Oh hey look, "We’re using weather balloons to go up to approximately 100k feet".
It also says, "Cloud cover, snow, and mechanical failure may postpone the launch, but we’re ready to give it our best shot this weekend." That was posted last Friday. No update since. Grrr.
Aha, their
wiki has more info. Seems their launch window is sometime between yesterday and tomorrow. Meanwhile, they had a successful tethered test.
Hehe, also from their wiki
"
[a fill diffuser?] diffuser determined unnecessary because gas output not strong enough to damage or shred test balloon (condom)"