Radiometrically inferred areal observations of the atmospheric water vapor burden have been made in the 270 to 520 cm-1 spectral band over western U.S. and the extreme eastern Pacific from the NASA C-141 Kuiper Airborne Observatory. Before this very few observations from the upper troposphere and lower stratosphere over such a broad area have been made. 30600 individual observations from eight separate synoptic situations involving eight jet maxima were computer-averaged over 2¿ latitude¿2¿ longitude boxes and related to the polar continental jet. Mean water vapor burdens ranged from 4.6¿10-4 g cm-2 to 14.3¿10-4 g cm-2 at 13.4 km with a striking peak just north of the jet wind maximum over a region of strong upward vertical motion.