Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: sark on May 18, 2019, 10:47:40 PM

Title: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on May 18, 2019, 10:47:40 PM
Opening this new thread in response to long range weather forecasting discussions in the main melt season thread.  From pages 14-15..  Anything goes.

I would propose a 'Long Term Weather Forcast Thread'.

There are obviously people not interested in this kind of content. By having it in a separate thread they could easily avoid it. And the ones interested wouldn't feel restricted and could post freely.

and I'll open with my "Autosquint" 500mb anomaly 21 day comp mean, with one of today's GFS runs tacked on to the end

This could use a synopsis of the SSW style final warming of 2019, with the ensuing coupled barotropic polar atmosphere that has beaten into the high north.  Analogues, models, papers

I feel like it'll calm down once the snow melts, but 2019 is a continuation of a really disappointing trend.  I spent 3 days curled in a ball last week.  I'm not a scientist and I don't play one so I can say this: The polar cell is failing.  It has been for years.  The trend is not your friend, but it's still a trend... and the emerging trend has to be indicative of the drastic, faster-than-expected breakdown of the polar cell.

What the hell is even happening?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: FishOutofWater on May 18, 2019, 11:30:18 PM
I wrote about what's happening over at a fading political blog the other day. Intense end warmings in the stratosphere have consequences. The sudden warming of the region from 60N to the pole from the surface to the top of the stratosphere is what I was referring to by the description "atmospheric convulsion." There's likely to be a horrific tornado outbreak on Monday and Tuesday as the storm that's now giving California a very late soaking reforms on the east side of the rocky mountains.

Zach Labe understands the physics of this situation better than I do - he's studying it for an advanced degree. I doubt he's reading this but I wouldn't mind being corrected if I made a mistake.

https://www.dailykos.com/stories/2019/5/15/1857911/-Atmospheric-Convulsion-Will-Cause-Historic-Disasters-of-Arctic-Melt-U-S-Storms-Next-Week
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: vox_mundi on May 19, 2019, 01:10:04 AM
Long-term weather starts to get into tele-connections ...

Hot Arctic and a Chill in the Northeast: What’s Behind the Gloomy Spring Weather?
https://blog.ucsusa.org/brenda-ekwurzel/hot-arctic-and-a-chill-in-the-northeast-whats-behind-the-gloomy-spring-weather

... It may seem counter-intuitive, but the story of the strange weather unfolding this spring in the US is related in part to snow last October in Eurasia. This indicator—the Eurasian October snow cover extent indicator—is proving to be worthy of additional attention by US weather geeks. The good news is that the scientists who were paying attention to the Eurasia snow extent behavior during October, along with a host of other indicators, gave advanced warning of the emerging US winter and spring weather pattern for 2018/2019. 

... I encourage those who want to know, to spend some time clicking on the links here or links in earlier blogs that point to even more information (see here, here, here, and here). These describe the details regarding how Arctic sea ice decline, particularly in the Barents-Kara sea ice, north of Scandinavia and Russia, contributes to ocean and atmosphere behavior. Which contributes to Eurasian snow cover extent behavior. And ultimately a wavy jet stream with episodic cold outbreaks over winter and spring in the Northern Hemisphere, including the US.

... Here is an example of the science as Judah Cohen explains, “There is a growing consensus that it is Barents-Kara sea ice in the late fall and early winter that has the greatest impact across Eurasia.  Therefore, low Barents-Kara sea ice in November for example, favors a strengthened Siberian high, increased poleward heat flux, a weak stratospheric Polar Vortex and finally a negative Arctic Oscillation. An important point regarding the Siberian high is that it strengthens or expands northwest of the climatological center.  For low snow cover and/or high sea ice the opposite occurs.”  Translation, a weakened polar vortex means more cold outbreaks deep into US territory like this past winter and spring. ...

North Atlantic Warming Hole Impacts Jet Stream
https://phys.org/news/2019-04-north-atlantic-hole-impacts-jet.html

The North Atlantic warming hole (NAWH), a region of reduced warming located in the North Atlantic Ocean, significantly affects the North Atlantic jet stream in climate simulations of the future, according to a team of researchers.

... To investigate how the development of the NAWH impacts the jet stream, the team conducted a series of large-ensemble, atmospheric model experiments in the CESM with prescribed SST and sea ice levels over three different time periods.

Their results indicate that the NAWH plays an important role in midlatitude atmospheric circulation changes in the model's future climate simulations.

"We found that it's really quite important for that region," said Gervais. "The NAWH seems to be elongating the jet even further and shifting it a little bit north. Instead of just thinking about how the tropics and arctic amplification are influencing the jet, we now also need to think about how this warming hole is going to influence the jet. These local changes in the North Atlantic jet are of a similar magnitude to the full climate-change response in the region, indicating that the North Atlantic warming hole could be an important additional factor in the tug of war on midlatitude circulation, that has received little attention."

Melissa Gervais et al, Impacts of the North Atlantic Warming Hole in Future Climate Projections: Mean Atmospheric Circulation and the North Atlantic jet, Journal of Climate (2019)
https://journals.ametsoc.org/doi/10.1175/JCLI-D-18-0647.1
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on May 26, 2019, 12:36:18 PM
1st image is ESRL 1000mb air temperature anomalies month by month, 2012-2018 compared to 1979-2000.  This shows that the temperatures have dropped significantly around Hudson Bay, especially in March April May.  The big signal here is that in recent years, the Polar Cell has elongated toward Hudson Bay and Siberia.  Meanwhile, ridging from both oceans has taken turns reaching into the Arctic and delivering those bursts of high temperature we all get excited about, the DMI 80N movers.  However, those Arctic incursions have always came singly, and not from both sides of the planet at the same time.

Dr Judah Cohen has published AER's summer temperature forecast.  https://www.aer.com/science-research/climate-weather/arctic-oscillation/

2nd image attached is AER's GEFS Polar Cap Height including forecast.  The current conditions are updated here: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.shtml

3rd image is now a 7 day composite of the 500 mb anomaly from ESRL, and the 18Z GEFS 5 day averages tacked onto the end, which is what I stare at to guess where in the Arctic will get hit by these recurring short circuit ridges.  Looks like once this Bering Blast wears out, another long reaching ridge coming across the Kara Sea brings another big block of high pressure right to the pole.

