| BillW |
| (Registered User) |
| Tue Oct 25 2005 09:20 PM |
Wind speed measurement?
|
Does the Official wind speed of a storm coming out of the NHC include the forward component (i.e. ~50MPH with Wilma as I type this) or just the circular component?
Bill
| Convergence |
| (Weather Watcher) |
| Tue Oct 25 2005 09:32 PM |
Re: Wind speed measurement?
|
Just the circular component.
| Chris Bryant |
| (Verified CFHC User) |
| Wed Oct 26 2005 12:46 PM |
|
Re: Wind speed measurement?
|
That was a question I was going to ask
So.. when Wilma had 115 mph winds, and was moving at 50 mph, the winds on the east side were 165 and on the west 65?
| Convergence |
| (Weather Watcher) |
| Wed Oct 26 2005 10:11 PM |
|
Re: Wind speed measurement?
|
Quote:
That was a question I was going to ask
So.. when Wilma had 115 mph winds, and was moving at 50 mph, the winds on the east side were 165 and on the west 65?
Yes, pretty much. Vector addition! You can see why that would have been rather unpleasant for New England.
| Clark |
| (Meteorologist) |
| Sun Oct 30 2005 09:24 PM |
|
Re: Wind speed measurement?
|
The NHC intensity estimates DO include forward motion factored into them. It is inherent to recon measurements and for recurving storms they will take it into account when determining storm intensity. The other posts are incorrect in assuming that the forward speed needs to be added or subtracted into the NHC intensity.
The clearest example comes from the last discussion on Wilma:
"THE INITIAL INTENSITY OF 75 KT IS BASED ON A SATELLITE INTENSITY FROM TAFB AND RESPECT FOR THE RAPID MOTION." (http://www.nhc.noaa.gov/archive/2005/dis/al242005.discus.043.shtml?)
Most storms where forward motion needs to be accounted for are storms that are rapidly weakening in an extratropical environment and undergoing extratropical transition, for which storm asymmetry is a very important consideration. The NHC knows this and takes this into account in their estimates.