Winds aloft question

[Flyforfood]

Hello again everyone,


I am still trying to prepare for an interview (hopefully), and I have once again stumped myself. My Instrument Flying Handbook is at my parents house, so I must rely on you fine people. (wink wink) Okay here is my question concerning winds aloft:

Example: At 34000 w/a = 762560. This means the winds are 260 @ 125kts and the temp. is -60.

Okay here's my problem:

Example: At 30000 w/a = 246825. Does this mean winds are 240 @ 68kts and temp. -25? Or winds are 260 @ 168 and temp. -25 ?

I was under the assumption that unless the numbers are coded with a seven or eight, then the velocity is less than 100kts and the -50/+100 rule did not apply. Thanks in advance for the help.

 

[Singlecoil]

You answered your own question. You've got it right.

 

[phishn@daves]

The only other thing you will run into would be like winds 729935
meaning the winds are 220 at (over) 200 kts, temp -35.

 

[sonofaeagle]

Valid time/Period of Use?

Can someone explain the Valid time and Period of use.

Thanks

 

[LewisU_Pilot]

Can someone explain the Valid time and Period of use.

Thanks

Comes out twice daily 0000z and 1200z valid for 24 hours.

 

[midlifeflyer]

Let's try looking at one:

DATA BASED ON 191200Z REQUESTED
VALID 191800Z FOR USE 1700-2100Z. TEMPS NEG ABV 24000 ALTITUDE
FT 3000 6000 9000 12000 18000 24000 30000 34000 39000 9500
DEN 3208+01 3318-06 2918-20 2723-32 252548 244055 254355 3209+00
PUB 3610+02 0109-05 3018-19 3014-32 262346 254453 264755 3609+00

There are three dates/times in a winds aloft forecast. Here's what they mean

DATA BASED ON 191200Z - The forecast is based on data collected 19th at 1200Z. The data is collected twice a day (every 12 hours, at 0000Z and 1200Z). The data is used generate three different forecasts, 6, 12 and 24 hours after the observation was made.

VALID 191800Z - This is one of the three different forecasts (in this case the 6 hour one) that was generated using the data that was collected at 1200Z. The data was used to forecast what the winds would be on the 19th at 1800Z.

FOR USE 1700-2100Z - use the forecast to plan flights between 1700Z and 2100Z. Think of them as the forecast's guesstimate of how long the forecast is really useful for.

If you take a look at forecasts with two valid times, you'll see that the use periods are different for each valid time. For example, the 6-hour forecast has a use period that runs from 1 hour before the valid time until 3 hours after it. The 12-hour forecast's use period begins when the 6-hour one ends and extends for 6 hours after it. The 24-hour one starts at the end of the 12-hour's use period and butts up against the beginning of the use period for the next data set.

Does that help at all?

 

[sonofaeagle]

I head that they were releasing data 4 times a day now. Is that true?

 

[User546]

I head that they were releasing data 4 times a day now. Is that true?

Not that I've seen from any official publication. They should though.