Some trivia about tropical storms, hurricanes, typhoons etc.

Last night at Jen's graduation party (to celebrate her earning her masters -- Yeah Jen!!!). We got to talking about storms and some basic questions were tossed around. We all had ideas and thought we knew some of the answers, but none of us was confident that we were an authority. So, I was assigned the task of finding those answers and blogging them for all to see since I have all this free time on my hands.

So from The Atlantic Oceanographic and Meteorological Laboratory (AOML) if found out the following --

What's the difference between Hurricane and Typhoon?

The terms "hurricane" and "typhoon" are regionally specific names for a strong "tropical cyclone". A tropical cyclone is the generic term for a non-frontal synoptic scale low-pressure system over tropical or sub-tropical waters with organized convection (i.e. thunderstorm activity) and definite cyclonic surface wind circulation (Holland 1993).
Tropical cyclones with maximum sustained surface winds of less than 17 m/s (34 kt, 39 mph) are called "tropical depressions" (This is not to be confused with the condition mid-latitude people get during a long, cold and grey winter wishing they could be closer to the equator ;-)). Once the tropical cyclone reaches winds of at least 17 m/s (34 kt, 39 mph) they are typically called a "tropical storm" and assigned a name. If winds reach 33 m/s (64 kt, 74 mph)), then they are called:

"hurricane" (the North Atlantic Ocean, the Northeast Pacific Ocean east of the dateline, or the South Pacific Ocean east of 160E)

"typhoon" (the Northwest Pacific Ocean west of the dateline)

"severe tropical cyclone" (the Southwest Pacific Ocean west of 160E or Southeast Indian Ocean east of 90E)

"severe cyclonic storm" (the North Indian Ocean)

"tropical cyclone" (the Southwest Indian Ocean)

Do they rotate different directions? and what was that myth about water out of a sink or toilet depending on where you are on the earth?

The reason is that the earth's rotation sets up an apparent force (called the Coriolis force) that pulls the winds to the right in the Northern Hemisphere (and to the left in the Southern Hemisphere). So when a low pressure starts to form north of the equator, the surface winds will flow inward trying to fill in the low and will be deflected to the right and a counter-clockwise rotation will be initiated. The opposite (a deflection to the left and a clockwise rotation) will occur south of the equator. NOTE: This force is too tiny to effect rotation in, for example, water that is going down the drains of sinks and toilets. The rotation in those will be determined by the geometry of the container and the original motion of the water. Thus one can find both clockwise and counter- clockwise flowing drains no matter what hemisphere you are located. If you don't believe this, test it out for yourself.

Bottom line, I'm glad that Hanna decided to stop raining on Maryland in time for Jen's outdoor party. Craig, you know how to do it right and Jen congratulations on finishing your degree.