Wind & forward speed question...

This is the general tropical discussion area. Anyone can take their shot at predicting a storms path.

Moderator: S2k Moderators

Forum rules

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

Help Support Storm2K
Message
Author
User avatar
TexasSam
Category 2
Category 2
Posts: 573
Age: 66
Joined: Thu Aug 28, 2003 12:16 am
Location: Port Arthur, Texas

Wind & forward speed question...

#1 Postby TexasSam » Sat Oct 22, 2005 8:46 pm

Is it true that you add the forward speed to the wind speed on the sice of the Hurricane that it's coming from?
Let's say Wilma has a wind of 100 MPH and a forward speed of 40 MPH, then you add that up to 140 MPH on that side of the storm?
In a way I can see that the storm spins at one speed, and it moves at another. so in this case the wind on the southwest side would be added, and the northeast side would be subtracted.
This is like the question if a tree fell in the forest and no one was there to hear it, would it make a sound?
I have heard this a few times over the years, and normaly it's not a factor.
0 likes   

inotherwords
Category 2
Category 2
Posts: 773
Joined: Mon Aug 30, 2004 9:04 pm
Location: Nokomis, FL

#2 Postby inotherwords » Sat Oct 22, 2005 8:56 pm

Max Mayfield answered this in a question earlier today. He said that the NHC takes the forward windspeed into consideration when forecasting and that the number you see from NHC includes it.
0 likes   

User avatar
Bgator
Category 2
Category 2
Posts: 649
Joined: Mon Sep 05, 2005 12:29 pm
Location: Orlando, FL

#3 Postby Bgator » Sat Oct 22, 2005 9:14 pm

inotherwords wrote:Max Mayfield answered this in a question earlier today. He said that the NHC takes the forward windspeed into consideration when forecasting and that the number you see from NHC includes it.


This only happens on the right side which in this case is the south side...
0 likes   

User avatar
TexasSam
Category 2
Category 2
Posts: 573
Age: 66
Joined: Thu Aug 28, 2003 12:16 am
Location: Port Arthur, Texas

#4 Postby TexasSam » Sat Oct 22, 2005 9:18 pm

Thanks! Over the years I just thought it was a "old wifes tale".
0 likes   

User avatar
WxGuy1
Professional-Met
Professional-Met
Posts: 538
Joined: Sat Oct 22, 2005 12:55 pm
Location: Oklahoma

#5 Postby WxGuy1 » Sat Oct 22, 2005 9:38 pm

Bgator wrote:
inotherwords wrote:Max Mayfield answered this in a question earlier today. He said that the NHC takes the forward windspeed into consideration when forecasting and that the number you see from NHC includes it.


This only happens on the right side which in this case is the south side...


Well, if the winds are ground-relative.... If the hurricane is moving forward at 20mph, and the max winds in the advisory are to, say, 130mph, that means that those winds are occurring in the forward side of the storm (assuming the storm is symmetric) -- thus the reason why the forward-right quad is often the worst. So, for Wilma, the southern side of the storm would have 130mph, while the northern side of the storm has 90mph winds (add the 20mph to the storm-relative wind in the forward half, and subtract the 20mph from the storm-relative wind in the souther half). Obviously, asymmetry in the ground-relative wind is introduced and becomes more prominent as forward/translational speed increases. This makes landfall location even more important when translational speed is relatively high (>15mph), as it could mean the difference of at least 30mph in wind strength (not even including the effects of friction on the reduction of offshore flow).
0 likes   

User avatar
TexasSam
Category 2
Category 2
Posts: 573
Age: 66
Joined: Thu Aug 28, 2003 12:16 am
Location: Port Arthur, Texas

#6 Postby TexasSam » Sat Oct 22, 2005 9:55 pm

Interesting! The more information I read, the more I understand, and it's also (true) then. Thanks!
0 likes   

User avatar
hookemfins
Tropical Storm
Tropical Storm
Posts: 200
Joined: Sat Aug 28, 2004 10:56 pm
Location: Miami, FL

#7 Postby hookemfins » Sat Oct 22, 2005 11:00 pm

Here is the answer from the FAQ's written by Chris Landsea:

http://www.aoml.noaa.gov/hrd/tcfaq/D6.html
0 likes   


Return to “Talkin' Tropics”

Who is online

Users browsing this forum: Hammy and 411 guests