18 July and the end of a spell

Having had some advice about making animations in Gimp, it occurred to me that the BoM charts are saved as .png images -a format I have found far better for animating the Tornado charts of NWS.

So I compiled this:

18 July 2014.BoM mslp-precipAs you can see there is only one chart with the correct colour:

18 July 2014.IDY20001.mslp-precip.006Time to get some more help I believe.

***

Here is the same chart animation converting the constituent charts to .jpg formatted images before construction:

18 July 2014.BoM mslp-precip

Problem solved. Click on the images to  get a larger version (backspace to return.)

***

Meanwhile the only interesting development on this chart is the dark mass south of Cape of Good Hope. It pretty nearly fills the smaller section of Antarctica. It decomposes tonight pretty much the same time as a cyclone on the opposite shore, under Australia (Midnight 19 July 2014.)

Another dark cyclone replaces that in a very few hours. I believe that that one is going to be just as interesting; how, I don’t know. Probably a long due eruption or just as likely, a tornado cell. Maybe even a small line storm although there is very little signalling of any of that on any of the other charts I look at.

There is nothing on the Atlantic charts to warn of any danger and the NA EFS is entirely blank. Here is midnight’s Met Office&Climategate chart for the 18th July 2014:

18 July 2014.FSXX00Originally stored as .jpg formats, I am pleased to see these have animated nicely.

Here are the individual charts -showing an interesting lack of development:

18 July 2014.FSXX00T_00

 

 

 

 

18 July 2014.FSXX00T_12

18 July 2014.FSXX00T_24

18 July 2014.FSXX00T_36

18 July 2014.FSXX00T_48

18 July 2014.FSXX00T_60

18 July 2014.FSXX00T_72

18 July 2014.FSXX00T_84

They run from Midnight on the 18th (t+00) to noon on the 21st July 2014 (t+84.)

What is interesting is that although there is a murderously severe super-typhoon killing people in the Philippines, there is no sign of the wave harmonic that usually goes with such phenomena. There is no large cyclonic system in the North Atlantic.

It was there recently and it comes back again in the later charts but as of today… nothing.

This has also “not” happened in the past (also with an anticyclonic spell such as this.) I believe it “didn’t” happened just a few days ago.

Thought so:

7 July 2014.FSXX00T

 

 

 

 

And here for a more deliberate perusal:

7 July 2014.FSXX00T_00

7 July 2014.FSXX00T_12

7 July 2014.FSXX00T_24

7 July 2014.FSXX00T_36

7 July 2014.FSXX00T_48

7 July 2014.FSXX00T_60

7 July 2014.FSXX00T_72

7 July 2014.FSXX00T_84

A similar occasion too: Neoguri:

19.70  129.10 07/06/18Z  130     - SUPER TYPHOON-4
20.40  128.20 07/07/00Z  135     - SUPER TYPHOON-4
21.60  127.30 07/07/06Z  135     - SUPER TYPHOON-4
22.50  126.80 07/07/12Z  130     - SUPER TYPHOON-4

http://weather.unisys.com/hurricane/w_pacific/2014/NEOGURI/track.dat

Here is the period for Ramassun (still active at the time of writing) as a Cat 4:

19.10  112.30 07/18/00Z  125     - SUPER TYPHOON-4
19.90  111.30 07/18/06Z  135     - SUPER TYPHOON-4

http://weather.unisys.com/hurricane/w_pacific/2014/RAMMASUN/track.dat

I’m not sure the graphics are required but here they are anyway:

Unisys track of Neoguri

Unisys track of Rammasun

http://weather.unisys.com/hurricane/index.php

I will post comparisons of the other super-storms earlier in the year with the corresponding North Atlantic charts on another thread. But take it from me, whatever causes tropical storms causes a sympathetic Blocking Low off Western Europe at the same time.

***

Now let’s see if we can identify what happened next.

