From 24 December and for more than 10 days, a thick fog invaded the Arabian Gulf countries resulting in limited night-morning visibility.
By Zamzam AL.Rawahi (Oman DGMAN)
Visibility in some areas was less than 50 m (recorded at Dubai airport), which led to many flight diversions and cancellations at Dubai and Bahrain airports. The low visibility also caused traffic problems.
The animated Meteosat-10 Night Microphysics imagery from 26 December to 4 January, taken each night at 00:00 UTC (Figure 2) and 03:00 UTC (MP4, 22 MB), shows that fog started over Qatar, Bahrain and parts of Saudi Arabia. The Night Microphysics RGB is the best one to use to observe night fog.
It shifted eastwards on 28 December and over the following days, to cover many parts United Arab Emirates and Saudi Arabia.
A strong north-westerly wind, that picked up high humidity in the area (shown in this plot of relative humidity. Source: Directorate General of Meteorology, Oman), then caused the fog to extend to the Strait of Hormuz.
A comparison between Meteosat-8 Night Microphysics RGB and Meteosat-10 Night Microphysics RGB, from 30 Dec at 03:00 UTC (Figure 3), reveals that, generally, the dense night fog can be seen in better resolution in Meteosat-8, while the thin fog is hard to detect due to minimal contrast between the fog and the ground.
However, in Meteosat-10 image the fog generally looks thicker and more white-greenish, as it is looking at the thin fog from a higher viewing angle (longer optical path through the thin fog).
Fog is a very common feature on the Arabian Peninsula at that time of the year and it usually doesn't last long — dissipating as the ground warms after sunrise.
However, the fog that was seen around Qatar's coasts and parts of the United Arab Emirates' coasts during the afternoons of 26 and 27 December, was a rare form of sea fog that forms offshore.
The Suomi-NPP True Color RGB image, 27 December 09:00 UTC (Figure 4), clearly shows the roll of sea fog off the eastern and western Qatar coasts. On the same day Doha only had about three hours of clear skies (08:00–11:00 UTC), according to the Doha international airport METAR observations — the horizontal visibility was below 5000 m, with a minimum of 150 m at night.
That fog formed because an upper air high pressure that prevailed over the area (Figure 5) coincided with a weak low level high pressure that caused continuous humid easterly to north-easterly, light winds.
The easterly humid air cooled by a few degrees as it moved over the relatively cooler sea around Qatar; it become saturated as it cooled and the excess moisture condensed to form a roll of fog in the sea, starting in the afternoon of 26 December.
During the night, as the inland temperature drop, the fog continued to form and spread inland to cover the whole of Qatar, Bahrain and parts of Saudi Arabia. It was still present in the early morning, before it gradually started to fade with with the heat of the sun.
Night Microphysics RGB overlaid with geopotential height at 500 hPa
Night Microphysics RGB animated gif
Meanwhile, the sea fog remained off the coasts throughout the day and swept a little further inland towards Doha, Al-Khor and Wakrah with the continued easterly flow.
The animation of the Meteosat-8 HRV images (MP4, 2 MB) shows the fog during the day on 27 December (05:15–13:00 UTC), while the animated gif of the Meteosat-10 Night Microphysics RGB (Figure 6) shows the fog during the night of 27 December.
Rare sea fog blankets Corniche area (The Peninsula, Qatar)
Unusual sea fog blankets Doha, could continue until Thursday (Qatar Living)
Dense winter fog blankets Arab Gulf countries (Al Jazeera)
Over 100 flights delayed, motorists struggle as thick fog blankets UAE (Gulf News)