Tropical air brings soggy and sultry summer weather
By Jared Shelton News-Press NOW meteorologist
June 2024 was a washout for the Mid-Missouri River Valley, with twice the average monthly rainfall coming down for much of the region, including the St. Joseph area. Early July has offered little relief from the soggy pattern, as rounds of thunderstorm activity dropped several more inches of rain over short timespans across large swaths of the area.
Flash flooding overwhelmed waterways on the southern end of the KC metro on July 1, submerging roads and walkways for several hours and even stranding motorists. The following day, torrential rain triggered flash flood warnings along the Highway 36 corridor, including in Buchanan County. That evening, a heavy thunderstorm drifted through the area, dumping high-intensity rain, in some cases for more than an hour. This added up to more than three inches in parts of central Buchanan County, which fell in relatively short order. While impactful flooding was avoided throughout the greater St. Joseph area, soaked soil could not have taken much more moisture before roads and low-lying areas began to go underwater.
Aside from flash flooding, the anomalously wet early summer pattern also has taken its toll on the Missouri River, which has sustained moderate flood stage for the past five to seven days, in some cases bursting its banks and inundating rural lowlands of Northeast Kansas and Northwest Missouri.
The recent flooding could be considered insignificant compared to major flooding that happened in years past, including in 1993 and 2018. However, the excess runoff is more than the mighty Missouri has seen locally in five years. Furthermore, catastrophic flooding has taken place this season along the Missouri and its tributaries north of the Interstate 80 corridor.
Between bouts of torrential rain, much of the heartland has been sizzling in hot, muggy air. Heat advisories have been issued due to triple-digit heat indices on at least three occasions in Northwest Missouri so far this summer, as high humidity and heat resulted in feels-like temperatures of 105 to 115 degrees.
Some would argue the soggy and sultry days have felt more like those of coastal regions across the deep south, or even a tropical rainforest. It’s a comparison that may seem hyperbolic but is more realistic than you may think as the excessive heat indices and rainfall plaguing the heartland as of late has been a direct result of tropical air surging northward.
Every year features a handful of days, and sometimes weeks, of tropical-like weather here in the central plains. So far, summer 2024 has delivered sustained streams of tropical air throughout the nation’s heartland, supporting the abundance of thunderstorm activity and highly efficient rainfall rates.
While there are multiple large-scale atmospheric regimes and smaller meteorological features that have contributed to weeks of tropical summer weather this far inland, above-average sea-surface temperatures likely have played a key role as well. This is also the case in the actual tropics, where hurricane season has gotten off to a record-breaking start, as Hurricane Beryl recently became the first category-five storm to ever form in the Atlantic basin this early in the year.
