The Banco de Mexico news comes at an interesting time.
1) Elliott Wave Count - We could be near the termination point of wave (C) or wave 3. Either way, a noticeable sell off is higher likely back towards 15.00-15.20
2) Wave relationships - As noted on the chart, wave (C) = 1.618* wave (A) near 16.44. Even if we are finishing wave 3 (not shown), wave 3 = 2.618* wave 1 = 16.71
3) Sentiment - According to the report, speculators (non-commercials) are the most short the MXN (ie-long USDMXN ) over the last 10 years - scroll down towards the bottom of the report below
( http://www.dailyfx.com/forex/technical/article/cot/2015/07/27/Gold-Ownership-Profile-Back-at-December-2013-Level.html?CMP=SFS-70160000000Nc3HAAS )
Since the trend is firmly planted to the upside, use Thursday's high as the risk level. From near current levels this provides a better than 1:2 risk to reward ratio. When consistently applied, a positive risk to reward ratio alleviates the need to be right on every trade.