Recognizing Phasing Jets prior to winter storms

[Cyclonicjunkie]

What graphical maps do you use to best recognize this phenomenon? (500mb)? (250mb)? (850mb)?

What are the key things you look for?

Whats the difference between 3 vort max, and 2 vort max phasing?

Can anyone show me outlined, detailed, circled, examples of this?

Any help will be much appreciated as I have tried to understand what exactly that it is i'm looking for, using the Phasing storms website, but cant seem to grasp it.

Thanks

[Cyclonicjunkie]

Anyone?.....

[JBG]

Is phasing more likely in certain ENSO states than others?

[Amped]

What graphical maps do you use to best recognize this phenomenon? (500mb)? (250mb)? (850mb)?

What are the key things you look for?

Whats the difference between 3 vort max, and 2 vort max phasing?

Can anyone show me outlined, detailed, circled, examples of this?

Any help will be much appreciated as I have tried to understand what exactly that it is i'm looking for, using the Phasing storms website, but cant seem to grasp it.

Thanks

The Jet streaks 300mb and 200mb.

I think by Phasing you mean Cyclogenesis. Phasing mostly applies most to split flow cyclogenisis (Like DEC 19 2009)

There are also big storms that don't phase like the Blizard of 1996 or April 1st 1997 or April 5th 1982.

[Cyclonicjunkie]

I think by Phasing you mean Cyclogenesis. Phasing mostly applies most to split flow cyclogenisis (Like DEC 19 2009)

Thanks and that sounds like part of what i'm talking about.

Care to go into more detail?

[usedtobe]

The Jet streaks 300mb and 200mb.

I think by Phasing you mean Cyclogenesis. Phasing mostly applies most to split flow cyclogenisis (Like DEC 19 2009)

There are also big storms that don't phase like the Blizard of 1996 or April 1st 1997 or April 5th 1982.

Here's what you want them to look like

Double jet structure

http://www.hpc.ncep.noaa.gov/research/snow2a/sld034.htm

Self development 500h trough evolution for big storms.

http://www.hpc.ncep.noaa.gov/research/snow2a/sld033.htm

http://www.hpc.ncep.noaa.gov/research/snow2a/sld031.htm

[Cyclonicjunkie]

Here's what you want them to look like

Double jet structure

http://www.hpc.ncep....ow2a/sld034.htm

Self development 500h trough evolution for big storms.

http://www.hpc.ncep....ow2a/sld033.htm

http://www.hpc.ncep....ow2a/sld031.htm

Could you show me how to recognize those jets on a winds and heights graphic?

[usedtobe]

Could you show me how to recognize those jets on a winds and heights graphic?

Note the northern Jet streak and second more southern one. The area between the two jets is a good one for strong development when the right rear of the northern one and the left front on the southern one are in play and work together.

[Cyclonicjunkie]

Note the northern Jet streak and second more southern one. The area between the two jets is a good one for strong development when the right rear of the northern one and the left front on the southern one are in play and work together.

Thanks for trying to help, but i'm having trouble with what you mean by right rear and left front?

[LocoAko]

Okay... If you start at the entrance to the jet streak, and divide it up into four quadrants, the front left will be the one on the left (traveling with the wind) near the exit ("front") of the jet streak. In this example the front left quadrant in the southern streak is over the mid Atlantic and the right rear is over southern new england. This is where upper level divergence, Nd therefore rising motions, occur.

[usedtobe]

Jet streaks.

http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/cyc/upa/vrt.rxml

Entrance region, right rear quadrant

http://www.crh.noaa.gov/lmk/?n=jet_streaks

http://www4.ncsu.edu/~nwsfo/storage/training/jets/straightjet.html

Curved jet streaks.

http://apollo.lsc.vsc.edu/classes/met390/Fingerhuts_notes/MooreVanKnowe.pdf

[Cyclonicjunkie]

Okay... If you start at the entrance to the jet streak, and divide it up into four quadrants, the front left will be the one on the left (traveling with the wind) near the exit ("front") of the jet streak. In this example the front left quadrant in the southern streak is over the mid Atlantic and the right rear is over southern new england. This is where upper level divergence, Nd therefore rising motions, occur.

Thanks for the explanation and I think I understand now.

So would that example be a phase of the Northern stream and Southern stream over New England?

[baroclinic_instability]

Here is a classic phase example, the Halloween storm 1991 from maps developed from the North American Reanalysis. Note, in the upper left panel, the 500 hpa vorticity maps, that the southern cutoff low (in this case an intense PV Anomaly) "phases" with the upper trough over Canada.

http://www.meteo.psu...91/us1101j3.php

[baroclinic_instability]

If you want another classic phase event, and one over the east coast, go no farther than the 1993 superstorm itself. A classic in terms of wave phasing, IPV analysis, coupled upper level jets, extreme diabatic heat release in the low levels, etc.

http://www.meteo.psu.edu/~gadomski/NARR/1993/us0313j3.php

[baroclinic_instability]

Okay... If you start at the entrance to the jet streak, and divide it up into four quadrants, the front left will be the one on the left (traveling with the wind) near the exit ("front") of the jet streak. In this example the front left quadrant in the southern streak is over the mid Atlantic and the right rear is over southern new england. This is where upper level divergence, Nd therefore rising motions, occur.

