Kansas weather: When the atmosphere runs dry
Kansas, especially western Kansas, is no stranger to periods of very dry weather. The past 130 days, however, have been remarkably dry. After a heavy October rain event which caused many producers to delay wheat planting, many areas in southwest and southern Kansas have received little to no moisture. This lack of precipitation has resulted in Moderate to Extreme Drought in over 36% of the state (Figure 1) and begun to approach some impressive records detailed below.
Figure 1. Drought Monitor data as of February 6, 2018 (droughtmonitor.unl.edu).
A wetting rain (at least 0.1 inches in a 24-hour period) is considered enough to minimally recover surface moisture. The Kansas Mesonet (mesonet.ksu.edu), which measures rain (and some melted snow), shows where the dry period persists the longest by counting the days since the last wetting rain occurred across the state (Figure 2). The areas with the longest dry streak coincide with where the most intense drought conditions are being observed. All of the moisture during the past three months has persistently tracked further north and east of this region.
Figure 2. Days since last wetting rain (at least 0.1 inches) on the Kansas Mesonet (mesonet.ksu.edu).
Historically, the streaks of 120-130 days are near/at the top of the list - and dry weather is still in the forecast for the next week at least. Here are some key historical values associated with dry spells in the state:
- Longest period in Kansas without 0.1” was at Tribune, with 147 days ending on 4/15/1976.
- In Elkhart, the longest period without a wetting rain was 120 days ending on 5/6/1936. Thankfully we are still in winter but we have already surpassed that number with 121 as of 2/8/2018.
- Manhattan reached 87 days in a row without wetting rain ending on 1/10/2018. That was the longest streak on record at that location beating 12/26/1927.
Despite the streaks of no wetting rain, some periods of 147 days (using the state record) were even drier in the state.
- Ending on 2/15/1911, Ulysses (3NE station) only received 0.05” in 147 days.
- Lakin also only measured 0.05” in a 147-day period ending on 4/14/1950.
- Outside of southwest Kansas, the driest period in the state was Alton (2SW station) in Osborne County. They measured 0.13” in a 147-day period ending on 1922.
As expected, the areas which have the longest dry streaks reside in the western half of the state. The winter months are also the driest on average during the year. Combining these two elements can create some impressive dry spells like the current one. Most of the dry spells ended in either April or May with the onset of stronger storm systems impacting the region and tapping into Gulf of Mexico moisture. As we continue into early spring in 2018, we can only hope that those spring rains come soon enough!
Christopher “Chip” Redmond, Kansas Mesonet
Mary Knapp, Weather Data Library