The presentation of the #ArabianMonsoonBurst has changed dramatically today with the consolidation of activity over the Arabian Peninsula into a single huge storm which is currently moving into the Red Sea over Makkah and Jeddah.

Today's rainfall forecasts follow.
The scale of the storm over Islam's holiest city is huge, larger than France. Two more huge storms loom over the greater region tonight. One on the Iranian Gulf coast and another supercell thunderstorm complex over New Delhi/Rajastan, India, the size of the United Kingdom.
The last six hours in three animations, first India which is experiencing a massive monsoon day today in the north.

[Here the initial frames show a blank SEA as their was a satellite data outage.]
The second animation, day 6 of #ArabianMonsoonBurst, is dominated by a huge #ArabianStorm over Western Saudi Arabia, with relatively minor activity elsewhere, mostly in Yemen and Oman + a massive storm over the northern Gulf and over the Iranian Coast.
And our third covers the #HornOfAfrica, including all of the Nile watersheds, the eastern Sahel and eastern core West African Monsoon.
In summary the #ArabianMonsoonBurst extreme weather event has evolved, in line with forecast structural parameters, but not as predicted when it comes to the location of rainfall. Noticeably the storm over Saudi Arabia is currently experiencing a massive burst of convection.
None of the global models have caught this quite as it seems to be playing out so in terms of forecasts I offer two which seem to have done a fairly good job with the PWAT parameter. Here's the ECMWF version.
The ECMWF forecast is for 10 days.

Here's a shorter (and possibly more reliable) three day high resolution PWAT forecast in three hourly intervals from the CMC.
Today's big picture takes in the greater region and the Sahara as night begins to fall over the Arabian Peninsula and the Horn of Africa.
Today's 10-Day Rainfall forecasts for North Africa from July 18th through July 29th. The #ArabianMonsoonBurst can be seen very clearly on the far right of the four accumulated rainfall forecasts.

All models now show less rain in the Middle East than in yesterday's runs.
48-hour rainfall forecasts (today and tomorrow from our standard four models: the European @ECMWF, @NOAA's GFS, Canada's CMC and the Korean KMA models.

Its safe to say that none of them have got it right.
Finally for #NorthAfrica we have the long-range 16-day (GFS) and 12-day (KMA) forecasts - which (as always) remain remarkably well aligned inspite of the 4 days difference.

[NOTE: We will have a better view of forecasts of the #ArabianMonsoonBurst later in the bulletin.]
Here's an animation of clouds over the Northern Ethiopian, core Nile tributaries which provide 80% of nile flow. With the change in direction of the #ArabianMonsoonBurst it is a little more restrained today, but still very rainy.
Today's July 18th 16-day rainfall forecasts for #Ethiopia (+1 12-day from KMA) and the #HornOfAfrica: #Somalia, #Somaliland, east #SouthSudan, south east parts of Sudan, #Djbouti and #Eritrea.

Purple heaviest rain covers #Tigray, & #Abbay (#GERD) & #TekezeAtbara basins.
48 Hour forecasts (today and tomorrow) from the same three models.
The #ArabianStorm over Saudi Arabia, covering both Mecca and Medina, and presumably bringing rain, this evening has an amazing symmetrical presentation.

#Makkah #Jeddah #Media #KSA

الله أعلم
July 18th 10-Day accumulated rain forecasts for the #MiddleEast from the GFS, CMC, KMA & ACG weather models.


#KSA #Yemen #Oman #Jordan #Sudan #Iran #Syria #GERD #Sudan #DesertRain #UAE

الله أعلم
Our first @ArabStorms image today shows an extraordinary site, a massive river has formed across a major transport corridor in Saudi Arabia.
And here another view of this event (I assume), this time from ground level. [Courtesy of @Arab_Storms]
48 Hour July 18th (today and tomorrow), accumulated rain forecasts for the #MiddleEast from the GFS, CMC, KMA and ACG weather models.


#KSA #Yemen #Oman #Jordan #Sudan #Iran #Syria #GERD #Sudan #DesertRain

الله أعلم
And so it appears the models are expecting another big rain day tomorrow also. In similar areas to today.

This video of a dam spilling, spectacularly in Saudi, via @Arab_Storms, was posted by Saudi Climate Change scientist @ALMISNID.
And finally we have today's long-range #MiddleEast July 18th rainfall forecasts.

The16-day GFS & GEFS models, the 12 day KMA and the 15 day EPS (Euro ensemble) model forecasts.

