Subtle Differences in Maps For Sunday NE Storm

As most of you guys know, although I am a meteorologist, I'm not an operational forecaster here at AccuWeather, and don't have time to immerse myself into the Forecast Models [JessePedia] and am not always privy to the "collective consciousness" of all of our operational thoughts here at AccuWeather.

For Sunday's winter storm in the Northeast, I wanted to point out some subtle but important differences in the models, AccuWeather.com's official forecast, and some of our bloggers' forecasts. And remember, too, that looking at weather models for you novices is not like the old days, you don't have to hold a degree in meteorology and run a bunch of calculations in your head; services such as AccuWeather.com Professional give you simple snow/ice/rain maps and snowfall amount maps from the major models (examples shown below).

First of all, for the big cities, our official map, published last night (an update may be posted later this morning to the Headlines at right) says 1-3 inches of snow for New York City and Boston, with a mix in Philadelphia, Baltimore, and D.C. Henry's Map (PREMIUM | PRO), published this morning, leaves these cities out of any winter precipitation with the exception of Boston at around 3 inches of snow.

The high-res 4-KM WRF model from last night looks a lot different this time than it did Thursday night, so we're dealing with an entirely different storm here. There is less precipitation overall, less ice in Pennsylvania, and it believes that Philly and New York will stay in rain only (and Boston will be on the border). It also thinks Baltimore and D.C. have a shot at ice or a mix.

But the latest NMM model from overnight says that all major cities will stay in the rain, with the exception of some snow early on in Boston. AccuWeather.com Professional's Joe Bastardi [BIO] (PRO USERS READ NOW | 30-DAY FREE TRIAL) says "I think northwest of I-95 from Philadelphia northeast, this is snow tomorrow morning and the coastal areas do what the coast loves to do... changeover [to rain]."

Everyone agrees that northwest New England will get a lot of snow out of this storm. As far as maximum snowfall amounts, Henry's map says 16" but he says 18" in his text; our official map says 12 inches but we normally are conservative on that highest amount, choosing to ignore local high mountains on a large-scale map such as this. The 4-KM WRF suggests 18" in the highest mountains of eastern New York, southern Vermont, and western New Hampshire, but it usually overestimates.