So About Next Week…

Tonight's 00Z European Model Forecast for Next Wednesday Evening (http://www.meteo.psu.edu/~gadomski)

I’m not one to go bonkers when it comes to any particular storm (in fact, you read me discussing how I would be apt to NOT hype next week a couple days ago). But I think now it’s obvious we have something rather significant showing up here. The three major models tonight all went nuts for the middle of next week, showing an absolutely massive storm slowly rolling up the East Coast. When all three models lock in on a massive storm, that very often means that they’re right. Models struggle and they can be a bit inconsistent at times, but when it comes to the extremely large, widespread or historic sized events, they are usually quick to hit on things. I’m not saying that next week’s storm will be historic, but there’s no question we’re now looking at a significant to major event for much of the Mid-Atlantic and Northeast.

Tonight's 00Z GFS Model Forecast for Next Wednesday Evening (http://www.meteo.psu.edu/~gadomski)

So what are the details? Well, it’s far too early to speculate, but we’ll do just that because we can. Based on tonight’s model runs, we’d be looking at a snow to mix/rain ending as snow event from I-95 to the coast (and even a little further inland from there), with extremely heavy snow/mix possible from the Smokeys north into Upstate NY and interior New England. The storm is also extremely slow moving. For example, the precip begins in Philly on tonight’s Euro run at about Midnight Wednesday and does not end until about 9-11 AM Thursday. Snow moves into the Albany area around 9 AM Wednesday and doesn’t depart until after Noon on Thursday. These aren’t forecasts…they’re just examples of what the model is showing and emphasis on a 24+ hour event.

Tonight's 00Z Canadian Model Forecast for Next Wednesday Evening (http://www.meteo.psu.edu/~gadomski)

The other issue then is track. Tonight’s runs are up along or just inland from the coast. That is extremely unfavorable for heavy snow from DC-Boston…that’s a wet track, not a white one. However, if you look closely at each model’s ensemble mean, you’ll see the track is still fairly far offshore. What does this mean? That the operational models *may* be on the extreme west edge of the track forecast envelope. I wouldn’t go shouting from the rooftops just yet, but it’s something to keep in mind.

We’ve seen a lot of storms the last couple winters, but this one I think is the most impressive looking in terms of physical size and slow track. We’re in a powder keg pattern right now, and this may be the fuse that helps things explode. I’m not going to get into details of the meteorology behind what’s happening right now, but we need to watch things very closely over the next few days. But each model run has looked more impressive with this storm, not less impressive, and that trend may continue as we get closer.

Unfortunately, I’m heading out of town Friday afternoon…well, actually I’m moving, but taking a week or so to drive to Texas, so my updates will be much more infrequent. However, make sure you “like” State of Occlusion on Facebook, as I’ll post updates each night/morning with the latest information. This really could be a big time event, so stay tuned!

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One for the Haters!

So not everyone loves snow. As a meteorologist, even if I dislike dealing with it (working four years in lake effect country will do that to you), I love the unique quality of events like this and appreciate what has to come together atmospherically for something like this to happen. It’s not THE perfect storm, but it’s one of the most perfect storms. But some people can’t deal with it, hate it, curse it, etc. And that’s fine. So I dedicate most of this post to you.

6-10 Day Average 850mb Temperature Anomalies from the GFS - http://raleighwx.americanwx.com

At least temporarily, there’s going to be a pattern change in the East. Once the energy and upper level trough from this storm lifts away, we’re finally going to see  some changes to allow the seemingly endless cold in the East to abate. Strong troughing is going to build into the West as the pattern sort of blocks up out here (a couple cutoff lows to allow for some of the coldest dry weather we’ve had here in some time). This will help allow a ridge to pump up in the East. There are still some questions as to how strong the ridge in the East will get and how long it will last, but at least as we go into the New Year, things begin to quiet down and thaw out a bit…and a lot of the snow that’s falling will be long gone. Enjoy it while you have it. The map to the left above, from http://raleighwx.americanwx.com, shows the average 850 mb temperature anomalies off the GFS model 6-10 days from now. It’s not a perfect representation, but you get the idea…cold West, warm East. It’s somewhat of an odd pattern, and truthfully, given the fact that blocking in the Arctic and Greenland wants to hold on, I don’t know how long it will last. But it is more “normal” for a La Nina pattern, at least temperature wise.

So truly an awesome storm unfolding. Storm totals are outrageous, 12-20″ widespread from Norfolk, VA-New England, and 6-12″ in parts of interior VA/NC, and even 1-3″ or so on the Outer Banks! It snowed as far south as Savannah, GA and Jacksonville, FL this morning. Pretty remarkable. I may do a wrap up post later, but pass on your totals if you’ve got them in your backyard!

