In recent months, the Lexington weather has been far from predictable. Warm, sunny days have quickly given way to freezing mornings, snow and sudden rainstorms.
Jumps in weather have created confusion amongst residents. The explanation lies in the distinctive terrain that surrounds the town.
Geographically, Lexington is located in the Shenandoah Valley, with the Allegheny Mountains to the west and the Blue Ridge Mountains to the east.
As storms move from the west, the Alleghenies act as a physical barrier. They remove moisture and block rain through orographic lifting, which is when the mountains force moist air upwards. The air cools and loses water as it moves up the mountains.
This air then enters the valley through a downslope wind, which is when dry air spills over a mountain slope and sinks rapidly to the valley floor. After descending, it compresses under the high atmospheric pressure of the valley floor. This process causes the air temperature to rise rapidly, according to Virginia Places.
The arrival of dry air explains why the area can experience sudden heat waves. A dry downslope wind can cause temperatures to spike by 15 degrees in a matter of hours, turning a freezing morning into a warm afternoon.
Lexington’s surrounding mountains create a distinctive atmosphere that blocks moisture and traps cold air. This leads to a meteorological process called the wedge, or cold air damming.
Cold air damming occurs when high pressure to the north pushes cold, dense air southward, according to the National Weather Service. The Blue Ridge Mountains trap the dense air, filling the Shenandoah Valley.
The dense air causes the extreme jump to cold weather. Even if other areas of the state are experiencing spring weather, the positioning of Lexington allows cold air to remain locked in place for days. This results in a local forecast that differs greatly from national weather trends.
The jet stream acts as the boundary between high-altitude arctic air and the tropical gusts from the Gulf of Mexico. Because Lexington sits in a mid-latitude transition zone, the jet stream frequently shifts over the area. This shift can be caused by the Arctic warming up or the tropics cooling down.
The jet stream pulls colder air over warmer masses when it shifts, leading to massive 30-degree temperature jumps.
While the geography provides a scientific answer for the temperature fluctuations, the practical reality remains a struggle. Students agree that the lack of day-to-day predictability is the most frustrating aspect of the recent weather.
“It’s very annoying,” said Jaqui Espana-Ramirez, ’28. “I typically have some sort of sweater or jacket with me in the morning, and then I have to carry it around in the afternoon because it is no longer cold.”
Michael Wang, ’28, said that experiencing these fluctuations is a first for him.
“Because I am from California, I am not used to this weather,” he said. “I can usually open my phone, and it will consistently be 75 degrees and sunny over there.”
