Jonas 2016: ♫ People Are Blowing Snow ♫

If you haven’t thought of the Weezer song with regard to this storm, you’ve failed me. It deserves some parody. I tried. Oh well. Onward…

What’s changed since yesterday, Matt?

Not much. Other than bread and milk supplies in the grocery store being dwindled.

  • The storm is still coming.
  • It still appears the metro Washington, DC area is the bullseye for snow.
  • Coastal flooding is still a serious concern.
  • Blizzard Watches have been expanded to include much of Jersey, Philly, and the New York City area and Blizzard Warnings are posted for DC and Baltimore.
  • The northern edge of the storm is still going to drive most meteorologists to their local bar.

So how much snow for me?

Here’s my updated map:

012116_Snow_Forecast
My own personal snow forecast as of 5:30 PM ET Thursday. Again, not official, but my way of expressing it.

Again, I’ve highlighted the two key areas of uncertainty. The northern fringe is going to be a royal pain. There are some models that still bring good snow 8-12″ to NYC, but I don’t personally buy that scenario right now. Based on my experience, these sorts of storms have disappointed on the northern fringe, so I’d rather take a conservative stance there.

From Philly into Baltimore and DC, it gets complicated too. You’ll have a number of factors driving snow totals. I expect there to be issues with mixing in spots. Convection (thunderstorms…yes, thundersnow) will also be likely with this storm. In those cases, sometimes strong bands of snow setup over one place and effectively “rob” another of snowfall. So it’s possible that the final snow totals will not look this uniform. You could easily go from 18″ one place, to 10-12″ a couple towns over, back to 18″ a couple towns over from that. It’s chaotic. Snow forecasts aren’t meant to be simple.

What about the blizzard part?

Yes, Blizzard Watches and Warnings are posted all over. Fun fact: The amount of snow you see has 0 factor in whether or not a storm is defined as a blizzard. Why is that? My honest answer is because we like to make things difficult on ourselves as forecasters and communicators. That aside, it has to do with impacts mostly. A blizzard is supposed to mean wind, which limits how many storms meet the criteria of one…thus making it special and making it stand out.

For a storm to be a blizzard, it has to have 3 hours of winds sustained at or frequently gusting to 35 mph and visibility below 1/4 mile. That’s all. So we’ll see if that gets achieved, but based on model data, yes, it looks like blizzard criteria will be met at many places. For the sake of yourself, stay home Saturday.

How about the coastal flooding?

Here are the very latest tidal forecasts for Cape May, Atlantic City, and Sandy Hook. You can select others from those sites.

I heard this was going to be like Sandy?

Here’s something that agitated me today. I heard from several people somewhat panicked, thinking this was going to be Sandy II. Sandy was a 940 mb monster storm to the south of NJ, that was dragging days of water across the Atlantic Ocean directly into Jersey and New York. This storm will be strong, but it will be moving away from the coast. It won’t have nearly the same characteristics as Sandy did. Meteorologically, it’s like comparing apples to oranges.

But in terms of actual impact what does it mean? It means something worse than what you saw back in October with Joaquin, but short of what you saw in Sandy. It means a lot of water, yes, and major coastal flooding and a top 10 event perhaps. It means problems. The coast is more vulnerable now than it was 5 years ago.

That said, it does not mean mass devastation like was seen in Sandy. So you are right to be preparing and be concerned. But should you panic? No. Make your preparations as you would for any major coastal storm. Remain calm and heed the forecasts of the National Weather Service.

This will likely be my final forecast post on this storm. Thanks for reading and hope you have some time to enjoy the power of nature without being impacted too hard.

Follow me on Twitter @mattlanza.

Jonas 2016: Make Snow Forecasting Great Again

I don’t have any mom texts to run with today, but I do have a map. We’ll get to that shortly. Let’s break things down.

So what’s changed since yesterday, Matt?

Honestly? Not much really. We still have a storm. It’s still early in the game for snow forecast maps, but we can at least make some assumptions. We still have a major coastal flooding issue to deal with. We do have blizzard watches posted, among other NWS watches and warnings. All this means is “prepare for a snowstorm.”

Where are the watches and warnings?

Glad you asked. Here:

012016_snowwarnings
National Weather Service Watch/Warning Map as of 5:45 ET Wednesday

In the East, the purple are winter weather advisories, the blue winter storm watches, the pink winter storm warnings, and the green near DC is a Blizzard Watch. Consult your local NWS office website for what it all means exactly, but the bottom line is a major winter storm is going impact places from Central Arkansas to New York City.

