DC Area Likely to See Snow Sunday Evening
While weather models are still assessing the weekend storm’s intensity and path, the current forecast indicates rain Sunday morning will transition to a wintry mix and then wet snow by Sunday night. FOX 5’s Mike Thomas provides the full report.
The threat:
WASHINGTON – The D.C. area has experienced a relatively mild week compared to recent ones. Despite persistent clouds and cooler temperatures, values have stayed above freezing, helping to gradually melt the ‘snowcrete’ that has covered the region for nearly a month.
Temperatures are predicted to stay above freezing through the upcoming weekend, with Saturday possibly being the week’s nicest day, featuring partial sun and afternoon temperatures in the mid-50s.
However, a pattern shift is anticipated by Saturday night, as a significant dip in the jet stream will cause temperatures to drop into the 30s overnight into Sunday. Simultaneously, a storm system is expected to form ahead of this cold air, potentially bringing various forms of precipitation, including accumulating snow, to the D.C. area.
The big snow debate:
The primary question, naturally, is the potential snow accumulation. This remains challenging to determine accurately, even with the storm just days away.
A storm system’s trajectory and intensity are crucial factors, and weather models have consistently found these difficult to predict.
Our weather team’s current assessment leans toward the European model. Given initial temperatures well above freezing, the system would likely begin primarily as a rain event during Sunday’s early hours.
Subsequently, as a surface storm moves eastward into the Atlantic, colder air will advance behind it, associated with an inverted surface trough. This scenario could lead to rain transitioning to a mix, and potentially a period of heavy, wet snow on Sunday night.
The complexity of forecasting an inverted trough lies in the fact that accumulating snowfall typically occurs within a relatively narrow band along the trough’s axis. This implies that significant snowfall would be localized within these bands, rather than widespread across the entire region.
Pinpointing the precise location of this band is extremely difficult; we likely won’t have a clear picture until closer to Saturday evening.
Should this European Model forecast, consistently suggested over the past few days, prove accurate, then parts of our region could anticipate 1-3 inches of snow, with a potential for 3-6 inches, by the time the storm departs late Sunday night into early Monday morning.
Conversely, the American model has, for most of a day, indicated a potentially far more significant storm. Its projection involves a stronger jet stream tilt, leading to a more intense system remaining nearer to the coastline. While also starting as rain Sunday morning, this model suggests the intensifying low-pressure system would rapidly draw cold air into the DC region, causing rain to transition into widespread heavy snowfall.
This model aggressively forecasts heavy, impactful snowfall across the board, with final accumulations potentially reaching double digits.
However, most forecasters tonight concur that this particular solution is quite extreme and improbable for this storm. Although it cannot be entirely dismissed, it largely stands alone, as most other guidance by Thursday night points to more modest snowfall totals.
Therefore, if the American model’s outcome is not widely accepted, what then is the current debate? The core problem is model consistency. Weather models have frankly struggled significantly with their predictions for Sunday’s storm. Even the European model, often more reliable than its American counterpart, has shown considerable variability, shifting the system eastward for less snow, then westward for more. Forecasters prioritize consistent model runs, a quality notably absent thus far for this system.
This inconsistency stems entirely from the atmospheric pattern. Multiple pieces of atmospheric energy, rather than just one, are influencing this storm. The more elements involved in a developing system, the higher the potential for forecast inaccuracies. Consequently, a clear understanding of this system’s impact on the DC region may not emerge until Friday night or even Saturday, once all contributing energy components are thoroughly sampled and analyzed.
What to be prepared for:
Determining snowfall amounts for this event will be a last-minute decision. However, I can assure you it will not be a repeat of the late January storm.
Even post-storm, temperatures won’t be as frigid; expect no ‘snowcrete.’ This will be wet snow, and some accumulation will likely melt on contact with the ground, especially in areas where January’s snow has already disappeared due to this week’s above-freezing temperatures.
An important point to address: Many people are noting, “But it’s too warm for snow on Sunday! My weather app shows temperatures in the 40s!” While it is indeed too warm for snow initially, remember that your weather app often displays the day’s peak temperature.
However, temperatures can drop through a phenomenon called dynamic cooling, as colder air is drawn in on the backside of a storm system, driven by an upper-level trough. Thus, temperatures are expected to decrease throughout Sunday.
Our primary concern regarding timing is Sunday afternoon, and especially the evening. While we don’t currently foresee a major, city-paralyzing snowfall, its most probable timing does suggest a risk of school closures and other activity delays on Monday morning.
The extent of these impacts, however, hinges entirely on the storm system’s ultimate path and strength. To maintain forecast accuracy, we are not yet confident enough to release specific snowfall predictions.
Stay tuned:
We will continue to provide timely updates and information regarding this potential Sunday event.
To reiterate, our current assessment leans towards a lower-impact accumulating winter snowfall, rather than a significant snowstorm.
FOX 5 will keep a close watch on the situation and inform you if a more impactful system appears likely for the region.
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