- Joined
- Feb 27, 2009
- Location
- Milan, NY 12571
How to (try) avoid Hurricane's path
Cyclones
Wind is the result of pressure differences. The speed of wind is proportional to the pressure gradient - the horizontal rate of change of pressure. Sometimes weather ilustration will show low pressure areas surrounded by isobars-lines of equal pressure- measured in millibars. As the air moves toward the center of the "low" it is deflected to the right by the coriolis force. If there were no friction, the wind would flow exactely along the esobars, but friction with the surface causes it to spiral in at about a 30 degree angle. The winds around a low blows counter-clockwise. Such a wind system is called a Cyclone.
Anticyclones
Winds blowing outward from the center of a high pressure area are similarly deflected to the right in the northern hemisphere. Again, rather than following the isobars exactely, the winds spiral outward at about 30 degree inclination. the deflection causes winds around a high to spin clockwise. The wind system is called an anticyclone because the winds are opposite to those of a cyclone.
To remember wind direction, just remember that as wind moves from higher pressure to lower pressure it is always deflected to the right in the Northern Hemisphere. In Southern Hemisphere, the deflection and resulting spins are just the opposite.
Buys Ballot's Law
If you face the wind around a low in the Northern Hemisphere, the center of the low will be about 30 degrees aft of your outstretched right arm. This is very importante cause it helps you evade the path of a Hurricane.
In the case of a Hurricane the law can be slightely improved by changing the 30 inclination to 20 degrees ahead of the storm and 45 behind the storm. The diferences are due to the fact that the wind vector is the resultant of the cyclonic wind speed plus the speed of advance of the storm.
winds around a high are not nearly as dangerous. however you can invert Buys Ballot's law to deduce the location of the center of a high as well. Facing wind, center of a high will be 30 degrees foward of your outstretched left arm.
Cyclones
Wind is the result of pressure differences. The speed of wind is proportional to the pressure gradient - the horizontal rate of change of pressure. Sometimes weather ilustration will show low pressure areas surrounded by isobars-lines of equal pressure- measured in millibars. As the air moves toward the center of the "low" it is deflected to the right by the coriolis force. If there were no friction, the wind would flow exactely along the esobars, but friction with the surface causes it to spiral in at about a 30 degree angle. The winds around a low blows counter-clockwise. Such a wind system is called a Cyclone.
Anticyclones
Winds blowing outward from the center of a high pressure area are similarly deflected to the right in the northern hemisphere. Again, rather than following the isobars exactely, the winds spiral outward at about 30 degree inclination. the deflection causes winds around a high to spin clockwise. The wind system is called an anticyclone because the winds are opposite to those of a cyclone.
To remember wind direction, just remember that as wind moves from higher pressure to lower pressure it is always deflected to the right in the Northern Hemisphere. In Southern Hemisphere, the deflection and resulting spins are just the opposite.
Buys Ballot's Law
If you face the wind around a low in the Northern Hemisphere, the center of the low will be about 30 degrees aft of your outstretched right arm. This is very importante cause it helps you evade the path of a Hurricane.
In the case of a Hurricane the law can be slightely improved by changing the 30 inclination to 20 degrees ahead of the storm and 45 behind the storm. The diferences are due to the fact that the wind vector is the resultant of the cyclonic wind speed plus the speed of advance of the storm.
winds around a high are not nearly as dangerous. however you can invert Buys Ballot's law to deduce the location of the center of a high as well. Facing wind, center of a high will be 30 degrees foward of your outstretched left arm.