Has the coastal flooding idea changed?

Not really. There have been some forecast tweaks, but overall you’re still looking at a top 5-10 coastal flooding event along the Jersey and Delaware Shore, and possibly for places south and north of there also. Basically, this should be the worst you’ve seen since Sandy. It should *not* match Sandy in most places (though in Cape May and Delaware it’s going to come close), but I don’t want that to diminish the significance. The coast is far more vulnerable in spots now than it was then, so just because it’s not Sandy II, does not mean it’s going to bust. This is a big deal. Here are the very latest tidal forecasts for Cape May, Atlantic City, and Sandy Hook.

This flooding event will rival some of the great nor’easters in memory. Think Ash Wednesday 1962, Halloween 1991, December 1992. This storm will have elements of those storms and it should be treated seriously if you live on the coast or back bays.

Alright, so talk to me about snow.

Here is *my* snow forecast thinking. This is not an official forecast. It’s subject to change, and you should always consult the official NWS forecast or local TV for the most up to date info. Yes, I’m a native of Jersey and spent 5 winters drawing snow maps in Upstate New York when I worked in Syracuse and Utica, but I live in Texas now. I can only do so much.

012016_Snow_Forecast
My snow forecast as of Wednesday evening. Not an official forecast, just my own opinion.

What do I think? Some key points.

The northern fringe of this storm is an absolute nightmare. If you live north of I-195 in NJ or I-76 in PA, this is going to be an incredibly difficult forecast to peg down. The tight gradient in snowfall that I spoke of yesterday is going to wreak havoc. A 20 mile shift in track of the storm (highly possible) could lead to a 6-12″ difference in snow totals, if not more. This is going to be a big problem for North Jersey, possibly the Harrisburg metro area, New York City and extreme southern Connecticut/Long Island.

The Jersey Shore is oscillating between a total mix scenario and a thumping snow. I don’t think this is like the storms of 2009 and 2010, where coastal South Jersey absolutely raked in snow totals. This will be more complex, and I’ve cautiously gone about 3-6″ there, but I do see risk for higher amounts depending on the exact final track.

The thump zone for this will be Northern/Western Virginia through DC and Baltimore. While I don’t expect a uniform 18-24″ in that zone, I do expect some locations to push 30″, contingent on mixing and thunderstorm potential. Other areas will see less than 18″. That’s the nature of snowstorms like this.

Yes, thunder is going to be likely from VA through NJ with this I think.

Winds of 30-50 mph are likely, and some gusts could be even stronger. This will create blizzard conditions. I would not be shocked to see Blizzard Watches expanded tomorrow.

Anything else I should know?

Snowstorms are fun. This one is going to be big, massive, and historic. While fun, it has a very serious element to it that should be respected. If you have plans on Saturday, I would strongly consider rescheduling them. Heed the warnings from NWS. They’re not just throwing this stuff out there. It’s serious.

And please consider taking pictures of something other than your patio furniture. Seriously. Get creative!

Follow me on Twitter @mattlanza.

Your East Coast Winter Storm Run-Up Survival Guide

As a forecaster and communicator, I try and approach my audience a lot like I would my mother. Would my mom understand what I’m talking about? Sometimes I deviate and get nerdy; we all do. But when it comes to the forecast details, it has to be simple, clear, and easy to understand.

So my mother sent me an interesting text message today. She said:

Ok. I’m getting anxious. Or curious. I’ve heard so many maybe this or maybe that’s. I want the truth. I’m sick of speculation.

That’s such a great mom text.

In the run up to this major East Coast winter storm, blizzard, Winter Storm Jonas, whatever you use to describe it, you’re going to get a ton of this speculation.

So today, you’re all my mother, and consider this my survival guide for you.

What’s going on here?

The weather models have been hooked on this idea of a major winter storm in the Eastern US for awhile now. There is good agreement among all the various models we use that something is going to happen. Someone’s getting a major storm.

So how much snow am I getting?

No one can answer that question today unfortunately. What we know is that a number of factors are going to contribute to this storm being loaded with moisture. In other words, someone is going to get a *lot* of snow. It’s just not possible to say who that is yet.

Right, right, I get that, but give me your best shot.

This storm is big, slow, and it has a number of complex parts to it that will make it difficult to peg down until we are closer in than usual. But, some trends have evolved in the last couple days that lead us to believe a few facts about this storm.

