Impactful Winter Storm This Weekend Becoming Likely For Delmarva

Confidence continues to grow that a significant winter storm will impact much of the Mid Atlantic, including the Delmarva Peninsula, beginning Saturday night and potentially lasting into Monday. While there is still uncertainty regarding the exact track and where the heaviest snowfall sets up, the overall signal for a high impact event continues to strengthen. […]

Confidence continues to grow that a significant winter storm will impact much of the Mid Atlantic, including the Delmarva Peninsula, beginning Saturday night and potentially lasting into Monday. While there is still uncertainty regarding the exact track and where the heaviest snowfall sets up, the overall signal for a high impact event continues to strengthen.

A developing area of low pressure is expected to organize near the Texas Gulf Coast on Saturday. This system will be fueled by several pieces of upper level energy diving south into the base of a persistent long wave trough dominating much of the continental United States. As these upper level disturbances interact and begin to phase Saturday night into Sunday, surface low pressure is expected to deepen while tracking east through the southeastern states and then turning north and east toward the Virginia coastline by late Sunday.

Forecast guidance has continued to trend northward with the track of the low, largely due to improved phasing of the upper level energy. While this trend increases confidence that the storm will affect the region, it also introduces uncertainty regarding snowfall totals and precipitation type, particularly for southern and coastal locations.

At this time, confidence is high that much of the region will see moderate to heavy snowfall. Probabilities for six inches or more of snow have increased significantly, ranging from around 60 percent in the southern Poconos to as high as 80 to 90 percent near and south of the I 95 urban corridor. Many areas also have the potential to receive over one inch of liquid equivalent precipitation, which supports the potential for impactful snow totals.

Snow is expected to break out across the region late Saturday night into Sunday morning. Temperatures will be cold enough at the onset for all snow, with overnight lows dropping into the single digits across northern areas and into the teens to near 20 degrees across Delmarva. These cold temperatures should initially support efficient snow accumulation.

Snow is likely to continue through the day Sunday and may fall heavy at times, especially as northeast winds increase, particularly along the coast. Late Sunday into Sunday night, there is the potential for some mixing across southern portions of the region, including Delmarva and parts of southern New Jersey, and possibly as far north as the Philadelphia area if the low tracks close enough to the coast. Given the strength of the arctic high pressure to the north and the entrenched cold air mass, plain rain appears less likely. Any mixing would more likely involve sleet or freezing rain rather than a full changeover to rain.

If mixing does occur, a return to all snow is expected later Sunday night into early Monday as colder air reasserts itself and the system begins to pull away. Precipitation should gradually taper off across the region during the day Monday.

While confidence has increased that this will be a significant winter storm, uncertainty remains regarding where the heaviest snowfall ultimately falls. Just 24 hours ago, the primary concern was whether the storm would pass far enough south to largely miss the area. Now, the focus has shifted to whether the track becomes far enough north to introduce mixing for southern and coastal locations.

As is often the case with large winter storms, the corridor of heaviest snowfall is typically narrow, sometimes only 100 miles wide. Areas southeast of this axis may experience more mixing or lower snow totals, while areas northwest may see lighter precipitation. Because of this, it will likely take another one to two forecast cycles to better resolve where any potential blockbuster snowfall sets up within the region.

Residents across Delmarva and the surrounding Mid Atlantic should closely monitor forecast updates over the coming days, as even small shifts in the storm track could have a significant impact on snowfall totals and overall impacts.