Escaping the rain

On Saturday morning some of us were woken up early by the sound of rain beating against the roof of our house and falling from it onto the ground. Being slightly angry about losing a few more minutes of morning sleep, we didn't expect it might not be the last meeting with precipitation today.

During the met briefing at noon we saw that Graciosa is exactly in the center of high pressure system extending over large part of the Atlantic Ocean, from Caribbean to central Europe. Two cloud layers were forecasted. Cumulus clouds can apear at low altitude and be accompanied by stratocumulus layer above capped with a temperature inversion. The real cloud structure turned out to be a bit more complex.

The helicopter took off at 14:51 and headed northwards from where clouds were coming. The flight started with a profile up to 2000 m which revealed the presence of a small cloud layer at ~1100 m and another one, thicker and more water-abundant, at ~1500 m. The latter was capped with a moderate inversion (2 K between ~1650 and ~1850 m).

Cumulus clouds below stratiform ceiling.




From above we could see the upper cloud layer was not uniform but consisted of large patches of two kinds - thin stratus with very flat surface and thicker stratocumulus with typical cauliflower-like top. ACTOS perfomed several porpoises through this top but diving into the cloud wasn't easy because patches often overlapped each other.

Over the stratus patch, stratocumulus patch in the distance.



Then we got a call that the rain is coming towards the airport and it's better to start thinking about the way back. Pilots found a hole in the cloudy deck, so that ACTOS could descend through it almost reaching ocean surface and passing cumuli level halfway. Now we spotted the rain pouring from the cloud into the ocean northeast from the island. The remaining time was spent to fly a horizontal leg over the water.

The hole we escaped through.

Rain over the ocean.

Eventually, ACTOS safely touched the ground escaping from the rain. However, the rain didn't give up at this point and caught us later ... We got a bit wet in the evening while walking back home after delicious dinner.

Showers seen from our house on the hill.










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