First, it will be a *big* storm. That means even if you don’t get snow, you may get impacts. It will be slow moving. It will have wind…lots of wind. It will have major, major coastal impacts. Depending on track, we could be looking at a top 5-10 coastal flooding event for folks from the Jersey Shore into Virginia perhaps. That is a serious issue.

But what about snow? The storm has slowly trended south on the weather models. Additionally, it has a very, very sharp gradient on the north side. In plain English? If you live on the northern fringe of this storm, there’s going to be a razor thin margin between major snow and conversational snow.

Here now, a map of where I think things stand as of Tuesday afternoon. Remember, this is subject to change.

011916_snowrisk
My Own Tuesday Evening Snow Synopsis for the Weekend

The trouble is in New England, New York City, and Northern NJ. The models show a tremendous cutoff in snowfall here. The next map is a weather model’s output for precipitation (liquid, not snow). I’ve focused on the NYC area.

011916_precip
18z GFS Model Precip for New York City area (Weather Bell)

Why am I showing this? Notice how in the Central Jersey area, the model spits out about 1.5″ liquid. Go 50 miles north from there. So, like Orange County, NY? About 0.5″ liquid. A 1″ liquid is roughly equivalent to about 10″ of snow. So 10″ snow difference over 50 miles, and the reality is likely that it will be even sharper than this. You’re talking about (surprise!) a major difference in snow totals likely over a short distance over a major population center.

Bottom line in all this: I have higher confidence in heavy snow hitting Virginia and probably DC right now than I do for the Northern half of NJ, New York, or New England. I don’t focus on North Carolina much since the majority of my family and friends are between DC and Boston. But this has potential to be a big storm in a good chunk of NC also.

Alright, so when does all this unfold?

Snow should start in Virginia as early as later Friday morning, and it probably won’t end until about Saturday night. In Philly, it’s a Friday afternoon start and late Saturday night finish. Add a couple hours to all this as you go north to NYC. I have lower confidence in anything further north, so I won’t speculate beyond this.

What about this coastal flooding?

Yeah, this one goes unchecked sometimes. Snow is way sexier, but this is way more damaging potentially. The NWS office in Mount Holly has done an excellent job highlighting this risk. If you look at storm surge guidance for Cape May, NJ, you’ll see the first high tide cycle impacted late Friday ends up at a water level of about 8.5-8.7 feet. Sandy saw a tide level of 8.9 feet there, October 29, 2011 was 8.7 feet, the December 1992 nor’easter was 8.6 feet. An 8.5 foot tide level would rank in the top 8 all time at Cape May. This one’s big. It’s like a 90’s throwback nor’easter.

011916_Cape May
Cape May Surge Guidance shows a tidal level over 8.5′ Friday night/Saturday AM. This would be a top 10 event without much trouble. (NOAA)

If you live along the coast or Back Bays of New Jersey, Delmarva, Virginia, you should begin planning for the possibility of 2-3 high tide cycles like this. If the storm track shifts a bit or the intensity changes, we could see these values change. It’s a fluid forecast, but it’s a serious issue along the coast. Follow your local NWS office for info and guidance.

So will it be a blizzard?

Maybe for someone. It’s entirely possible, but specific criteria must be met regarding wind speed and visibility. It’s too soon to say exactly where and who or how long, but it’s a distinct possibility.

That’s all for now. Feel free to ask any questions and follow me on Twitter at @mattlanza.

Winter Doesn’t Give Up That Easily…

If you’ve lived in the Northeast for any length of time (in years), you know full well that spring almost never comes without a price. Temps in the 60s, 70s, and even 80s over the last week are going to give way to the harsh reality that winter can still rule in March and even April.

Latest plot of recent and forecasted NAO from CPC

To the left you’ll notice a plot of the NAO..the North Atlantic Oscillation. You’ve probably heard of it before, but in layman’s terms, it’s a measure of atmospheric blocking (high pressure) in the vicinity of Greenland. Traditionally in winter, a negative phase of the NAO spells more troughing and thus colder conditions in the Eastern US. You’ll notice from the graph that since the beginning of February, the NAO has been almost locked in a neutral or positive phase. As such, you haven’t seen quite the harsh conditions you all experienced earlier in the winter. But the red lines indicate the forecast, and that, my friends, is what we call a tanking NAO.