Gav's weather vids on YouTube has been doing analogs and seasonal models of interest in the UK.  The analogs have been extremely interesting.  https://www.youtube.com/user/GavsWeatherVids

Michael Ventrice on Twitter: "With a strong suppressed phase of a Kelvin wave to pass the Western Hemisphere during early June, I'm thinking severe thunderstorm activity in the U.S. quiets down. Good news for parts of the Plains.  Early June likely meaning June 7-20+"

Michael Ventrice regularly reports on the synoptics and there's a great image here.  Little bit over my head with the MJO.  He's been "bearish" on El Nino lately. 

https://twitter.com/MJVentrice/status/1132225653867204609?s=19

I've been staring at models until I can see it with my eyes shut.  I've been doing this because it seems like something is very wrong.

Firstly, GFS runs hot & is a little bit fast at the end.  When I see a high 500mb anomaly, the resulting action is much more diffuse and less sharp.  The GFS paints a bright dot on an area, reality waters it down.  Same amount of ink, just spread out.

The timing of GFS is a little bit fast in the 10-16 day.  Whatever it was developing speeds up at the smaller resolution and the temperature and speed runs away.  What is depicted turns out to be less energetic.

I like how it is "sensitive" and one run van vary widely from the next, but you get great indications of major moves 16-20 days out in the hour 384.

Yeah and it will suffer a heat wave right over the Beauforts area, above zero temps with high pressure in 15-20 days.  I guarantee it.

Ask me how I know

Someone asked me how I knew the Beaufort would be buried in high pressure & heat May 21-26.  I wanted to say something pithy about the value of long range GFS.  I mean, it's working.  But there's more to it. 

Hurricane Oscar, the last named hurricane of the 2018 Atlantic Season was turned out to sea and became and extratropical cyclone.  It entered the Arctic on November 1.  500mb charts from GFS and ECMWF showed it entraining with the polar cell and landing right at the north pole around November 5th.  Within days, the stratospheric polar vortex began ping ponging around the Arctic.  Displacement eventually yielded elongation, splitting, and a notable 3 PV setup.  The PV split worked its way down to the ground for 5 weeks, and then we had the major arctic air outbreaks of last winter.

Since all this happened, the flow has been often split and two major sections of polar cell depart the Arctic for colder land.  The two cells find separation while the jet stream reaches up from both oceans and short circuits at the pole.

4th image.  Big time separation.  There are now two areas of polar cell instead of one.  It is a repeating pattern of meandering, pinching in half, churning in heat at the pole, and then slapping back together again.  It repeats and repeats coming every 6 or 8 weeks.

Now you can expect there will be ridging from opposite sides of the planet at the same time, nearly reaching the pole simultaneously.  The aggressiveness of GFS often shows waves crossing the Arctic and landing on the other side of the planet.  In reality, it's a little bit less simultaneous, a little bit less of a short circuit.

So, what we can all see in the models is a new block of high pressure forming in Russia and then curling into the Arctic, buring the Kara Sea in high pressure and warmth incursion, and delivering another parcel of high pressure to the Arctic.  This is shown in the June 1-9 period.  It is accompanied by a ridge from the Pacific reaching toward the Beaufort.  Models are showing this one a little less energetic and low pressure begins to deepen in the region of Greenland & Baffin Bay around June 10.


Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on May 26, 2019, 12:41:30 PM
I made my guesses at beyond June 10th below
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: be cause on May 26, 2019, 01:01:22 PM
Great contributions Sark .. but could you please up size to 701pixel so that they don't all load together .. and eat up resources unnecessarily  ? Also allowes the viewer a little more control ..  cheers b.c.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: jdallen on May 26, 2019, 10:05:42 PM
I made my guesses at beyond June 10th below
Brilliant work in both posts, Sark!

Thank you for condensing, presenting in imagery and describing what I've been wondering about.

I tend to agree - the GFS has been improving on predicting general regional conditions further out, if not the exact details to their distribution and intensity.

I think we've all been seeing the general pattern of HLHL around the pole, if not fully comprehending it. Though at times I've thought I've seen it divided out even further - HLHLHL or even HLHLHLHL; the overall takeaway is, the Polar cell has been blown to tatters, and circulation is becoming nearly as chaotic as water on the boil.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on May 26, 2019, 10:20:38 PM
Great contributions Sark .. but could you please up size to 701pixel so that they don't all load together .. and eat up resources unnecessarily  ? Also allowes the viewer a little more control ..  cheers b.c.

I haven't figured out how to correct the scaling & sizing issues of this forum yet, can you be more specific or point me to the right place to read about some better practice?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: b_lumenkraft on May 26, 2019, 10:37:18 PM
I haven't figured out how to correct the scaling & sizing issues of this forum yet, can you be more specific or point me to the right place to read about some better practice?

It took me some time to understand that myself but i think i get it now:

If you post a GIF which is 700 pixels wide or high (or smaller), the forum software would load the GIF automagically without leaving you to decide if you want to download it. This is rather shitty for folks on throttled internet connections.

Now, if you chose to make the GIF 1 pixel wider or higher (701 pixels or more) you need to click it to download. If every GIF in a thread has this (bigger) size, you save data consumption on both sides, Nevens servers and your computer because you only download the GIF you really want to see opposed to all the GIFs in the thread.

If you have a GIF with 700 pixels, you can easily resize it to 701 pixels here >> https://ezgif.com/resize

When a GIF is very small in file size (i.e. less than 1MB), i wouldn't bother resizing, but the GIFs you posted above are very big file size wise. Those would be better if the user could decide if they want to download it ergo they should be 701 pixels.

I hope this makes sense. :) 
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: FishOutofWater on May 26, 2019, 11:42:27 PM
El Niño appears to be fading fast. The excess heat stored in the upper ocean, that drives El Niño, is exhausted.