الله أعلم
This is the latest long-range 16-day precipitable water (PWAT) anomaly forecast for the Middle East. It suggests the event has now reached its peak. But also that significantly unusual weather may continue for some time regardless.
And here is the PWAT simulation data that the previous plot is based on. This suggests a second phase to this monsoon burst activity, albeit this time on the traditional trajectory. West south west, instead of west north west, as we have with this one.
Returning to @Arab_storms videos, here we see a man floating down a river in the back of his ute in #Oman.
Omani flooding looks pretty bad based on @Arab_Storms videos. Here we are back in Saudi Arabia with another huge area of flooding, this time in an urban area.
Also in #SaudiArabia we have this video of a spectacular cataract in full flood.
We now move to a big picture view. North Western Hemisphere zero hour simulation data (i.e. now).

1. Precipitable water PWAT anomaly
2. PWAT (potential rain + energy)
3. MLSP (Mean Sea Level Pressure)
4. 250Hpa (jet stream winds approx 11-15 kms high)
And this is the last plot for today. The North Atlantic GFS Hourly model PWAT 1hr % anomaly for 120 hours, five days. And during that period it looks as if there will be a gathering of waters over the Eastern and Central Sahara.

What that will deliver will be interesting to see.

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More from @althecat

19 Jul
Congratulations to Ethiopia and Ethiopians everywhere on today's completion of the 2nd filling of the #GERD. It has been a great honour to follow along during this moment.

Today's rainfall forecasts for #NorthAfrica, #HornOfAfrica and #MiddleEast follow.
In honour of the #GERD we will change up the order of today's bulletin and get right to the most important issue, rain over the #Abbay basin, which due to its great quantity and consistency made this possible over such a short time period.
But first a brief explanation, as when it comes to the GERD not all rainfall counts. The first image here shows the path of the #BlueNile / #Abbay from Lake Tana to Khartoum where it meets the White Nile and becomes "The Nile".
Read 40 tweets
19 Jul
Today's #FabianPH #INFA, #Olympics, #Olympics2021 disruption update thread.

See yesterday's thread below.

TL/DR: There is a significant typhoon/extreme rainfall threat to Japan in the opening days of the Olympics.
Here's a view of the two storms, #FabianPH / #INFA whose interaction is forecast to produce a 3rd storm in 4 days time which was forecast yesterday to arrive in Tokyo two days after the Olympics opening.

#Olympics, #Olympics2021
In the latest GFS 1hourly simulation model the solution remains the same as of today. A large typhoon like low (in terms of water content) will make landfall in Japan and stay over the country for some time bringing torrential rains during #Olympics2021

#Fabian #FabianPH #INFA
Read 14 tweets
18 Jul
This attached thread from this morn looks at Typhoon #INFA ("In-fa" TS09W) which is poised to be extraordinarily disruptive to the 2021 Olympics in Japan.

It has since come clearer what we can expect from a dangerous and unusual weather system developing over the West Pacific. Image
This is the story of three storms rather than one, but IN-FA will play the starring role.

1. TD10W currently menacing Hong Kong
2. "IN-FA" which is technically still TS09W (fmrl. #invest98w)

& a 3rd storm which models forecast TD10W & IN-FA will bring about in 5 days time. Image
Here's the latest satellite imagery of TD10W (left) and #INFA (right) ImageImage
Read 17 tweets
18 Jul
This killer #EuropeBigWet storm is still packing a punch. Here you see it yesterday over Italy and the Balkans.
And here it is today. It still has a clearly defined circulation over the Adriatic Sea.
This shows the jet stream forecast for today which pretty perfectly matches what we are seeing here from the satellite imagery.

But while the circulation is gone the jet remains. This jet looks like it is going to move into the business of delivering moisture to the Middle East.
Read 5 tweets
18 Jul
A Portrait of Earth's Biosphere

This thread provides a tour of the global biosphere in pictorial form.

The animations were acquired from @zoom_earth on July 14th, and take us on a journey beginning in the North East Pacific over the course of a single day.
The first image ^^ is of North West America.

Here we see the South East Pacific
North East Pacific
Read 24 tweets
18 Jul
There has been a sharp increase in discussion of climate change weather extremes in the context of the flood calamity in Western Europe, wildfires in the North West US, and the #ArabianMonsoonBurst

This thread looks at the big picture right now. What's next?
The image above from @Meteoblue shows most of the Northern Hemisphere & rainfall at the moment. The intense blobs of colour indicate high rainfall from thunderstorms.

What is immediately apparent looking at this is that there is an immediate issue now in the West Pacific.
What will soon be Typhoon In-Ha is forecast to make landfall in Taiwan and then stall bringing massive rainfall to the Philippines, China and Taiwan.

There is second tropical storm to the left of what will soon be In-ha which is simultaneously bringing extreme weather to HK.
Read 9 tweets

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