The models have hinted at this possibility since late last week and continue to indicate that it is a real possibility, although certainly not a lock.
For the snow to materialize, the responsible storm will need to take just the right track, far enough south to allow cold air to spill into the Mid-Atlantic and far enough north to supply sufficient moisture. If the track deviates, the Washington region would either receive more rain or no precipitation at all.
The whole set of simulations from the American (GFS) modeling system do a nice job showing the range of possible precipitation scenarios on Saturday afternoon.
Each box is a different simulation. Blue is snow. Orange and red are a wintry mix. Green is rain. White is nothing.
If a snowy scenario materializes, the effect on the region probably would be limited because of the high April sun angle and air and ground temperatures only marginally cold enough for accumulation. Here are some things to keep in mind:
- Accumulation, if any, will depend heavily on snowfall intensity and time of day.
- If the snow is light and intermittent, it will simply melt on most surfaces, day or night.
- Snow that falls steadily at night and in the early morning can accumulate, especially if moderate to heavy.
- Snow that falls between midmorning and late afternoon will have a hard time accumulating, especially on pavement, unless it is very heavy. Typically, daytime April snow melts and/or compacts faster than it can accumulate.
- Any snow accumulation will tend to be very elevation-dependent, simply because temperatures cool with altitude. Typically, during spring snowstorms, temperatures are above freezing at low elevations, which limits accumulation potential. However, snow can still pile up as you head toward the mountains.
The American model suggests that light precipitation could develop in the region before dawn Saturday, possibly starting as rain. But it suggests that any rain would quickly change to mostly snow and could be moderate to heavy at times from early in the morning through the midafternoon before tapering off.
The model shows the potential for light accumulation — perhaps an inch or two, mainly on grassy areas around the city. To the north and west, it indicates the chance of moderate accumulations, a few inches perhaps; even more in the mountains.
The European model has a similar snow forecast, maybe even a little heavier.
The Canadian model presents a similar storm evolution to the American and European models but suggests that the storm will pass a little farther south. Therefore, it forecasts somewhat lighter precipitation in the D.C. area, which would greatly cut down on snow accumulation potential. Light snow falling during the day in April with temperatures above freezing simply won’t amount to much, if anything.
If you want to see accumulating snow from this event in the immediate metro area, you want the precipitation to come in fast and furious before dawn Saturday. The American and European models come close to predicting that scenario. If it happens, Washington could receive its first inch of snow in April since 1924.
Although models presently show the chance of wet snow in the region Saturday, we expect them to bounce around in the coming days. It may not snow or snow enough to matter. But the chance is on the table, so trust we’ll be monitoring it in the coming days.