As the impact of the intense end stratospheric warming fades along with the El Niño, expect weather patterns to shift and heat to build up in the tropical and subtropical Atlantic. The Indian monsoon has been delayed but it could come on with a vengeance because of the heat build up in the north Indian ocean.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: jdallen on May 26, 2019, 11:54:02 PM
El Niño appears to be fading fast. The excess heat stored in the upper ocean, that drives El Niño, is exhausted.
<snip>

Saw some of this elsewhere; the other take away I got from the graphing of sub-surface anomalies was that it doesn't suggest a flip into La Nina, but rather to more ENSO neutral conditions.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on May 26, 2019, 11:56:34 PM
fixed the heavy loading of gifs, thank you for the help
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: b_lumenkraft on May 27, 2019, 08:23:42 AM
I think this belongs here:

Quote
Karsten Haustein has comparisons 'of previous model runs for current forecast time step', and they show that GFS forecast mostly run too hot.
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg201291.html#msg201291

and

Quote
We should be very skeptical about GFS temperature predictions over snow and ice.
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg201291.html#msg201291

The 'Comparison of previous model runs for current forecast time step (model bias)' is here >> http://www.karstenhaustein.com/climate.php#forecast
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on May 27, 2019, 07:33:20 PM
Air temperatures in the Arctic.  This is DJF 1000mb potential temperature.  You'll get the same signal from 1000-850mb for air temperatures.

In the cylindrical view it has the character of a standing wave.  No wonder chaos reigns.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: be cause on May 27, 2019, 08:59:08 PM
Thanks sark and b.lumenkraft .. every little helps to save our planet .. cheers b.c.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on May 28, 2019, 02:36:00 AM
     NOAA's new FV3GFS replacement/upgrade for GFS scheduled to go live on June 24.  This is 3rd scheduled operational date, first delayed by shutdown, then they found a temperature bias issue which needed correction.  I think this time they will actually do it. 

     FV3GFS 1.0 not expected to provide better accuracy right away, but the new platform provides a better foundation for development.  Original plan call for extending hourly runs at 13km resolution from current 10 day limit out to 16 days.  (Current GFS runs at 35km resolution and 3-hour time steps for days 11-16).

   New model will make better use of the awesome new GOES East and West satellites.  (Think color TV vs B&W still pictures).

   A version 2.0 of FV3GFS planned for a year after 1.0 version.  2.0 will bring new physics package.  And about a year after that, timeline shows a possible resolution improvement down to 9km.  Improved ensemble forecast system scheduled for FY2020. No mention of seasonal forecasting until at least FY2023. 

   This all driven by playing catch-up with ECMWF that called Superstorm Sandy path change a day earlier than GFS.  Of ECMWF isn't standing still either.  This is the kind of arms race we need.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on May 31, 2019, 02:17:57 AM
As noted by Sedziobs in #1333 of the 2019 Melt Season forum:
A sneak peek at GFS FV3 running in parallel mode is at
https://www.tropicaltidbits.com/analysis/models/?model=fv3p&region=nhem&pkg=T2ma&runtime=2019053012&fh=6 (https://www.tropicaltidbits.com/analysis/models/?model=fv3p&region=nhem&pkg=T2ma&runtime=2019053012&fh=6)
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 01, 2019, 04:24:31 AM
:0 https://www.tropicaltidbits.com/analysis/models/?model=fv3p&region=nhem&pkg=z500_mslp&runtime=2019053118&fh=0

That's a wave 4
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 01, 2019, 05:58:06 PM
Hour 108 T2anom from the interim GFS-FV3.  I find it interesting that the heat is stacking up right over the two cold poles that have been driving the polar atmosphere to circulate in two parcels.  what this means?

this model produced a wave 8/4 pattern in the final hour of yesterdays 18Z.  forecasters are offering views of wave 6, i dunno.

in my view, this June is going to be extremely chaotic & patterns hard to describe, but 8/4/2 makes sense given the splitness of the polar cell
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 01, 2019, 08:55:59 PM
Incredible FV3-test model run from last night.  These things turn down different paths around hour 150 and derive some pretty wild results.  today's 12Z fv3 is sickening

click to run if you wish
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: jdallen on June 01, 2019, 09:05:09 PM
Incredible FV3-test model run from last night.  These things turn down different paths around hour 150 and derive some pretty wild results.  today's 12Z fv3 is sickening
4 cyclonic heat pumps shoving warm air from lower latitudes into the Arctic Circle.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 02, 2019, 10:16:37 AM
Fast atmospheric response to a sudden thinning of Arctic sea ice

Semmler, T., Jung, T. & Serrar, S. Clim Dyn (2016) 46: 1015. https://doi.org/10.1007/s00382-015-2629-7

https://link.springer.com/article/10.1007/s00382-015-2629-7

https://link.springer.com/content/pdf/10.1007%2Fs00382-015-2629-7.pdf

In order to understand the influence of a thinner Arctic sea ice on the wintertime atmosphere, idealized ensemble experiments with increased sea ice surface temperature have been carried out with the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts.

The focus is on the fast atmospheric response to a sudden “thinning” of Arctic sea ice to disentangle the role of various different processes. We found that boundary layer turbulence is the most important process that distributes anomalous heat vertically. Anomalous longwave radiation plays an important role within the first few days before temperatures in the lower troposphere had time to adjust. The dynamic response tends to balance that due to boundary layer turbulence while cloud processes and convection play only a minor role. Overall the response of the atmospheric large-scale circulation is relatively small with up to 2 hPa in the mean sea level pressure during the first 15 days; the quasi-equilibrium response reached in the second and third month of the integration is about twice as large. During the first few days the response tends to be baroclinic in the whole Arctic. Already after a few days an anti-cyclonic equivalent-barotropic response develops over north-western Siberia and north-eastern Europe. The structure resembles very much that of the atmospheric equilibrium response indicating that fast tropospheric processes such as fewer quasi-barotropic cyclones entering this continental area are key opposed to slower processes such as those involving, for example, stratosphere-troposphere interaction.


Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 03, 2019, 12:12:47 AM
Jennifer Francis discussing jet stream in 2017

timestamp 2255 (37:35)

https://www.youtube.com/watch?v=wtmuBoolHQg&t=2255
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Alphabet Hotel on June 03, 2019, 12:32:29 AM
Incredible FV3-test model run from last night.  These things turn down different paths around hour 150 and derive some pretty wild results.  today's 12Z fv3 is sickening


That high just sits there for the whole run. Is there somewhere I can find an explanation for that?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 03, 2019, 12:59:15 AM

Recent Arctic amplification and extreme mid-latitude weather
https://www.nature.com/articles/ngeo2234

Impact of sea ice cover changes on the Northern Hemisphere atmospheric winter circulation
https://www.tandfonline.com/doi/abs/10.3402/tellusa.v64i0.11595

Stratospheric response to Arctic sea ice retreat and associated planetary wave propagation changes
https://www.tandfonline.com/doi/abs/10.3402/tellusa.v65i0.19375

Amplified Arctic warming and mid‐latitude weather: new perspectives on emerging connections
https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.474

Evidence linking Arctic amplification to extreme weather in mid‐latitudes
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL051000

Weakening of the stratospheric polar vortex by Arctic sea-ice loss
https://www.nature.com/articles/ncomms5646?cmpid=newscred

Go to Google Scholar and key in Jennifer Francis, Judah Cohen, Jason Furtado, Baek-Min Kim, Kai Kornhuber, Dim Coumou, Stefan Rahmstorf, Potsdam Institute, etc etc.

Best briefing available is to read the papers if there isn't an academic lecture available on YouTube

for example:

Stratosphere-troposphere coupling across timescales - Jason Furtado
https://www.youtube.com/watch?v=gm1Pi3sXPQM&t=1531s

Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 03, 2019, 01:15:42 AM
Long story short?  The cold is pulled away from the Arctic ocean and over the land.  Mirrored by atmospheric circulation.  This much is obvious.  Why that's the case .. ??  The literature points to the thinning sea ice.

Nobody expected the blocks from E-W to show up like they have and cause this much trouble, this early.  In fact, nobody has come out and said much about what's happening now.  But I am not a scientist.  I'll say it:  Earth's northern polar cell is failing.  This looks like the abrupt scenario.

You be the judge.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: bbr2314 on June 03, 2019, 01:35:04 AM
Long story short?  The cold is pulled away from the Arctic ocean and over the land.  Mirrored by atmospheric circulation.  This much is obvious.  Why that's the case .. ??  The literature points to the thinning sea ice.

Nobody expected the blocks from E-W to show up like they have and cause this much trouble, this early.  In fact, nobody has come out and said much about what's happening now.  But I am not a scientist.  I'll say it:  Earth's northern polar cell is failing.  This looks like the abrupt scenario.

You be the judge.
I think you are correct but I don't think it's exactly accurate to say the polar cell is failing -- the *single* polar cell system is now changing into a state where we have two smaller continental polar cells centered over North America and Eurasia, with increasing dominance of the NAmerican cell (IMO).

So, yes, the single-polar-cell system is failing, but we still have polar cells, they are just centered in abnormal locations and are now advecting heat into the High Arctic instead of dissipating heat entering the High Arctic (at least, advection is now occurring more often than dissipation).
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 03, 2019, 01:45:36 AM
Hahaha.  Ok
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Alphabet Hotel on June 03, 2019, 06:28:11 AM
Someone just posted this on Twitter. Frost and freeze warning around the Great Lakes tonight. I'm not sure if this is the right place for it.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Dharma Rupa on June 03, 2019, 07:56:05 PM
So, yes, the single-polar-cell system is failing, but we still have polar cells, they are just centered in abnormal locations and are now advecting heat into the High Arctic instead of dissipating heat entering the High Arctic (at least, advection is now occurring more often than dissipation).

WACCy weather.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 03, 2019, 09:47:02 PM
In the model runs (look at fv3 hour 200-262 from today 06z!)  The high pressure incursions are traveling CCW about Hudson Bay, incursions from the Atlantic are blowing right through the polar cell and exciting on the other side of the planet

Similar story on the Scandinavian block

The ridiculously resilient ridge and Scandinavian block are meeting at the North Pole

So far it has been exaggerated by the models and reality has seen the polar front remaining intact even when the ridge pushed above 80N and fed out anticyclones over the North Pole.  Instead of such sharp features derived by the model you see reality much more diffuse and maybe not as severe--but still

We do not have words for what is happening, so I will defer to one of the greats

https://www.youtube.com/watch?v=s86K-p089R8
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 04, 2019, 05:29:30 AM
James G Anderson

watch this interview.

https://www.youtube.com/watch?v=Y12P76EYQJ8
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 04, 2019, 07:13:18 AM
For the past 1-2 days, none of the models can decide where the next block comes from.  I hope this means the polar front stays intact

however a few runs have given a very high (360 meter plus) 500mb anomaly within 240 hours, something i've not seen since February-March

must be lining up with some wave action?  none can decide where it shows up

these blocks ripping through the jet stream into the arctic / ridges pinching off highs in the arctic / jet stream amplitude causing accelerated arctic warming... whatever has been happening more and more over the past 18 months

STILL is showing no sign of changing pattern.  Already looks like a lot of summer outlooks are going to be invalidated.  it just keeps getting worse and worse and worse
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: binntho on June 04, 2019, 07:32:08 AM
These forecasts are more than ten days out - might mention that in the text.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 04, 2019, 07:42:21 AM
I think you are correct but I don't think it's exactly accurate to say the polar cell is failing -- the *single* polar cell system is now changing into a state where we have two smaller continental polar cells centered over North America and Eurasia, with increasing dominance of the NAmerican cell (IMO).

So, yes, the single-polar-cell system is failing, but we still have polar cells, they are just centered in abnormal locations and are now advecting heat into the High Arctic instead of dissipating heat entering the High Arctic (at least, advection is now occurring more often than dissipation).

I think I understand what you're saying..  is it like the pattern of "polar cell" has become more chaotic? 

What traces would this leave on a chart?  I'm seeing a lot of 500mb & even some 250mb easterly winds.  When the jet stream breaks in the Arctic and leaves an in intense anti-cyclone, it often moves in retrograde.  I bet that would look good on a map... but which one?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 04, 2019, 08:03:23 AM
These forecasts are more than ten days out - might mention that in the text.

i am not a scientist <-- it says it right here.  of course they are.  the topic of the thread ends with "long range weather forecasting".  You know, just like summer outlooks, CFS, CanSIPS, RCPs, and millions of conversations about next year, none of which are splashed with warnings about uncertainty in the 10 day forecast

I'm not responsible if you show up with an umbrella when it's sunny out.  But that granular focus to which 5, 8, 10 day uncertainty applies is not relevant to the topic.  I'd rather see a model fail and stipple out on something it can't grapple with so I can think about that and observe how whatever patterns it was projecting actually play out in real life

this isn't an observational science to me.  this is runaway climate change.  whatever climate & weather communications thus far have resulted in the US being record breaking short corn going into a planting season with no prospect of better conditions coming

Quote
In 1930 and early 1931, the Oklahoma and Texas panhandles were known as the most prosperous regions in the nation. For plains farmers, the decade opened with prosperity and growth. But in the summer of 1931, those farmers would face the most difficult eight years of their lives.... The rain simply stopped.

https://www.u-s-history.com/pages/h1583.html

Maybe you don't realize it yet.  I'm safe saying the US corn yield will be down 20-30% in 2019

and that's just the tip of the iceberg

All I'm doing is seeing the truth and telling it like it is.  I'm clearly not playing scientist.  I'm trying to figure things out, do I buy my family food or air filters?  do I move?  Because I want to do that before the rush.

