diff --git a/lib/xmet/skew_t.py b/lib/xmet/skew_t.py
index 30bb4d0..f9db523 100644
--- a/lib/xmet/skew_t.py
+++ b/lib/xmet/skew_t.py
@@ -236,20 +236,11 @@ class SkewTGraph():
 
         cr.restore()
 
-    def draw(self,
-             cr: cairo.Context,
-             x: float,
-             y: float,
-             sounding: Sounding):
-        cr.rectangle(x, y, self.width, self.height)
-        cr.clip()
-
-        self.draw_isotherms(cr, x, y)
-        self.draw_isobars(cr, x, y)
-        self.draw_adiabats(cr, x, y)
-
-        params = SoundingParameters.from_sounding(sounding)
-
+    def draw_params(self,
+                    cr: cairo.Context,
+                    x: float,
+                    y: float,
+                    params: SoundingParameters):
         if self.opts.draw_lcl:
             self.draw_special_isobar(cr, x, y, params.lcl[1])
 
@@ -271,6 +262,22 @@ class SkewTGraph():
             cr.set_source_rgb(0.8, 0.8, 1.0)
             self.draw_series(cr, x, y, params.saturated_mr_line)
 
+    def draw(self,
+             cr: cairo.Context,
+             x: float,
+             y: float,
+             sounding: Sounding,
+             params: SoundingParameters=None):
+        cr.rectangle(x, y, self.width, self.height)
+        cr.clip()
+
+        self.draw_isotherms(cr, x, y)
+        self.draw_isobars(cr, x, y)
+        self.draw_adiabats(cr, x, y)
+
+        if params is not None:
+            self.draw_params(cr, x, y, params)
+
         cr.set_source_rgb(1, 0, 0)
         self.draw_sounding(cr, x, y, sounding, lambda s: s.temp)