Latest Plot of Recent and Forecasted PNA from CPC

Off to the right, you’ll see another, similar chart…this for the PNA, or Pacific-North American Oscillation. This measures blocking near the West Coast. When this is positive, there is traditionally a ridge present out west, which usually can translate to a downstream trough. When you have the NAO in a negative phase and the PNA in a positive phase, that’s a usual rock solid combination to generate warmth out West and cold in the East. It appears, we have these factors ready to lock in for a good 10+ days, with the +PNA holding on a little longer perhaps than the -NAO.

What’s this mean? With them both in concert, it spells strong cold conditions for the Eastern US and a developing warm pattern and end to storminess out West. As the NAO starts to fade, but the PNA stays relatively positive, it means the cold in the East will ease some, but there’s absolutely no sign of a return to the 60s and 70s you’ve seen recently. Expect some 30s, 40s and maybe occasional 50s if you live in the Northeast Corridor through at least next weekend.

How about snow?

A few snow chances exist over the next week or so. I won’t go into many details about the one on Sunday and the one next Wednesday, but suffice to say, the conditions do exist for potential snow.

3/22 12Z GFS Snow Forecast from Earl Barker's Model Site: http://wxcaster.com/regional_snowfall.htm

In the immediate term, we’ve got a situation tomorrow. The map to the left is this morning’s projection of accumulated snowfall from the GFS model. If you live in NYC, you can ignore this for the most part (think the model is a little too aggressive with snow there). This is mainly west of I-287 and north of I-80…but you can clearly see the risk. For Northwest NJ and the Scranton area, despite what this model is showing, I’d be shifting those bands south a bit, and a solid 6-10″ thumping seems likely…very elevation sensitive this time of year, so the higher up you are, the better your odds for snow. The highest amounts seem banded in an area east of I-81, north of I-80, west of I-87, and south of US Route 20. There is some model debate as to how far south the snow will get (one model brings heavy snow as far south as Central NJ). I am going against that model for now due to a poor track record this winter. But you will want to keep an eye on this situation. And if you live in Northwest Jersey/Northeast PA, tomorrow and tomorrow night look very unkind.

Wish I had better news, but enjoy this last gasp of winter if that’s your thing.

Oh, and you can find State of Occlusion on Facebook too!

Facebook Us…Oh, And Snow.

It’s been a disruptive month for State of Occlusion! Transitioning my life offline from the West Coast to the East Coast, so haven’t had time to blog. I’ve discovered Facebook to be an extremely useful tool to communicate short bursts of information and post maps quickly. I will occasionally use this blog to elaborate on various significant events, but in the meantime, for the latest thoughts and information from me, like the Facebook page and tell your friends. We’ve already got 100 fans…let’s go for 200!

Follow State of Occlusion on Facebook for the latest!

In the meantime, while many in the Northeast enjoyed record warmth this Friday, winter is around the corner ready to take its season back. It will be cooler and extremely windy Saturday, followed by a leveling off of temps Sun and Mon. One storm will swing through Monday, potentially dropping heavy snow on Upstate NY, far N PA, into Connecticut and Southern/Central New England. Round two will affect areas south of I-80, somewhere between DC and New York, bringing the potential for very heavy snow on Tuesday as colder, Arctic air pours in. Right now the best odds for this appear to me to be between Baltimore and Allentown, back west across all of PA into Ohio and east into NJ. Potential does exist for 6″ or more with this storm, so this may cause significant travel issues in the Mid-Atlantic on Tuesday. Cold Wednesday followed by another semi-thaw (though not to the extent you saw this week).

I will post updates on Facebook through the holiday weekend.

Here We Snow Again!

Snowfall Forecast for Tues/Wed.

There’s the snow map at the left. Here’s some ideas by region.

– Boston area could see some very high snow amounts of 16-20″, depending on the exact track of the storm. If the storm tracks just right, they could get slammed, as some models suggest. Interior Southern New England right now would appear to be the jackpot, but I wanted to emphasize the risk to the Boston area. Parts of CT and MA may see some 20″+ amounts, with generic 8-16″ amounts as you approach the coast (some coastal areas and the CT River Valley may see lesser amounts). Cape Cod will likely be close enough to the storm to mix or change to rain. This will cut down on snow amounts a bit there. Additionally, wind will crank on Wednesday, leading to blizzard conditions in parts of New England.

