diff --git a/lib/xmet/sounding.py b/lib/xmet/sounding.py
index cd384b3..ea1f192 100644
--- a/lib/xmet/sounding.py
+++ b/lib/xmet/sounding.py
@@ -220,6 +220,9 @@ class Sounding(DatabaseTable):
         series = Series()
 
         for sample in self.samples:
+            if sample.pressure is None or sample.temp is None:
+                continue
+
             series[sample.pressure] = sample.temp
 
         return series
@@ -228,7 +231,7 @@ class Sounding(DatabaseTable):
         series = Series()
 
         for sample in self.samples:
-            if sample.dewpoint is None:
+            if sample.temp is None or sample.pressure is None or sample.dewpoint is None:
                 continue
 
             tv = virtual_temp(sample.temp, sample.dewpoint, sample.pressure)
@@ -241,6 +244,9 @@ class Sounding(DatabaseTable):
         series = Series()
 
         for sample in self.samples:
+            if sample.pressure is None or sample.dewpoint is None:
+                continue
+
             series[sample.pressure] = sample.dewpoint
 
         return series
@@ -339,7 +345,12 @@ class SoundingParams():
         return 9.8076 * cape
 
     def load_sounding(self, sounding: Sounding):
-        surface = sounding.samples[0]
+        surface = None
+
+        for sample in sounding.samples:
+            if sample.temp is not None:
+                surface = sample
+                break
 
         temp_line         = sounding.follow_temp()
         virtual_temp_line = sounding.follow_virtual_temp()