Comparing 1978 and 2013

Growing up as a weather-obsessed child I always regretted not being a little bit older so I could have been alive for the 1978 blizzard. Being a once-in-a-lifetime event it was certainly possible I would never be able to see a storm like it. Just days after the 35th anniversary of the 1978 blizzard Connecticut was clobbered by the worst blizzard since ’78.

The easiest way to quantify a snowstorm is by the amount of snow that falls. There’s no question the Blizzard of 2013 dropped the most snow across a large portion of the state since 1888. Looking through Northeast Snowstorms from Kocin-Uccellini there was no storm since 1888 that came close! The state record 24 hour snowfall was likely broken in several towns – the National Weather Service is investigating this now.

WVIT Blizzard 2013 Totals

Here’s a look at the official snowfall measurements from the NWS cooperative observers.

Blizzard of 2013

  • Bridgeport (Success Hill) – 30.0″
  • Norwich – 24.0″
  • Staffordville – 31.4″
  • Bakersville (New Hartford) – 28.0″
  • Norfolk – 17.2″

Blizzard of 1978

  • Brooklyn – 21.0″
  • Haddam – 20.0″
  • Coventry – 18.0″
  • Danbury – 20.0″
  • Groton – 17.2″
  • Mansfield – 24.0″
  • Middletown – 18.5″
  • Hamden 23.8″
  • Norfolk – 24.0″
  • Washington – 18.0″
  • Stamford – 15.0″
  • Storrs – 22.0″
  • Thompson – 24.0″
  • Woodbury – 19.0″
  • Windsor Locks (BDL) – 16.9″
  • New Britain – 21.5″

The first thing that jumps out at you is how few cooperative observers we have in 2013 reporting snowfall as compared to 1978. It’s a shame. The second thing is that there’s no question the snowfall in 2013 was more impressive than 1978. In fact, based on snowfall alone, the ’78 storm doesn’t seems to be much worse than other storms like January 2011, January 1996, Februrary 1983, etc., right?

Blizzard of 2013 / Courtesy: Chad Lyons in Branford
Blizzard of 2013 / Courtesy: Chad Lyons in Branford

It was the wind that truly set 1978 apart from the pack. The 17″-24″ of snow in 1978 (and up to 30″ in far eastern Connecticut) was whipped by winds that gusted to near hurricane force.

This is how John Bagioni who owns Fax Alert Weather Service recalls the 1978 blizzard. John is one of the best meteorologists in the state!

The 78 storm had ferocious winds that were much strong than this storm. Widespread winds in the 50 to 70 mph range were common with some 80+ winds… At Wolcott High School (elevation 700+) where I was working and running a CT Weather Forecasting class, had a Maximum Gust Master anemometer with a battery back-up… A week later when we got back, peak wind gusts was 83 mph!!! I was just starting to consult with a few towns and DPW back in 78. The superintendent came over the weather office at 7 AM (Monday); we saw the amazing obs starting to show up to our southwest; the students got off the buses at about 7:15 and were put right back on by 7:30 to head home… We just shut it down right then and there… The winds caused extreme drifting in the 78 blizzard. Drifts to 5 to 10 feet were common with much higher drifts than 10 feet noted. At Wolcott High School a drift almost made it to roof level and had to be knocked down to keep students from climbing up it on getting on the roof days later once it had hardened!!!

The 78 storm followed shortly after a terribly forecasting bust in late January. A big storm was expected and it was almost a total fail and the public was disgusted with the inaccuracy of the forecasting. When the blizzard was predicted (and it was well predicted, in fact the old Travelers Weather Service based in Hartford indicated Sunday in their forecast that where you were late Monday afternoon is where you would likely be for several days! The old LFM model nailed the storm), many did not believe the forecast, and did not follow the advice about getting to a safe location by early to mid afternoon. By mid/late afternoon travel was almost impossible and by late afternoon hundreds were stranded and it continued to spiral out of control; few folks had 4 wheel drive vehicles back then. Even though we had less snow, the combination of extreme wind, unbelievable drifting, the lack of public awareness made for a crippling storm… Travel band lasted days and work and/or schools were shutdown anywhere from 3 to 5 days. Many towns had to bring pay loaders in to open up streets; also I believe National Guard to a much greater degree than today was needed as well. I remember night after night of listening to pay loaders working on all the neighborhood streets (I was living in Bristol then). While very disruptive, in my experience, the 78 storm was more crippling and life-threatening, primarily due to the powerful surface winds.

