The latest on Sunday’s Nor’easter: Snowfall amounts continue to increase, but still a few lingering questions | Weather

Here we go again! Another weekend, another winter storm. It certainly is an all-too-common occurrence this winter season.

With just one day before the snow starts falling again, odds seem to be increasing that much of the region will be experiencing a high impact/major snowstorm. However, a few uncertainties still remain even this close to the start of the storm. It revolves around just how close to the coast our Nor’easter will track, and how far inland the steadiest and heaviest snows will get. So let’s first start with what we know, and then discuss the lingering uncertainty.

WHAT WE KNOW

• Nor’easter definite: A coastal storm will develop on Sunday, rapidly strengthen Sunday night, and lift northeast off the Mid-Atlantic coast. This will be a powerful Nor’easter, with blizzard conditions along the shore and a widespread accumulating snow for the Northeast Corridor.
• The coast and much of New Jersey for that matter gets the most: Blizzard warnings are hoisted for the New Jersey and Delaware coasts and on Long Island. These Blizzard warnings have also been extended inland to include much of central and southern New Jersey now. These areas will see heavy snow, 50+ mph gusts, and whiteout conditions at times, in addition to easily a foot or more of snow. Keep in mind, the true definition of a blizzard does not involve snowfall amounts. You must have winds sustained or frequent gusts of 35mph or greater and visibility ¼ mile or less for at least 3 hours.
• Timing: Occasional light snow will develop during the early morning hours of Sunday, and become steadier by the afternoon. The heaviest snow likely falls from Sunday evening, through the overnight hours Sunday night, and then into first thing Monday morning.
• Type: While the majority of this storm will feature all snow, initially when the precipitation arrives early Sunday, we could see some rain mixed in near and south of I-78 and even plain rain south and east of I-95. But overall this will be a significant/major snowstorm. It will also be a heavier and wetter snow than our big late January storm. That means it’s a more troublesome snow to clear due to its heavier weight.
• Totals: There are certain things we know about expected snowfall totals, but this is the area of the most lingering uncertainty as well. A widespread accumulating and plowable snow is likely area-wide, and a heavy, wet snow that clings to everything. The closer to the coast you travel, the higher the totals will be. From roughly I-81 east to the Delaware River which would include the bulk of our region, we are now predicting 8-14 inches of snow, for much of New Jersey, the Philly area, and northern Delaware, we are predicting 14-22 inches of snow. And some locations right at the Shore could potentially see 2 feet of snow if not even a little more.
• Winds: Increasingly brisk easterly, then northeasterly, and then finally northerly winds are expected as our Nor’easter cranks up off the coast. Winds will be strongest at the shore, where 50-55mph gusts are expected. Farther inland, winds may still gust 30-40mph.
• Watches and warnings: Winter storm warnings are now in effect for all of eastern Pennsylvania, far northwestern New Jersey, and northern Delaware. These areas are likely to get at least 8 inches of snow, with 12 inches or more of snow increasingly likely the closer you are to the Delaware River. For most of central and southern New Jersey, blizzard warnings have been issued for likely blizzard conditions mentioned above at times.

WHAT STILL REMAINS A LITTLE UNCERTAIN

• Track: Just how close to the coast will the storm track. A closer to the coast track spreads the heavy snow farther inland. A more offshore track keeps the heavier snow closer to the coast.
• Totals: Our initial snowfall forecast on Friday was “conservative”, given the uncertainty in storm track and how far inland the steadier snow gets. We had 3-6 inches for the heart of our area, 6-12 inches along the I-95 corridor, and 12-18 inches east of there to the shore. In our Saturday morning update, we brought the higher amounts back a little farther west, but not all the way through the entire area. Now, we have pushed those higher amounts even further to the west with at least a foot of snow seeming more probable all the way into far eastern Pennsylvania. While most forecast model guidance seems to be pointing in that direction, we still have a couple models that show significantly less snow, especially for those in eastern Pennsylvania and points west. Case in point, our “American” computer models continue to deliver a foot or more of snow to much of our area (and even some totals up to 2 feet or more in New Jersey!), while the “European” model, while heavier compared to earlier runs, still has totals more on the order of 6 to 10 inches. That’s an incredible discrepancy just 24 hours before a storm starts, and highly unusual. So we’re now putting a lot of our region in a zone of 8 to 14 inches of total snowfall with 14 to 22 inches for most east of the Delaware River. But these numbers may still need to be adjusted.

WHAT TO WATCH FOR

• Our next round of computer model guidance comes out this evening, and hopefully we’ll start to see even better agreement amongst the guidance on expected totals.
• Snowfall amounts may still change, and have to be increased (or decreased) depending on the likely storm track that develops. Pay close attention to future forecasts for these changes.