Figure 1. Source: Centers for Environmental Information.

The first 6 months of 2016 were the third hottest ever across the United States, according to data from the Centers for Environmental Information (See Figure 1). The average temperature was 50.75°F, which is 3.22°F above the average for the 20th Century.

(Click on chart for larger view.)

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Figure 2. Source: Centers for Environmental Information.

During the same period, precipitation across the country was slightly above average, at 15.58 inches (Figure 2), which is 0.27 inches above the average for the 20th Century.

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Figure 3. Source: Centers for Environmental Information.

Combined, the temperature and precipitation resulted in moister than average soil conditions as measured by the Palmer Drought Severity Index. For the first half of 2016, the PDSI was 2.61, which is 2.23 above the average for the 20th Century.

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Figure 4. Source: Centers for Environmental Information.

In Missouri, the temperature for January-June was the 7th highest on record, at 52.9°F. It was 3.1°F hotter than the average for the 20th Century.

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Figure 5. Source: Centers for Environmental Information.

Precipitation in Missouri was low, however, at 16.86 inches, a shortfall of 3.70 inches compared to the average for the 20th Century. For those of us here in St. Louis, this may come as a bit of a surprise, as our local rain has been the 5th highest on record for the first half of the year.

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Figure 6. Source: Centers for Environmental Information.

The PDSI in Missouri during January-June was 2.90, which is 2.67 above the average for the 20th Century.

I’m not sure why significantly above average temperature and below average precipitation should result in above average soil moisture. Generally, high temperature and low precipitation is thought to resulting in dry soil conditions. If anybody knows, please write a comment and let us all know.

I also follow the Palmer Hydrologic Drought Index for the Northern Rockies and Plains. The PHDI measures long-term trends in soil moisture, which are thought to affect river and reservoir levels. I follow this region because it is the watershed for the Missouri River, the most important source for drinking water in Missouri. For the first half of 2016, the PHDI in the Northern Rockies and Plains was 1.29, which ranks exactly in the middle of the years measured (since 1895).

In California, which I have also been following, the temperature for January-June was 57.1°F, the 3rd highest on record, 3.8°F above average. Precipitation has been 15.04 inches, which is 0.86 inches above average. The precipitation came primarily in the first 3 months of the year, and the last 3 have been slightly drier than average. Since the bulk of California’s water comes during the winter, it is good that those months were the above average ones. The PDSI is -2.22, which is 2.20 below average. The soil in California is still very dry.

Source:

Centers for Environmental Information. Climate at a Glance. Data accessed and downloaded 7/25/2016 at http://www.ncdc.noaa.gov/cag/time-series/us.