Cool weather stunting crop growth; big warm up ahead!

Remember that old saying "Knee high by the 4th of July?"

Compared to last year, "Half as high by the 4th of July" appears to be the mantra in Minnesota cornfields this year.

Our cool wet spring (and chilly first 2 days of summer) has taken a toll on Minnesotans. The latest Minnesota Crop Report shows corn and other crops are feeling the chill too.

The numbers:

10" average height of the corn crop in Minnesota this week

18" Running 5 year average height of corn crop in Minnesota this week

20" average height of the corn crop in Minnesota last year at this time

Also, 25% of the corn crop in Minnesota is rated as "fair" or "poor."

KIMT TV in mason City, Iowa has the story.

One way to measure crop growth is by calcualting so called "Growing Degree Days."

UM's Dale Hicks explains.

"Temperature affects crop growth and development. Accumulation of heat during the growing season can be used as a predictor of plant developmental progress. Growing Degree Days (GDD's) is a calculation to express the heat accumulation. GDD's are calculated using the maximum and minimum daily air temperature to determine the average daily temperature. From the average temperature, the base of 50° is subtracted to arrive at the daily GDD's. There are temperature limits used when calculating GDD's because little or no growth occurs when the temperature is greater than 86°F or less than 50°F. So when the maximum temperature is above 86°, then 86 is used as the maximum temperature and when the minimum temperature is below 50°, then 50 is used as the minimum temperature for the day. Daily GDD's are summed for the season beginning May 1."

So far in 2011, most Minnesota locations are behind average in GDD.

Crop report showers cool temperatures again this past week. Black box on right highlights below average "Growing Degree Days" since May 17th.

There's no way to say for sure why 2011 is off to a slower crop start that the past 5 years, but our La Nina spring is one possible explanation. Actually this year's crop progress is closer to long term averages for Minnesota.

Pattern Change: Heat builds next week:

The good news is that next week the jet stream finally shows signs of lifting north into Canada. This should bring an extended period of warmer weather, with highs consistently in the 80s, and even a shot at 90 by late next week.

The added heat or "growing degree days" should give crops a boost in the next two weeks.

CPC 8-14 day outlook calls for warmer temps!

Hang in there...sunshine returns Friday and warmer weather is just around the corner!

PH