Istanbul’s ‘heat island’ thwarts predicted snow

ISTANBUL

Despite forecasts issued by the Turkish State Meteorological Service, the provincial governor's office and the disaster coordination center (AKOM), snowfall has eluded Istanbul as the "heat island" effect is preventing the anticipated winter wonderland from materializing.

"The problem here is that temperatures do not drop sufficiently. The city's own internal energy, such as the exhaust and energy released by vehicles, the energy from heating, and the mobility in the city, is preventing temperatures from falling. What we call a heat island is when the temperature of the city is slightly higher than the countryside," stated Adil Tek, the head of Boğaziçi University Kandilli Observatory Meteorology Laboratory.

Evaluating why the weather forecasts may have failed, Tek said, "In general, forecasts are interpreted from atmospheric models. The results of these models are already easily accessible to everyone. One of the reasons for the errors in prediction is that some forecasts have been made with data that are not particularly high resolution in atmospheric models. More detailed regional forecasts need to be made with higher resolution."

"One of the biggest issues is primarily in the prediction of temperature. When we look at the latest weather systems, we see that the temperature varies between minus 1 and 4-5 degrees for Istanbul. This is a very critical level. When the temperature starts to drop below zero, snowfall starts to fall, but the errors in this 2-3 degree temperature share change the form of the precipitation. When the temperature is at 3-4 degrees, the precipitation is already in the form of rain or sleet," Tek added.

Noting that seawater temperatures need to drop to 8 degrees Celsius for the occurrence of snowfall in Istanbul, Tek said, "Sea water temperatures play a role in the absence of snowfall. Nowadays, the seawater temperatures in Istanbul are between 10 and 11 degrees Celsius. The heat island effect prevents the temperatures from dropping to those minus values," he said.

Tek listed climate change as another reason for the insufficient drop in sea water temperature, as the seas absorb a large part of the accumulated energy due to climate change.

Stating that the precipitation expected in the rest of the winter season will mostly fall on Istanbul in the form of rain, Tek said, "There will likely be more warm days than cold days. But this does not mean that it will never snow. The number of warm days is high, but there is also the possibility of snow. Snowfall may be expected in the second week of February."