Lastly, I’m curious if people are content with this format of either RSS/Google Reader, getting a link on Facebook, or email subscribing…or if you’d also like see a Facebook “Like” page for more short-form updates before and during events and occasional links of interest. Vote below and we’ll see what sorts of changes we can make.

Also, enjoy this video of the blizzard from NYC, including thundersnow around 1:45-1:50:

The Boxing Day Blizzard

Well, it’s underway, and miraculously, there haven’t been any dramatic changes in the forecast in the last 12 hours. The main areas of concern to me seem to be:

  • Cape Cod/Providence/Boston/Long Island: How much falls as sleet/rain vs. snow, thus cutting down snow totals there. The low should ride the coast from about Montauk to Martha’s Vineyard, so this will both lead to a mix/changeover scenario on Cape Cod/southeast Connecticut/Rhode Island and may even have to a dry slot cutting down totals in general. Will this make it as far north as Boston? Doubtful, but we’ll see.
  • Jersey Shore from LBI south: There could also be some mixing issues here. In my experience there are almost always mixing issues in this region when a low passes this close to the coast. So this may cut down totals, and I’ve lowered the range a little to 7-14 (down from 8-16). It’ll still be a good storm, but the combination of a little less precip and this mixing scenario has me cutting back a smidge.
  • Philly-Morristown-Albany: The biggest question of all is regarding how far west the heavy snow will get. And this corridor stands the most to gain or lose depending on the exact amount the precip shield barges inland. I could see this being as little as 6″ in Philly to as much as 12-16″ there depending on the exact track (same goes for the I-287 corridor in Jersey and I-87 from Newburgh to Albany.
  • NYC-Hartford-Interior New England: This could be an absolute wallop for places like Worcester, the Berkshires, the Litchfield Hills, etc. A lot of potential for a lot of snow in these areas, and there could be a cluster of significant 20″+ amounts anywhere between NYC and Boston depending on where the best mesoscale banding sets up.

Lastly, the wind impact from this cannot be stated enough. This is a storm which is going to see its barometric pressure fall from about 996mb off Cape Hatteras to perhaps 970 mb or lower south of Long Island. In meteorological terms, we call this an atmospheric “bomb.” In other words, it’s going to be rapidly deepening, and it will be progressing along close to shore. This is going to create absolutely ferocious winds all the way up the coast and rather far inland. With everyone’s Christmas lights up, coupled with heavy snow, the wind has the potential to cause a LOT of damage/mess. It may not be a bad idea to secure some of the holiday displays Sunday morning. There will also be the potential for significant power outages as well, so be prepared, especially because temperatures will drop into the low 20s to teens Monday night and Tuesday morning, with wind chill on top of that.

Travel is going to be next to impossible and is not recommended, especially from Northeast NJ into New England after about 9 AM-Noon tomorrow. And it may be that this is the case throughout most of eastern PA/NJ/DE/eastern NY as well. This really to me seems like last February, shifted a couple hundred miles further north. So please use caution if you have to travel, and be prepared for numerous road closures/states of emergency by Sunday evening.

7:30 AM Sunday Update: I would likely trim some of the snow totals back east a bit in the 3-7″ range, esp in NY/PA. The storm is moving along at a decent clip. The real intensification takes place this evening…that’s when the “blizzard” aspect will begin to take shape. In terms of the actual amounts, I might be apt to trim back south Jersey/Delaware a bit (more like 6-12 now to me). Overnight models (not going to read into them too much at this point) did cut back snow totals there to the 6-10″ range). Still looks good that the bullseye is between NYC and Boston..but not IN NYC or Boston. Boston may end up on the lower end of my forecast range, but inland areas will push the higher end. The western extent of the snow between the Delaware River and the Hudson River is going to be EXTREMELY sharp now it appears. Could easily go from 2-4″ far west to 12″+ over a very short distance. Whether that gradient is centered over the Delaware Water Gap or Denville in North Jersey, I’m still not sure. Still a tough forecast. Keep an eye on things throughout the day. Also, from northeast NJ into New England, the bad travel may not start until more like 11-2, rather than 9-12.

1:30 PM EST Update:  Everything still on track. Morning model guidance and current radar trends validating a major storm that’s underway. Latest SPC Mesoanalysis showing that the storm is rapidly deepening off the NC coast as it gradually pulls north. This will bring blizzard conditions to most of coastal NJ/Delmarva and inland to about Rt. 206. The blizzard conditions will spread north into NYC and New England this evening. The worst of the weather will be bounded on a line south of I-90 in New England and east of I-287 in NJ-I-87 in NY.