Yes, sometimes. Curved jets behave much differently than the standard left/front, right/rear regions of divergence. Also worth mentioning rising motion does not necessarily occur at this level and often rising motion occurs as a response to upper level divergent fields well below these quadrants and "flow" into the jet isentropically. Also, upper level divergence does not always mean surface cyclone development as there may be multiple levels of non-divergence (LND). Finally, coupled jet streaks don't always mean extreme cyclogenesis, and care must be taken in assessing the whole synoptic environment, not just looking at jet streaks.

[baroclinic_instability]

Honestly too lazy to write about atmospheric dynamics, but jet streaks only play one part. I wrote about a storm over the northern plains a month ago where a number of factors resulted in rapid cyclogenesis. Read it if you are interested. It is about cyclones...seems to fit you well based off your name

http://jasonahsenmac...nt-1112-142010/

[Chris L]

Yes, sometimes. Curved jets behave much differently than the standard left/front, right/rear regions of divergence. Also worth mentioning rising motion does not necessarily occur at this level and often rising motion occurs as a response to upper level divergent fields well below these quadrants and "flow" into the jet isentropically. Also, upper level divergence does not always mean surface cyclone development as there may be multiple levels of non-divergence (LND). Finally, coupled jet streaks don't always mean extreme cyclogenesis, and care must be taken in assessing the whole synoptic environment, not just looking at jet streaks.

This might sound pretty dumb on my part, but I am not a Met, so here it goes:

More Divergence ,Stronger Jet Streak, in turn creates a stronger surface low, and better cylogenesis?

And...

Stronger Jet streaks = more Voritcity-more divegence aloft (or PVA) = stronger sfc low?

Thanks. I always had these quesitons.

I been reading a lot on cylogenesis... I have some powerpoints on it, but its always to ask a Met.

[Cyclonicjunkie]

Honestly too lazy to write about atmospheric dynamics, but jet streaks only play one part. I wrote about a storm over the northern plains a month ago where a number of factors resulted in rapid cyclogenesis. Read it if you are interested. It is about cyclones...seems to fit you well based off your name

http://jasonahsenmac...nt-1112-142010/

Thanks for all this but a 500mb height and winds graphic still utterly confuses me, and I dont know if I am looking for a phase in the heights lines or if i'm looking for the areas of vorticity to make the phase.

Forgive me if all that sounds stupid because I am rookie when it comes to 500mb graphics. Is there anyway you could actually save one of those graphics and circle the actual phasing taking place?

[baroclinic_instability]

This might sound pretty dumb on my part, but I am not a Met, so here it goes:

More Divergence, Stronger Jet Streak, in turn creates a stronger surface low, and better cylogenesis?

And...

Stronger Jet streaks = more Voritcity-more divegence aloft (or PVA) = stronger sfc low?

Thanks. I always had these quesitons.

I been reading a lot on cylogenesis... I have some powerpoints on it, but its always to ask a Met.

Your question is actually quite loaded

Intense, curved jet streaks can exhibit large values of divergence, and therefore, can support large regions of rising motion. The atmosphere follows the laws of mass continuity, in other words, if there is a region of divergence, there must be a region of convergence because mass can't be created/destroyed. Let us assume there is one level of non-divergence right around 500 hpa for simplicity. Then, if there just happens to be a curved jet streak, one can expect strong ageostrophic flow with regions of divergence on the cold side of the jet streak and regions of mesoscale ascent. In strong storms, this can hasten or "work with" other synoptic scale motions to increase cyclogenesis. In other instances, a divergent jet circulation can actually initiate cyclogenesis. As I said, all things must be considered when determining how intense cyclogenesis may be and if it is tropospheric deep or just low level (for instance, typical Alberta CLippers are strong low level cyclones with a mid/upper level wave aloft).

PVA is incorrect. This is commonly mis-used term relating to quasigeostrophic theory. In reality, PVA DOES NOT equal rising motion, but differential cyclonic vorticity advection does. In other words, cyclonic vorticity advection by the geostrophic wind must increase with height for rising motion to occur on the synoptic scale. My blog talks about quasigeostrophic theory and synoptic scale motions of ascent as well. Regardless, regions of significant DCVA (differential cyclonic vorticity advection) commonly but incorrectly referred to as PVA can lead to significant surface cyclogenesis. This can be increased during the "self development process" stated above, which is actually a positive feedback process.

[baroclinic_instability]

Thanks for all this but a 500mb height and winds graphic still utterly confuses me, and I dont know if I am looking for a phase in the heights lines or if i'm looking for the areas of vorticity to make the phase.

Forgive me if all that sounds stupid because I am rookie when it comes to 500mb graphics. Is there anyway you could actually save one of those graphics and circle the actual phasing taking place?

Using the Halloween storm again, here is the phasing in the height field.

