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Sun eclipses have some noticeable effect (e.g. drop in air temperature). Inspired from Eclipse Flights (xkcd) I'm curious if eclipses are notified as NOTAM or as weather notice. How?

Never seen such notification (but there are also few sun eclipses).

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  • $\begingroup$ For whatever it's worth, I live in the totality path and the airport I fly out of (which is almost exactly in the center of the totality path) does not yet have any NOTAMs issued for the eclipse. The nearby major airport (also in the totality path, but not quite as close to the center) doesn't have one, either. It's still 3 weeks away, though, so that's not to say that they definitely won't issue one later. $\endgroup$
    – reirab
    Jul 31, 2017 at 18:32
  • $\begingroup$ Anyone flying under VFR might be more concerned that it goes completely dark for a couple of minutes, than by a temperature change! Any temp change wlll be very dependent on the wind speed and direction. Also, the speed at which the light increases can be too fast for your eyes to comfortably adjust (personal experience observing a couple of solar eclipses from the ground). $\endgroup$
    – alephzero
    Jul 31, 2017 at 21:02

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For the solar eclipse of March 20, 2015, I found this example below, seems like it's the opposite of a warning.

E) A SOLAR ECLIPSE WILL TAKE PLACE ON THE 20TH OF MARCH.
SPECIAL ROUTES HAVE BEEN DEFINED FOR FLIGHTS PLANNING TO VIEW THE ECLIPSE.
THE ROUTES ARE DEFINED AS FOLLOWS:

(...)

ANY ADDITIONAL REQUESTS FOR A SOLAR ECLIPSE PROFILE SHALL BE SENT TO REYKJAVIK OACC SHIFT MANAGER, SEE CONTACT INFO BELOW. SOLAR ECLIPSE FLIGHTS WILL BE GIVEN PRIORITY DURING THE ECLIPSE.
OTHER FLIGHTS MAY EXPECT A REROUTE AND OR LEVEL CHANGE FOR SEPARATION PURPOSES.

Regarding the temperature drop, from NASA:

Because the patch of the shadow travels faster than the speed of sound, weather systems will only be affected very locally directly under the instantaneous footprint of the eclipse. The main effect is in the "radiant heating" component which goes away suddenly at the moment of eclipse and produces a very fast temperature decrease. If the wind is blowing, your body probably exaggerates, by evaporative cooling, how large the actual temperature swing actually is.

Due to the Earth's geometry, the shadow's speed differs from location to location, the slowest equates to Mach 2.2 at 50,000 feet for an F-15 to fly along.

Even for that F-15 in constant complete darkness, every instance is a new darkness. Some sources mention the drop at the surface being 3°C (5°F), but it looks like it's not a thoroughly studied field (impact of solar eclipses on local weather).

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    $\begingroup$ Especially with the eclipse occurring in early afternoon here, I'm curious to see how daily high temperatures are affected. Totality is supposed to be around 1:30 pm here with partial from around noon to 3, IIRC, so solar power received at the surface should be quite a bit lower than usual during the time of day where daily high temperatures would normally occur. $\endgroup$
    – reirab
    Jul 31, 2017 at 18:24
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    $\begingroup$ I'd think the 3 hours of partial eclipse would have more effect on overall surface heating during the day than the 2.5 minutes of total eclipse. I've seen some discussion of it from the NWS office here (the office itself is in the totality path) and they didn't really seem to know exactly what to expect, either (which supports your statement about it not being thoroughly studied...) I'm guessing some interesting data will be collected during this eclipse, though, with it sweeping across the entire width of the U.S. $\endgroup$
    – reirab
    Jul 31, 2017 at 18:36
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    $\begingroup$ @reirab Most of the partial eclipse duration is still brighter than a typical cloudy day. As measured by a photographic light meter (or human eyeballs) the significant "darkening" only kicks in during the 15 minutes or so either side of the total phase. $\endgroup$
    – alephzero
    Jul 31, 2017 at 21:20
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    $\begingroup$ Note that the 2015 eclipse probably had a lot more demand for sightseeing flights: the only points on land it was visible from were the Faroe Islands and Svalbard, neither of which is known for sunny weather in March. $\endgroup$
    – Michael Seifert
    Aug 1, 2017 at 2:49
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    $\begingroup$ @alephzero For whatever it's worth, the temperature here started dropping about an hour and 15 minutes before the totality started and dropped sharply starting about 20-30 minutes before the totality. Overall, the temperature dropped from 89 F to 78 F from 12:15 PM to 2:00 PM (the totality was at 1:30 PM.) After 2 PM, the temperature began rising again. There's a graph here. There were no clouds in the sky, so this effect was entirely from the eclipse. $\endgroup$
    – reirab
    Aug 21, 2017 at 19:22
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I live in the totality path (totality occurred here about 45 minutes ago.) I don't see NOTAMs for the eclipse at any of the nearby airports, including one whose runway is about 1 mile from the center of the totality path.

While NOTAMs may be issued for traffic purposes as ymb1's answer points out, it seems that there's no general requirement for a NOTAM to be issued for airports in the totality path.

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