PREVIEW-Mexico economy seen shrinking 6.39 pct Aug yr/yr

* What: Mexican economic growth data for August

* When: Wednesday, Oct. 28, 2:30 p.m. (2030 GMT)

* Economists' median forecast: 6.39 pct contraction

MEXICO CITY, Oct 27 (Reuters) - Mexico's economy likely shrank in August but the rate of decline continued to slow as the U.S. economy shows signs of recovery and lifts its southern trade partner, a Reuters poll showed.

The monthly IGAE survey is expected to show a 6.39 percent contraction in Mexican economic activity from a year earlier, the fourth straight month in which the decline moderated.

Roughly 80 percent of Mexico's exports head directly over the northern border, making the country's economic fate closely tied to the United States. (Reporting by Jean Luis Arce; Editing by James Dalgleish)