Date: 201411
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Thunderstorm; Turbulence; Icing; Rain
Light: Daylight
Aircraft: PC-12
Operator: Air Taxi
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Cruise
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Weather Radar
Reporter organization: Air Taxi
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Commercial
Human factors: Other / Unknown
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Landed As Precaution; Flight Crew Regained Aircraft Control; Flight Crew Diverted
Contributing factors: Aircraft; Weather
Primary problem: Ambiguous

Narrative: We had departed for Airport ZZZ in IMC conditions associated with a cold front passage. The frontal system was stirring up rain and thunderstorms associated with the convection. Both crew members checked weather together within 10-15 minutes prior to departure and had determined that there was sufficient room for maneuvering as we climbed to our enroute phase. We queried ATC prior to takeoff of our departure clearance to confirm the latest instructions. After departure we climbed to our cruise altitude without incident and began receiving vectors around weather by ATC. Prior to reaching our filed cruise altitude we requested right deviations based on our on-board radar indications. We were asked to expedite to 16;000 before we could receive any deviations. After leveling off at 16;000; we requested the deviations again with no response. Moments later we were asked when we could turn to the left. We replied; not for 10-15 miles. We were instructed; when able proceed to ZZZ VOR. Utilizing on-board as well as NEXRAD radar we began to inch our way around towards a course to ZZZ VOR when we encountered icing. We had already leveled off at our cruise altitude and we turned our deicing equipment on. Within moments we began to encounter heavy rain; moderate to severe turbulence and we immediately requested vectors to the closest departure from the weather. ATC responded that there were no exits (our radars; both on board as well as NEXRAD) did not show any signs of such intense weather. Within moments we encountered what felt like a downdraft and severe turbulence causing a stall warning alert; but no pusher activation. We immediately applied full power and reduced AOA; attempting to keep wings level and airspeed within maneuvering limitations. After recovering the aircraft; we [advised ATC] and requested lower altitudes for positive temperatures. We flew the RNAV 11 approach into Airport ZZZ1 and landed without issue. We performed a post-flight walk around to check for damage; but could not determine anything. We contacted Dispatch; Maintenance Control; and the Duty Manager. Be extremely cautious when flying around frontal activity (especially fast moving cold fronts.) Consider embedded thunderstorms and keep a close check on go/no-go decisions.




Synopsis: PC12 Captain experiences severe turbulence and heavy rain while attempting to fly through a cold front with thunderstorms. Neither NexRad nor onboard radar displayed the severity of the weather encountered. Once clear the flight diverts to a suitable airport.