Today's weather is literally the calm before the storm. Other than a low pressure system passing well to our north there's nothing much going on. Look for a mix of sun and clouds and a high in the low 30s. While that's warmer than yesterday a stiff westerly breeze will keep the wind chill in the 20s. Sometime this evening that low will drag a weak cold front across the region, and behind that front is the first ingredient for a snowy Saturday.

A cold, dry air mass will park itself over lower New England late tonight. By itself that high won't produce any snow, but a low pressure system moving eastward from the Ohio Valley and a coastal storm that will develop in the first storm's wake will push humid air up over the cold air mass and that will wring snow out of the air starting Saturday morning. How much snow depends on how long the cold air mass holds out against the onslaught of the coastal low.

AccuWeather says 2-4 inches for the city while the National Weather Service is calling for 4-8 inches. Inland areas and higher elevations will definitely seeing enough snow to warrant a Winter Storm Watch.

Warmer air is expected to arrive Saturday evening, right about the time when precipitation intensity should be greatest. We can expect more snow if that arrival is delayed a bit, so good thing rock salt is plentiful. Near the coast the transition from snow to rain should be fairly smooth, which is good news for anyone flying into JFK. A much more messy transition may be in store just a few miles inland, where there the snow may change to sleet and freezing rain before switching over to all rain near the tail end of the storm on Sunday morning.