Small Transport; Low Wing; 2 Turbojet Eng
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 60; Flight Crew Total 14500; Flight Crew Type 3500
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control
Weather
Controller gave us descent to 7;000 from 13;000. I was in area of thunderstorms with moderate turbulence. Started descent mode in Autopilot VS mode; hit severe updraft; autopilot disconnected; airplane gained altitude at a great rate. As I gained control of aircraft I had climbed 1;800 feet. Severe turbulence; moderate rain; night time conditions.
Beech Jet Captain reported large gain of altitude in descent from severe updraft in the vicinity of thunderstorms.