow depth through New York State and all of New England except for Maine is still below average.  Those antecedent conditions provided a fresh supply of shallow cold air that I have never seen before or since.  The only winter I ever recall a transitional precipitation event going from snow to freezing rain to rain and then back to freezing rain during the day.  Even so at 40N we struggled to get snow,  it was a tale of two winters in our CWA.  

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There was a confluence of events that occurred that winter.  The reason the -epo/+nao combo worked so well was that there were a number of snowpacking events north of our cwa through December.  As of today snow depth through New York State and all of New England except for Maine is still below average.  Those antecedent conditions provided a fresh supply of shallow cold air that I have never seen before or since.  The only winter I ever recall a transitional precipitation event going from snow to freezing rain to rain and then back to freezing rain during the day.  Even so at 40N we struggled to get snow,  it was a tale of two winters in our CWA.  

 We also had a more active southern storm track coming off 2 prior el nino winters. The year of the ice storm down here.

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There was a confluence of events that occurred that winter.  The reason the -epo/+nao combo worked so well was that there were a number of snowpacking events north of our cwa through December.  As of today snow depth through New York State and all of New England except for Maine is still below average.  Those antecedent conditions provided a fresh supply of shallow cold air that I have never seen before or since.  The only winter I ever recall a transitional precipitation event going from snow to freezing rain to rain and then back to freezing rain during the day.  Even so at 40N we struggled to get snow,  it was a tale of two winters in our CWA.  

Yea that winter was just strange, especially the gradient between abe and phl. I was just saying that most people don't realize that our brutal cold air masses are more so related to a -epo than a -nao. 

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12Z canadian looks the most juicy for the 19th, but still can't get the northern stream involved

 

It also would be rain (I95 centric).  The next time the Canadian scores a coup in days 3 to 6 will be the first

time this winter. It just has not had a good winter around us, although its ensembles have not hurt the

NAEFS temp outlooks.

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Yea that winter was just strange, especially the gradient between abe and phl. I was just saying that most people don't realize that our brutal cold air masses are more so related to a -epo than a -nao. 

 

Agree, wouldn't do the -nao much good if its blocking Pacific Ocean air.  The 12z ensembles look better at keeping us normal to

cold throughout once the arctic front comes through next week.

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Agree, wouldn't do the -nao much good if its blocking Pacific Ocean air.  The 12z ensembles look better at keeping us normal to

cold throughout once the arctic front comes through next week.

 

 However, taking all the indices into account, the chances of a 4+ inch snowfall between now and through the first week of February aren't looking too good?

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 However, taking all the indices into account, the chances of a 4+ inch snowfall between now and through the first week of February aren't looking too good?

Its the best chance we have had all season. We finally have the cold, which we haven't had all year which makes it better so far. Their will definitely be clippers that rotate around the pv like mitchell stated. One of those could blow up once it hits the coast or not.

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Yea that winter was just strange, especially the gradient between abe and phl. I was just saying that most people don't realize that our brutal cold air masses are more so related to a -epo than a -nao. 

 

how bout the gradient within the city limits, 23" at PHL & just 12 miles up the road in Roxborough 44"

 

strange winter definitely however there were also  suspect snowfall recording processes taking place at PHL back in those days

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 However, taking all the indices into account, the chances of a 4+ inch snowfall between now and through the first week of February aren't looking too good?

 

 

Can't really say.  Could get a champagne powder 20:1 clipper.  I like to look at the analog years in the 8-14 day CPC outlook and see how many are snowy.  Beyond seven, eight days we really don't know, plus sometimes they just develop within that time frame.  The GFS likes to bring these arctic air masses to the equator, reality is farther north.  Or as Tombo put it, before next week, we had no chance, now we have a chance...  

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so i'm guessing the lakes region will get pounded with snow since lakes are not frozen?

 

chilly but not brutal for us locally.

 

 

 

BAmEGkwCMAA0Ble.png

Still will be the coldest of the winter (ok that's not exactly going out on a limb  :whistle: ).  If a clipper drops some

snow before the core makes its closest pass, that would be cold...

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Still will be the coldest of the winter (ok that's not exactly going out on a limb  :whistle: ).  If a clipper drops some

snow before the core makes its closest pass, that would be cold...

 

yeah we could use some snow cover, even you down south :) , need to freeze the bike into the mud :)

come on clipper :)

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 However, taking all the indices into account, the chances of a 4+ inch snowfall between now and through the first week of February aren't looking too good?

 

 

Could get lucky with a clipper but better chance is if the W coast ridge weakens as forecasted around D10 setting up split flow and potentially a more favorable storm track to our south. Today's euro shows a storm from the Pacific near iowa at day 10 with cold air in place. . 

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way out in time, but the euro around day 8 has a late blooming miller b that hits nyc and esp sne good. We get some light precip. The biiger story is what its doing with the cold. It's most likely overdone, but it has 504 thickness to nc border almost, with 498 thickness sliding over pennsylvania.

which would translate to what temp range at ground level?

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