** KeyBanc Capital Markets expects commodity petrochemicals markets to tighten in the U.S. as a result of winter storm Enzo, at least for one to two months

** Brokerage says immediate effect will likely be operational earnings headwinds from unplanned outages for Dow DOW.N, LyondellBasell LYB.N, Westlake WLK.N and Olin Corp OLN.N in Q1, and from higher cost of feedstocks and energy

** Adds medium-term effect of the storm may also be muted by potential trade frictions with Canada and Mexico, both important destinations for the U.S. petrochemicals exports

** KeyBanc expects companies to face logistical challenges in Q1 as a result of port closures and atypical snow conditions in the region

** However, brokerage also sees storm as a modest upside risk to coatings raw materials prices and costs of other specialty chemicals producers such as Axalta Coating Systems AXTA.N, PPG Industries PPG.N, RPM International RPM.N, Sherwin-Williams SHW.N, Celanese Corp CE.N and Eastman Chemical EMN.N

(Reporting by Pooja Menon in Bengaluru)

((Pooja.Menon@thomsonreuters.com;))