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poleshiftnow

Sudden Stratospheric Warming Begins! Significant Cold Ahead For January-February:CROSS POLAR FLOW !

73 posts in this topic

Nice read



[color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]Polar Vortex Collapse, Arctic Freeze Imminent [/size][/font][/color]
[color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]By Andrew at 9:24 AM The model forecasts above both show big high pressure centers interrupting the polar vortex and splitting it into two pieces. Such a split exemplifies the traditional weakening of the polar vortex. When that polar vortex is weakened, the cold air locked up in said polar vortex flows south, possibly into North America, maybe into the US. This is a very good sign coming from the models at this point in time to go along with the stratospheric observations.[/size][/font][/color]

[color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]Continuing with watching the models, we turn to a charted forecast of the ECMWF model. I want you to look at the bottom image, called the EP Flux. In short, the EP flux shows the direction and strength (shown by length of arrow) that air moves into the stratosphere. In events where warm air enters the stratosphere, long, extended arrows are commonly seen. The forecast into the days before New Year's Day show a batch of extended arrow motions, suggesting a large motion of warming may be incoming into the stratosphere. This enhanced EP Flux would theoretically enhance warming potentials in the Arctic, thus further weakening the Polar Vortex. I find it likely that the aforementioned 50mb wave over East Asia would be to blame for this rise in EP Flux values.... [[/size][/font][/color][url="http://www.godlikeproductions.com/external?http%3A%2F%2Ftheweathercentre.blogspot.de%2F2012%2F12%2Fpolar-vortex-collapse-arctic-freeze.html%3FshowComment%3D1356230240926"]link to theweathercentre.blogspot.de[/url][color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]] Posted 30 September 2012 - 00:42[/size][/font][/color]

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The medium-range indicators suggest a nice +PNA with a strong subtropical jet providing a very favorable set-up for some CAD over the south-central Appalchians in about six days and beyond. Given the extended outlook for an NAO rapidly shifting within +/- 3 to 5 standard deviations of its current mean, the forecast for a stratospheric warming event over AK in the same time frame also favors a +PNA as shown by surprisingly good agreement between the ECMWF and NCEP ensembles, with both depicting a strong Bering vortex in the same time frame, beginning in the four-day time frame and amplifying days 5-7. I would give a good prospect for snow over Appalachia and OH / WV / W PA in this time frame, extending up into portions of NY and NW New England. Also, I see a good potential for a series of wave-breakling events with potential for at least one big severe-wx outbreak over a wide portion of the far South due to the strong subtropical jet overspreading an increasingly cool 700-mb environment over the Gulf Coast / FL. At least one severe-wx outbreak over FL appears likely because this type of pattern was seen in 02/28/1998--granted, a Niño year--and occasionally in some neutral ENSO years.

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We are relying on this SSW because 3.4 temp anomolies are gone

[img]http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/ssta_c.gif[/img]

GLAAM has dropped off again


[img]http://www.esrl.noaa.gov/psd/map/images/gcm/gwo_40d.gif[/img]\

Overall pattern is not much better than last year.

[img]http://www.meteo.psu.edu/%7Efxg1/ECMWF_12z/test8.gif[/img]

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[quote name='poleshiftnow' timestamp='1356897140' post='1972601']
Nice read



[color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]Polar Vortex Collapse, Arctic Freeze Imminent [/size][/font][/color]
[color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]By Andrew at 9:24 AM The model forecasts above both show big high pressure centers interrupting the polar vortex and splitting it into two pieces. Such a split exemplifies the traditional weakening of the polar vortex. When that polar vortex is weakened, the cold air locked up in said polar vortex flows south, possibly into North America, maybe into the US. This is a very good sign coming from the models at this point in time to go along with the stratospheric observations.[/size][/font][/color]

[color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]Continuing with watching the models, we turn to a charted forecast of the ECMWF model. I want you to look at the bottom image, called the EP Flux. In short, the EP flux shows the direction and strength (shown by length of arrow) that air moves into the stratosphere. In events where warm air enters the stratosphere, long, extended arrows are commonly seen. The forecast into the days before New Year's Day show a batch of extended arrow motions, suggesting a large motion of warming may be incoming into the stratosphere. This enhanced EP Flux would theoretically enhance warming potentials in the Arctic, thus further weakening the Polar Vortex. I find it likely that the aforementioned 50mb wave over East Asia would be to blame for this rise in EP Flux values.... [[/size][/font][/color][url="http://www.godlikeproductions.com/external?http%3A%2F%2Ftheweathercentre.blogspot.de%2F2012%2F12%2Fpolar-vortex-collapse-arctic-freeze.html%3FshowComment%3D1356230240926"]link to theweathercentre.blogspot.de[/url][color=#000000][font=Verdana, Arial, Helvetica, sans-serif][size=3]] Posted 30 September 2012 - 00:42[/size][/font][/color]
[/quote]
Whoever wrote that is completely ignorant of the actual dynamics involved, E-P flux tells you the direction and strength of wave energy, not the movement of air. When the E-P flux is pointed poleward it induces a reversal of the westerlies as the wave energy is absorbed, leading to warming via the thermal wind law.

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[quote name='TropicalAnalystwx13' timestamp='1356990772' post='1974954']
Warming already beginning.

[img]http://www.cpc.ncep.noaa.gov/products/intraseasonal/temp10anim.gif[/img]
[/quote]

Nice, I was looking for a genesis of an event. It does appear that if not for the Himalayas, there'd be far fewer warming events.

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[quote name='Coach McGuirk' timestamp='1356996237' post='1975118']
What does this mean?
[/quote]

I'm still teaching myself about this but I believe it is a pre-cursor to cold weather around the corner. Usually a SSW takes 2-3 weeks for us to feel the affect of it.

