As summer takes hold, the atmosphere is revealing its hand, and once again, the Lezak Recurring Cycle is proving that weather is not random chaos, but a well-organized pattern we can decipher. Today, we’ll walk you through how the evolving summer pattern fits into the larger cycling pattern and what it means for your region and your industry in the weeks ahead. Whether you’re planning around agriculture, travel, energy, or events, this is where the science and the art of weather prediction come together. In our Winter Forecast Guide we had already recognized two distinct phases of this year’s LRC. Here is a graphic showcasing the two phases.
Now, take a look at this next slide for a minute.
Over the past few months, we’ve boldly put the spotlight on the Corn Belt and placed the full weight of the LRC model on the line. Back in our early spring reports, we forecast that Phase 1 of this year’s unique cycling weather pattern would return in late May and into the first half of June. We emphasized just how critical this return would be, not only to validate the pattern’s consistency, but more importantly, to bring timely rainfall and alleviate deep-rooted drought concerns across key agricultural zones. And right on schedule, the pattern has delivered.
Now that we’ve established the LRC is cycling right on schedule, it’s time to shift our focus to what unfolds every summer, not just across North America, but throughout the entire Northern Hemisphere. The recurring pattern we’ve been tracking will continue cycling through the summer months, holding steady until the atmosphere resets with the formation of the new LRC in the fall. But summer brings with it a major atmospheric shift, one driven by the intense heating of land masses under longer daylight hours.
As the sun angle increases and land surfaces heat rapidly, especially over the southwestern deserts, stronger thermal ridges develop aloft, raising mid- and upper-level heights across the continent. This expansion of hot, stable air masses begins to dominate the central and southern U.S., and as a result, the jet stream weakens and retreats northward. Why? Because the contrast between warm and cold air, the very fuel for the jet stream, diminishes significantly.
We’re beginning to see the early signs of this transition now, and we expect this shift to become much more pronounced over the next two to three weeks. It’s this evolution that typically brings an end to the spring tornado season, which historically winds down between June 15th and 25th, as the stronger dynamics retreat north with the weakening jet. This is a classic seasonal transformation, and it’s unfolding. The cycling pattern continues with the storm systems shifting north and getting weaker as we move into late June as shown below.
While many assume heat waves simply build and stagnate, it’s the LRC that determines where, when, and how these hot air masses develop, intensify, and move. The heat dome doesn’t just sit in place, it follows the recurring pattern embedded in this year’s cycle. So how will this summer’s unique pattern influence heat across the Corn Belt? Based on our analysis, we anticipate two or three notable stretches of heat, each potentially lasting no more than about a week in this region. But here’s the key thing, the timing of the rainfall that follows each hot spell. It’s that return of moisture aligned with the cycling LRC that will shape how impactful these bursts of heat are on agriculture and regional drought trends.
This next slide is a direct snapshot from the Weather 20/20 Vision Dashboard. I’ve selected the key agricultural states, and expanded a bit this week, shown below to generate this region-specific outlook. What you’re about to see gives us a powerful window into precipitation rhythm that will play out in the weeks ahead. I will work on the timing of the heat waves in the coming weeks.
| The LRC-guided forecast indicates that most areas across the Corn Belt can expect near-average rainfall this summer, with a few localized regions potentially trending below average. But here’s the reality, average may not be enough. Once daily highs consistently reach the 80s and 90s, crop water demand increases sharply and many fields will require close to 2 inches of water per week just to maintain healthy growth. That kind of weekly moisture is well above climatological norms, which means even with a normal summer, drought stress remains a possibility, especially if rain doesn’t arrive at the right time. As we’ve seen in many summers past, weather can vary sharply even within a few miles. It’s not uncommon for one county to receive timely rains and produce a bumper crop, while a neighboring field just down the road faces stress, yield loss, or increased irrigation costs. This underscores why timing, not just totals matters. And that’s exactly what the LRC helps us anticipate, not just if it will rain, but when. Speaking of timing, which is everything in agriculture and forecasting, let’s take a look at the latest 15-day forecast from the American model, the GFS. |
| It’s important to remember that we are still within Phase 1 of this year’s LRC pattern during this stretch. This means the current setup is directly tied to what we observed earlier in the season, and as we’ve shown, it’s playing out remarkably close to schedule, and now it may begin to be more influenced by the summer season influences. Looking ahead, Phase 2 is set to return in about two weeks, likely bringing with it a shift in storm tracks, rainfall distribution, and jet stream positioning. For now, the GFS offers a useful snapshot of how the current phase is expected to behave through mid-June. To learn more about how the LRC and Weather 2020’s Dashboard is saving time, money and stress for growers across the country, click HERE. |
