Another winter storm is set to impact the region as we move into Tuesday and Wednesday, bringing a mix of heavy snow, ice, and rain across the Delmarva Peninsula. Snow and wintry precipitation will begin Tuesday afternoon and continue through Wednesday morning, leading to widespread travel disruptions and hazardous conditions.
This storm is developing as a new area of low pressure forms over the Deep South and tracks northeastward along a stalled frontal boundary. At the same time, a strong high-pressure system to the north will funnel cold air into the region, setting the stage for a classic overrunning event. In this setup, warm, moisture-laden air from the Gulf of Mexico moves over the dense, cold Arctic air advancing southward from Canada, creating widespread heavy snowfall from the Midwest into the Mid-Atlantic. This process, known in meteorology as isentropic ascent, drives the formation of clouds and precipitation as the warm air rises and cools.
In a winter storm overrunning setup, isentropic ascent occurs when warm, moist air is forced to rise over a cold, dense air mass at the surface. This typically happens along a stationary front or warm front, where the warm air follows sloping isentropic surfaces (constant potential temperature). As the air rises, it cools adiabatically, leading to cloud formation and precipitation.
Since winter storms involve subfreezing surface temperatures, this precipitation can fall as snow, sleet, or freezing rain, depending on the temperature profile. Stronger isentropic ascent enhances moisture transport and lift, leading to heavier and more widespread winter precipitation.
Snowfall Potential and Accumulation Estimates
The latest ensemble model guidance indicates a significant increase in snowfall probabilities across central and northern Delmarva. There is now a 60-90% chance of at least 3 inches of snow north of the Maryland-Delaware state line, with 40-60% probabilities for accumulations exceeding 6 inches from Delmar, DE to Smyrna, DE.
The heaviest snowfall totals are expected between the MD/DE line and Smyrna, where an average of 4 to 8 inches is forecast. This extends westward toward Washington, D.C.. However, localized snow bands could produce isolated totals up to 10 inches, particularly across central Delmarva.
Coastal and Southern Delmarva Impacts
Further south, near the coastal areas including Berlin and Pocomoke City, the storm will begin as snow but may transition to a mix of snow, sleet, and rain as temperatures rise above freezing. This will reduce overall snowfall totals due to melting overnight Tuesday into early Wednesday.
Meanwhile, areas further north will remain all snow, though the intensity may be slightly lower compared to central Delmarva. Regardless, this storm is shaping up to be a significant winter weather event across the region, bringing hazardous travel conditions and potential disruptions.
Stay tuned for updates as forecast details continue to evolve.