The surface observations show the strength of the wind during the height of the 1978 storm. In Bridgeport the winds were sustained at 41 m.p.h. with gusts to 55 m.p.h. at the storm’s peak at 5 p.m. In fact winds gusted above 50 m.p.h. occasionally between 4 p.m. and 3 a.m. the following morning. Bridgeport also had 6 straight hours of winds gusting >35 m.p.h. with visibility <1/4 mile (either 1/8SM or 1/16 SM) between 1 p.m. and 6 p.m. on February 6th.

In Groton the 1978 blizzard produced a sustained wind of 46 m.p.h. with a gust to 69 m.p.h. at 3:06 p.m.! That’s a ferocious wind for a blizzard in Connecticut. The visibility at the time of that observation was 0.1 miles.

In Hartford winds gusted to 52 m.p.h. (sustained at 34 m.p.h.) at 8:06 p.m. on February 6, 1978 with a visibility of 0.1 mile. Brainard had gusts >35 m.p.h. and <1/4 mile visibility for 4 straight hours.

Blizzard of 2013 / Courtesy: Mike in Portland
Blizzard of 2013 / Courtesy: Mike in Portland

Comparing ’78 to ’13 is almost an apples to oranges type of comparison. 2013 had more snow and 1978 had more wind. ’78 occurred on a Monday and many people left for work not thinking the storm would be as bad as forecast. Everyone knew 2013 would be a monster and it peaked Friday night when most people were hunkered down at home. More people have 4 wheel drive now than they did 35 years ago. All of those things make the comparison tough. Snow is just one piece of the puzzle – societal impact is by far more important when judging where a storm will fall in an historical context.

For example, do you remember the February 2006 snowstorm? I do but I’m sure many don’t. People certainly won’t be talking about it 20 years from now even though it dropped 20″-30″ of snow and is the largest snowstorm on record  up at Windsor Locks. It was a lame storm, though. Winds were dead calm, it struck on a Sunday morning, and it was total fluff. You could shovel your car out in a few minutes without breaking a sweat. Within hours the snow was compacting and sublimating making it a rather pedestrian storm for a record breaker at BDL.

The Blizzard of 2013, on the other hand, contained an incredible amount of “liquid” for a storm that dropped 30″ of snow.  This wasn’t fluff! 3.00″ to 4.00″ of liquid was common in the area hardest hit. A period of sleet/graupel also fell which made moving this stuff next to impossible.

This snowstorm has undoubtedly joined the pantheon of historic Connecticut snowstorms that people will talk about for generations to come. The blizzard of 1888, the blizzard of ’78, the October Snowstorm of 2011, and The blizzard of 2013 are the top 4 (since the late 1800s) without a doubt in my mind.

Blizzard of 2013 – Thursday Evening Nemo Update

chart_3

15″-25″ of snow with gusty winds will make the blizzard of 2013 one to remember. A beautiful phase between the Polar jet and sub tropical jet will result in a powerful nor’easter just off the coast. The storm will stall and do a loop-de-loop off of Cape Cod which is a characteristic of some of our most powerful and memorable storms.

Here’s the bottom line

  • 15″-25″ of snow statewide. It’s possible someone in southern New England gets 30″-36″ of snow but it’s too early to say where that will be.
  • Wind gusts to 60 m.p.h. in southeastern Connecticut and 40-50 m.p.h. elsewhere will result in isolated to scattered power outages. Not a huge deal but some people will be in the dark.
  • Blizzard conditions (wind gusts >35 m.p.h. and visibility <1/4 mile) will be possible in parts of the state.
  • The storm begins as light snow after 8 a.m. A steadier and heavier snow overspreads the state after noon.
  • The heaviest snow will be during the evening and overnight when snowfall rates may approach 3″ or 4″ an hour.
  • Travel will be difficult so stay off the roads if you can.
  • A period of mixing with sleet is possible in coastal Connecticut but it’s possible that this remains an all snow event in many areas including New Haven.

