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Guest alexhn

Deciphering WX charts

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Guest alexhn

Hi guys,Just need a bit of help deciphering these wx charts, am unable to find a key. http://aviationweather.gov/data/iffdp/2260.gifFirstly the winds chart above - i understand that the temperature is written in numerals for each position, but the lines (or pointy bit) on the end of each wind indicator are confusing. I remember someone told me once that these indicate the wind speed.Secondly, can anyone help with this SIGWX chart? There are a few abbreviations there which are unknown to me as well as the symbol which looks like _^_ and _:(_http://aviationweather.gov/data/iffdp/2131.gif Cheers,Alex

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The wind "barbs" are vector representation of the wind direction and velocity... think of the barbs as feathers on an arrow, then the wind is blowing in the direction of the arrow. The thick barbs represent 50 kt velocity, the thin 10 kt and the half-length 5 kt.The _^_ symbols are for turbulence.There's lots of weather on the web.. check out http://weather.unisys.com/upper_air/details.html#mand


Dan Downs KCRP

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Guest benhoffman

Alex;First is the wind chart. The trianges and barbs indicate wind speed, the two numbers are the temperature and the end of the symbol with the triangles and barbs on it is the tail of the wind.Triange = 50kts Full barb = 10ktsHalf barb = 5kts E.g. triangle. full barb and half barb is 75ktsIn the chart given above, if you were flying from Sydney to Melbourne you would have a headwind and the opposite applies if going to Sydney.To work out your average wind component, plot your route of flight on the chart and find the symbols that are along your route. Add the value of these up and divide by the number of symbols.E.g. 10 symbols with total value of 500kts/10 is 50kts. Multiply this by the scheduled flight time, e.g. 5hrs. So 5hrs x50kts = 250nm extra.Now for the SIGWX (significant weather) chart. The dashed lines are turbulence. The little triangle symbol represents the intensity and the two numbers are the highest and lowest level respectivley. One triangle is light turb, two is moderate to severe.A thunderstorm is the puffy cloud looking symbol. ISOL EMBED CB means isolated, embedded cumulonimbus cloud. These are to be avoided because they mean hail/rain/icing/lightening/severe up and downdrafts.I use the weather radar from www.addongauges.com and while not perfect, its pretty good. Turbulence/hail/rain/windshear is shown and it makes avoiding bad weather much easier.The thick black lines with the barbs and triangles are the jetstream. I think the +/- numbers indicate max wind speed and the altitude in FL (ie 1000s of feet)A complete decoding guide is at http://www.flightplanning.navcanada.ca/cgi...&TypeDoc=wxsymb while if you use the flight folder at www.aviationweather.gov, just go to the page you want and click "FYI/Help" for more information.Hope this helps

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Guest alexhn

Ah i get it, thanks a lot guys!

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