While we still have time I'm going to use my intelligence to figure out exactly how this thing is swinging, with or without this forum.  Please help examine the models & present conditions & reanalysis so the developing catastrophic situation can be understood

that's the last I'll say about it.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: binntho on June 04, 2019, 08:04:51 AM
These forecasts are more than ten days out - might mention that in the text.

i am not a scientist <-- it says it right here.  of course they are.  the topic of the thread ends with "long range weather forecasting".

Sorry - I was being stupid ...
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 04, 2019, 08:18:00 AM
I'm scared.  We're seeing an inability to adapt to minor stuff.  This thing has been coming on & growing for over 18 months.  We saw it in November 2016, and in November 2018 it accelerated even more.  Nobody's talking about it, why?  Are we afraid of being laughed at or ran out of town? 

You're not stupid.  You're just supporting the orderly process of discussion and discovery that worked great when we weren't in a catstrophe.

It's not scientists responsibility to fight for our lives, it's people like me who can see it... who don't have a responsibility to science, but have a responsibility to our family & communities... it's we who need to stand up and start understanding and talking about this.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Rodius on June 04, 2019, 09:05:27 AM

It's not scientists responsibility to fight for our lives, it's people like me who can see it... who don't have a responsibility to science, but have a responsibility to our family & communities... it's we who need to stand up and start understanding and talking about this.

This is a very good point.
The general public are the ones responsible for forcing the adaptions we need to save ourselves. And we all can do our small part. For me, I no longer care if people think I am paranoid of negative, I simply ask people questions and go from there while providing the supporting information when required.

I really dont know what else can be done given the reluctance for change.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 05, 2019, 08:48:12 AM
https://www.tropicaltidbits.com/analysis/models/?model=fv3p&region=nhem&pkg=z500_mslp&runtime=2019060418&fh=0

Actually a calmer looking projection in that run.  Models flip flop between continued high polar cap height anomaly and some calming, well under 240 hrs before the next block either bobs into the Arctic, or the polar front stays intact and the pattern shifts

I think I'm gonna go get some corn
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on June 06, 2019, 01:16:35 AM
According to recent study as described by NSIDC Arctic Sea Ice News & Analysis - June 4 edition:
https://nsidc.org/arcticseaicenews/ (https://nsidc.org/arcticseaicenews/)
 
    "While Arctic sea ice extent is declining sharply, it is also highly variable from one year to the next. Scientists from the Max Planck Institute for Meteorology and the University of Stockholm have proposed that this strong variability is closely related to fluctuations in the air temperature above the Arctic Ocean driven by atmospheric heat transport into the Arctic from lower latitudes.
 
      In contrast to previous assumptions, they argue that other factors, such as the ice-albedo feedback, cloud and water vapor feedbacks, and oceanic heat transported into the Arctic together explain only 25 percent of the year-to-year sea ice extent variations. Most of the sea ice variations are thus directly caused by mid-atmospheric temperature conditions..."
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 07, 2019, 09:28:54 AM
https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=z500a&runtime=2019060618&fh=168

983mb June 12th, forecast hour 132

We're making GFS great again
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: be cause on June 07, 2019, 09:52:32 AM
'983mb' .. does my LAC become a GAC ? or is our new GFS as wild on deepening lows as the old was at overheating the Arctic ? .
  I do wish TTb's maps ( and Windys ) came with fewer isobars .. Highs look like lows and lows look like hurricanes to those who grew up with 4 isobar spacings .. b.c.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Sterks on June 07, 2019, 03:24:52 PM
'983mb' .. does my LAC become a GAC ? or is our new GFS as wild on deepening lows as the old was at overheating the Arctic ? .
  I do wish TTb's maps ( and Windys ) came with fewer isobars .. Highs look like lows and lows look like hurricanes to those who grew up with 4 isobar spacings .. b.c.
No but it’s going to give a stir to the blocks floating around.
All in all the forecast, I think, has improved, but there’s a general circulation around Greenland that does not go away. Who knows how persistent. (Hey its a non-rhetorical question: who knows?)
And in any case expect big roast in Laptev Sea and Siberian coast in general, as well as CAA surface melting.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 07, 2019, 09:47:11 PM
Dr Judah Cohen has updated the AER blog June 7:

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

Continued northern blocking predicted by GFS ensemble rolling forward

*edit how do I make a chart like this?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on June 09, 2019, 12:20:49 AM
    I just read about yet another feedback mechanism I was not previously aware of:
      ' Freshly melted ice ... creates a layer of cold water that protects sea ice above from more melting.   "It isolates the ice from the hot devil water sitting at the bottom waiting to come up" Wagner explains.  Less sea ice means there will be less of that protective cold layer, leading to even more melting. '
https://www.cnn.com/2019/06/08/world/arctic-beneath-ice-intl/index.html (https://www.cnn.com/2019/06/08/world/arctic-beneath-ice-intl/index.html)

     Which got me thinking it would be useful to have an inventory of all the significant reinforcing ("positive") and suppressive ("negative") feedbacks that affect Arctic sea ice.

    I did not find any forum title where this would fit, but this section seems to be the most closely related topic.  It could require its own thread, similar to the Glossary.

Here is the kind of list I have in mind:

Reinforcing feedbacks:
1. Melted ice creates cold layer that insulates remaining ice from warmer subsurface water.  Less ice to melt reduces this insulating layer.  Which leads to even less insulating cold layer water.

