One Final Morning Update

Everything is on track at the moment for an historic storm for the Mid-Atlantic. One major change to my map would be to drag the 10-15" line north to an E-W position through Trenton. North of that, the 6-10" line would go along I-78. And the 3-6" line would get dropped about 10 miles further south. Here are some revised snow total expectations:

NYC: 1-4" Bronx to 4-8" Staten Island/Brooklyn (higher amounts possible)
Morristown: 3-6"
New Brunswick: 6-10"
Coastal Monmouth/Ocean: 6-10" Sandy Hook, 10-15" Belmar, 12-18" Seaside Heights, 12-24" LBI
Trenton: 10-15"
Philly: 10-15" North, 12-18" Airport
Allentown: 6-10"
Atlantic/Cape May/Cumberland Counties: 15-24", with isolated higher amounts.
Wilmington: 12-20"
Dover: 15-24"+
Baltimore: 15-30"
DC: 15-30"
Delmarva: 12-24" south of Dover, 6-12" Salisbury, 2-5" Chincoteague

Sleet concern areas: Along and south of a Bethany Beach, DE-Fredricksburg, VA-Just S of Charlottesville, VA line. Some sleet still likely in NJ, but should not make major impact on final totals.

Final Forecast: 2/5-2/6 Winter Storm

You can click the map to make it bigger.

Here's my final call for the storm. Snow starts Friday early afternoon in DC and gradually spreads north and east.

Wind will crank up on the coast and blizzard conditions are likely in coastal Delaware and probably coastal NJ as well.

In terms of confidence...it's difficult to quantify. Never have been a fan of attaching probabilities to things verifying, so let me explain this to you as best I can.

On a scale of 1-10, with 10 being the most difficult, here's how I'd rank the challenge presented by this forecast for a few locations.

Richmond: 6/10
Washington DC: 3/10
Baltimore: 3/10
Delaware south: 5/10
Delaware north: 6/10
Philly: 7/10
South Jersey: 6/10
Trenton: 10/10
NYC: 10/10

Ironically, it's the areas forecasted to get hit the hardest (DC/Baltimore into NoVA) that are the easiest to forecast. This shouldn't be much of a surprise. In big events, this often happens.

The problem is multi-fold. This storm is running into a wall. This will limit how far north the snow shield can get. One model, which has been fairly reliable this season, the NAM, suddenly shifted its forecast this evening, giving NO snow to NYC and most of North Jersey and considerably cutting down on totals in South Jersey (10-12ish), Philly and parts of Delaware. Still hammered DC/Baltimore. This model was missing a critical upper air observation from New Orleans however, so I cannot put much stock into it yet. But there is definitely risk that there are underachieving totals.

My "line of demarcation" extends from Atlantic City-Wilmington, DE-York, PA.

South of this line...high confidence forecast, with the exception of the southern fringe. North of this line, there is a HIGH risk that snow totals will either be drastically less...or around what I am forecasting. In other words, it's an "all or nothing" storm (except north of I-78 in NJ...where amounts of 3-6" are likely the best you'll do in any scenario).

Unfortunately I won't have much time to comment tomorrow on this, but after the morning runs (around 11 AM), I should be able to tell you if that high risk area will be impacted or not. Otherwise, this should be it. Big winners will be DC area/Baltimore and portions of South NJ/Delmarva. I say max totals of 20-25" possible, but in reality, I wouldn't be shocked to see absolute maximums pushing 30" in these areas, especially in DE/MD/VA. Stay safe and enjoy!!

PS: Next week's storm may finally be the one that gets folks in New England some love. Stay tuned.

Quick Afternoon Update

Won't be posting my final thoughts until this evening, but the basic ideas are holding. However, just based on the continued consistency of the models, I'm likely going to be raising snowfall totals, almost across the board. This looks like an all-time top 5-10 storm for DC, Baltimore, Delaware and South Jersey...and may end up pushing top 3 status in spots. This will still be a solid hit outside of those areas, south of NYC...

Still a TON of uncertainty on that northern fringe...who gets shafted? Right now that line extends from about New Brunswick to the NY border. Someone in there might end up with 6-8", while someone not far away may end up with 1-2". Pretty solid storm from Trenton south and Richmond north/west.

Highest amounts could push 30" from interior South Jersey back through Delaware and portions of Maryland. Could be talking 20" in DC and Baltimore. Even the coast now may not see as much mixing as originally anticipated. While it will still occur, we could be looking at 14"+ even on the barrier islands of NJ and beach towns of DE.

An updated map will be put out around 10-11 PM EST tonight.

2/4 Morning Thoughts on the Weekend Storm

Won't be able to analyze much again until tonight, but just took a look at the newest NAM model data from this morning.....

