Saturday, September 18, 2010
Igor Takes Aim at Bermuda
Virtually dropped from the main stream US News media Igor is closing in on Bermuda's 22 mile long southern shore line. The island nation may take a direct hit and should begin to feel the effects as early as this morning.
You can see real time data of sea and winds conditions south of Bermuda here and on Bermuda proper at the Esso pier here.
Bermuda Weather Service web cam is here.
And wind/temp/precipitation/radar at BDA here.
The National Hurricane Center has issued a Hurricane warning for Bermuda and gave this update at 23oo Friday:
IGOR HAS MADE A TROCHOIDAL WOBBLE TO THE RIGHT OF THE PREVIOUS FORECAST TRACK...BUT THIS IS LIKELY JUST A TEMPORARY MOTION. IGOR IS EXPECTED TO MOVE BACK ON OR CLOSE TO THE PREVIOUS ADVISORY TRACK BASED ON 00Z UPPER-AIR DATA FROM BERMUDA SHOWING 24-HOUR MID-LEVEL HEIGHTS HAVE INCREASED BY 20 METERS AND WINDS HAVE SHIFTED AROUND TO AN EASTERLY DIRECTION.
Trochoid is the word created by Gilles de Roberval for the curve described by a fixed point as a circle rolls along a straight line. As a circle of radius a rolls without slipping along a line L, the center C moves parallel to L, and every other point P in the rotating plane rigidly attached to the circle traces the curve called the trochoid. Let CP = b. If P lies inside the circle (b < b =" a),"> a), the trochoid is described as being curtate, common, or prolate, respectively.
Parametric equations of the trochoid, which assume L is the x-axis, are where θ is the variable angle through which the circle rolls. A curtate trochoid is traced by a pedal when a bicycle is pedaled along a straight line. A prolate, or extended trochoid is traced by the tip of a paddle when a boat is driven with constant velocity by paddle wheels; this curve contains loops. A common trochoid, also called a cycloid, has cusps at the points where P touches the L.