Deadly tornadoes, large hail and damaging winds have regularly pummeled the southern United States in recent weeks, and as April turns to May, severe storms traditionally start to increase in Colorado.
But will the South’s active severe weather season translate to increased spring storm activity in Colorado?
The quick answer: no. The more detailed answer: There could be some subtle influences that increase chances for higher-end severe weather events.
Two factors have been cited as contributing to the recent severe weather across the South: an active jet stream and unusually hot sea-surface temperatures in the Gulf of Mexico. While both of those factors can also have an influence on severe storm chances in Colorado, they both need to come together, along with a wide series of smaller-scale factors, to increase severe storm chances in Colorado.
Projecting an above- or below-average severe weather season can be especially difficult in Colorado, even if other broad indicators could point to more activity for other parts of the country.
“Severe weather in Colorado is so dependent on all the right ingredients coming together in the right way,” said Paul Schlatter, a meteorologist at the National Weather Service office in Boulder. “Seasonal convective forecasting for Colorado is so dependent on all the ingredients of that day. We usually don’t get much advance notice.”
Colorado’s severe weather season typically starts to ramp up during May, while peaking in late June. Severe storms can take place in Colorado, however, as late as August and early September due to the annual monsoon season.
There are, however, subtle hints that our severe weather season may potentially lean a bit more active, including the two factors leading to severe weather in the South. The jet stream supplies the upper-level energy to produce and sustain long-lived severe thunderstorms. The Gulf of Mexico is the primary driver of surface moisture to eastern Colorado, and warmer sea-surface temperatures there can mean stronger storms here, because warmer air can hold more moisture.
Last year, The Post examined the possible strong correlation between 60-degree dew points in Denver and severe storm development (dew points are a key measure of the amount of moisture in the atmosphere). Because eastern Colorado is so much drier than other big severe weather hubs like Texas, Oklahoma, Mississippi and Alabama, moisture is often the big holdup in generating severe thunderstorms in Colorado.
“If you get the moisture, then the event itself could be more severe, because there’s more warmth in the Gulf,” Schlatter said.
But moisture is still just one part of the lengthy series of processes needed to create large hail, damaging winds and tornadoes in Colorado.
As far as Colorado’s overall severe weather outlook is concerned, it’s still probably a coin flip. While the huge west Denver metro May 2017 hail event was generally well forecasted, the massive August 2018 Colorado Springs hail storm was much more of a surprise. Large Colorado hail and severe weather events are often difficult to predict until the day of a possible outbreak of storms, and even then they can be fickle.
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