Snow, sleet and freezing rain to impact central and northern New Jersey
Wintry weather begins Monday night, ends Tuesday night
Morning commute impacted in central and southern New Jersey
Afternoon commute impacted in central and southern New Jersey
Up to 6 inches of snow and sleet, up to .3 inches of ice accumulation
A winter storm is bearing down on New Jersey Monday evening and promises to deliver a mixed bag of wintry precipitation to much of New Jersey over the next day and night. Tuesday travel will be difficult and dangerous in some parts of the state, depending on how long sub-freezing temperatures remain in place. Up to a half a foot of snow and sleet accumulation is expected.
As of Monday evening, a powerful area of high pressure anchored in southeastern Canada has reinforced cold air in the lowest levels of the atmosphere, including the surface. It also has pushed back the leading edge of precipitation into extreme southern New Jersey, where it has been lightly snowing and raining all day. Gradually Monday evening, as a surface low moves from the Ohio Valley into the eastern Great Lakes, warmer air will push precipitation north across the state. By daybreak, almost everyone should be seeing snow and sleet, except perhaps extreme northern New Jersey. Eventually, that warm air surge will also change precipitation type to rain — freezing or plain rain depending on surface temperature.
Of course, for New Jersey and the rest of the mid-Atlantic, the devil is always in the detail of how quickly this transition from frozen precipitation to rain occurs. This setup suggests its a prolonged bout of frozen precipitation, but I think it’s sleet that dominates the day for central and northern New Jersey. The cold surface high will do its dirty work in locking cold air in place, barely moving from its position in southern Quebec for the duration of this storm. That will encourage surface winds to maintain a northerly component, in turn making it difficult for surface cold to be scoured out by warming air surging aloft.
This is also a setup that favors icing. When snowflakes fall through the column and melt into liquid, they can refreeze into sleet if there is a sufficiently deep layer of sub-freezing air on its way down. If not, and the air just at the surface is below freezing, icing will occur. Some parts of New Jersey will see mostly sleet once warm air nudges in aloft, but others will contend with ice accrual.
As the morning progresses, the frozen/rain line will trudge north across southern New Jersey. By noon, 195 seems like a likely area for the transition line to straddle. It will gradually creep north as surface cold is overwhelmed, reaching northern New Jersey by evening. As the storm wraps up around midnight Tuesday night, temperatures will be above freezing almost everywhere except perhaps far northern New Jersey, north of Route 80. Although there will be some melting Wednesday, cleanup will be difficult as any snow and sleet accumulation will absorb the weight of rainwater that falls on top.
Central and southern New Jersey will have a harder time on the roads in the morning, while northern New Jersey commuters will have a hazardous ride home in the evening. Travel is not recommended anywhere north of 195 Tuesday. Regardless of what falls, it will be a nasty winter day.
Expect 3 to 6 inches of snow and sleet accumulation with up to .3 inches of ice accrual north and west of Route 202. South and east into the Routes 1 and 95 corridors, expect 1 to 3 inches of snow and sleet accumulation, with up to .25 inches of ice accrual. Lesser amounts, an inch or so, are expected with little to no ice accumulation are expected south and east of Philadelphia.