How bright does an Iridium Flare need to be to see it during daytime?

[Fermenter]

There is an Iridium flare predicted for two mornings from now for my location.  The flare is going to happen a little less than 2 hours after sunrise (at 09:15:56), and the flare's magnitude is predicted to be a -7.3 magnitude, and at Elevation 76°.  Is this something that will be easily visible given that it is essentially full daylight at that point?  

I've never seen an Iridium flare before, and the new fleet of satellites which are going to replace this fleet will not flare like these.  So I want to make sure that I see one before they are all decommissioned and gone.

PS - The "Heavens Above" Android app is pretty sweet, they really took full advantage of a smartphone environment with that app's design.

[ecuador]

If it is -7.3 then it should be visible during the day. But it won't be impressive like it is with a dark sky as background.

[Fermenter]

1 minute ago, ecuador said:

If it is -7.3 then it should be visible during the day. But it won't be impressive like it is with a dark sky as background.

True, -7.3 would be very bright at night.  I think that simply seeing a satellite in the sky during the day is impressive, but I understand and agree with your point.  I definitely still need to bag one at night as well.  Thanks for the reply.

[ecuador]

1 hour ago, Fermenter said:

True, -7.3 would be very bright at night.  I think that simply seeing a satellite in the sky during the day is impressive, but I understand and agree with your point.  I definitely still need to bag one at night as well.  Thanks for the reply.

Well, the point is that it doesn't have to be -7.3 at night  You see, -7.3 is about 2-3 magnitudes brighter than the faintest visible during the day would be, so the difference would be a bit like seeing a 2-3 mag flare on a 5 mag sky, i.e. *visually* not as impressive as some brighter ones at night.  However, as you say, knowing how very bright it needs to be in order to be visible in the day makes it very impressive in that way. A bit like seeing M31 on a small telescope and being underwhelmed visually (faint blob), but starting to think how our eyes are collecting photons that left Andromeda 2.5 million years ago...