– Metro NYC area/NE NJ won’t be the jackpot this time around. However, this still appears to be a respectable, business hampering snow. Think of the last system that went through, think of post-Christmas, and expect this storm to end up somewhere in between the two. There will yet again be a very sharp cutoff to significant snows, somewhere within the I-287 corridor. Blowing and drifting snow will occur in this region Tuesday night and Wednesday.

– Southern NJ will be close to the center of the storm, so I do expect the possibility of a mix. It also appears the storm will really explode a little too far away from this area this time. I still expect a respectable 4-8″, with the potential for higher amounts in mainland Cape May, Atlantic, Burlington, and Ocean Counties (6-10 perhaps?). Coastal sections may even see less, primarily in Cape May County. If mixing for some reason does not occur, tack on an additional 2-4″ to these forecast amounts. Blowing snow will cause a few problems Wednesday.

– Philly/Trenton will be solidly in the 4-8″ range, with potential for higher amounts (8-12) as you get closer to Trenton/New Brunswick and slightly lesser amounts as you slide south and west of Philly. Blowing snow will be a problem on Wednesday.

– DC/Baltimore appear to be in the 1-4″ range, with again potential for higher amounts in the northeast corner of the map. Much of the interior back through OH/MI will average 1-4″ as well, with potential for a few 4-6″ amounts in spots, depending on how things shake out.

And that’s that! After this storm, it appears we’ll head into a relative period of calm in the Northeast. So enjoy this if you like big storms and snow. Winter is certainly not over though, so stay tuned.

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Just a reminder… State of Occlusion is on Facebook. I’ve posted some additional cool links, quick model updates, and snow maps early on that page. “Like” the blog by clicking here!

More Wintry Mayhem

This might be the worst period of travel of all the storms we’ve seen the last two winters. With 1,000 flights cancelled in Atlanta tomorrow, and the odds increasing that this southern storm is going to become a major Northeast snowstorm, airline schedules are going to be absolutely logjammed this week. This is looking ugly right now. Travel in the Deep South is becoming difficult if not impossible in spots. A stripe of 3-6″+ of snow, plus a stripe of 1/4-1/2″ ice accretion, and you have issues.

Snowfall Outlook for the Midweek Storm (Not a forecast)

My snowfall outlook for the Northeast is at the left. We’re still a solid 48 hours away from things beginning. But this is just meant to give you an idea of the highest probabilities of the highest snow. This is not meant to be a forecast and should not be treated like one. To sum up the models this morning: All models take the low and develop off the Northeast coast. Some are closer than others (NAM/Euro) and bring heavier precip. There’s going to be (again) a sharp cutoff of the western extent of the real heavy snow, vs. generic 3-7″ totals. There will also be a sharp southwestern cutoff to this as well.

So what does this mean? It means that in specifically New Jersey I think, there’s going to be a very sharp gradient that cuts off somewhere between Atlantic City, Trenton, and about Parsippany. North and east of that line, odds for heavy snow (6-12+) increases significantly. South and west of it, the odds drop off. It will be a little while before we can really peg that down. So for now, roughly from about NYC into New England stands the highest odds for significant snow. There is a strong possibility of a 12-18″ area of major snows, somewhere between the immediate north and east side of NYC into Southern New England. Mixing may cut down some totals in Eastern Long Island and coastal S New England, but for now, I just carpet bombed the whole area for potentially significant snows until we can know more. The DC and Baltimore areas, as has been the case most of this winter, look to get shafted by this storm, caught in between the developing coastal and dying inland low. I think this means 1-3″ at most, but we’ll see. Philly is on the cusp between the heavy stuff and nuisance stuff, so think 4-8/5-10 type snows for now.

Can things change? Yes. The NAM and Euro models are the beefiest right now in terms of heavy snow. In my opinion, they’ve had some strengths this winter, so I’m leaning more heavily on them together. The GFS model is a little too far offshore in my opinion, and thus produces lighter snow. The short range ensembles are also not very excited about this storm, but they also underestimated snow in the last event, so I would take them with a grain of salt.

So stay tuned, as there will be tweaks and changes, but I feel personally that this will be a nuisance event in DC/BWI, moderate event for Philly and South Jersey (potentially significant for the Shore), a significant to borderline major event for NYC, and a major event for much of interior Southern New England (some shadowing may occur in some areas, so it may not hammer ALL of SNE, but it looks promising to be good for many).

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Just a reminder… State of Occlusion is on Facebook. I’ve posted some additional cool links, quick model updates, and snow maps early on that page. “Like” the blog by clicking here!