Istanbul’s anticipated snowfall turns to rain amid releasing heat
Despite meteorological warnings from the governorship and Istanbul Metropolitan Municipality’s Disaster Coordination Center (AKOM), Istanbul’s much-anticipated snowfall transformed into rain, defying forecasts.
Adil Tek, head of Boğaziçi University Kandilli Observatory Meteorology Laboratory, shed light on the challenges behind the unmet snowfall expectations, attributing the phenomenon to Istanbul’s status as a “heat island.”
Tek explained, “The city is a heat island. When you look at the system, snowfall comes all the way to Silivri and when it comes to Istanbul, it turns into rain and sleet. The problem here is that the temperatures do not drop sufficiently. The city’s internal energy, the exhaust of the city’s vehicles, the energy originating from the vehicles, the energy originating from heating, the mobility in the city keeps the temperature higher than normal.”
Despite earlier forecasts from the General Directorate of Meteorology and AKOM predicting a snow thickness of 10 to 20 centimeters (3.94 to 7.87 inches) in certain parts of Istanbul, the expected snowfall did not materialize, except for higher-altitude areas.
Tek highlighted the critical role of temperature in snowfall predictions, stating: “When the temperature starts to drop below zero, snowfall is already normal. However, a narrow 2-3 degree temperature margin can alter precipitation patterns, with temperatures around 3-4 degrees leading to rain or sleet instead of snow.”
Explaining the complexity of weather predictions, Tek mentioned the impact of seawater temperatures in Istanbul, which currently hover between 10 and 11 degrees. For a snowfall to occur, seawater temperatures must drop to 8 degrees Celsius (46.4 degrees Fahrenheit). Istanbul’s urban heat island effect, while influencing sea water temperatures, prevents them from reaching the necessary level for snowfall. As a result, precipitation in the city predominantly took the form of rain and sleet instead of the anticipated snowfall.
“Systems are expected to arrive in the second week of February. If seawater temperatures drop further, reaching around 8-9 degrees Celsius, a similar weather system could bring snowfall to central Istanbul. The sea water temperature needs to decrease a bit more. While not solely attributed to climate change, it does play a role. Owing to climate change, seas absorb a significant portion of accumulated energy, preventing water temperatures from dropping very low in the 10s and 20s. Historically, during those decades, seawater temperatures easily reached 8 to 9 degrees Celsius,” he explained.
Discussing the anticipated precipitation for the remainder of winter in Istanbul, Tek stated: “There is no immediate snowfall expected. Seasonal forecasts indicated above-average temperatures for December and January. February appears to follow the same pattern, meaning more warm days than cold. Although there will be occasional cold days, there is a possibility of snow, particularly in the second week of February. Starting this week, temperatures will rise again, providing milder weather. February is expected to have above-average temperatures and this trend will likely continue into March and April. Despite above-average rainfall, dams will continue to see increased occupancy as we go through a critical period.”
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