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Disconnect between METAR & NAVLOG winds Messages in this topic - RSS

Flyhound
Flyhound
Posts: 2

20 days ago
I love flight planning with iFlightPlanner overall. My biggest problem is a big disconnect between the METAR data shown on the graphic map for my flight, and the winds in the NAVLOG. Just this morning, I'm planning a flight to KAWO and the METAR data on the chart shows the winds at KAWO to be 020 degrees at 5 knots. The NAVLOG produces for my flight shows the winds at KAWO to be 104 degrees at 14 knots. That's a BIG difference. It can't be explained by altitude because my flight is just at 1500' and the winds aloft shows the winds at KAWO to only be 149 degrees at 4 knots at 3,000'. So, where does the wind data for the NAVLOG come from?
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John Burnside
John Burnside
Posts: 207

20 days ago
Thanks for your post! We're always happy to answer questions.

The wind data used depends on the date/time of your flight. The National Weather Service produces wind forecasts at many different altitudes in six hour forecast increments and updates these forecasts four times per day. When producing a navigation log, the flight planning engine determines the best wind forecast to use for each part of your route. When your scheduled departure date is outside the timeframe of current wind forecasts, historical wind data will be used.

For example, if you perform initial planning for a flight five days from now, historical winds would be used. As you get closer to the flight day/time, we recommend generating a new nav log to utilize currently forecasted winds.

METARs are not used in generating nav logs because the wind data in a METAR is an observation from the past (typically within the last hour) rather than a forecast looking ahead to the actual time of your flight. TAFs would be more helpful as a forecast mechanism but don't include winds aloft data.

We're happy to investigate odd scenarios like the one you described in your post if you can provide further details, especially the departure, destination, route, departure date, and cruise airspeed. It can sometimes be difficult to reconstruct the result, though, as the forecasts may have changed.

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John Burnside
Co-Founder, Director of Technology
iFlightPlanner.com
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