Thursday, January 17, 2013

Rain To Snow Later Today South Of City

Rain and snow are on the way later today to the city's south and southeast...with the city remaining dry and cloudy as the storm system likely is unable to spread precipitation north into Philadelphia.  Modeling has generally centered in on precipitation getting into South Jersey, Delaware, and the balance of the Delmarva later this afternoon and evening, starting likely as light rain before transitioning over to snow after sunset.

There is uncertainty on how much snow falls -- and where precipitation cuts off -- later this afternoon on the northern extent but modeling does all keep the northern edge of precipitation south of the city.

While some rain has been falling off and on this morning across Delaware, there will be a few breaks in precipitation down there from time to time.  Steadier shield of precipitation will spread in again this afternoon. transitioning towards snow in areas where precipitation falls at a steadier and heavier clip.  That transition will likely take place in the evening hours.  How fast the transition takes place is dependent on precipitation rate, as a heavier rate of precipitation will help pull down some additional cold air from aloft and help the transition from rain to snow take place more effectively.  If precipitation remains light, transition over will be tougher to pull off.

That said, we think that most areas south of a Dover-Long Beach Island line should change over to snow in the evening hours and see some accumulations.  Modeling has scaled back a bit on precipitation intensity from yesterday afternoon and the result is a scaled back snowfall forecast.

We're projecting one to three inches across Southeast New Jersey and the southern half of Delaware. Some spots, particularly in Southwest Delaware near Seaford and Georgetown, could see four inches but we're favoring mainly one to three across the blue shaded areas on the map below.  A steadier/heavier band of precipitation will push through somewhere in the Delmarva and be responsible for "highest" snowfall totals but exact amounts will depend on intensity and how quick changeover takes place.

Flurries and sprinkles are possible in Millville, Smyrna, and Hammonton. If the precipitation shield nudges far enough north, you could see a coating of snow tonight but odds favor it just being a sprinkly or flurrying type of event there.

For the rest of us, mainly clouds, perhaps some radar effect as precipitation spreads in aloft but doesn't make it to the surface here.