The jet stream blowing high above Egypt, from the southwest, arcs over the Levant and southern Caspian.

These rivers of air are not always visible, blowing 5,000 metres above the ground.

This one can be observed by the vast number of high clouds it has generated and some rather pretty skies, as seen from the ground.

When the jet stream starts to buckle, it generates deeper clouds and ultimately serious weather.

This has just happened and has brought rain from Sinai to Iran.

At Ras Sedr, a dry town on the shores of the Gulf of Suez, 51mm of rain fell in 24 hours - the average for the whole of February is 2mm.

This rate of rainfall brings flash-flooding down wadis in the Middle East and flooded roads in towns and cities.

Baghdad, Iraq's capital, suffered flooding in the city on Friday as 42mm of rain fell in 30 hours of continuous downpour. The average rainfall expected in Baghdad in the month of February is 19mm.

The heaviest falls of rain underneath this jet stream have been near the Iraq-Iran border where Khanaqin, Iraq, received its average for the month in 36 hours.

And Ilam, in Iran, recorded 104mm in 24 hours, ending on Saturday morning - over twice the average for the month.

Persistent rain can bring the temperature down and in Baghdad, Friday's maximum temperature was a full six degrees Celcius below Thursday's, at 15C.

Conversely, south of all the action, over northern Saudi Arabia, the induced southerly wind brought a duststorm through Riyadh on Wednesday, as the temperature hit 34.5C.

This is 0.3C shy of February's record and a full 12 degrees above average.

Qatar was similarly warm, five degrees above average on Wednesday, in a dusty atmosphere.

Manama, Bahrain's capital, hit 30C on the same day, 9C above normal. These sorts of variations are unusual on the Arabian Peninsula.

As the jet stream buckles and forms a deep u-shape which then drags across the skies of the Middle East, another storm system will cross.

Already winds have been recorded in Piraeus, southern Greece, in excess of 85km per hour as the storm system winds up.

Saturday will be an increasingly windy day for Lebanon and the Gaza Strip. Sunday looks persistently windy throughout eastern Turkey and Cyprus, Syria, Israel, Jordan, Iraq and northern Saudi Arabia. Gales are possible in the Zagros Mountains of Iran.

Another 75mm of rain is possible in Lebanon, northern Syria, northern Iraq and western Iran.

Further flooding and generally miserable conditions are inevitable.

Snow is likely to be confined to the mountainous areas of eastern Turkey, northern Iraq, the Zagros and northwestern Iran.