Technical Discussion

Here’s the 15z SREF plume for BDL which shows a mean QPF of about 2″. This matches well with the European model (though is a bit less) and is a bit higher than the GFS. Each line here represents an ensemble member’s forecast with the black line representing the mean.

Screen shot 2013-02-07 at 8.02.15 PM

 

There still remains uncertainty as to whether the blizzard of 2013 will be an historic storm or a more pedestrian (yet major) snowstorm. The two questions that remain are

  • Whether the southern stream disturbance (which is firing impressive convection and being modulated by strong latent heat release and PV generation) will truck east a bit and stay farther offshore.
  • How mesoscale banding (and associated subsidence) will modulate snowfall totals.

To answer question one here’s a look at the 18z GFS and 18z NAM 700mb height and RH forecast for 00z Saturday. Notice the NAM (which actually agrees with the Euro) is much closer to the coast with the center of the 700mb low than the GFS. The GFS – off the coast of Nantucket – is too far east for monster snow totals here in Connecticut.

700MB

The second point, about mesoscale snow bands, is just about impossible to pin down ahead of time. Given the strong frontogenesis and -EPV signal we know there will be strong banding and the potential for 3″ or 4″ per hour rates but where and how transient those bands are remains to be seen. 

Enjoy the storm! I’ll see you on Twitter and I’ll be on WNPR tomorrow around 7:10 a.m.

Finding Nemo – Blizzard Forecast to Impact New England

9hva

For some reason I think it’s just hilarious that The Weather Channel has named our Friday blizzard Nemo! While naming storms is just a silly enterprise it looks like Nemo may really be a beast!

Earlier today we were all having fun with the 12z NAM that was showing 40-60″ of snow in parts of New England. No big deal, right? The NAM is just not designed to be used for rip and read snowfall forecasts. It’s a curiosity and is of no use. Toss it. You can toss other QPF forecasts from non-hydrostatic models out the window at this juncture as well.

The global models are in exceptional agreement that this storm is going to be huge. The GFS/Euro combination along with their respective ensemble members have honed in on an impressive solution. Here’s my latest thinking in a probabilistic way.

chart_1

While a chart like this would give TV news consultants heart palpitations it’s really the best way to express forecast uncertainty! I know my blog readers have a lot of weather geek in them… so enjoy! If you notice here the odds of more than 18″ of snow are pretty low… there’s a reason for that! The greater Hartford area has only recorded 5 snowstorms (officially) of 18″+ in the last 108 years! The Bridgeport coop observer has never recorded an 18″ snowstorm since the 50s! They’re just not all that common. We’re also still 36 hours before the storm’s onset and a lot can change.

Before I get accused of being a debbie downer. Let me now talk about how amazing this storm looks meteorologically. Here’s the 18z GFS valid at 6z Friday.

f36

Here’s the GFS which is in fair agreement with the Euro (though the GFS is a bit more impressive with an earlier phase/capture). Synoptically, a digging northern stream disturbance mananges to be timed and located perfectly to dig and capture a moisture laden southern stream disturbance. Beauty! Without blocking downstream there’s not much wiggle room. The timing has to be PERFECT for this to work out for Connecticut. 6 hours in either direction will make a huge difference (keep in mind the northern stream disturbance is over Montana and the southern stream is over Texas).

All of our models show the perfect phase though the Euro is a bit late and therefore a bit less impressive in Connecticut compared to places around Boston. So assuming that actually occurs and it’s not late (a late phase would still clobber the Cape and eastern Massachusetts but give us a more pedestrian storm) let’s watch the beauty unfold at 700mb from 18z Friday to 6z Saturday in 6 hour increments on the 18z GFS.

