Yesterday’s flight took us out over the open sea, where we expected to see some beautiful convective clouds towering up to 4 km. That meant we had to climb higher again — this time to about 4.5 km. Just before takeoff, we checked the latest satellite images and saw that we’d be flying right into a cold air outbreak (CAO) combined with a small low-pressure system moving eastward towards the Barents Sea. Such weather conditions are always fascinating to fly in, as you can expect an interesting mix of clouds and clear sky. In a CAO, cold air is advected over the relatively warm ocean, leading to a strong temperature difference between the sea surface and the higher layers of the troposphere. This causes the atmosphere near the ground to become unstable – the air can rise, cool down – and condensation occurs: clouds form that can tower up impressively. These promising prospects were, of course, particularly exciting for Mika. During the flight, he carefully monitored the dropsondes – and even threw one or two of them out of the plane himself (but only once they were ready for measurement, of course!). And when there was nothing to do, he was busy taking photos of the beautiful clouds that we were able to admire during our flight. Thanks to Mika, we were able to drop a total of 9 dropsondes, the highest number ever during our campaign! This flight was truly special, as our PI of this flight, Marcus, had his 40th birthday! After landing back in Kiruna, our ground team surprised him with a chocolate birthday cake. Naturally, we gathered the whole crew for a birthday photo. Not only did we have a successful flight with lots of stunning clouds along our track, but we also had a special birthday celebration for our PI. Happy 40th birthday, Marcus!