Ground temperatures play key role in precipitation this weekend
For only the second time this century, Columbia has seen one of the coldest starts to a new year. Since record keeping began in the late 1800s, there have only been eight years, in which the average temperatures of the first four days fell below 10 degrees. 2018 happens to be one of those years, as the extended period of being in a deep freeze continues. At 9.3 degrees, 2018 comes in as the 6th coldest start to a new year, during a cold period that has lasted for nearly two weeks, in which the average temperature over the entire period is about 15 degrees below average.
The last time temperatures were above the freezing mark, was at 3:54 p.m. on Saturday, Dec. 23. This extended freeze has not only left many of us battling the bitter cold, but ground temperatures falling at or below freezing at least a foot into the ground. Information provided by Missouri Mesonet and the University of Missouri show that the frost line extends to a depth of 12 inches in the soil, with temperatures as low as 28 degrees 4 inches deep. It’s these temperatures that will play a key role in precipitation type as we head into the weekend.
Starting Sunday, Mid-Missouri will be heading into the start of a great thaw, but this will come at a cost. With southeasterly winds through the weekend, we’ll see the Gulf of Mexico open up and moisture begin to stream into the region. This moisture, along with a surface low over the Texas Panhandle will bring the potential for a wintry mix along with freezing rain. While surface temperatures are expected to climb through the day on Sunday, ground temperatures will play a key role.
A wintry mix consisting of sleet and freezing rain and drizzle will build into areas near Highwy 65 as early as 7 a.m. and gradually track east. Temperatures will climb above freezing by the afternoon hours, but surface ground temperatures will ultimately determine the precipitation type and could prolong the freezing rain and bring many areas more than the forecast one-tenth of an inch of ice.
Air is a fluid and will quickly modify itself based on temperatures of the surrounding environment, but with the ground being a solid, it will take some time to climb above freezing. With freezing rain looking very likely, now is the time to make sure you take the necessary precautions as Sunday nears.
For more on the timing of the system and what to expect, read our blog on the ice potential Sunday here.
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