Monday November 14 was my first full day in the Maldives. The night I arrived, it started raining right on cue, just about the time I got off the plane. There were at least a couple hours of heavy rain that evening, and even some thunder (which is relatively unusual here). The next morning, there was again heavy rain for a couple of hours. It caused a lot of the streets to turn into deep puddles that lasted through the day, and completely soaked S-Polka radar chief scientist Bob Houze on his bike ride to work. Here's what it looked like on the SMART-R radar in the thick of it, about 10 AM local time (5 UTC):
In the infrared satellite image - which basically sees high, thick clouds, similar to outgoing longwave radiation which we have discussed in previous posts - there is no trace of anything at Gan. (The tiny white speck you see if you look close is not a cloud, it's there in every image and is apparently some permanent feature.) Our rain here was invisible from space in the IR.
This line continued to develop more later. Maybe this line was related to our earlier shower, or maybe the coincidence in time was incidental; from the radar it seemed that the cells on top of us were not the same as those that turned into the line, though they were close in both space and time.
This episode shows how localized tropical convective rain can be. What amazed me about it was how long the rain lasted here at one spot, while still remaining invisible from space. Systems are usually moving, so if they last a while at one spot, that usually means they are big, and then one would think they'd show up on satellite images. This one went on for a couple of hours while staying out of the satellites' view; I suppose it was just moving slowly.
It's a cliche in our field to say that weather varies on a wide range of scales. In the field, one can gain a new appreciation of the truth behind the cliche by observing many of the scales at once.