Thread by @althecat

Widespread rains have started to fall over Egypt, the Sinai and in Jordan as expected as the active phase of a new #MiddleEast #ExtremeWeather event which is expected to run for the next nine days begins.

This is the 2nd large regional rain event in January.

#ClimateChangeNow.

The event is exactly as forecast, though timing and location of rain fall, particularly heavy rainfall is extremely hard to forecast.

This is the satellite presentation of the event this morning. There are two streams which are delivering rain, now dividing over the Red Sea.

3 hour update to 3.45pm local time. The size of the cloud covered area is now 1.5 million KM2. If past is prologue the heaviest rainfall should be expected over night as the atmosphere cools.

Update of the satellite rainfall picture (over 12 hours) from @Meteoblue this time including the arrival of the northern storm which is expected to play a large part in this event. Note that model rainfall forecasts predicted minimal rainfall over the desert areas of Eqypt.

A near live radar image of rain on the outskirts of Medina Saudi Arabia.

At 6.30pm in the Middle East, light/moderate rain has now moved in to Syria and Iraq and some model forecasts suggest rain this evening and overnight in Jerusalem. The final image here shows cloud extent at 4.15pm local time, before sunset begins.

Quoted tweet shows a summary nine-day advisory of what to expect over the next nine days posted on the 7th.

For the duration I will be posting observation updates on what is happening and model forecast updates.

https://twitter.com/althecat/status/1479179844827160580?s=20

A GEFS [@NOAA GFS Ensemble] forecast shows where the rain is expected to fall each day for the next four days. The first frame shows today.

The longer range forecast is fairly alarming, especially for the mid Saudi, Nth Gulf, Kuwait and Iran mountain areas affected last week.

This plot [Integrated Water Vapour Transport] shows dynamics of of the weather, esp. wrt energy. It combines moisture (expressed in cloud and rain) with wind and MLSP data measured as energy kg/m/s.

Here we see the next seven days. The bright red bit is the cause for concern.

Today the maximum is forecast at 632 kg/m/s. But from the 14th Jan onwards the atmospheric river across the middle of Saudi Arabia is forecast to remain over 600 continuously for five days continuously and peak at close to 987kg/m/s. over South West Iranian mountains on the 17th.

This plot shows what is forecast now to be the very dangerous phase of this a period of 78 hours (3 days) where mass airborn water transport is maintained continuously at a level over 700kg/m/s.

This is today's forecast peak - on 17th January, which occurs as the second atmospheric river collides with the atmospheric river we see now, currently in an early strengthening phase.

For the purposes of expressing the sheer scale of this event which is beginning today this graphic shows the next 10 days.
You see:
1. a beginning burst (underway now)
2. a second wave which arrives around the 13th...
3... and then bursts, whilst merging with 2nd stream

For visualising where all this rain is coming from this graphic is great. A week long PWAT forecast for all of Africa...

Watch how the level of atmospheric water over Sudan bursts beginning today. This should be very obvious in the satellite imagery in coming days.

This is not an #ExtremeWeather event to trifle with, all those in the path of the main stream beginning on Jan 13th in Saudi, the Gulf and Iran need to prepare for unprecedented quantities of rain over following days through to the 19th of January.

These final two animations show a near live view one of the major processes involved in causing this weather, the South American and Atlantic storms which are feeding these atmospheric rivers. A new bust of activity is currently underway.

Here we see a close up of a new Amazonian atmospheric river making landfall on the West African Coast.

P.S. I have just noticed a new contributor to this ME #ExtremeWeather rain event, namely a storm over the Gulf of Guinea. I have previously reported on the role of the Great African Equatorial Forest in this.

This storm sparked up today. Note the outflows to the North East.

This animation shows this storm in context and its outflows (and others from the the great forest) heading north over the course of today.

As of this evening this thunderstorm complex is 33% larger than Greater London at 2000km2.

This visualisation from @Meteoblue shows the rainfall footprint of this remarkable storm.