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).

————-

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!

Historic (?) Southeast Storm Could Be Next Northeast Snow Threat

Overall pleased with the forecast for the current storm for the Big Cities. Definitely underestimated parts of CT that saw 8-16″ of snowfall on average in the western part of the state, even down to New Haven County. Just a reminder… State of Occlusion is on Facebook. I’ve posted some additional cool links and snow maps early on that page. “Like” the blog by clicking here! On to the fun…

The Eastern 2/3 of the US are going to be peppered by winter events over the next five days or so. Let me run through things here.

Snowfall Forecast from Friday Overnight-Sunday Morning

First off, tomorrow, as all of the energy responsible for the unsettled eastern weather the last couple days starts to slide offshore, it will begin to develop into a nor’easter, but rapidly exit to the east. However, as it intensifies, it could produce a pretty well organized band of snow from about Southern NJ/Central DE through E Long Island and possibly Cape Cod. The snow map is over to the left if you want to enlarge it and see my thoughts through Sunday morning. Not a big storm, but there could be some heavy snow for an hour or two, especially east of Rt. 206 in NJ as the storm pulls away. Lingering snows will produce perhaps a couple more inches in New England, with upslope areas of the Green Mountains and Berkshires more favored. I don’t believe accumulations will be that high. There is some chance the Cape and Islands, as well as the Boston area may see some enhancement too.

GFS Forecast of Total Ice Through Tuesday Morning (Credit: wxcaster.com)

That will exit tomorrow night and by Sunday morning or so, things will be quiet. But that sets the stage for the next event, and this one might be an absolutely punishing doozy of a storm. The map to the right shows the GFS forecast for total accumulated freezing rain through Monday. A strong storm system is going to trek across the Southeast in an unusually cold air mass, and with it will come plenty of moisture…almost an El Nino type storm. Winter Storm Watches are posted almost to the Gulf Coast for Mississippi and Alabama, and for most of northern Georgia and Louisiana, as well as Arkansas. This amount of ice this far south would be absolutely crippling…that isn’t hyperbole either…these are places that almost never see frozen precipitation of any kind, let alone to this extent. The raw model outputs in some of these places is absolutely mind boggling. Atlanta is showing anywhere from 6-12″ of snow, with 1/4″ of ice! Of course, that’s raw model and has to be taken with a grain of (road) salt. But still, that’s absolutely insane, The all-time snow record for Atlanta is (I believe) 10″ in January 1940. It’s tough for me to put this in historical context, as I’m not THAT familiar with Southeast wintry climatology, but this would be, from a meteorological perspective, one of the most incredible things we’ve seen over the last couple winters (and we’ve seen a LOT). Check out the total snowfall forecast through Tuesday morning in the Southeast below (from http://wxcaster.com/regional_snowfall.htm).

Southeast NAM Snowfall Forecast Thru Monday Night (Credit: http://wxcaster.com/regional_snowfall.htm)

The next question becomes, where does it go? The three main models to look at for tonight, taking them (since the NAM only goes out 84 hours) to Tuesday morning shows the low sitting somewhere off the northeast South Carolina coast. Not surprisingly, where this storm sets up, will determine how it impacts areas up the coast. The European model sets up the furthest northwest. Not surprisingly, as you run it out further in time, the European delivers a quick moving, but solid snow event (6-12″ish) for most areas from I-95 south and east. The GFS is a glancing blow, but mainly a miss (not bad for New England). The NAM stops at hour 84, but is a little closer to the European model than the GFS. So my feeling is that despite model flip flopping the last couple of days, we could still see a pretty potent little storm from the Carolinas up into New England. The timing on the snow would be later Tuesday to the south, ending Wednesday from Jersey through New England. Stay tuned on this, especially if you have midweek plans. I’ll do my best to keep you posted.