Image 1:

Note the upper level cutoff low (PV Anomaly) and the separate trough over Canada.

Note how the two waves become one larger negative tilted trough later in the day:

Negative tilt troughs are typical of intense cyclogenesis. Will also delve into that some other day.

This is a very basic consideration, wave mergers are actually far more complex than simply "2 becoming 1", maybe someday I will write more about it from a dynamic stand point.

[Cyclonicjunkie]

Using the Halloween storm again, here is the phasing in the height field.

Image 1:

Note the upper level cutoff low (PV Anomaly) and the separate trough over Canada.

Note how the two waves become one larger trough later in the day:

This is a very basic consideration, wave mergers are actually far more complex than simply "2 becoming 1", maybe someday I will write more about it from a dynamic stand point.

Appreciated very much, This was my main area of interest that I was trying to gain knowledge in. That was very helpful to me

Just one more question and I will leave you alone, If that third wave off the New England coast were to merge with those already merged waves in the next graphic, would you call that a triple phase?

[baroclinic_instability]

Appreciated very much, This was my main area of interest that I was trying to gain knowledge in. That was very helpful to me

Just one more question and I will leave you alone, If that third wave off the New England coast were to merge with those already merged waves in the next graphic, would you call that a triple phase?

Haha, it doesn't happen much. I guess you could, but I can tell just from looking at the trough off the coast that it is weak and vertically stacked. Note the heights are rising. In other words, it is a leftover remnants of a once baroclinic trough but is now weakening and warming. If it did manage to "phase", it wouldn't positively affect cyclogenesis in this case.

[baroclinic_instability]

Here is a good site for non-mets. This guy talks about all sorts of wave merger events.

http://greatlakes.salsite.com/PhasingStorms.html

[Cyclonicjunkie]

Haha, it doesn't happen much. I guess you could, but I can tell just from looking at the trough off the coast that it is weak and vertically stacked. Note the heights are rising. In other words, it is a leftover remnants of a once baroclinic trough but is now weakening and warming. If it did manage to "phase", it wouldn't positively affect cyclogenesis in this case.

Gotcha!! ........Thanks again

[Chris L]

Your question is actually quite loaded

Intense, curved jet streaks can exhibit large values of divergence, and therefore, can support large regions of rising motion. The atmosphere follows the laws of mass continuity, in other words, if there is a region of divergence, there must be a region of convergence because mass can't be created/destroyed. Let us assume there is one level of non-divergence right around 500 hpa for simplicity. Then, if there just happens to be a curved jet streak, one can expect strong ageostrophic flow with regions of divergence on the cold side of the jet streak and regions of mesoscale ascent. In strong storms, this can hasten or "work with" other synoptic scale motions to increase cyclogenesis. In other instances, a divergent jet circulation can actually initiate cyclogenesis. As I said, all things must be considered when determining how intense cyclogenesis may be and if it is tropospheric deep or just low level (for instance, typical Alberta CLippers are strong low level cyclones with a mid/upper level wave aloft).

PVA is incorrect. This is commonly mis-used term relating to quasigeostrophic theory. In reality, PVA DOES NOT equal rising motion, but differential cyclonic vorticity advection does. In other words, cyclonic vorticity advection by the geostrophic wind must increase with height for rising motion to occur on the synoptic scale. My blog talks about quasigeostrophic theory and synoptic scale motions of ascent as well. Regardless, regions of significant DCVA (differential cyclonic vorticity advection) commonly but incorrectly referred to as PVA can lead to significant surface cyclogenesis. This can be increased during the "self development process" stated above, which is actually a positive feedback process.

Now this is a wonderful answer! Well Done on this explanation.

One more follow up question.

http://www.comet.uca...tframesTWO.html *Click on the Potential Voriticiy Analyze) and it says isentropic potential vorticity

IPV is something new for me to learn about cyclognensis, I recently found that website, and was wondering what exactly what is IPV in relation to cylogenesis??

Thanks again!

I think this webpage is very good, but it is a bit complex. http://www.comet.uca...tframesTWO.html

All of this things makes me angry that I am not a Met major because of the math....

[baroclinic_instability]

Now this is a wonderful answer! Well Done on this explanation.

One more follow up question.

http://www.comet.uca...tframesTWO.html *Click on the Potential Voriticiy Analyze) and it says isentropic potential vorticity

IPV is something new for me to learn about cyclognensis, I recently found that website, and was wondering what exactly what is IPV in relation to cylogenesis??

Thanks again!

I think this webpage is very good, but it is a bit complex. http://www.comet.uca...tframesTWO.html

All of this things makes me angry that I am not a Met major because of the math....

IPV is Isentropic Potential Vorticity developed in the mid 80s by Hoskins. It is a "competing" mathematical discussion of synoptic scale motions to quasigeostrophic theory. I say competing because they both result in the same thing, but they explain it much differently. Most universities teach QG Theory because it came first and it dominates the textbooks. However, IPV is also a useful tool in synoptic analysis, especially certain types of explosive cyclogenesis.