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We present new L-band ($1\mbox{--}2$ GHz) observations of the nearby spiralgalaxy M33 with 80 pc resolution obtained with the Karl G. Jansky Very LargeArray. The HI observations, combined with HI measurements from the Green BankTelescope, improve the spectral resolution and sensitivity ($2.8$ K rms noisein a $0.2$ km s$^{-1}$ channel) compared to previous observations. We findindividual profiles are usually non-Gaussian, harbouring line wings, multiplecomponents, and asymmetries. Given this spectral complexity, we quantify themotions in the atomic ISM through moment analysis of the spectra and fits toaligned, stacked profiles. The measured value of the HI line width dependsstrongly on the method used, with the velocity stacked profiles aligned to thepeak velocity giving the minimum value of $\sigma = 7$ km s$^{-1}$ and allother methods giving higher values ($\sigma\sim10$ km s$^{-1}$). Allmeasurements of the line width show a shallow radial trend, with $\sigma$decreasing by $\sim2$ km s$^{-1}$ from $R_{\rm gal}=0$ to $R_{\rm gal}=8$ kpc.We consider a number of energy sources that might maintain the line widthagainst turbulent dissipation, but no single source is adequate. We find excessemission relative to a Gaussian in the stacked profile line wings, ranging from9% to 26% depending on how the spectra are aligned. By splitting the line wingsinto symmetric and asymmetric components, we find that the lagging rotationaldisk accounts for one-third of the line wing flux. We also find emission farfrom the rotation axis of the galaxy in multiple discrete HI clouds, includinga filament with a projected length of $\sim8$ kpc.

Kinematics of the Atomic ISM in M33 on 80 pc scales