NASHVILLE, Tennessee — A dramatic and rapidly evolving weather pattern is taking shape across the Southeast, Southern Appalachia, and the Tri-Cities region this week, as unseasonably hot and primarily dry conditions push temperatures into the 80s and even 90s across much of the region through April 18-19 — before a significant pattern shift brings stormier and cooler conditions back to the Southeast in the final 10 days of April.
The contrast playing out across the country right now could not be more stark. While the central United States battles a historic 5-day severe weather outbreak, the Southeast including Southern Appalachia and the Tri-Cities is sitting under a heat dome delivering summer-like temperatures weeks ahead of schedule — and the atmospheric mechanism driving that shift later this month is already in motion.
Who Is Feeling the Heat This Week
- The Tri-Cities region — including Johnson City, Kingsport, and Bristol — along with Nashville and the broader Middle Tennessee corridor are experiencing unseasonably hot conditions with highs surging into the 80s
- Southern Appalachia: Communities across the mountain region of western North Carolina, northeast Tennessee, and southwest Virginia are seeing temperatures well above normal for mid-April
- Southeast — South and East of the Region: Areas to the south and east of Southern Appalachia are experiencing even more extreme heat with highs pushing into the 90s — making this one of the hottest April stretches in recent memory for parts of the Deep South
- Broader Southeast: The hot and mainly dry pattern shown on the upper-level map covers the entire eastern United States from the Tennessee Valley southward through the Gulf Coast states
What Is Driving the Heat — And What Ends It
The current heat pattern is being driven by a dominant upper-level ridge — a dome of high pressure sitting over the eastern United States that is suppressing storm development and allowing temperatures to soar well above seasonal averages. This ridge is clearly visible on the 500mb anomaly map showing a large area of positive height anomalies — meaning the atmosphere is running significantly warmer and more stable than normal — draped across the Southeast and Mid-Atlantic.
But the pattern is not permanent. A large-scale atmospheric wave known as the Madden-Julian Oscillation is currently on the move, cycling through phases 8, 1, and 2 — a progression that historically brings increased storm activity and eventually cooler conditions back to the Western Hemisphere. This is the same type of atmospheric shift seen in March 2023 when a similar oscillation transition helped end a prolonged dry and warm period across the Southeast…