You could be correct, but please know, I personally spoke with someone in the Azores, (middle of the Atlantic) from the west coast U.S., on HF during recent thunderstorm activity, and this was using 100 watts of power, with an antenna only 40 feet off the ground.
Aircraft in heavy weather, even snow, will build up St. Elmo's fire and it will play havoc with communications.
I never flew a jet, but I have a lot of twin engine recip in weather time and I can tell you that at night, little green things marching across the windshield, the props lit up like rainbows, etc., do things to your communications.
Not really bad with VHF, but other stuff like Loran, for instance, which is outmoded now, but makes the point.
ADF is a good example.
As for the comments about weather radar, aircraft should stay out of storms, etc., almost every pilot tries. There are some hard noses that plow on, but no matter how hard you try there are a lot of opportunities for error.
An area of heavy rain can paint as heavy rain, so it is OK to go through it. Suddenly the rain gets heavier and heavier and the radar can no longer penetrate. Radar range is greatly reduced. Beyond whatever that range limit is, the radar is blank leading you to believe that is the end of the rain. No, it is not. It is worse.
So if the range on a jet's radar is reduced substantially, that combined with the high speed gives you a very short time to make a decision.
I know little about high speed high altitude jets, but I had 10,000 hours before I retired.
So any one of many things could have caused the beginning of the chain, but heavy weather in combination with some malfunction does seem to be the most likely. The fact that the plane took 14 minutes from the onset to the end seems to indicate that there was a malfunction in the control system or the instrumentation that gives speed and attitude information, that they managed it for a while before it beat them. That being a pure guess and probably not accurate.