Previous work has found a strong correlation between the frontness of closure location for velar stops (measured manually from ultrasound images by a trained expert) and the frontness of the following vowel (measured by F2). In this study, semiautomatic measures of tongue frontness for vowels were made from ultrasound images of the vowel articulation. However, it was found that the acoustic measure, F2, correlated more closely with the frontness of the preceding consonant than any of the ultrasound based articulatory measures of the vowel. Explanations for why an acoustic measure of coarticulation would be better than an articulatory measure will be discussed. It may be that the ultrasound based measures do not adequately capture retraction of the tongue root, which would influence F2 and presumably affect coarticulation with the consonant. Surprisingly, it was also found that the frontness measures for the consonant were more highly correlated with F2 than the frontness measures for the vowel, suggesting that the tongue frontness measures may be indirectly affected by tongue height in some way. Overall, the manual measures of an expert appear to be superior to semiautomatically generated measures.