700mbEvolution

I mean if that’s not breathtaking I don’t know what is. We even manage a little loop-de-loop there as the 700mb low tightens and matures. Exceptionally powerful frontogenesis on the northwest flank of that mid level low would result in a super band the likes of which you rarely experience. All of this is taking place under an area of strong divergence thanks to a coupled jet streak (classic KU setup).

The result of this “perfect scenario” is a large swath of 1.5″ to 3.0″ of liquid and likely a snowfall on the order of 1 1/2 to 3 feet.  Wowzers.

The perfect scenario is only one such possibility, of course, and small changes in the next 24 hours with the 2 disturbances we’re watching can make a large difference down the line. In order to start picking up over 15″ of snow in this part of the country you need small-scale (mesoscale) features on your side. These are notoriously challenging to forecast even 6 hours ahead of time!

That said, as of right now this has all the makings of a classic. Odds are better than 50/50 that many inland areas see a foot of snow. Along the shoreline some sneaky mid level warmth may  bring a period of sleet and a bit of mid level drying may promote some dry slotting. Big “IFs” here though with plenty of potential for a crippling snowstorm if the shoreline is able to hold the sleet and dry slotting at bay.

Will this turn into an historic storm? It’s possible. Too early to say for sure. The amount of liquid being generated by the normally reliable models (like the GFS and Euro – ignore the NAM) are staggering. I’m excited for this one 🙂

Sandy Sets Records and Reshapes Coast

It’s been a long few days covering Sandy but my long days are nothing compared to the people throughout the northeast who have lost homes, businesses, or even loved ones.

Sandy brought a storm surge that was devastating to the Connecticut shoreline. In many respects, however, we dodged a bullet.

Water levels reached benchmarks that haven’t been seen since the 1938 hurricane in some towns. Thankfully, the peak storm surge was reached several hours before high tide.

The storm moved ashore in New Jersey and winds began to diminish prior to high tide’s arrival. In the case of the central and western Sound the peak wind and surge occurred just an hour after low tide and 5 hours prior to high tide.

Here is a look at the Stamford Hurricane Barrier observed water level, predicted astronomical tide, and residual/surge which is the difference between observed water level and what the astronomical tide would be without a storm surge.

Stamford Hurricane Barrier (Courtesy: Army Corps of Engineers). Green – astronomical tide, Blue – observed water level, Pink – surge/residual.

The maximum storm surge at the Stamford Hurricane Barrier was an incredible 11.24 feet! That surge peaked around 7:00 p.m. when the astronomical tide level was quite low. The maximum water level of 11.03 feet was reached at 10 p.m. when the surge had dipped to 8.73 feet. By high tide (around midnight) the surge had dipped to 4.4 feet.

At the Battery in New York City  the peak surge coincided with high tide. The same occurred along a large swath of the Jersey Shore.

The storm surge, however, was still catastrophic on parts of the Connecticut shoreline even though the worst case scenario was narrowly avoided. Many towns, including Milford and Fairfield, experienced coastal flooding worse than Irene and the worst since the great hurricane of 1938. In New London the tide reached a level not seen since hurricane Carol in 1954.

Had the peak winds (which occurred around 6:00 p.m.) and the peak surge (which occurred around 7:00 p.m.) occurred several hours later the destruction in Connecticut would have been unimaginable.

A last minute increase in the storm’s forward speed saved the state from what would have been its greatest natural disaster since the 1955 flood.

If Sandy made landfall in New Jersey closed to midnight entire neighborhoods would have been decimated, inundated by a storm tide 4 or 5 feet higher than what we saw. This would have most likely claimed lives. Water would have reached places that most in Connecticut would have never thought possible. As bad as Sandy was our state really lucked out. The dire message we were trying to get out along with the governor was necessary given the data we were seeing and the potential for a truly unthinkable event. If you need to see how bad it could have been look just to our west in New York or New Jersey where high tide was several hours earlier.

In East Haven, 2 houses were destroyed and 4 houses will likely be condemned. In Fairfield 5 houses were swept out to sea and at least 12 will likely be condemned. Fairfield’s coastal flooding was the worse since 1938. East Haven’s coastal flooding damage fell short of what was seen last year during Irene.