After Neoguri we had a large earthquake. Not an exceptionally large one but in the Mag 7 league for a short while. It was later marked down to a 6.9 I believe:

2014/07/07 @ 11:24 & @ 11:23
17.1N. 91.8 W. 6.2 M. Mexico-Guatemala border
14.8 N. 92.4 W. 7.1 M. Near coast of Chiapas, Mexico.

https://groups.google.com/forum/#!topic/sci.geo.earthquakes/nwmv2RYJKyo

2014/07/07 11:23 14.7 N. 92.4 W. 6.9 Mag. Near coast of Chiapas, Me

http://www.seismo.ethz.ch/eq/latest/index_EN?list=w

So we should be looking at something similar later today as the present super-typhoon turns up its toes.

We’ll see.

What happens with a flaccid spell such as we are enjoying at the moment -a cycle that has been going on for months, is that there is little cyclogenesis going on.

I believe this is due to the declinations of the moon but have little more than a surmise to go on. What is true is that with massive cyclones filling the southern hemisphere (a so called Positive AntArctic Oscillation (called AAO to distinguish it from the Arctic version or AO)) the systems in both the North Pacific and the North Atlantic rarely grow to lavish proportions.

When in more normal cycles of the Pacific and Atlantic, a cyclonic system forms, it can drop down to 950 or 960 millibars quite easily. When such a cyclone goes ashore, in North America or in Western Europe, the constituent parts separate out almost as through filter paper. This is “cyclosis”, the death of cyclones.

At sea, almost as soon as the bulk of the remnant has crossed the continent -even as it pauses on the eastern continental shelf, pressures build up a few millibars at a time, seldom more than 5 millibars a day. These systems seem to need to drop before they can continue. But then they falter again at the Mid Atlantic ridge in particular. The behaviour is not so marked in the Pacific, as that ocean is still relatively young. (Young in the way we refer to rivers, not young in geological terms.)

While there is a marked dissimilarity in the eastern and western floors of the Pacific, at the moment it lacks the divides that the Arctic, Atlantic and the continent of North America enjoy. And hence the flow of air across the North Pacific is somewhat different.

The flow of air across the Atlantic is stifled until the pressure build up or “differential” reaches whatever magic number is required to continue. This is the source if not the cause of the Icelandic Low.

There is a similar phenomena in the North Pacific with the Aleutian chain. And meteorology is more or less identical for both regions. Notably the signals for tornadic activity and the replacement of the flowing cyclones with Blocked Highs before a relatively severe earthquake.

Obviously the pressures required for the normal state of play are very different in Negative and Positive phases of the ocean cycles. But the phenomena are still pretty much identical.

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One thought on “18 July and the end of a spell

  1. > When in more normal cycles of the Pacific and Atlantic, a cyclonic system forms, it can drop down to 950 or 960
    > millibars quite easily. When such a cyclone goes ashore, in North America or in Western Europe, the constituent parts
    > separate out almost as through filter paper. This is “cyclosis”, the death of cyclones.

    From Wikipedia:
    A permanent low-pressure system over Iceland (the Icelandic Low) and a permanent high-pressure system over the Azores (the Azores High) control the direction and strength of westerly winds into Europe. The relative strengths and positions of these systems vary from year to year and this variation is known as the NAO.
    A large difference in the pressure at the two stations (a high index year, denoted NAO+) leads to increased westerlies and, consequently, cool summers and mild and wet winters in Central Europe and its Atlantic façade.
    In contrast, if the index is low (NAO-), westerlies are suppressed, northern European areas suffer cold dry winters and storms track southwards toward the Mediterranean Sea. This brings increased storm activity and rainfall to southern Europe and North Africa.
    https://en.wikipedia.org/wiki/North_Atlantic_oscillation

    Contemporary Meteorology takes averages for the winter months but this condition has covered both the Pacific and the Atlantic for several months now (At least since May 2014.) Conditions are not quite what the above description says. I believe the cause to be the state of the Southern Ocean or AAO. Since the ice started to build up in April, the Antarctic has enjoyed/suffered very large cyclogenesis. Too large to be maintained and they have reached across Australia several times, also broken off on southern Africa, at times, too.
    It remains to be seen how condition will be restored.

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