QNH Difference Alerts

As per Xavi J. Request, I’ve added a new Alert type: QNH Difference Alerts.

What is a QNH Difference Alert?

According to Xavi J. -an experienced glider pilot- when the difference in QNH from two airfields is higher than a particular threshold, they have mountain wave at their local airfield. This could be explained by the fact that winds tend to go from higher pressure areas to lower pressure areas. And in Xavi’s particular case, when the wind blows strongly from the North and there is marked stability, they get the valued mountain wave at La Cerdanya (LECD).
I am not sure whether lots of people will be able to benefit from this kind of alert. But, who knows? You will find out, won’t you? And then, please let me know.

How do I configure the QNH Alert?

Very easy, just navigate to the appropriate Your Preferences menu and input the airport ICAO code for both stations. Then, input the QNH difference threshold (in HPa, please).

When the QNH at the second airport is higher than that of the first airport by the amount you have just cofigured, you’ll get an alert in your email (well, of course you need to Register first, if you hadn’t before)

By the way, La Cerdanya -in the Spanish Pyrenees- is a gorgeous place for mountain soaring (they get thermal, slope and wave soaring).
At the same aerodrome, you can eat at Urvati Sidrería where Eva and Urtus will make you feel at home. And last but not least, you can get your PADI degree for high altitude scuba diving at SCUBA 0.76

2 thoughts on “QNH Difference Alerts”

  1. Sometimes, an airport will only file METAR reports from sunrise to sunset. In these cases, if the QNH in the second airfield kept changing overnight, we could be issuing alerts based on an obsolete METAR report.
    I’ve changed the code to issue alerts only for reports that are less than 60 minutes apart.

  2. Oh! and PLEASE, take into account that a difference in QNH of more than a couple of millibars (or hPa, which is the same) is highly unlikely.
    We’ve seen alerts configured to fire when the QNH difference is above 60 hPa !!!
    The winds that would result from such a pressure gradient would be tremendous! (I’ll try to find an approximate value and post it here)

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