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I believe you are a bit confused still...the location of the SSW doesn't plays any roll in where the cold air will go. The weather systems in the tropo. at 60-90N around the cold air's genesis region will determine where it ends up going. Also there is no relation to and "active" period nor specifically "active" period for the NE after a SSW. If a SSW "propagates" to the lower levels of the stratosphere and there is a wind reversal which weakens the vortex, it could possibly produce a vortex split which a split and weakening of the vortex coincides with a -AO. -AO is indicative of a weakened polar vortex which allows colder air to escape the polar region. As most know just because we have -AO doesn't automatically mean cold in N. America. As HM describes it, the PV is like a tornado circulating above the polar region with all the cold air trapped in the center deprived of O3 from the tropics which allows it to cool even more. When you weaken the vortex that colder air is allowed to escape. A complete break down of the vortex or split allows larger quantities of cold air than normal to escape the vortex...as compared to when the vortex is just weakened and smaller amounts of cold air escape.

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That animation of the SSW starting is pretty cool!
---

Zonal wind forecast at 10hPa:

Wind reversal around the 11th in the Arctic.

[img]http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_fcst_err_U10_7.gif[/img] [img]http://wekuw.met.fu-berlin.de/%7EAktuell/strat-www/wdiag/figs/ecmwf1/fluxes.gif[/img]

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[quote name='QVectorman' timestamp='1356999651' post='1975210']
I believe you are a bit confused still...the location of the SSW doesn't plays any roll in where the cold air will go. The weather systems in the tropo. at 60-90N around the cold air's genesis region will determine where it ends up going. Also there is no relation to and "active" period nor specifically "active" period for the NE after a SSW. If a SSW "propagates" to the lower levels of the stratosphere and there is a wind reversal which weakens the vortex, it could possibly produce a vortex split which a split and weakening of the vortex coincides with a -AO. -AO is indicative of a weakened polar vortex which allows colder air to escape the polar region. As most know just because we have -AO doesn't automatically mean cold in N. America. As HM describes it, the PV is like a tornado circulating above the polar region with all the cold air trapped in the center deprived of O3 from the tropics which allows it to cool even more. When you weaken the vortex that colder air is allowed to escape. A complete break down of the vortex or split allows larger quantities of cold air than normal to escape the vortex...as compared to when the vortex is just weakened and smaller amounts of cold air escape.
[/quote]

That's a good way to put it. Thanks for clarifying.

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Interestingly enough there are two events going on in synch here. One centered at the 1mb the other centered at 40mb.


[attachment=83526:ecmwfzm_ha2_f168.gif]

Both the GFS and EC eventually breaks into a very stable wave 2 pattern. Those PVs hardly budge day 10-16 on the GFS.
[img]http://wekuw.met.fu-berlin.de/%7EAktuell/strat-www/wdiag/figs/ecmwf1/ecmwf50f240.gif[/img]

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It's interesting to note that, while the GFS shows below average temperatures across much of the United States during the day 11-15 period, the ECMWF has the exact opposite. Nearly blowtorch warm to be exact. The end of winter.

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you might want to reference last winters great stratospheric warming event that was assured to deliver us all from the bowels of a craptastic winter...

 

...then get back with us on how that worked out.

It delivered on the other side of the globe if i recall correctly?

 

Not all will deliver the goods. Still it helps our odd's.

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It delivered on the other side of the globe if i recall correctly?

 

Not all will deliver the goods. Still it helps our odd's.

 

I agree, just because last year was a bag of crap doesn't mean every winter from here on out will be. People need to stop looking at last year as if it were the rule.

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The SSW event last year didn't propagate down far enough if I can remember right. It didn't fully split the PV and what damage was done - the PV was able to reconsolidate. This time around we have one SSW going over Europe roughly and another one firing off over the Asian continent high in the stratosphere. I doubt the polar vortex will be able to survive two bombardments in a row.

 

Edit:

 

The GFS has been hinting at a 3rd SSW event starting over Canada in the long range. http://theweathercentre.blogspot.de/

 

50hPa animation

 

temp50anim.gif

Edited by Geos

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It's such a fine line to play...just as there have been ssw's which delivered, there have been ssw's that have not. So...what it boils down to is playing the odds.

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If you want to look back at past SSW events here are some notable ones below. I think this could be close to 1985..maybe! The hardest part of forecasting the impacts is which side of the pole the arctic air goes. Last year this happened a few times but it all the cold went into Siberia. 

 

1985_01_03.gif

 

More events here.. http://curriculum.pmartineau.webfactional.com/ssw-animations/ 

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Nice animation wxbrad! Unfortunately the link doesn't work for me!

 

----

Polar vortex looks to split in about 96 hours or less. (In the upper stratosphere first)

 

ecmwf10f96.gif

 

 

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Nice site Dacula!

 

I noticed the E-P flux has been really strong the last couple days. Vectors shooting straight up close to the Arctic circle.

 

ep_12z_st_nh.gif

 

Zonal winds in the upper stratosphere has really crashed in the last few days.

 

fluxes.gif

 

 

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Nice site Dacula!

 

I noticed the E-P flux has been really strong the last couple days. Vectors shooting straight up close to the Arctic circle.

 

ep_12z_st_nh.gif

 

Zonal winds in the upper stratosphere has really crashed in the last few days.

 

fluxes.gif

 

EP flux always have stronger vectors during SSWs. They have been equatorward, but will turn more poleward tomorrow. Central date for the MMW is in 2 days. It's not a coincidence that models show a lot stronger ridging in the medium range.

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