The Wednesday Weekly (and month) Weather Review

The past 7 days continued the overall dry pattern the area has been in for the past several weeks.  There were certainly pockets of rain, mostly this past weekend, but the most widespread rain fell in South Dakota and Minnesota.

Percent of Normal Rainfall from August 6 through 12, 2014
Percent of Normal Rainfall from August 6 through 12, 2014

Percent of normal rainfall since July 1 has a high percentage North Dakota and northwestern Minnesota near the 50th percentile.

Rain Since July 1
Percent of Normal Rain since July 1.

Actual rainfall totals are presented below.  Southern Barnes County into northern LaMoure and Ransom Counties have been the driest area with our FIngal, North Dakota station recording only 0.45 inches of rain since July 1.

total rain since July 1
Total Rain Since July 1 at the NDAWN stations

Although June finished wet, this prolonged period of generally dry conditions is occurring during the warmest period of the year.  Meaning, evaporation potential is high this time of year.   Total Potential Evapotranspiration (PET) since July 1 using the Jensen-Haise equation has been in the 8″ to 9″ range since July 1.  PET is the potential evaporation that would occur if a sufficient water source were available.  Our State Climatologist via the CoCoRaHS (Community Collaborative Rain, Hail and Snow) Network has an ET (Evapotranspiration) gauge that measures actual, not potential evaporation.  His gauge in Fargo has recorded 5 inches of liquid evaporation since July 1.   

Potential Evapotransipiration since July 1, 2014
Potential Evapotransipiration since July 1, 2014

 

Because of this net loss of soil moisture, the Drought Monitor continues to show a small portion of south central North Dakota in Abnormally Dry conditions, or Drought Status D-0.  Any further continuation of these dry conditions will likely create conditions that would expand this area into other regions in North Dakota.  It is the above normal rainfall from the May through June time period that keeps the D-0 conditions from expanding to this point.

 

 

Drought Monitor from August 5, 2014
Drought Monitor from August 5, 2014

 

Not only has it been dry lately, but also cool.  That past week was one to three degrees below average across the southern one-half of North Dakota with areas near the Canadian border near or even slightly above average.  This continues the trend since October 2013 for below average temperatures in North Dakota.

 

temperature anomalies
Temperature Anomalies from August 6 through August 12

 

The National Climatic Data Center (NCDC) released their analysis of the temperature and precipitation trends for July 2014.  Last month finished as the 25th coldest on record and the 17th driest July since their records began in 1895.

July 2014 Temperature Rankings
July 2014 Temperature Rankings

 

July 2014 Precipitation Rankings
July 2014 Precipitation Rankings

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Of note, this was the 2nd straight Top 10 driest July in southeastern North Dakota.

 

Top 10 Julys
Top 10 Julys in North Dakota Climatic Zone 9 (southeastern ND)

 

With cooler than average temperatures in the past week, Growing Degree Days for both Wheat and Corn had limited increases.

 

weekly wheat GDDs
Weekly Wheat GDDs for the period of August 7 through the 12th

 

weekly corn GDDs
Corn GDDs for the period of August 7 through the 12.

That brings total GDDs for the season for those two crops to the following levels.

2014 Corn Growing Season GDDs
2014 Corn Growing Season GDDs
2014 Wheat Growing Season GDDs
2014 Wheat Growing Season GDDs

 

The next 7 days should bring an overall positive temperature anomaly for the area.  The first above average temperature week for most locations since June.  Temperatures generally in the 80s the next week with a few 90° readings expected.  Precipitation will be hit and miss with western North Dakota having more days in the next several with at least some precipitation.  But all areas will have at least the chance of seeing rainfall with the weekend, Saturday and Sunday, being the highest probability days for precipitation.

Daryl Ritchison