I visit tropics, tropics visit me.

I grew up (and beyond) in the US northeast. There, the weather was pretty good at coming at us from the West, though a nor’easter blowing in from the North East (unsurprisingly) was not uncommon in New England. Although I had studied sea level rise and some Pleistocene climate reconstruction, when I first went to the field in Central Africa I was pretty unschooled in areas of climate and weather. I remember the first several days in the Ituri Forest. I though I knew which way was North, South, East, etc. but then I would get turned around because the big storms — that came in every single day in the afternoon — were confusing me. It turns out that on the equator (which I was, almost, 3 degrees north of it) the “trade winds” come in from the east, not the west. So now you know.

I recently spent a few days on the Yucatan and some of that was spent watching clouds. For the first few day, the clouds came from the west and headed east though the surface winds never stopped being from the east-southeast (the direction of the sea). After two days of this, a nice big set of storm clouds formed, not supercells but big cloud formations. One of the clouds dropped a couple of wall clouds, and then a handful of twisters, the non-supercell type that sometimes become water spouts. They existed as thin threads hanging from the clouds for just a few minutes, then disappeared. By the next day, cumulus clouds were coming from the East, not the West, and did so thereafter.

I checked satellite images each day, and I believe this is what was happening: At first I was within the zone where the trade winds blow mostly from West to East, but the line between the meteorological tropics and the sub-tropics shifted past my location at about 20 degrees N. Latitude, so I ended up in the tropics. I’m not going to claim it got warmer, but it might have. I did switch from Beer to Tequila at about that time, so there’s that.

Idealized Trade Winds

Idealized Trade Winds

Comments

  1. #1 Laurent
    Caribbean
    April 4, 2014

    Interesting. Here we actually developped another sensing methods: storms and rains comes toward the mountain (the reverse actually happens at most a dozen times a year). But that’s still coherent with the picto from the post. We just add in the mountains, which act as a barrier leading to cloud accumulation. We did not switch beverage, because we’re only casual social drinkers living on water. :)

Current ye@r *