2016 was an above average year for precipitation in Missouri and across the United States.

Source: NOAA Centers for Environmental Information.

In 2016, precipitation across the Continental United States averaged 31.70 inches. That is above average, but not a record. Figure 1 shows the precipitation trend over time. The green line represents measured precipitation, the blue line represents the linear trend over time, and the black line represents the average yearly precipitation over the reference period (1901-2000). The trend suggests that precipitation is increasing, and that the United States receives, on average, about 2 inches more precipitation per year than it did in 1895.

Some parts of the country receive more precipitation, others less. In addition to the trend, we want to see is how various regions of the country fared compared to usual. Figure 2 shows 2016 precipitation anomalies for climate divisions across the Continental United States. On the map, green represents above average precipitation, while yellow, red, and purple represent below average.

Figure 2. Source: NOAA Centers for Environmental Information.

Regions of the Pacific Northwest, Texas/Louisiana, Minnesota/Wisconsin, and the Mid-Atlantic Coast received rainfall much above average. The Mid-Atlantic Coast was impacted by 7 tropical storms (!), but none of the other regions were. Louisiana was the site of massive flooding in August that was related to an extraordinary heavy rainfall event, but not a tropical storm. (See here for my post on heavy rainfall events.)

Dry areas included Oklahoma, portions of the Northeast, and a large area centered near Atlanta, GA. This last area received as much as 18 inches of precipitation less than normal, and it has entered a drought that is graded as “Extreme” by the U.S. Drought Monitor.

Meanwhile, precipitation in the Pacific Northwest has brought much of that area out of short-term drought, and a recent set of storms hold promise for the California snowpack. Mammoth Mountain (a ski resort in the Central Sierra Nevadas) is running about 4% ahead of the October-January total for last year, and there are still 2+ weeks left in January.

Parts of California, however, were so far behind that they haven’t yet resolved the long-term drought situation. This is particularly true for a region of mid-coastal California, from about Big Sur down to Santa Barbara. This area remains in an “Exceptional” drought, and as of 12/20/2016, the Gibralter Reservoir was completely empty, and the Cachuma Reservoir was down to 8% of capacity. San Diego relies on these two reservoirs for 82% of its water supply. As I write, it is raining today in Santa Barbara, and since January 1, it has rained about 2.1 inches more than average. Hopefully, even this most stubborn remnant of the drought will finally break.

Figure 3. Source: NOAA Centers for Environmental Information.

Figure 3 shows annual precipitation in Missouri over time. Statewide, Missouri received 0.55 inches less precipitation than average, basically an average year. The trend, however, suggests that over time precipitation is increasing across the state at the rate of 0.24 inches per decade.

Looking at Figure 2 shows that precipitation varied by region of the state. The northwestern and southeastern portions of the state received above average precipitation, while the rest of the state received below average. In particular, Southwest Missouri, the area around Springfield, Branson, and Joplin, was on the edge of the dry region centered on Oklahoma, and it received 4.3 inches less than average.

For the period 1895-2016, no region of the country shows a strong trend toward decreased precipitation. The Northeast, the Ohio Valley, the Upper Midwest, and the South all show significant trends towards increased precipitation.

Sources:

City of Santa Barbara. Drought Information. Viewed online 1/10/2017 at http://www.santabarbaraca.gov/gov/depts/pw/resources/system/docs/default.asp
utm_source=WaterConservation&utm_medium=Drought&utm_campaign=QuickLink.

National Drought Mitigation Center. U.S. Drought Monitor for 1/3/2017. Viewed online 1/10/2017 at http://droughtmonitor.unl.edu.

NOAA Los Angeles/Oxnard Weather Forecast Office. Climatological Report (Daily) for January 11, 2017. Viewed online 1/12/2017 at http://w2.weather.gov/climate/index.php?wfo=lox.

NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, Average Temperature, published January 2017, retrieved on January 9, 2017 from http://www.ncdc.noaa.gov/cag.