Those Key Magafters on the wind charts

[MILO]

I have been scratching around on the weather sites but can not find any descriptor for those little keylike symbols on the charts (Demon's Todays Weather post). Can anyone shed some light here?

[Rudix]

I have been scratching around on the weather sites but can not find any descriptor for those little keylike symbols on the charts (Demon's Todays Weather post). Can anyone shed some light here?

They indicate wind speed (Lines in the key "tip") and direction (shaft).

Fly safe,
Rudi

[Rudix]

If I remember each full line at the end is 10 knots, and a 1/2 line 5 knots, so if it looks like an arrow with 2 1/2 feathers, its 25 knots wind

Yep, that is correct !

[cobra]

.. those little keylike symbols on the ..

These

[cobra]

Observed Winds represented by wind barbs



The symbol highlighted in yellow (in the diagram above) is known as a "Wind Barb". The wind barb indicates the wind direction and wind speed.

Wind barbs point in the direction "from" which the wind is blowing. In the case of the diagram below, the orientation of the wind barb indicates winds from the Northeast.



The term easterly means that the winds are from the east. In the example above, the winds are out of the northeast, or northeasterly. On the otherhand, the term "eastward" means that the winds are blowing towards the east.

Wind speed is given here in the units of "knots" (knt). A "Knot" is a nautical mile per hour.

1 Knot = 1.15 Miles Per Hour (MPH)

1 Knot = 1.9 Kilometers Per Hour (KM/HR)

Each short barb represents 5 knots, each long barb 10 knots. A long barb and a short barb is 15 knots, simply by adding the value of each barb together (10 knots + 5 knots = 15 knots). If only a station circle is plotted, the winds are calm.



Pennants are 50 knots. Therefore, the last wind example in the chart below has a wind speed of 65 knots. (50 knots + 10 knots + 5 knots).

The chart below spans the entire spectrum of cloud cover reports, from clear to overcast skies.






Site - http://ww2010.atmos.uiuc.edu/(Gh)/guide ... s/wnd.rxml

[John Boucher]

Cobra

Wind Direction indicated as all should know is True and not corrected!

[skybound®]

Cobra

Wind Direction indicated as all should know is True and not corrected!

Except for the TAFs and METARs. They are corrected. Basically surface winds (below 15m) are magnetic.

Upper air winds are as you say - true.

[John Boucher]

FOR THOSE WHO ARE INQUISITIVE......

http://aviationweather.gov/static/help/taf-decode.shtml

[John Young]

Hi Guys,

Nice thread - only thing missing is a "wind rose".

Below is an example (left hand panel) of a basic wind rose constructed from an 8-point compass.

Each arm or petal of the rose covers wind directions in percentages - remember that wind "comes from" and a sea current "sets to".

Wind roses lose some of their flowery demeanor when statistics are added to the rose such as the wind rose with speed intervals (right hand panel) where the frequency of wind speed categories (indicated by the width of the line) within that particular direction are plotted.

Wind roses generally apply for a given month - so each area will have a set of 12 wind roses.

Personally, I prefer wind roses that have barbs for wind speed using the length of the line to see the frequency percentages.

Will see if I can find examples for our locations.

Regards
John ZU-CIB

[John Young]

Hi Guys,

Have found these wind roses.

Although they don't have barbs, it is very interesting to compare the August wind roses for Cape Town, Durban and Johannesburg (shown below).

No wonder that our buddies in Cape Town fly less than us during August.

Johannesburg is by far the best.

Regards
John ZU-CIB

[Dre'man]

In Jhb we have had particularly good weather for the past couple of months. But i think the August winds are upon us now.

[Dre'man]

Sorry connetivity going on th blink, duplication of post

[John Young]

In Jhb we have had particularly good weather for the past couple of months.

We know - how many Mr. Greens to prove it?

Regards
John ZU-CIB

[MILO]

Nice replies, some individuals did some research. Thanks for the feedback :D :D