2. Less ice leaves darker ocean water with lower albedo, thus energy from solar radiation is absorbed into water instead of reflected.  Warmer water leads to less ice.

3.  Overall, fractured ice is more mobile and thus more susceptible to being exported via Fram Strait or Nares Strait.  There is chance of an ice bridge to block export via Nares Strait with fractured, reduced ice cover.  Increased export results in less multi-year thick ice, and more mobile young ice the next year.

4.  Fractured or thin sea ice floes have more surface area per unit volume and therefore melt at lower temperatures than thicker ice, or larger ice floes.  This leads to less surviving ice the summer to become thicker multi-year ice.

5.  Fractured vs. contiguous ice allows more wave action that interferes with freezing of ice and allows wave action to break ice into smaller pieces less resistant to melt.  Resulting in more fracturing of the remaining ice and even more wave action.

6.  Albedo reduction by replacing ice with dark water leads to warmer water and more energy in the Arctic Ocean system.  That in turn increases frequency, intensity, or both, of cyclones causing wave action that break up ice. Which reduces albedo even further.

7.  Weakening of the Polar Cell results in more frequent occurrence of Arctic Dipole, that increases export of ice out of the Arctic, which lowers Arctic sea ice, which leads to warm Arctic Ocean water, which leads to further weakening of the Polar Cell.  (whew, that's a long chain)

8.  Loss of ice cover weakens the polar cell which in turn allows more incursion of of warm moist air masses from the south into the Arctic, which leads to more weakening of the polar cell.

9.  Weakening of the polar cell allows more cyclonic systems to move into the Arctic.  Those cyclones disrupt the Arctic sea ice, and in doing so further weaken the polar cell.

10.  Younger, thinner ice has higher salt content and thus lower melt temperature.  Therefore it has less chance of surviving the summer melt to become more resistant, thicker multi-year ice.

11.  Reduced snow cover allows earlier spring warm up of Arctic land mass, which results in warmer air flowing onto the Arctic Ocean. This warms the system as a whole, leading to reduced snow cover and earlier snow loss the following year. 

12.  More open ocean leads to higher humidity and more extensive or thicker cloud cover over the Arctic Ocean in the fall and winter.  More extensive or thicker cloud cover in fall and winter reduces heat loss thus reduces winter refreezing.

13.  Earlier spring warm up of Arctic land mass, results in increased permafrost and land ice thaw, resulting in earlier and more melt water flowing from land into the Arctic Ocean. The meltwater warms the Arctic Ocean and reduces Arctic sea ice.  Which leads to more open water with lower albedo to absorb solar radiation in the summer, increasing summer heat content of the system  More open water allows this heat to escape to moderate winter air temperatures and earlier spring warm up.

14.  Reduction of Arctic sea ice allows increased flow of warmer Pacific or Atlantic water into the Arctic, leading to further decline of Arctic sea ice, leading to more Pacification and Atlantification of the Arctic Ocean.

***
Compensatory or Suppressive feedbacks:
1.  Ice cover insulates the Arctic Ocean in winter.  With less sea ice cover there is faster energy loss and winter cooling, and thus faster winter ice increase after a lower September minimum extent.

2.  Thin ice grows much faster than thick ice.  Thus faster winter ice increase compensates for thinner ice after a strong melt season. 

3.  More open ocean leads to higher humidity and more extensive or thicker cloud cover over the Arctic Ocean in the summer.  More extensive or thicker cloud cover in summer reflects more solar radiation and thus reduces summer ice melt.

*****************************

     My wording is no doubt less than perfect for many of these.  Some may be just plain wrong.  Some I just made up!  Maybe I should just find a good book or review article with such a list.  Any suggestions?

   If you think a proposed feedback is incorrect or wrongly stated, it would helpful to have that noted.  But I'm not looking to start multiple debates about which feedbacks are most important. 

      I don't get a commission for each new proposed feedback, so there's no need to get heated.  The planet is hot enough as it is.  These are just suggested entries.  There must be suppressive feedbacks missing from the list.

   I just thought a list would be interesting because I keep finding out about feedbacks I had not previously been aware of. 




Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: wili on June 09, 2019, 02:42:35 AM
I have been more or less obsessed with feedbacks since I first understood their significance. These are a good start for this region. For now, I'll just also point out that more open water in the Arctic allows for bigger waves to form, which in turn can more easily churn up whatever ice (or slush) is left.

The larger amplitude waves may also lead to churning of that lower strata of warmer, saltier water up toward the surface. Both of these processes of course melt more ice, creating more open water, allowing for bigger and bigger waves...

We are probably mostly now past this stage, but I suspect that a few years ago, a 'flash melt' event we had was exacerbated by the fact that some old ice as it broke up formed icebergs, some of which went down to considerable depths. When high winds hit the top of these, their much deeper and bigger sub-sea bodies would sway back and forth, churning that deeper, warmer strata up toward the surface.

This is just my theory, and we now will see very little of this, except from icebergs calved from glaciers, since nearly all of the thick old ice is now gone.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Bruce Steele on June 09, 2019, 05:53:31 AM
This list by ASLR on the Blue Ice thread #7 May 15 , 2016 includes fresh water flushing and the slowdown in the MOC. This results in less carbon sequestration into bottom or deep water.

- Resource extraction (oil, gas, coal, iron etc) will increase.
- Both wave action & Ekman Pump action will increase the bottom water temperatures in the East Siberian Arctic Shelf, which will increase methane emissions from hydrate decomposition.
- Permafrost decomposition will accelerate; which will increase both CO2 and CH4 emissions.
- Boreal wildfires will increase (like in Fort McMurray only further north and worse).
- The atmospheric thermal gradient will decrease, which will decrease the constraints on the Jetstream, which will increase blocking events which will increase extreme weather events.
- Warming over Greenland will accelerate, which will increase ice mass loss & associated SLR.
- The specific humidity in the Arctic will increase, and as water vapor is a GHG, this will increase Arctic Amplification; which will decrease snow cover that will act as a positive feedback for more warming due to decreasing albedo.
- Shrub growth in the tundra will increase, which will also act as a positive feedback for more warming by decreasing albedo in the tundra.
- Pests will more further north, which will attack boreal forests and tundra shrub growth.
- Ground burrowing animals (like ground squirrels) will more north, which will accelerate permafrost degradation.
- Farmland will more northward, which will decrease albedo and will accelerate permafrost degradation.
- Plankton growth will accelerate in the Arctic; which will be smaller in size than the current average, which will sequester less carbon.
- The thermohaline  circulation (great oceanic conveyor) will both slow and will also convey more warm into the Barents/Kara Sea areas.

