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Breaking down Omega Blocking and how it affects Mid-Missouri’s weather

April of 2023 has officially ended and the rainfall totals have fallen severely short of the average of 4.88" for Columbia.

Just a handful of showers and storms passed through Columbia throughout the past month. Various high pressure systems this past month have acted as a shielding mechanism in an atmospheric pattern known as Blocking. This lead to a departure from normal of 4.3".

The latest drought monitor from the last week of April added severe drought conditions to portions of Northwestern Callaway county and extended moderate drought conditions across over six counties.

Looking into the start of May, the need for additional rainfall increases as growing season for farmers commences. Conditions from May 1st through May 3rd begin with sunshine and cooler temperatures. This means more dry time for the region. The main reasoning for these conditions paired with stronger winds points into the upper atmosphere. A pattern known as Omega blocking has set up over Colorado. The reasoning for the name of "Omega Blocking" is tied to the shape of the upper-level jet steam where a ridge like feature forms creating the shape of the greek letter omega. Because we are under an area that sees a steep change in pressure, we see gusty winds much like what we have seen Sunday the 30th. Eventually, this strong high pressure system will begin to break down and will allow for the return of showers as the second half of the week approaches.

With a combination of strong winds, low relative humidity caused by winds out of the northwest, and an already dry ground, the risk for wild fire dangerous increases. Although there are no advisories or warnings currently issued for this particular danger, burning should be postponed until after this upcoming weekend as measurable amounts of rainfall are expected.

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Chance Gotsch

Chance Gotsch grew up just south of St. Louis and moved to Columbia to attend the University of Missouri to pursue a degree in Atmospheric Sciences.

His interest in weather begin as a child when he used to be afraid of storms.

Chance joined the ABC 17 Stormtrack Weather Team in February 2021. He is currently the weekday noon meteorologist.


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