Some tips on avoiding thunderstorm weather...
1. If you see a storm with continous lightning activity, then its up and down draughts are likely to be very severe and therefore avoid such cells by at least 20 miles in the upwind side.
2. never try to fly under a storm cell even if you can see through to the other side. You are still likely to encounter severe wind-shear and microburst drafts which can cause loss of control.
3. Remember Hail and severe turbulence can be encountered even outside a large storm cell and this is why it is a recommendation to avoid such cells in the upwind side by at least 20 miles or more.
4. If turbulence is encountered, then fly the aircraft at the recommended (Va) turbulence penetration speed as advised by the Aircraft Flight Manual.
5. If you do penetrate a cell, then do not turn as this increases aircraft stresses. The fastest way out is keeping a straight path and attitude whilst maintaining the (Va) speed setting as you accept altitude and speed variations.