AUSTIN (KXAN) — We’ve all heard the saying “too much of a good thing can be a bad thing.”
In terms of weather across Central Texas, too many sunny days can lead to drought, and too many rainy days can lead to flooding risks. One of the weather setups that can lead to flooding is what’s called a “cutoff low.”
The jet stream is the river of air thousands of feet in the atmosphere where storm systems (or low pressure systems) “ride” along, producing the world’s weather. Typically, a storm system can move through at a fairly good clip, bringing healthy amounts of rain to an area followed by periods of dry weather before the next storm arrives.
However, at any time of the year, a low pressure system can get pinched off from the main jet, and become stalled. This is where cutoff lows get their names from.
Cutoff lows can stall over an area for a few days to even longer than a week, until something comes along to push it along, or until the jet stream moves to an area for it to get picked back up again. And while we use the term “stall” to describe it’s movement, the low will usually meander over the same area. What this means is that the area will favor wet and stormy conditions, but they won’t necessarily happen every single day.
Anytime there’s stagnant weather over an area can lead to a bad thing. And when it comes to cutoff lows and Central Texas weather, we usually see prolonged rain events when they cutoff anywhere to our south and west.
This is because the counter-clockwise flow around the low pulls in an endless supply of moisture from the Gulf of Mexico, fueling the chance for rain across Central Texas until it moves east of our area.