The actual tide leve in East Haven from Sandy was higher than during Irene. The damage, however, wasn’t as bad. Of the 28 homes destroyed during Irene many weren’t rebuilt. The ones that were rebuilt were raised to avoid surge like this. There simply wasn’t nearly as much to destroy on Cosey Beach!

Another issue that gets overlooked sometimes is that the wave action on the coast from New Haven and points east was greater during Irene. Winds were due easterly in Sandy (parallel to the shore) while during Irene the winds were more backed and southerly. A more onshore wind brought even more significant and destructive wave action to the beaches. It’s the wave action on top of a surge that can start eating through a house. In Farifield, due to the coast’s geography, an easterly wind is able to bring higher and more destructive wave action right to the beaches as the wind is more perpendicular to the West Haven to Greenwich coast.

Hurricane Sandy likely produced winds near category 1 strength along the New Jersey coast. Farther north, the storm produced hours and hours of tropical storm force winds including occasional gusts exceeding hurricane force. The worst of the wind occurred when the boundary layer mixed a bit promoting the efficient transport of stronger winds aloft to the surface.

There’s no question the winds were stronger statewide in Sandy than during Irene. However, with the exception of the immediate shoreline, the tree damage from Sandy was less impressive than Irene.

Here is a look at maximum wind gusts in Connecticut from Sandy and Irene.

  • New Haven* – Sandy: 50 mph / Irene: 67 mph
  • Bridgeport –  Sandy: 76 mph / Irene: 63 mph
  • Groton – Sandy: 75 mph / Irene: 58 mph
  • Danbury – Sandy: 68 mph / Irene: 47 mph
  • Hartford** – Sandy: 54 mph / Irene: 46 mph
  • Willimantic – Sandy: 53 mph / Irene: 51 mph
  • Bradley – Sandy: 62 mph / Irene: 51 mph

* No reports at KHVN past 5 p.m. during Sandy
** No reports at KHFD past 7 p.m. during Sandy

There are several reasons for the parity in tree damage from Irene and Sandy in most towns. One reason is that the trees were mainly bare away from the shore! A leafed tree is much easier to knock over than a bare one. Irene also dropped 5″-10″ of rain across Connecticut prior to and during to the strongest winds. Saturated and weakened soil makes it easier to uproot a tree. Another reason is that Irene and the October snowstorm knocked down a lot of weaker trees and limbs. There was less to destroy after the 2011 storms!

Courtesy: Debra Bogstie / NBC Connecticut – Guilford Green lost at least 6 trees with more substantial damage than seen during Irene. Just a mile or two inland, however, the damage from Sandy was less than Irene.

That said, the hurricane force wind gusts from Sandy within a mile or two of the Sound resulted in substantial damage in some shoreline towns. Structural damage, including roof and siding damage, occurred in Sandy and generally didn’t during Irene.

Meteorologically, this was the oddest storm I’ve ever covered. Strangely, it occurred 1 year to the date after the second oddest storm I’ve ever covered.  I’ve never seen a hurricane take the path this one did. Not even close. In the beginning (7 or 8 days out) it was easy to dismiss some of the computer models as they were predicting something that had never been seen before. As time went on the weather pattern became more clear and it was evident that something truly extraordinary was about to happen.

This hurricane made landfall with a pressure of 946mb making this the strongest storm to make landfall in the northeast in more than 70 years.

Sandy was an incredible storm. It will likely change the way coastal residents,  emergency managers, and government officials  in the northeast think about just how vulnerable our coastline is. The northeast has been lucky in the last several decades with a relatively quiet period of tropical activity. History has shown that hurricanes can move onshore here and they frequently do so with disastrous results.

So far it seems the state and the utilities were prepared for Sandy. The response and the preparation, in my opinion, has been impressive from the governor right on down to local officials.

Our work as a state isn’t done. We need to make sure we are prepared for the “big one” because Sandy wasn’t it. In fact it wasn’t even close to a “doomsday” storm like a repeat of 1938.  Let’s take the lessons learned from the last 3 storms and make sure we are ready for the next hurricane.

