I have been tracking the cause of the suddenly extreme weather which is currently underway for past month. The immediate cause is described in this thread

There was a precursor event from April 17-19.

This one is a lot bigger.
And it is far from over. There is at least three more days of incoming #WestAfricaWaterPlume
The forecast above is from Europe's main weather forecasting computer model the @ECMWF, one of the two two models in the world.

However it has not been great at modelling what is underway in the Sahara. The 10 day forecast below is from the CMC (Canadian) model which has.
The key take-out from this forecast model is that the flow of water into Europe continues, but weakens after 6 days. Looking at European forecasts over this period enables us to see what the models think will happen. There are four 24 hour snaphots from CMC.
And four corresponding snapshots, 24 hours apart from the @ECMWF model.

[NOTE: All of these images show the picture before the fire hose of water across the Sahara significantly weakens.]
That the models are in agreement is a good sign.

It makes it easier to see what is going on if you watch an animation. This one runs through till May 6th at midday.

It appears that each day there is a burst of water.
There is another important process. Which matches what happened after the earlier smaller event 17-19 April. In the top left. A large mass of cold arctic air comes down over the north Atlantic and the British Isles. Here is the CMC model.
The immediate impact of the Plume is likely to be yet another extension to the period of cold weather. For much of Europe for a week, and for some longer.

This animation shows how much colder it is than the average for this time of year over 10 days.
The two severe weather parameters we have are also looking fairly active, increasing over the 10 day period. Here is the K-Index from the @ECMWF model.
Both weather parameters are associated with the production of thunderstorms and other forms of extreme weather.

The GFS Cape Index is specifically related to thunderstorm potential and it seems to rise considerably over the 10 day period - especially near the Medditerranean.

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More from @althecat

1 May
There is something glorious about the images that @zoom_earth captures. I especially like the large symmetrical and fairly stationary area of cloud in the North Atlantic in this image.

Today's May 1sy Forecasts for #Ethiopia and #MiddleEast rainfall follow.
The main action today was in Europe where the strengthening #WestAfricaMonsoon #WMA has today had a spectacular impact on European Weather.

A detailed thread covering those events can be found here.
Today's North African long range (12 day) rain forecast is taken from the Korean KMA model as it looks to be a lot closer to what we are seeing in the skies today.
Read 13 tweets
1 May
The transformation of #WestAfricanPlume's presentation overnight is extraordinary. It's line has moved 1000kms east. It's still running as hot as last night.

A rough estimate of the speed of the cloud movement last night put it an over 220 kms per hour.
To comprehend the scale of this thing a series of three animations follows.
Africa and Western Europe...
Read 27 tweets
1 May
This #WestAfricaWaterPlume thingamy is ruining May in Europe. /1
The wet Atlantic air is set to make its way up into the arctic and settle a low pressure system over Scandinavia.

Together these two factors result in a continuous flow of cold air from the arctic over Scandinavia and North Sea and the UK.
I spent May 2017 in Glasgow and it was glorious. By the end we were getting 29 degree days and everyone was out in the Botanic Gardens with shirts off.

And in Geneva the past two years it’s been a bit thunderstormy, but only in the afternoon.
Read 4 tweets
30 Apr
Today's #ArabianStorms went in a different direction during the day, but ended up in a familiar place in the end.

Today's #MiddleEast and #Ethiopia #HornOfAfrica rain forecasts follow in the thread below.
In the animation above you can see a flow of clouds from Sudan to Oman. This flow actually originates to the South West in the Central African Republic. Here you see the CAR to Khartoum leg of the journey.
Over the day this stream of moisture intensified powering storms in Oman, which then split into two streams, one heading north over Iran and one to the East to India.
Read 13 tweets
30 Apr
In the world of Africa/Europe/MiddleEast weather today has been quite spectacular, in a new and revealing way. And the star of the show has been the #WestAfricaWaterPlume.

See also.. a thread from this morning....
.. and for a full backgrounder this thread from April 27th.
The plume has now stolen the European stage entering stage left and heading directly towards Moscow. The precipitation animation below is from @Meteoblue. Rain reports are not 100% accurate as they are satellite & not radar driven.

But as for #DesertRain?
There has been a lot.
Read 11 tweets
30 Apr
The #WestAfricaWaterPlume is rather spectacular in its presentation this morning. Roughly the size of Mexico and growing rapidly - a massive river of moisture which has just reached Italy.
This view shows satellite estimations of rainfall. Again the European @ECMWF weather model appears to have massively underestimated this event. Also on the face of what we can see so far it is turning Eastwards - which is not what many models were predicting.
Here are the current ECMWF predictions as of now, at midnight today, and at midnight Saturday and Sunday.
Read 7 tweets

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