Small Aircraft; High Wing; 1 Eng; Retractable Gear
Air Traffic Control Fully Certified
Situational Awareness; Confusion
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Regained Aircraft Control
Procedure; Weather
Aircraft X was a departure out of ZZZ climbing to ZZZ1 VOR. The aircraft first entered a 036 MVA climbing through 024. I issued expedite climb; but failed to issue LA (Low Altitude) alert. The aircraft reached 028 as it entered the next MVA of 037; but briefly indicated a descent to 027 before resuming a climb. The aircraft the entered a 040 MVA climbing through 031; but descended to 027; before resuming climb. At that point LA alert activated and I issued LA alert. Pilot stated they were experiencing downdrafts.[Recommend] insuring a positive climb rate.
TRACON Controller reported vectoring an aircraft that was experiencing downdrafts; below the MVA; and failed to issue low altitude alert.