07/29/2025
⛈ July 29th, 5:30am- A conditional threat for severe weather is expected today. The Storm Prediction Center has highlighted much of the region in a Slight Risk (Level 2 of 5) for severe weather this afternoon and evening. Damaging winds, hail, and heavy rainfall are the primary hazards.
⚠️ Two rounds of severe weather are possible today: one to the south and one to the north. The first round will likely impact areas south of Highway 26, while the second round will likely impact areas north of Highway 26. Damaging winds, hail, and heavy rainfall are possible with both rounds.
☁️ However, low clouds and fog this morning will potentially limit the severe threat today, hence "conditional threat". If clouds erode this morning after sunrise, severe weather becomes more likely. If they do not, severe weather becomes less and less likely with every hour that passes with no relief from the clouds. Either way, severe weather is possible today, though it is heavily dependent on whether or not these pesky clouds erode as the sun rises this morning. Stay tuned!
💭 For more information about conditional threats (that are a bit “down in the weeds”), please see text below…
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So what is a “conditional threat”? A conditional severe weather threat is a threat for severe weather that depends on a certain factor or factors panning out. For today, that factor is the fog and low clouds across much of the area. The low clouds and fog act to keep the atmosphere very stable and prevent much daytime heating across the region. Storms need three things: moisture, instability, and lift. Moisture is plentiful today, hence the low clouds and fog. Actually, it could be that there’s too much moisture today. The lifting mechanism today looks on track along with an approaching cold front. The instability is the main question today, as low clouds and fog are not conducive to destabilizing the atmosphere. This goes back to the statement about too much moisture. This happens a lot in this area, where there’s so much moisture that the atmosphere handles it with low clouds and fog. For lack of better terms, the atmosphere essentially sees this much moisture in a usually dry region, screams in confusion, and produces low clouds and fog as a way to “get rid” of the moisture. Then this act of getting rid of moisture acts to also prevent storms from developing as low clouds do not allow the surface to warm up as much. Therefore, if these clouds and fog erode this morning, the atmosphere will be able to prime itself for severe weather. If not, severe weather chances drop dramatically.
So, why don’t we know this factor? Well, several of our short range weather models show the clouds clearing out and severe weather impacting the region today. However, these models tend to be a bit quick to erode away the clouds, therefore, allowing more instability to develop across the region. However, forecaster experience here suggests that the low clouds may stick around long enough to prevent significant destabilization of the atmosphere today. Therefore, it comes down to whether or not the clouds clear. If they do, severe weather is quite likely across the region today. If not, severe chances diminish significantly for every hour (after about 9am) that clouds do not erode.
So why bother putting out this graphic if severe weather is uncertain? There’s a pretty easy explanation about this… We (NWS Cheyenne/the forecaster behind this post) want to inform people of a potential hazard, such as the potential for severe weather this afternoon, even if there’s a nearly equal chance that nothing or sub-severe storms occur. This way folks can prepare for severe weather, rather than being caught unaware.
