do whirlwinds or twisters?

Question

always spin the same way and do they only arrive in daylight?

Answer 1

Tornadoes are a type of cyclone. There are cyclones and anti-cyclones.

Cyclones almost always spin counterclockwise in the northern hemisphere, and anti-cyclones spin clockwise. In the southern hemisphere, cyclones almost always spin clockwise and anticyclones spin counterclockwise. Rotation of large air masses is governed by the Coreolis effect. Smaller storms and tornadoes should not be affected by the Coreolis effect, but they are generated by larger systems, and the fact remains that fewer than 1% of tornadoes spin the "wrong way."

Cyclones are more likely to happen during the day time, because they are generated by storms. In the regions in which cyclones form, storms are more likely to form during the day. However, tornadoes do form at night frequently enough that this is not considered rare.

Answer 2

Well, I am not sure but I would bet that a whirlwind can happen at night. A twister can definately happen at night. There are many times in the past when tornados have kicked up very late at night. The only one that I ever got a good look at started around 10:30 pm.

Tornados also do not always spin the same direction.

http://en.wikipedia.org/wiki/Tornado#Rotation


A cool pic on this one of a tornado at night
http://www.snopes.com/photos/natural/sedalia.asp

Answer 3

While it is tempting to apply the Coriolis effect to tornado rotation, this is absolutely not the case. The rotation of a tornado is forced by vertical wind shear and internal thunderstorm dynamics. Climatologically, this results in most tornadoes spinning cyclonically (CCW in NH, CW in SH). However, there are a number of tornadoes which spin anticyclonically. Previously thought to be very rare (about 3% of tornadoes), some studies have put the number as high as 30%. It is actually quite difficult to determine this number, as many tornadoes go unseen, and surface observing systems cannot be concentrated densely enough to determine the character of rotation. Doppler radar can be useful, but limitations would require visual confirmation of a tornado for accurate statistics, again causing problems.

Climatologically, most tornadoes do occur in the late afternoon and early evening while the sun has not yet set. The thermodynamic scenario most supportive of tornadic thunderstorms is generally realized most often during this time frame. However, there is a very wide range of atmospheric conditions that may yield a tornadic storm, which means that tornadoes are possible and do occur at any time.

Answer 4

I don't think that whirlwinds or twisters spin in the same way every time - it has to do with the situation and previous winds... No they don't only arrive in daylight, they can happen at night.

Answer 5

if by whirlwinds you also mean dust devil then no. Dust devils are create by the heat created by the sun rising off the ground. Tornados, yes can happen at night and often do.

Answer 6

Maybe they spin in the same direction all the time, I'm not really sure of that.

But they can come at night as well as in the day time hours.

Answer 7

twisters go clockwise but in australia i would imagine they would anti clockwise - as the water down a sink does

Answer 8

A... depends on whether you are in the northern or southern hemisphere.

B... no, they also come at night.