This afternoon's nor'easter forecast update suggests that South Jersey will feel far more wintry effects of this winter storm than North Jersey.


I made some slight tweaks to our snow accumulation forecast contours, but nothing major. I contemplated adjusting nothing at all, since I remain pleased with how my forecast is trending against the latest models.

Of course, that excludes the NAM, which for yet another run has pumped out more than two feet of snow across most of New Jersey. Yikes again. However, a few things, including the placement of the peak snow contours on the latest NAM, just don't make sense to me. So I'm going to continue ignoring the NAM... although this ominous possibility will stay in the back of my mind for now.

It's becoming clear that there is going to be a ridiculously tight gradient between "hardly anything" in North Jersey and "the sweet spot" in Central and South Jersey. The difference between 0 and 12 inches of snow could literally happen in the distance between I-195 and the top of the state - a short 74-mile drive along the Parkway! As you can imagine, that presents a huge forecasting challenge. The GFS, European, and Canadian all agree on this "almost too close to call forecast". I'll once again make the suggestion I've passed out on Facebook a few times already today... When you look at any snow total forecast for this storm, blur your eyes a little bit - don't look at exactly where the colors and lines fall, as there needs to be a "margin of error" to any weather forecast (especially this one).

You may notice that I pulled the rain-snow line back closer to the coast. The afternoon models were several degrees colder, both at the surface and especially at the 850mb (1 mile up) level. Colder temperatures means the duration and geographical extent of any mixing or rainfall will hug closer to the Atlantic coast. The GFS continues to confirm this "coastal rain" line of thinking, while the Euro continues to run colder and keep the precipitation almost exclusively as snow.

As I mentioned this morning, I feel quite comfortable where my forecast sits right now among the other local media meteorologists, private forecasters, and the National Weather Service. I believe it's a realistic, middle-ground forecast. Could totals nudge higher as the storm gets closer (especially if the NAM forecast holds firm)? Sure. Could the storm dip further south, pushing the snowfall bullseye further south? Sure. Am I ever going to get the snow forecast exactly perfect? Never.

"Watch" Out!

As of this writing, several weather watches have been issued in advance of our nor'easter's arrival. Remember, a watch serves as a "heads up" from the National Weather Service that potentially dangerous weather is expected within 48 hours.

--A Blizzard Watch is in effect for Atlantic, Burlington, Camden, Cumberland, Essex, Gloucester, Hudson, Mercer, Middlesex, Monmouth, Ocean, Salem, Somerset, and Union counties for Saturday morning through Sunday afternoon.

--A Winter Storm Watch has been issued for Bergen, Cape May, Hunterdon, Morris, Passaic, Sussex, and Warren counties for Saturday morning through Sunday afternoon.

--A Coastal Flood Watch calls for moderate to major flooding along tidal waterways this weekend, and includes coastal Monmouth, Ocean, Atlantic, Cape May, and Cumberland counties.

--A High Wind Watch for 60+ mph winds has been issued for coastal areas of Ocean, Atlantic, and Cape May counties.

Timeline - South Jersey

This is how I envision the storm will play out for areas south of Interstate 195... The first snowflakes from this nor'easter will arrive along the Delaware Bay Friday evening (probably after about 7 p.m.) As the snow spreads northward, bands of heavier snow will push through South Jersey from early Saturday morning through the late afternoon hours. Along the southern coast, a changeover to mostly or all rain is possible, which would limit snow totals to some extent. By sunrise on Sunday morning, the snow should be done for the southern part of New Jersey. As skies clear through Sunday afternoon, an occasionally gusty wind will probably continue.

Timeline - Central Jersey

This is how I envision the storm will play out between Interstate 195 and Interstate 78... The first snowflakes for Central Jersey will come in the early morning hours of Saturday, and steadily pick up through the rest of the morning. For the middle part of the state, the storm will peak from mid-morning to the late evening hours, with snowfall rates up to an inch per hour possible. By sunrise on Sunday morning, the snow should have largely (if not totally) tapered off. A gusty wind will likely remain through Sunday afternoon, as skies clear.

Timeline - North Jersey

This is how I envision the storm will play out north of Interstate 78... Friday stays clear for North Jersey, as the first snowflakes will probably hold off until after sunrise on Saturday. Be patient - the snowfall will eventually peak between the early afternoon and late evening hours on Saturday. The storm will start to taper off early Sunday morning, with snow showers (and light accumulations) potentially continuing through midday Sunday.

Timeline - Storm Surge

As I've been saying for several days, the risk of coastal flooding and significant beach erosion from this storm should not be underestimated. As fierce northeasterly winds push water against the Jersey Shore, ocean waves of 14 to 17 feet will be possible along with storm surge up to 4 feet.

The highest risk for flooding will occur from tidal waterways (including the ocean, bays, back bays, lagoons, etc.) at the times of high tide on Saturday and Sunday. High tide along the Atlantic Ocean will occur around 6:45 a.m. and 7:15 p.m. on Saturday, and around 7:30 a.m. and 8:00 p.m. on Sunday.

Tidal levels should return to normal on Monday.

Our next forecast update will be published around 7 a.m. Friday.

Dan Zarrow is the Chief Meteorologist for Townsquare Media New Jersey. Follow him on Facebook or Twitter for the latest forecast and realtime weather updates.