diff --git a/lib/xmet/skew_t.py b/lib/xmet/skew_t.py
index 783fe45..935c518 100644
--- a/lib/xmet/skew_t.py
+++ b/lib/xmet/skew_t.py
@@ -3,7 +3,7 @@ import cairo
 
 from typing    import Callable
 
-from xmet.sounding import Sounding
+from xmet.sounding import Sounding, SoundingParameters
 from xmet.thermo   import loft_parcel, moist_lapse_rate, \
                           LAPSE_RATE_DRY, PRESSURE_MAX, PRESSURE_MIN, \
                           PRESSURE_STEP