Significant Severe Weather Threat Increasing Monday Across the Mid Atlantic

A potent storm system is expected to bring the potential for severe thunderstorms across the Mid Atlantic on Monday, including portions of the Delmarva Peninsula. Forecasters are becoming increasingly concerned about the risk for significant damaging winds as a powerful cold front sweeps east through the region. The setup begins with a deep upper level […]

A potent storm system is expected to bring the potential for severe thunderstorms across the Mid Atlantic on Monday, including portions of the Delmarva Peninsula. Forecasters are becoming increasingly concerned about the risk for significant damaging winds as a powerful cold front sweeps east through the region.

The setup begins with a deep upper level trough moving out of the Mississippi Valley and toward the Great Lakes on Monday. As this system strengthens, surface low pressure will deepen while tracking north through the Great Lakes into Canada. Trailing behind the system, a strong cold front will move toward the East Coast and is expected to cross the Mid Atlantic Monday afternoon and evening.

Ahead of the front, strong southerly winds will transport warm and increasingly humid air into the region. A warm front lifting north will allow temperatures to climb into the 60s across much of the area, with some locations potentially reaching the lower 70s. At the same time, dew points will surge toward 60 degrees, creating a more unstable and moisture rich environment ahead of the approaching cold front.

Showers are expected to develop Sunday night into Monday as warm air advection increases across the region. These showers will likely become more widespread through the day Monday as the large scale storm system approaches. Even with cloud cover and showers potentially limiting instability, the atmosphere will feature very strong wind fields capable of supporting organized severe storms.

The Storm Prediction Center has highlighted the potential for an enhancement of significant damaging winds across portions of the Mid Atlantic on Monday. Forecast models show extremely strong winds just above the surface, with winds at around 5,000 feet reaching 50 to 70 knots. When thunderstorms develop along the cold front, these winds could be transported down to the surface, producing corridors of damaging wind gusts.

In addition to the wind threat, the overall wind shear profile will be very favorable for storm organization. Forecast soundings show strong turning of winds with height, which may allow storms to rotate. If storms develop ahead of the cold front in the warm sector during the afternoon, a few supercells could form. These storms would have the potential to produce isolated tornadoes, especially from the Carolinas into eastern Virginia before moving northward.

The most likely severe weather scenario, however, involves a fast moving squall line developing along or just ahead of the cold front during the afternoon and evening. This line of storms could produce widespread damaging wind gusts, with embedded tornadoes also possible due to the intense low level wind shear.

Heavy rainfall will also accompany the storms as deep moisture moves northward into the region, with atmospheric moisture values climbing above one inch of precipitable water.

Once the cold front passes Monday night, conditions will change quickly. Much colder air will surge into the region on gusty northwest winds, bringing temperatures back closer to seasonal levels for Tuesday and Wednesday.