Under these conditions the pilot recognized the signature of an approaching thunderstorm. Like the pilot of the Cardinal, he requested an immediate right turn after takeoff. During the takeoff roll the 414 pilot encountered strong crosswinds and had some control difficulties all the way down the runway. After the aircraft passed 300 feet agl, the turbulence subsided and the flight control became easier. Lightning strikes were noted 1 to 2 miles west of the airport, and the NTSB concluded that the accident occurred at the edge of a thunderstorm.
Several items are noteworthy here.
The wind shift of 30 knots that the 414 pilot reported is not something to explore in a heavily loaded aircraft during takeoff. The risk definitely outweighs the reward. Given the witnesses' statements regarding the slow climb, nose-high attitude, and wobbly wings, it's a safe bet that the Cardinal was probably climbing more slowly than VY in a futile attempt to eke out some more performance. Several significant differences in aircraft may help to explain why one flight made it. Also, the twin departed a few minutes earlier and may have had more time to gain airspeed before encountering the shear.