Two persistent climate patterns in Minnesota

It is disconcerting to us in the weather and climate science professions that among the many climate changes we are measuring two problematic and persistent patterns have emerged in Minnesota over the past several years and are validated strongly by the state data: warmth and dryness. This is not to say that these patterns are universal across the state or completely consistent at any particular location. Nevertheless they are indicators of how our climate is changing and the persistence and strength of these measured trends are the reasons why Paul Huttner and I talk about them so much.

As evidence for the dryness pattern, please consider that every summer since 2005 (8 consecutive years) severe drought has unfolded and had consequence somewhere on the Minnesota landscape. This is validated by tracing the history of the Palmer Drought Index readings of -3.0 or lower across Minnesota’s climate divisions year by year. The severe drought has appeared with consistency each summer, but at different locations around the state. This year, it is especially observable in the northwestern and southwestern counties.

As evidence for the pattern of warmth, please consider the past ten months following what was an essentially “normal” September of 2011. All ten months, starting with October 2011 have shown significantly warmer than normal mean monthly temperatures (from pooled climate data all over the state). The average departure from the monthly mean over this ten month period has been +6.2 degrees F, the warmest such period in Minnesota history.

Regardless of any comprehensive explanation for what is behind these trends, this level of aberration in the state’s climate patterns is problematic and unprecedented. As consequences from these climate patterns play out don’t you think that we should be discussing in a more public way what to do?

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