Originally Posted by
Jeff767
Anytime you fly into convective activity the onset of turbulence is rapid. In almost all cases however you have considerable notice well before that. Onboard weather radar sees storms out to at least 160 miles. Weather updates are issued. Radar overlays from ground radar stations are available on WiFi equipped aircraft. ATC broadcast warnings and offers suggested routings many times. The company dispatcher should have supplied updates. The area in question was forecast to have storms and should have been discussed in the crew briefing before the flight so the flight attendants could restructure the service schedule.
According to the analysis of AA pilot Juan Browne (YouTube video "0UYNFthOx1o"), a strong thunderstorm cell can block the signal of another cell behind it because strong radar beam reflections reduces the signal from behind. (Just look at any strong typhoon/hurricane/TC offshore on radar and you'll notice.) The second cell on the eastern half of the Burmese peninsula that SQ321 went through was apparently what caused this incident. So (1) I don't think the pilots had considerable notice, (2) any Burmese ground weather radar data go into the cockpit, (3) Burmese ATC would suggest routings. Nowadays geostationary weather satellites scan speed can outperform ground radars, and the aviation industry should improve data availability so they don't need onboard radar to see the rapidly developing second cell behind the first.