Saturday offers the only lingering chance of accumulating snowfall, and it’s hanging on by a very loose thread.

Saturday’s snow chance

The timing for precipitation Saturday is between the predawn hours and midday for a rather fast-moving disturbance.

On balance, computer models have shifted the track of the disturbance far enough south that precipitation should be light. For the Washington region to see accumulating snow, the precipitation needs to be heavy to cool the air; otherwise it will remain too warm for much, if any snow accumulation. In fact, rain or a rain-snow mix might fall instead.

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Remember, high temperatures are forecast to reach 60 on Friday, so they’ll need to fall a long way for accumulating snow to materialize.

The only way Washington sees accumulating snowfall is if it’s in the sweet spot where precipitation is heavy and temperatures fall to 31 or 32 degrees.

The European model tracks the disturbance far enough south for just a rain-snow mix and little accumulation. If its forecast is verified, precipitation would probably begin as light rain early Saturday morning before possibly mixing with and changing to light snow at times. A little light snow could accumulate on grassy areas but unlikely on paved surfaces.

However, the American model nudged the track of the disturbance north in its latest run. It projects more precipitation than the European model but keeps temperatures above freezing. It might suggest an inch of snow, mainly on grassy areas, if it’s right.

“But If the model makes one more shift to the north, then D.C. might be in the accumulating snow area with temps right at or below freezing,” cautions Capital Weather Gang’s winter weather expert Wes Junker.

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Right now, we would place the chance of at least an inch of accumulating snow on Saturday around 30 percent to 40 percent, down from around 50 percent Wednesday.

Because the Washington region resides right along the edge of where accumulating snow may start and stop, stay tuned to forecast updates.

No snow Sunday

The disturbance Sunday will pass too far to our north and west for snowfall. The predicted track will draw too much mild air north. Just some chilly hit-or-miss light rain showers are likely in the region Sunday afternoon and evening.

Tuesday night ice?

The third in the series of disturbances will track to our west Tuesday night. Enough cold air may linger at low levels for rain to freeze on contact in our colder areas, mainly west and north of the Beltway. This event may bear some similarity to last Monday night, when ice built up on trees and caused some problems with broken limbs and power outages. However, pavement temperatures may be high enough to avert widespread icy roads if current model projections hold.