If you live in Southeast Jersey, snowfall rates of at least 1″/hour are occurring and those heavier bands will continue to push onshore from time to time this afternoon and evening. Heavier snow continues to gradually push inland, and to be honest, the snowfall map from last evening doesn’t look too bad at this point (though I’d still shift the 4-8″ area a little further east). Some totals so far include Somers Point at 6″, ACY at 4.3″, a little over 3″ at Ocean City, MD, and 6-10″ in the Hampton Roads area of Southeast VA and parts of Northeast NC, back through Raleigh/Durham. The DC/Baltimore areas have been for the most part “shut out” of the storm so far, and it’s not looking likely that those areas will be hit nearly as hard as others north and east.

Travel and conditions in general will continue to deteriorate this afternoon. Be safe!

Here’s your map for new snow tonight-Monday (click to make it bigger). Feel free to add any questions in the comments, and if you like the updates or have any comments/ideas for future items, let me know! And Happy Boxing Day!

Final Snowfall forecast for Boxing Day Blizzard (click to enlarge)
The storm is moving along at a decent clip. The real intensification takes place this evening…that’s when the “blizzard” aspect will begin to take shape. In terms of the actual amounts, I might be apt to trim back south Jersey/Delaware a bit (more like 6-12 now to me). Overnight models (not going to read into them too much at this point) did cut back snow totals there to the 6-10″ range). Still looks good that the bullseye is between NYC and Boston..but not IN NYC or Boston. Boston may end up on the lower end of my forecast range, but inland areas will push the higher end. The western extent of the snow between the Delaware River and the Hudson River is going to be EXTREMELY sharp now it appears. Could easily go from 2-4″ far west to 12″+ over a very short distance. Whether that gradient is centered over the Delaware Water Gap or Denville in North Jersey, I’m still not sure. Still a tough forecast. Keep an eye on things throughout the day.

Yes, This is a Christmas Miracle

Irony of ironies, almost all the models are converging on a solution. There are still uncertainties on this storm, especially regarding how far inland the significant snow goes. One model is suggesting it goes almost all the way to Pittsburgh. Another says it barely crosses the Delaware River. So that will be what needs to be worked out over the next 12-18 hours. Not going to be a very relaxing Christmas for many meteorologists in the East.

This storm has truly been remarkable to watch. It’s been all over the place, and there are a number of very well seasoned meteorologists I’ve heard from that say they have never seen anything even remotely this poor in their careers. This just serves to remind everyone that weather is a VERY inexact science…and it will always throw us curve balls. I’ve included an updated snowfall forecast map below, and like I would encourage you with any snow map you see today and tonight, take it with a grain of salt. There’s uncertainties that still cloud this forecast. The bottom line: There will be a high impact storm for most areas north and east of Baltimore. Regardless of specifics, this will be significant for a number of areas, and travel within and to the Northeast and Mid-Atlantic is going to be difficult to perhaps impossible on Sunday afternoon through Monday afternoon. There will be mixing issues along the coast of NJ, Long Island and Southeast Massachusetts. Those mixing issues could even extend inland a bit too, depending on the exact track of the storm. Any mixing will cut significantly into snowfall totals in those areas. There is the potential for higher amounts in the eastern areas of the blue color (4-8) region, again, depending on the exact track. There will be blizzard conditions when it’s snowing on the coast and possibly a bit inland.

This is a big storm, so despite the uncertainties, doubts, and changes you’ve heard of, and the jokes you may be inclined to make about “those weather people,” do take it seriously, as it will be a high impact storm that could still throw curve balls. And if you hate snow, it looks to warm up a bit with an early January thaw soon after this storm.

Click the map to enlarge.

Revised Snowfall Forecast for Christmas Weekend-Monday

It’s a Christmas Miracle? Flip a Coin.

Just a quick update. I won’t be drawing a snow map this evening for a couple of reasons: One, it’s Christmas Eve, two, the Euro won’t be out for another hour+, and three, the amount of inconsistency and volatility regarding this storm is something I’ve heard people with years of forecasting experience beyond my own, say they have never ever witnessed. In other words: You’re looking at one of the most complex storm systems we’ve ever seen…moreso because of the location it may or may not impact rather than because of the storm itself.