There are many other positive feedbacks (like Hansen et al (2016)'s ice-climate feedback), but I need to do my shopping.

Best,
ASLR
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 10, 2019, 02:28:33 AM
don't forget Whales & Dolphins that might show up & drive up shoaling of deep ocean water.  I wanted to include Biology and Chemistry in the topic.  I'd rewrite for a new topic if anyone has a better heading.  I'm reminded of a book

https://en.wikipedia.org/wiki/Superforecasting

https://www.gjopen.com/ - put yourself to the test
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on June 10, 2019, 10:43:10 PM
     Stepping away from the feedback discussion (I'm still hoping for more suggestions or critques), here is an abstract I bumped into today that is entirely in sync with the thread topic.

Multiweek Prediction Skill Assessment of Arctic Sea Ice Variability in the CFSv2
Liu, Yanyun; Wang, Wanqiu; Kumar, Arun. Weather and Forecasting; Boston Vol. 33, Iss. 5,  (Oct 2018): 1453-1476. DOI:10.1175/WAF-D-18-0046.1
Publisher logo. Links to publisher website, opened in a new window.

Abstract
     "Skillful Arctic Sea ice prediction is becoming increasingly important because of its societal, industrial, and economic impacts over the polar regions and potential influence on lower-latitude weather and climate variability. In this work, we evaluate the multiweek forecast skill of Arctic sea ice using the Climate Forecast System, version 2 (CFSv2). To the authors’ knowledge, this is the first effort to diagnose and assess the skill of multiweek Arctic sea ice prediction from a coupled atmosphere-ocean model. Analysis of a suite of retrospective 45-day forecasts spanning 1999-2015 shows that CFSv2 captures general features of sea ice concentration (SIC) variability.

    Total SIC variability is dominated by interannual variability, which accounts for more than 60% of the total variance. Submonthly variability accounts for 29% of the total variance in December, 20% in March and June, and 12.5% in September. We assess the ability of CFSv2 to predict the pan-Arctic SIC, as well as regional SIC in nine Arctic regions. Results show that the SIC prediction skill is highly region dependent (e.g., higher prediction skill for Kara/Barents Seas and lower for the Canadian Archipelago). Overall, the maximum anomaly correlation coefficient (ACC) of SIC for both melt and freeze-up seasons is near the marginal zones, and their spatial distribution shows a relationship with the distribution of the variance. If the ACC of 0.5 is taken as the critical value for skillful prediction, the predictability of weekly SIC near the marginal zones is about 5-6 weeks. Prediction skill for Arctic sea ice extent is above 0.6 for the entire six target weeks and has a large contribution from interannual variability."
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 21, 2019, 09:13:51 PM
Dr Judah Cohen has published an update to the AER blog.  Forecast ensemble sees a continued cooling in upper level polar cell with continued troposphere warmth into the first weeks of July.

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

I was really hoping this pattern would break as soon as the snow melted of land
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: FishOutofWater on June 23, 2019, 04:58:00 AM
Ocean heat is impinging on the Arctic from both the Atlantic and Pacific sides. That's what's intensifying the warm Arctic cold continents pattern. Blocking highs tend to form over the oceans at preferred locations near 0 and 180 degrees. This leads to increased heat transfer from the Atlantic and Pacific ocean heat sources to the arctic atmosphere. This situation weakens the polar vortex and  causes WACCy weather. I wouldn't call it the failure of the polar cell, but the polar circulation is increasingly being disrupted by heat advected from the Atlantic and Pacific oceans.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on June 24, 2019, 02:01:23 AM
Fish - Is there precedent for Atlantic ocean heat intrusion meeting up with Pacific side?  Any chance of that happening this year?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on June 24, 2019, 03:52:35 AM
I think you are correct but I don't think it's exactly accurate to say the polar cell is failing -- the *single* polar cell system is now changing into a state where we have two smaller continental polar cells centered over North America and Eurasia, with increasing dominance of the NAmerican cell (IMO).

So, yes, the single-polar-cell system is failing, but we still have polar cells, they are just centered in abnormal locations and are now advecting heat into the High Arctic instead of dissipating heat entering the High Arctic (at least, advection is now occurring more often than dissipation).

Pretty much how I see it.  Except there's sort of a third polar cell going on, often over Sea of Okhotsk.

I love this video of a winter PV split

https://www.youtube.com/watch?v=aOlmDvYn3Fc
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: uniquorn on June 24, 2019, 09:56:39 PM
Quote
I love this video of a winter PV split
So do I. How do you make one?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: Glen Koehler on June 28, 2019, 08:08:32 PM
RE post #2751 about albedo in the 2019 Melt Season thread

Radiative Heating of an Ice‐free Arctic Ocean
Kristina Pistone Ian Eisenman V. Ramanathan
First published: 20 June 2019
https://doi.org/10.1029/2019GL082914

"During recent decades, there has been dramatic Arctic sea ice retreat. This has reduced the top‐of‐atmosphere albedo, adding more solar energy to the climate system. There is substantial uncertainty regarding how much ice retreat and associated solar heating will occur in the future. This is relevant to future climate projections, including the timescale for reaching global warming stabilization targets. Here we use satellite observations to estimate the amount of solar energy that would be added in the worst‐case scenario of a complete disappearance of Arctic sea ice throughout the sunlit part of the year. Assuming constant cloudiness, we calculate a global radiative heating of 0.71 W/m2 relative to the 1979 baseline state. This is equivalent to the effect of one trillion tons of CO2 emissions. These results suggest that the additional heating due to complete Arctic sea ice loss would hasten global warming by an estimated 25 years."

Trillion tons CO2, i.e. about 25 years of current annual global emissions.  That's just a theoretical benchmark number of course, we are a long way from Arctic being ice free all summer.  But every portion thereof adds another slice of warming energy. 

