Feeding the pigs

Put the Moccus on these Americans that would steal 35 dollars off you and call it a sale:
http://journals.ametsoc.org/doi/full/10.1175/JAS-D-15-0238.1
Purchase 30 days access for $35.00

Let’s see what we can work out from the abstract:

The intrusion of lower-stratospheric extratropical potential vorticity into the tropical upper troposphere in the weeks surrounding the occurrence of sudden stratospheric warmings (SSWs) is examined.

The analysis reveals that SSW-related PV intrusions are significantly stronger, penetrate more deeply into the tropics, and exhibit distinct geographic distributions compared to their climatological counterparts.

While climatological upper-tropospheric and lower-stratospheric (UTLS) PV intrusions are generally attributed to synoptic-scale Rossby wave breaking, it is found that SSW-related PV intrusions are governed by planetary-scale wave disturbances that deform the extratropical meridional PV gradient maximum equatorward.

As these deformations unfold, planetary-scale wave breaking along the edge of the polar vortex extends deeply into the subtropical and tropical UTLS. In addition, the material PV deformations also reorganize the geographic structure of the UTLS waveguide, which alters where synoptic-scale waves break.

In combination, these two intrusion mechanisms provide a robust explanation describing why displacement and split SSWs—or, more generally, anomalous stratospheric planetary wave events—produce intrusions with unique geographic distributions: displacement SSWs have a single PV intrusion maximum over the Pacific Ocean, while split SSWs have intrusion maxima over the Pacific and Indian Oceans.

It is also shown that the two intrusion mechanisms involve distinct time scales of variability, and it is highlighted that they represent an instantaneous and direct link between the stratosphere and troposphere.

This is in contrast to higher-latitude stratosphere–troposphere coupling that occurs indirectly via wave–mean flow feedbacks.

Naughty words escape me!
From the Met Office:

A Sudden Stratospheric Warming (SSW) of the atmosphere refers to a swift jump in temperatures in the stratosphere that is sometimes linked to the onset of cold weather in winter. The term SSW refers to what we observe – rapid warming (up to about 50 ­°C in just a couple of days) in the stratosphere, between 10 km and 50 km up.

Jet streams high up in our atmosphere, in both the northern and southern hemisphere, circumnavigate the Earth from west to east. One of these, the Polar Night Jet, circles the Arctic.

Sometimes the usual westerly flow can be disrupted by natural weather patterns or disturbances in the lower part of the atmosphere, such as a large area of high pressure in the northern hemisphere. This causes the Polar Jet to wobble and these wobbles, or waves, break just like waves on the beach. When they break they can be strong enough to weaken or even reverse the westerly winds and swing them to easterlies. As this happens, air in the stratosphere starts to collapse in to the polar cap and compress. As it compresses it warms, hence the stratospheric warming.

How does it move down through the atmosphere?

As it turns out, waves can only move around the Earth’s atmosphere in westerly winds.[unless there is a volcanic eruption or some other reason.] Fluctuations in our weather send waves up through the atmosphere to the easterly winds in the stratosphere, where they travel no further, and instead break and reinforce the easterly winds, bringing the easterlies lower. This pattern continues until the easterlies have moved down to the troposphere – the lowest part of the atmosphere where our weather is.

It can take anything from a few days to a few weeks for this process to take place.

We normally expect our weather to come in from the west – with a flow of relatively mild air coming in off the Atlantic.

When an SSW brings easterly winds this tends to alter our weather patterns slightly, weakening areas of low pressure and moving our jet stream further south. This leads to high pressure over the North Atlantic, ‘blocking’ that flow of mild Atlantic air and dragging in cold air from the continent to the east. Exactly how cold it might be depends on the details of where the air comes from.

SSWs don’t always result in this outcome – but a cold snap follows more often than not, so the SSW greatly increases the risk of wintry weather.
Can we predict these events in advance?

Currently we can reliably predict individual SSWs about a week in advance, and we can detect them early on with satellite and other observations. This means we have some time to see how they develop and may impact our future weather.

Clear as mud, (Includes hand signals.) https://www.youtube.com/watch?v=1MiUlTthSNA

Here is New Zealand surrounded by warm water so it is going to get cold there in a day or so:
4.png

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-190.84,-34.17,175/loc=176.021,-38.074

http://www.weatherwatch.co.nz/content/weather-video-warm-wednesday-rain-then-a-cold-change

And we all know what that means don’t we children?

Wherever it is and however many volcanic eruptions there are, this stuff will be going on all through tonight’s model run:

14 May 2017

With the last tropical storm out of the way it looks like there is potential for a large earthquake at the same time.

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