Interesting hybrid low set to drench Spain's Canary Islands

An interesting 1002 mb low pressure system with some characteristics of a tropical storm has developed off the coast of Africa, a few hundred miles west-southwest of the Canary Islands. An ASCAT pass from last night revealed top winds of 40 mph near the center, so the low is probably near tropical storm strength. This low is moving east-northeast towards the Canaries, and will likely bring sustained winds of 30 - 35 mph, gusting to 50 mph, to the islands tonight. The storm formed over the weekend from an isolated cold-cored low that was wandering over the Atlantic, and phase space analyses from Florida State University revealed that the low developed a partial warm core over the weekend. A respectable amount of heavy thunderstorm activity has built near the storm's center, characteristic of a tropical storm. The low is over cool 21 - 22°C water, far colder than the typical 26°C needed for a tropical storm to form. These SSTs are about 1 - 2°C warmer than usual for this time of year. Wind shear is marginal for tropical storm formation, about 20 knots. The comma-shaped structure of the storm's spiral bands is characteristic of an extratropical cyclone, and it is pretty unlikely that NHC will view this hybrid storm as being sufficiently tropical to warrant naming it a subtropical depression or subtropical storm. The low is headed towards colder waters of 20°C that lie near the Canary Islands, and the system should become less tropical today.


Figure 1. Hybrid 1002 mb low approaches the Canary Islands, in this visible METEOSAT image from 7am EST 2/1/10.

You can use our wundermap for the Canary Islands to watch the storm roll through the islands. There are two web cams to watch (currently showing thick clouds) that might be interesting. EUMETSAT satellite images loops will also be interesting.

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My next post will be Tuesday (Groundhog's Day), when I plan to discuss Punxsutawney Phil's forecast for the rest of winter. I'll throw in my two cents worth, too.

Jeff Masters