Six inches of snow or slushstorm? Estimates vary greatly
Can we expect four to six inches of snow on the ground by Thursday morning? Or is this another near miss for Philadelphia and much of the city's suburbs in a year of "penny snowfall"?
It all depends on what weather service you subscribe to.
The National Weather Service's hourly forecast Tuesday evening predicted 3.8 inches starting 5 p.m. Wednesday into early Thursday before rain kicks in again (rain should also fall Wednesday morning and afternoon before turning to flurries).
Accuweather's latest graphic Tuesday night showed three to six inches for Philadelphia and its suburbs, yet took a very hedged approach in its description of possibilities: "Many other locations in the region ... could receive anywhere from a couple of inches of slush to a foot or more of back-breaking snow and power outages. These include Washington, D.C., Baltimore, Philadelphia, New York City, Dover, Del., and Vineland, N.J."
Then there's Weather.com's take: "Lighter snow accumulations are expected from Philly to New York City. Rain should alternate with snow in Philly and New York Wednesday before changing to snow Wednesday night. Snow may continue in these areas for the Thursday morning commute."
In other words, the storm dubbed "Saturn" that dumped lots of snow on places like Minnesota and Chicago during parts of Tuesday has yet to make its intent known to much of the northern mid-Atlantic and New England.
A winter storm watch that mentioned three to five inches was expanded Tuesday afternoon to include Philadelphia and most of its surrounding counties. Chester County was under a more serious winter storm warning, with up to seven inches possible, according to the National Weather Service.
The forecast changed several times Tuesday as to whether some snow might mix in tonight, perhaps creating a little slushy accumulation by Wednesday morning.
By late afternoon today, the forecast for Philadelphia itself suggested the rain might hold off till after midnight, becoming likely on Wednesday, with snow or a wintry mix making its appearance late Wednesday afternoon.
How much snow areas will get, and how much will stick, was unclear, depending on temperatures and the timing and track of this significant storm, dubbed winter storm Saturn by the Weather Channel. Coming out of the upper Midwest, it was expected to dump more than a half-foot of snow on Chicago and Indianapolis before setting its sights on West Virginia, Virginia and Maryland, which could also see a half-foot in some areas.
Philadelphia was expected to only flirt with the freezing mark Wednesday night, so treated highways and busy streets might be mostly wet or slushy Thursday morning, while sidewalks and back roads, especially in elevated rural areas, might be more problematic.
Recent forecasts have tended to err on the high side, producing less snowfall or or more melting than expected.
Then again, snow, especially heavy snow, can sometimes create its own favorable conditions, cooling the air and ground so what falls is less likely to be wet and easily pack or turn to slush.
Things will also get windy, with gusts in the mid 30s in Philadelphia, up to 50 m.p.h. at the Shore.
Mild to moderate coastal flooding is also possible in Jersey and Delaware, along the ocean and in the bays.
For more on the forecast, see Philly.com's weather page.
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