Couple things to keep in mind about the NAM model. It has a fairly decent track record this winter after being much maligned the last couple of years. I have noticed that it has a tendency to get some of the bigger storms right on.

Total Precip...
ACY: 2"
Cape May: 3"
NYC: 0.2"
Morristown: 0.25"
Trenton: 1.2"
Philly: 1.7"
Baltimore: 2.2"
BWI: 2.5"
DC: 2.3"

The model shows only the coastal plain getting above freezing aloft (which would translate to sleet and/or rain). At this point, only southeast Delaware through Cape May County, NJ get there long enough to really dent snow totals.

So with that in mind...some quick ranges.

NYC: I'll keep 3-6" for now, but it's getting close to being dropped to 2-4".
North Central NJ: 3-6" should be safe for now.
New Brunswick: 4-8"
Trenton: 6-12"
Coastal Ocean/Monmouth: 6-12", with higher amounts in Ocean.
Coastal Atlantic (~ LBI-Ocean City): 7-14"
Cape May County/GSP Corridor in Atlantic County: 7-14", with chance for higher amounts
Interior South Jersey (most of Atlantic County W of GSP, Cumberland, Salem, Gloucester): 12-20", may be some isolated higher amounts from ACY-Millville...may be some isolated lower amounts in the GSP corridor.
Dover: 12-20"
Salisbury: 5-10", with higher amounts possible if sleet never materializes.
Philly: 6-12" N & W suburbs, 12-18" City, 12-20"+ Delaware/Chester Counties
Harrisburg: 6-12"
Baltimore: 12-24"
DC: 12-24"

All amounts subject to change, obviously. I'll have another (probably final) map tonight around 11 PM EST for you all.

Wednesday night update on 2/5-2/7 Storm

In what has been an incredible winter thus far, it becomes difficult to really say one storm is more than the others. This one is just another in what has been a long line of tremendous snowstorms since December for areas that don't always see the big ones.

Just to put this winter in perspective. Albany, NY has received 21.1" of snow, approaching 20" below normal. Williamsport, PA is at about 15"...or close to approximately 10" under average. Philadelphia is at 27.8", Atlantic City is at 24.6", Baltimore is at 35.6", and Washington is at 27.3" or roughly 15-25" above normal. It's well known that climatologically, snowfall behaves VERY erratically. Normal snowfall is rarely normal. It's 2-3 seasons of mega snows followed by several low total seasons that make average. This year is turning into one of the mega-snow seasons from southern NJ through DC and most of Virginia.

Enough history. Here are details. The image up top is a water vapor satellite image. It shows basically the amount of moisture in the atmosphere. Notice...the bright greens and purples over the southern US and Mexico...that's the influx of moisture that's literally coming right out of the center of the Pacific Ocean. To use a sports analogy: The southern branch of the jet stream is basically on steroids...and has been for awhile. Thus, you're getting loads of moisture. Couple that with levels of blocking in the atmosphere that have been almost unheard of in the last 20 years for how sustained they've been, and you've got cold air pouring into the Northeast and Mid Atlantic. Cold air + moisture = Fun.

So this storm will continue to lift toward the Northeast, wind itself up and scoot out to sea, somewhere south of Jersey. This means a couple things. First, it means, like the December 19th storm, there will be a tremendously significant cutoff to the northern extent of the snow. In other words, yes, you can go from 2-3" to 12" over the course of 10 miles. Second it means it looks chilly, which means most/all of what falls in many areas will be frozen (snow or sleet).

The next issue we have to address is whether or not the models are right. There are four scenarios. Two involve track, two involve speed. Mix and match for the scenarios. Does this storm pass just south off of Ocean City, MD? Does this pass off the Virginia Capes? Does it scoot out to sea at a steady clip? Or does it get blocked in by a tremendously massive storm in the middle of the Atlantic Ocean that basically blocks the storm's escape route...thus slowing it down and pouring back heavy snow. We simply can't answer these questions yet.

Right now, my feeling is that the storm will pass somewhere off of Ocean City, MD. It won't crawl out to sea, but it won't be in a major hurry either. Therefore, this increases the risk...both for areas north of southern NJ and in terms of maximum totals from Southern NJ back through Virginia.

So with this all in mind, here's my first call map based on today's model runs and trends. Areas north of a line from about Barnegat Light, NJ-Chester, PA-York, PA need to keep a VERY close eye on this. Because even a 20 mile shift in the track or a slightly slower track will mean MAJOR differences in what you see (aka, more snow). Feel pretty confident about what I have in South NJ back through DC. Totals in Virginia will also be dependent on the storm track, but there's an enhanced risk of higher totals north and west of Richmond.


Click to enlarge.

I'll be glad to post another update on Thursday.

Oh, and PS...could be doing this all over again Tuesday or Wednesday next week....albeit with a smaller storm...but still snowy.