Same authors did an earlier, more practical study:
Observational determination of albedo decrease caused by vanishing Arctic sea ice
Kristina Pistone, Ian Eisenman1, and V. Ramanathan
322–3326 | PNAS | March 4, 2014 | vol. 111 | no. 9
www.pnas.org/cgi/doi/10.1073/pnas.1318201111


"The decline of Arctic sea ice has been documented in over 30 y of
satellite passive microwave observations. The resulting darkening
of the Arctic and its amplification of global warming was hypothesized
almost 50 y ago but has yet to be verified with direct
observations. This study uses satellite radiation budget measurements
along with satellite microwave sea ice data to document
the Arctic-wide decrease in planetary albedo and its amplifying
effect on the warming. The analysis reveals a striking relationship
between planetary albedo and sea ice cover, quantities inferred
from two independent satellite instruments. We find that the Arctic
planetary albedo has decreased from 0.52 to 0.48 between 1979
and 2011, corresponding to an additional 6.4 ± 0.9 W/m2 of solar
energy input into the Arctic Ocean region since 1979. Averaged
over the globe, this albedo decrease corresponds to a forcing that
is 25% as large as that due to the change in CO2 during this period,
considerably larger than expectations from models and other less
direct recent estimates. Changes in cloudiness appear to play
a negligible role in observed Arctic darkening, thus reducing
the possibility of Arctic cloud albedo feedbacks mitigating future
Arctic warming."

Note that study period ended in 2011.  After 2019 easy to think that 25% could be up to 30%.

Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on July 04, 2019, 03:03:21 AM
Scary storm fires up off thunderstorm activity in the GFS, hour 70-180
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: wdmn on July 04, 2019, 03:23:54 AM
What am I looking at here? Green is rain? Am I looking at the part over the lower Great Lakes St. Lawrence?
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on July 04, 2019, 06:28:13 AM
That's the Eastern US and East Atlantic. Click to run gif.  Midlats cyclone headed north up the Eastern seaboard in hour 70+


Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: b_lumenkraft on July 04, 2019, 07:37:17 AM
Sark, there is no GIF. :P
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: jdallen on July 04, 2019, 08:42:20 AM
Scary storm fires up off thunderstorm activity in the GFS, hour 70-180
I'm just hoping for a Thunderstorm in DC just in time for the parade.
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: sark on July 04, 2019, 07:16:38 PM
Storm granted

https://twitter.com/capitalweather/status/1146790127169150976?s=19
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: vox_mundi on July 04, 2019, 07:31:54 PM
^ +1 ... LMAO
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: jdallen on July 04, 2019, 08:42:03 PM
^ +1 ... LMAO

Ditto.  My Schadenfreude meter just pegged itself.  ;D  XD XD XD
Title: Re: Atmospheric connections, structure, and long range weather forecasting
Post by: vox_mundi on July 08, 2019, 11:05:34 PM
Indian Ocean Causes Drought and Heatwaves in South America
https://phys.org/news/2019-07-indian-ocean-drought-heatwaves-south.html

New research has found the record-breaking South American drought of 2013/14 with its succession of heatwaves and long lasting marine heatwave had its origins in a climate event half a world away—over the Indian Ocean.

(https://media.springernature.com/w685/springer-static/image/art%3A10.1038%2Fs41561-019-0393-8/MediaObjects/41561_2019_393_Fig5_HTML.png)

It all started with strong atmospheric convection over the Indian Ocean that generated a powerful planetary wave that travelled across the South Pacific to the South Atlantic where it displaced the normal atmospheric circulation over South America.

"The atmospheric wave produced a large area of high pressure, known as a blocking high, that stalled off the east coast of Brazil," said lead author Dr. Regina Rodrigues.

"The impacts of the drought that followed were immense and prolonged, leading to a tripling of dengue fever cases, water shortages in São Paulo, and reduced coffee production that led to global shortages and worldwide price increases."

That impact wasn't just felt on land as the high-pressure system stalled over the ocean.

"The result of this blocking high was an unprecedented marine heatwave that amplified the unusual atmospheric conditions and likely had an impact on local fisheries in the region."

(https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41561-019-0393-8/MediaObjects/41561_2019_393_Fig3_HTML.png)

... The 2013/14 South American drought and marine heatwave is the latest climate case study to show how distant events in one region can have major climate impacts on the other side of the world.

"Researchers found that Australia's 2011 Ningaloo Nino in the Indian Ocean, which completely decimated coastal ecosystems and impacted fisheries, was caused by a La Niña event in the tropical Pacific," said Australian co-author Dr. Alex Sen Gupta.

"Here we have yet another example of how interconnected our world is.

Regina R. Rodrigues, et.al., Common cause for severe droughts in South America and marine heatwaves in the South Atlantic (https://www.nature.com/articles/s41561-019-0393-8), Nature Geoscience (2019).

------------------------------------

Summer Eurasian Nonuniform Warming Found Related to the Atlantic Multidecadal Oscillation
https://phys.org/news/2019-07-summer-eurasian-nonuniform-atlantic-multidecadal.html

(https://3c1703fe8d.site.internapcdn.net/newman/csz/news/800/2019/summereurasi.jpg)

"Previous studies indicate the Eurasian nonuniform warming since the mid-1990s may be related with the phase shift of the AMO, and we validate this point by using ensemble experiments with three AGCMs [atmospheric general circulation models]," the lead author says. "The overall consistency among the three AGCMs illustrates the robustness of the AMO's influence, although the models are not the most recent updated versions," she adds.

The authors diagnose the underlying mechanism of the AMO's influence on the Eurasian nonuniform warming from the perspective that the boundary forcing modulates the intrinsic atmospheric variability. The results highlight the role of the Silk Road Pattern.

"The AMO-related tropical diabatic heating anomaly excites the Silk Road wave-train over Eurasia with positive geopotential height and anticyclonic circulation anomalies over Europe-West Asia and Northeast Asia, but negative geopotential height and cyclonic circulation over Central Asia. Such opposite circulations lead to opposite changes in temperature advection, precipitation, cloud cover and solar radiation. When these effects overlap the signals of global warming, it causes amplified warming," the authors explain.

Xueqian Sun et al, Simulated Influence of the Atlantic Multidecadal Oscillation on Summer Eurasian Nonuniform Warming since the Mid-1990s (https://link.springer.com/article/10.1007%2Fs00376-019-8169-z), Advances in Atmospheric Sciences (2019)