One tropical wave to watch in the mid-Atlantic

A tropical wave that emerged from the coast of Africa late last week is now near 8N 35W, way out in the middle of the Atlantic. This wave has heavy thunderstorm activity and some counterclockwise spin to it, as seen on both visible satellite loops and QuikSCAT. Wind shear is 10-20 knots, and is forecast to fluctuate between 10 and 30 knots in the region over the next two days. Sea surface temperatures are 27-28 C, which is warm enough to support some tropical development. Dry air does not seem to be a hindrance, as the Saharan Air Layer is about 150 miles to the north of the wave. The GFS model does indicate a tropical depression might form here, although our other three reliable models, the NOGAPS, UKMET, and ECMWF, do not. Climatologically, formation of a tropical depression in this region of the Atlantic this time of year is quite rare. Due to this fact, plus the somewhat marginal wind shear and the position of the wave so close to the Equator, I'm not expecting it to develop. However, we should keep an eye on it this week as it moves very slowly to the west at less than 5 mph.



I'll be back this afternoon with my bi-monthly hurricane outlook, for the first half of July.

Jeff Masters