Tropical cyclone Cristobal circulated with its centre just offshore on the east coast of the US, but it hasn't become any better organized since the afternoon of Saturday, actually winds on the North Carolina and South Carolina coastline were quite light. Cristobal brushed the coast on Sunday with only minor impact on land (locally heavy showers and energetic weather, but be wary of rip currents if you are out in the ocean!).

A tropical cyclone is a storm system characterized by a low pressure storm centre and many thunderstorms that produce intense winds and often devastating, flooding rain. A tropical cyclone feeds on heat released when moist air rises, resulting in agglomeration of water vapour held in the damp air. These storms are fuelled by a completely different heat mechanism than other cyclonic formations such as nor'easters, European depressions, and polar lows, leading to them being classed as "warm core" storm systems.

The axiom "tropical" refers to both the geographic creation of these systems, which form almost wholly in tropical regions of the earth, and their formation in maritime tropical air masses. The phrase "cyclone" refers to such storms' cyclonic nature, with anti-clockwise rotation in the Northern Hemisphere and clockwise rotation in the Southern. Depending on their location and strength, tropical cyclones are referred to by other names, including hurricane, typhoon, tropical cyclone, cyclonic storm, tropical system or just plain and simply cyclone.

Cristobal, however, brought back thoughts of Alex in 2004, which was in an almost identical position, slipping along side the coast and delivering a much stronger punch than had seemed likely initially. The storm suddenly became a Cat 2 hurricane, its storm centre adjacent to the shore, its western eye-wall clipped the Outer Banks. Ocracoke Island was hit particularly hard. Luckily Cristobal promised much, but delivered little!

Cristobal did look good on radar, with a defining hook and even starting to circulate at it's core but as it ran out of energy the main damage came from the line of storms causing strong winds along the outer edges.   So the effects on the North Carolina coast were nowhere near as bad as from hurricane Alex ($7.5 Million damage from Alex), and this is helped by the lack of a storm surge from Cristobal to inundate the coast. So, Cristobal has behaved herself and remained the carrier of a fair bit of precipitation but little else! But we are in hurricane season and already the next system is brewing off the coast of Africa. Watch this space, who knows when the next cat 5 Hurricane will sweep across the atlantic.