Special thanks to the Connecticut National Guard, the Fairfield Police Department and the Army Corps of Engineers for pictures and data. 

Dangerous Sandy Eyeing the Northeast

Hurricane Sandy / Courtesy: WeatherTap

The northeast is facing a serious threat from Hurricane Sandy with the potential for a devastating impact somewhere in the storm’s path. The exact track is still uncertain as we are about 96 hours out before the brunt of Sandy will approach.

Hurricane preparations should begin for people living in Connecticut tonight or tomorrow. You will have Friday, Saturday and most of Sunday to prepare. Threats include serious coastal flooding, inland flooding, wind damage, and prolonged power outages. The extent of any of these threats is too early to know but it’s important to be prepared for any event.

I do think, however, that this storm will be an historic event for someone in the northeast. Too early to say if it’s New England or Washington, D.C.

This is the 5 p.m. forecast from the hurricane center. The forecast shows Sandy jogging east of North Carolina (over the Gulf Stream, by the way) and then hooking left toward the northeast. This type of track is virtually unprecedented for a New England hurricane (accurate records back into 1800s) yet is forecast by virtually every tool at our disposal.

The NHC keeps the storm a hurricane up until landfall and then transitions it to a “post-tropical” low that still contains powerful 65 mph sustained winds (which is what Irene was at landfall in New York).

Our computer models are in remarkable agreement with a track that takes the storm into New England or the northern Mid Atlantic. There are a few outliers, such as the 12z op Euro, that bring the hurricane into the southern Delmarva penninsula but that seems unlikely to me. It would be extremely difficult to get a hurricane to take such a hard left hook to start moving due west of event south of west like the Euro shows.

While the vast majority of these tracks would produce a signifcant impact in Connecticut the exact track may mean the difference between a full fledged hurricane and what would seem similar to a more typical fall-like nor’easter.

The question becomes what will the intensity of Sandy be at landfall and will she still be a hurricane? The answer to the second question is, in my opinion, yes. As I discussed yesterday the models keep Sandy as a warm core system during its slow extratropical transition. That continues today per Bob Hart’s cyclone phase space diagrams.

With Sandy expected to maintain a warm core and feature an expanding wind field the concern for serious impacts is quite high. Our computer models indicate that the hurricane may actually strengthen as it approaches the northeast. With colder waters to our south how is that possible? The answer is that the models show a remarkable amount of synoptic scale lift that will make strengthening of the storm possible as it heads to our latitude.

We always talk about the jet stream and how it influences our weather. Local maxima in the jet stream, called jet streaks, are what lead to really fun kinds of weather.

From quasigeostrophic theory it’s easy to come figure out which areas of a jet streak feature rising air or sinking air. It can be done with PV thinking too (which I actually think is a cooler way of demonstrating) but here’s the deal with QG.

Jet Streak Schematic / Courtesy NC State
108 Hour GFS 250mb height/isotach Forecast

In a jet streak you have rising motion in the right entrance region and left exit regions. In Sandy’s case you can see 2 powerful jet streaks in the eastern U.S. There’s also a smaller (easterly) jet streak over Newfoundland and a second jet out over the north Atlantic southeast of Nova Scotia.

I labeled the favored areas of the jet stream for QG upward motion with LFQ for left front (exit) quad and RRQ for rear right (entrance) quad. I’ve never seen a coupled jet structure like this in my life over this part of the Atlantic. The “Boom!” indicates what will happen in between the 4. Even if there wasn’t a hurricane coming north we would probably still see a sizable nor’easter given this setup near the tropopause.

All of this results in an extremely large area of upper level divergence that will be located over Sandy. This divergence will help keep the storm intense and possibly, depending on how the Sandy’s extratropical transition goes, intensify the hurricane.

All of this means we need to be prepared for a direct hit from a hurricane. While it’s certainly possible that this storm will just miss us to the east or west the wind, rain, and coastal flooding from Sandy will stretch far from the actual landfall location. It looks like Sandy will be quite a storm for someone… let’s hope it’s not here!