But I will provide you with a couple of major teases. The two maps I place at the end of this entry are raw snowfall forecasts from the GFS and NAM computer models from this evening. Now, don’t go shouting from the rooftops. I STILL am not behind this storm. I still see flaws. I still think the models are suffering problems (given their wild swings and disagreements over the last 2-4 days or so, this may seem obvious). And I still think we’re in for changes here in the final 36-48 hours before gametime. The Hydrometeorological Prediction Center’s model discussion this evening is once again hinting at the potential that the models are erring, and that could be leading to solutions later in their runs that are, well, incorrect.

CONSOLIDATING UPPER LOW OVER THE EAST...
LOW PRESSURE FORMING UP THE EAST COAST...PREFERENCE FOR A 00Z
NAM/15Z SREF MEAN COMPROMISE
THERE ARE SMALL SCALE DETAILS THE NAM/GFS/ECWMF ARE SHOWING ISSUES
WITH WHICH MAY IMPACT ITS FORECAST LATER ON.  THEIR SOUTHERN
STREAM SHORTWAVE IN TEXAS ARE 30-40 METERS TOO WEAK AT THE 500 HPA
LEVEL BASED ON RAOB REPORTS FROM TEXAS.  THE NAM DOES NOT CAPTURE
THE ONGOING CONVECTION IN EASTERN TEXAS.  THE 18Z AND 00Z GFS RUNS
ARE SHOWING SIGNS OF CONVECTIVE/GRIDSCALE FEEDBACK AS THE SYSTEM
MOVES ALONG THE GULF COAST WHICH COULD BE MAKING ITS SOLUTION AT
THE SURFACE AND ALOFT TOO STRONG.  THERE ARE HINTS THAT THE RIDGE
INITIALLY ALONG THE EAST COAST IS MORE AMPLIFIED THAN THE
NAM...WHICH WOULD BE CLOSEST TO THE 12Z ECMWF/12Z ECMWF ENSEMBLE
MEAN FORECASTS FOR 00Z.  ANY OF THESE DETAILS COULD
DEGRADE/NEGATIVELY AFFECT THE SHORT RANGE FORECAST.

So there’s still much uncertainty. I mean, honestly, there’s NO forecast out there now that stands much chance of being right on, including my own. This is simply one of those storms where you sit back, roll the dice, and pray you come close.

Consider a compromise of the maps below as the potential for the maximum impact of this storm. Click on either map to enlarge it. Consider my forecast map from earlier this morning the potential for minimum impact of this storm. So enjoy the tease, because tomorrow is going to tell us that either a hefty dose of reality is going to kick in, or you really will believe in miracles. Merry Christmas!

00Z NAM Forecast Snow: http://wxcaster4.com (Worth bookmarking)
00Z GFS Forecast Snowfall: http://wxcaster4.com

Models Throwing Punches for Boxing Day Storm

Maps from Sunday and Monday Morning from this morning's European Model: http://raleighwx.americanwx.com

I’m still not ready to commit entirely to a major storm yet for the I-95 cities or the coast, but this morning’s Euro run is holding serve awfully steadily. The Euro, as you can see to the left (click to enlarge), is an utter monster. Keep in mind, this model has little to no support for a solution like this, but it has also been quite consistent. Its ensemble mean is a bit further away from shore, but this would still imply a good hit for a lot of locations. The GFS is a big storm, but just grazes the coast and hits far Eastern New England hard. The Canadian model is somewhere in between the two models.

Again, I will emphasize that the pattern out west with a ridge axis centered over CO/WY is not exactly ideal for a major East Coast storm for the Megalopolis. Yet, something is going on here to allow it to happen on the Euro. The Euro model solution is absolutely incredible. It implies the potential for heavy snow as far south as Jacksonville, FL and on up the East Coast through New England, with the heaviest snow likely in interior VA-NJ/PA and southern New England.

My take:

  • Odds for a storm to impact the coastal areas are equal or greater than it was this time yesterday.
  • Odds for a storm to impact the interior/Megalopolis are about the same as it was yesterday; maybe slightly higher.
  • Odds for an epic blizzard like the Euro model is showing are very low to near zero in my opinion.
  • But…the odds for a significant plowable snow in a lot of areas are slightly higher than yesterday.

Tonight’s model runs will be the first real key, as the main energy involved in blowing this storm up is now onshore here in California. If tonight’s Euro shows something similar to this morning, and/or the GFS model trends closer to the Euro model, we have to think odds are increasing for a big Boxing Day Knockout. If the Euro trends toward the GFS tonight, I think the chances of a major, high impact storm drops substantially. I can’t emphasize this enough: The Euro stands alone right now…it CAN score a coup; it has before, but it also has not been its usual stellar self this winter, which is why I sit here still skeptical. If the models trend toward any given solution on consecutive runs both tonight and Thursday morning, I think the odds of whatever that solution is increase multi-fold. So the next two main model runs (7-10 PM tonight & 7-10 AM tomorrow) are absolutely key in all this. Stay tuned.

