A verb appearing as G. sûtha- “blow (of wind)” in the Gnomish Lexicon of the 1910s (GL/68), related to G. sû “noise of wind” and thus probably based on the early root ᴱ√SUH(Y)U (QL/86) as suggested by Christopher Tolkien, though he miswrote this verb as súltha (LT1A/Súlimo).
Neo-Sindarin: For purposes of Neo-Sindarin I would update this verb to ᴺS. súda- “to blow (of wind)”, since √SŪ “move with audible sound (of air)” survived in Tolkien’s later writings, but -tha was no longer a common verbal suffix in Sindarin of the 1950s and 60s.
A noun appearing as G. sû “noise of wind” in the Gnomish Lexicon of the 1910s (GL/68), probably derived from the early root ᴱ√SUHYU “air, breath, exhale, puff” as suggested by Christopher Tolkien (LT1A/Súlimo; QL/86).
Neo-Sindarin: Since Q. sú “sound of wind” appears in Tolkien’s later writings (VT47/12), I think ᴺS. sû “noise of wind” still works for Neo-Sindarin.