High Level Sig WX Symbol

Nick

Nick

Well-Known Member
Look at this chart:
Hi Level Sig Wx Chart

What does the +200 / -200 under the wind flight level mean? There are others on the other regions and on that on further south that is +70 / -70. I've done a search on the internet and can't find anything. Thanks.
 
This denotes the range of the winds from the designated flight level, plus or minus 20k, for example.
 
So 150 knots at FL350 +100 / -100 means 150 knots from FL250 to FL450.

Thanks!
 
The +/- applies to the wind speed not the altitude. So the interpretation of that symbol is at FL350, the winds vary from 50 to 250kt.
 
Nick

Are you sure about that? While I could not find a reference, the answer I gave matched the comparisons between some various charts. If you have a reference, I'd be interested to see it and happily stand corrected, along with my meteorologist bud...
 
Actually, I have confirmed I am correct, they are the altitudes. First off, on some charts the speed would be negative if you were correct (that was the first clue). Second one, is that I found the answer on the web. The addition was to comply with ICAO requirements, and can be read here:

http://aviationweather.gov/notice/jetdelta.shtml
 
That is actually what I meant by my response. +100 would be 10,000 feet above the level and -100 for below.
 
[ QUOTE ]
That is actually what I meant by my response. +100 would be 10,000 feet above the level and -100 for below.

[/ QUOTE ]You were correct. Part of the confusion is that seagull said
[ QUOTE ]
Nick

Are you sure about that?

[/ QUOTE ] when he actually meant [ QUOTE ]
pscraig

Are you sure about that?

[/ QUOTE ]
 
Yep, I stand corrected. After I made that post I called up Reno FSS and asked them what that symbol meant. The briefer called the weather bureau and they didn't know, but did know it was a new symbol to comply with ICAO.

Good post!
 
True, I named the wrong person on that first reply, and it wouldn't let me edit it when I realized it later.
 
[ QUOTE ]
http://aviationweather.gov/notice/jetdelta.shtml

[/ QUOTE ]

Great catch on that link! Note that the altitudes are the distance to what's considered the "edge" of the jetstream--the point beyond which the winds are less than 80 kts. In other words, the jetstream itself is defined by the lower and upper limits indicated, with peak winds at the flight level indicated. Correct?
 
You must log in or register to reply here.
Back
Top