Boxing Day Storm Chances

Apologies for not really blogging much…been a busy time here…and it’s been raining here, a lot. Up to about 6.5″ of rain since Friday and more coming tonight and tomorrow. One of the wettest December storms on record in SoCal. And 15.5′ of snow at the summit of Mammoth Mountain! Ski the West this year!

On to this weekend. The last couple weeks we’ve seen two noteworthy storm threats in the East. The first ended up going across the Midwest and burying Minnesota. The second went wide right and brought some decent snows to southeastern Massachusetts and Cape Cod (6-12″).

So this is number three. And number three is different than Nos. one and two. The players on the field are much different. But the end result is essentially the same…the East Coast and Northeast are targeted for snow and we’re about 4-5 days out. Let’s do some quick modelology and then discuss more specifics.

Morning Computer Model Forecast for Sunday Morning (from http://raleighwx.americanwx.com), clockwise from top left: GFS, GFS Ensemble Mean, Euro (Mon Morning), Canadian

The GFS has been back and forth on a storm impacting the NE. This morning’s run was substantially more suppressed with the storm, lending to very light, but widespread snow Christmas Night and Boxing Day (Sunday). The Euro has been steadfast on a fairly potent storm. And this morning’s run was absolutely epically biblical, with massive snow for a lot of folks. There’s also a Canadian model that has been flopping back and forth and today is similar to the GFS in terms of impact.

 

Right Click the image to the left and open it in a new window. These are the main model runs from this morning forecasted for Sunday morning. Let me explain. The top left is this morning’s GFS…clearly suppressed a bit and well east, but the one to the right of it is the GFS Ensemble Mean (an average of a bunch of different GFS runs with different parameterizations basically).  This looks to be slightly further suppressed and further east. That’s not uncommon, as it’s an average of about a dozen runs. But, it doesn’t inspire increased confidence.

The bottom left is the Canadian…a little more aggressive than the GFS, but still mostly a swing and a miss. But then we get the Euro at bottom right. I had to fast forward this to Monday morning, as on Sunday, it shows the center of the storm off the GA coast.  This is a massive hit for a lot of folks. Essentially 12-18″, if not 24″ over a large area.

What do I think? Here are some pros and cons…pros being things suggesting snow…cons being things that act against it.

Pros

  • Large storm system hitting much of California (this occurred a lot last year preceding the big ones in the East and has not happened yet this year.
  • European model being steadfast about a large storm.
  • NAO transitioning from strongly negative to neutral (NAO= North Atlantic Oscillation…blocking over Greenland. Often times the biggest storms are the ones that occur when this oscillation transitions from negative to positive).
  • Other factors in the Atlantic in place that would suggest a storm is possible.

Cons

  • Axis of the ridge of high pressure in the Western US is centered over Wyoming (For a major storm to hit, you oftentimes need to see this axis set up around Boise, ID. I would feel FAR more confident in this storm if that ridge axis were to set up about 200 miles further west, which could still happen, but we have a way to go).
  • Models have had a tendency to overdo storms in the East thus far this year (in terms of snow impact).
  • GFS model has not been terrible this year, and the fact that it’s showing and has trended more suppressed is not encouraging.

In a nutshell, we have things supporting this and things working against it. We need to wait until tomorrow night’s runs to REALLY get a grasp on this, as the storm hitting California will finally have come ashore. The models have done a fairly decent job modeling this massive event out West, and while that doesn’t always translate East, that means they are on to something. So if I had to break down the situation:

  • At the least, light snow is likely Saturday night and Sunday in much of the East.
  • The highest odds for significant, plowable snow is south and east of I-95, along the Jersey/Delmarva Shore and southeast New England.
  • The odds for significant, plowable snow significantly diminishes substantially north and west of the Northeast Corridor (essentially a line from Concord, NH-Danbury, CT-Norristown, PA-Frederick, MD).
  • This is a Boxing Day/post-Christmas Storm right now and Christmas Day looks satisfactory (except south of the Mason-Dixon Line, nuisance snow could snarl travel in some areas).
  • This is not a guaranteed, knock out forecast by any means.

Stay tuned on this, as there will be much to discuss in the coming days.