Pennsylvania residents should prepare for a potentially significant winter storm late this weekend. Meteorological indicators, along with weather models, suggest this could be the first major snowfall event in several years, and markedly different from storms experienced since the Blizzard of 2016.
A Shift in the Pattern
Recent winter storms in Pennsylvania have often been impacted by sleet or freezing rain, diminishing potential snowfall totals. However, current forecasts indicate temperatures – ranging from 5-15° across the state during the event – will support snowfall throughout the duration of the storm.
Timing and Potential Impacts
Snow is currently modeled to begin moving into Southern Pennsylvania Sunday morning, spreading across the southern portion of the state south of Interstate 80 by early Sunday afternoon. Snowfall is expected to be moderate to locally heavy, and due to the unusually high snowfall ratios, accumulation will occur rapidly.
If a coastal low develops and tracks far enough north, snow could exit the state from west to east on Monday morning.
Three Potential Scenarios
While the exact track and intensity remain uncertain five days out, forecasters have identified three potential scenarios, each with varying probabilities.
Scenario 1 (50% Probability)
The most likely scenario involves a coastal low developing off the Carolinas, with a secondary, weaker low forming near Alabama. This would result in a 12-18 hour storm, with major snowfall amounts – potentially exceeding 10 inches – across Southern and much of Eastern Pennsylvania.
Scenario 2 (25% Probability)
This scenario suggests a weaker storm that doesn’t fully phase with northern energy. While snowfall totals would likely be lower, significant accumulations – potentially reaching 6 inches even with minimal precipitation – are still possible along the Southern Pennsylvania border, extending as far north as Interstate 78 in Eastern Pennsylvania.
Scenario 3 (25% Probability)
The least likely scenario involves a classic “Miller A” coastal storm, with full phasing of energy from both northern and southern air streams. This could lead to an 18-28 hour storm with crippling snowfall totals – exceeding 15 inches – in parts of Pennsylvania.
What to Expect
Regardless of the specific scenario, residents in Southern and Eastern Pennsylvania should begin planning for an impactful winter storm. Given temperatures expected to remain below 15°, salt may be ineffective at melting snow, but the light, fluffy consistency of the snow should make shoveling easier.
Frequently Asked Questions
What is a snowfall ratio?
A snowfall ratio describes the amount of snow that falls for each inch of liquid precipitation. A typical ratio is 10:1, meaning 10 inches of snow for every 1 inch of precipitation. This storm is expected to have ratios of 20:1 or higher.
When will we know more about potential snowfall amounts?
A first look at potential snowfall amounts is expected at 5:00 PM Wednesday.
What areas of Pennsylvania are most likely to be impacted?
Southern and much of Eastern Pennsylvania are currently considered most likely to experience significant snowfall, though the exact extent of the impact will depend on the storm’s track and intensity.
How will you prepare for the potential impacts of this approaching winter storm?
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