Why do we have fog during September?
Drive safely in low visibility: Experts explain the phenomenon
Dubai: As the UAE transitions from extreme heat to cooler weather, residents brace themselves for thick fog blanket that swirls around from 2 am to 8 am in the morning.
The National Centre for Meterology and Seismology (NCMS), Abu Dhabi has issued an alert to all drivers for drop in horizontal visibility to less than 100 meters in the forthcoming days.
As we progress into the month, the fog gets thicker and we can expect visibility as poor as 50-100 meters in the early hours of morning.
Why do we have thick fogs?
Ever wondered why we have the fog phenomenon during these months every year?
Fogs are a direct indication of the waning heat of summers gradually moving to cooler months ahead until we hit proper winters in December.
However during the transition, fogs can be explained through pure science.
Misty eye glasses phenomenon
Have you ever experienced the misting of your glasses as you step out of your air-conditioned home or car into the hot exterior?
Momentarily the cooler glass surface complete mists as one steps out as the humidity in the air precipitates into tiny droplets of water when it comes in contact with the cold surface.
While that is addressed by quickly taking off your glasses and wiping it dry, think about how the entire outside atmosphere handles this kind of precipitation.
Blow hot blow cold
Yashbeer Singh Gaharwar, chemistry teacher for secondary school at the Indian High School, Dubai, explained: “In a coastal desert like UAE, we have a mix of hot and cold air.
"As summer tapers into cooler weather, the air that blows from the sea to the land is cooler, while the desert sands which are heated during the day, give off hot air in the night.
"This air rises and mixes with the cooler breeze precipitating into humidity."
"The humidity gets as high as 90 per cent during these transition months especially in the early morning time. With the fine sand and silica particles that fly into the air due to breeze, the mist changes into a long lingering fog which the sun is unable to clear until the rays get really hot."
"That is why fog begins to disappear after 8 am when usually business and traffic appears on roads during the day.”
Precautions for driving through poor visibility
- • Drive only if you have to if visibility is as low as 100-200 metres. Consider taking the metro to work. Usually fogs in the UAE clear after 8.30- 9 am, so consider calling in at work and informing that you will be late.
- • Keep your speed low as is permissible on the highway ( about 80 kmph) and on inner roads to less than 50 kmph) and drive in the slow lane.
- • Use dipper lights and do not use a full beam as that condenses the fog further dispersing the dust particles and diffusing the light. Do not use hazards as it can mislead the drivers behind
- • Keep a distance of at least two cars from the vehicle in front of you.
- • Plan your trip well and do not make sudden swerves, break jamming or sudden lane changing decisions. If you have to go from right to extreme left begin indicating from at least a km and changing one lane at a time.
- • If the visibility drops and one is not confident of making it, it is better to stop at petrol station and wait for the fog to clear. Better still if a friend stays close by, opt to break journey and spend time at the friend’s place or at a coffee shop until the visibility improves.
Weathermen explain this as being caused by "thermal radiation" — usually triggered the cooling of the Arabian Sea overnight which brings air temperatures close to the surface of the water down.
Then the air’s ability to hold moisture is reduced. This allows condensation to form. The result: Low cloud or fog.
Fog formation in the country's interiors, not just in the coastal areas, are also common. Due to lower temperatures on the land during the late night and early morning, inland fog forms, which may also take longer to lift.