US Satellite

In the United States, the second strong storm of the season impacted the Northeast.  This storm dropped more than 4 inches of snow through an area from NJ through Massachusetts   In fact, it was the earliest Central Park has recorded more than 4 inches of snow in its long history!  Normally this storm would be nothing more than a nuisance, but unfortunately there was a historic storm the week before which caused massive destruction in the Big Apple as well as most of the Jersey shore.  I’m positive it will be back to normal before you get a chance to visit, but it is a storm that will be studied for years to come.  Your mother and I both thought that you would be born during it because we lost power for a little while.

Looking at the visible satellite, there was some thick marine stratus off the California coast.  Maybe I can teach you why this forms when you’re older but the feature is quite obvious on the image.  Also clear is a jet streak on the top of the ridge in the west.  At first is may look like con-trails but looking at the model initialization and the water vapor imagery you can clearly see that there is a jet streak in the region.  Other than the stormy-ness in the east, the west was quite warm with several record highs reported in the southwest.  But overall it was quite tranquil there.

It is also interesting that you were born on a day where meteorologists int he Philly metro area blew the forecast, we were expecting 2-4 inches of snow and only saw a few flurries.  The storm formed a bit later and further east than we (including your daddy) had expected.  People are not happy when this happens.

Weather Image Gallery

Surface analysis showing conditions throughout the US

National Radar Mosaic; much of the reflectivity around Texas is just surface clutter. The winter storm is shown off the coast.

Model initialization on the day you were born showing the many levels of the atmosphere.

What I would like my readers to do is name something that happened to you on Wednesday.  Whether it is something stupid like a jerk cut you off or something huge like you found out you are pregnant.  I want Shane to know what everyone was doing when he entered the world.  Even if you want to add something to the weather part of this.  List it in the comments!

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the destructive potential of the storm surge was exceptionally high: 5.7 on a scale of 0 to 6. This is a higher destructive potential than any hurricane observed between 1969 – 2005, including Category 5 storms like Katrina, Rita, Wilma, Camille, and Andrew.

 

That is pretty impressive!  But what doe this mean to property in NYC?

 Sandy’s storm surge will be capable of overtopping the flood walls in Manhattan, which are only five feet above mean sea level. On August 28, 2011, Tropical Storm Irene brought a storm surge of 4.13′ to Battery Park on the south side of Manhattan. The waters poured over the flood walls into Lower Manhattan, but came 8 – 12″ shy of being able to flood the New York City subway system. According to the latest storm surge forecast for NYC from NHC, Sandy’s storm surge is expected to be several feet higher than Irene’s.

Several FEET higher, not inches.  This would be catastrophic to the NYC subway system.  Definitely something worth keeping an eye on as we head into this week.  I do hope that the water does not make it to the subway system, but it can not be ignored.

So it begins. The effects of Sandy are already being felt in the Lehigh Valley and Suburbs of Philadelphia.  Light rain has been falling since roughly 7am in Allentown while the wind has been steadily increasing through the morning and has been consistent out of the NE.  Expect deteriorating conditions through Sunday, Monday and into the early morning hours of Tuesday with the worst of the storm expected to strike the area in the evening hours Monday.

Current Conditions

Sandy is beginning to show signs of strengthening, with pressure down to 951mb (Normal Sea Level pressure is 1013mb) and dropping!   Winds are still assumed to be at hurricane force on the south western quadrant but these are satellite estimates, hurricane hunter aircraft have not measured any hurricane force winds in the areas surrounding the eye.  Much of the strengthening is now becoming more due to baroclinic (temperature gradient) processes rather than tropical, what this means is that the storm is starting to transition into a hybrid monster. Jet energy is currently located in the lower Mississippi valley and is continuing to propagate towards Sandy.

Forecast

Sandy is still forecast to make landfall somewhere on the New Jersey coast late Monday night.  It must continually be noted however, that for communities inland, landfall should not be the focus of attention; this storm is enormous and will have a large impact regardless of where the center hits the mainland first.

Upper level energy is located over the Southeast US and should reach the storm sometime in the next 24 hours.  Vorticity is one way to locate the high energy in the upper levels and in the map below you will see an area of high vorticity coming around the trough and meeting up with Sandy.  At this point, the low will rapidly deepen while making the final approach toward the New Jersey coast.

Current Conditions

Sandy is a weak category 1 hurricane but the rain surrounding the storm is easily seen on Radar along the east coast.  One thing that must be noted is how large Sandy is; clouds associated with the system stretch from just north of Miami to almost Boston!  Some other features on the visible sat image are the cold front and some, what I assume are, foggy conditions in Iowa.

Rainy conditions located in the region around Lake Erie are associated with an upper level jet entrance region; this is NOT the upper level energy which will cause Sandy to transform into the hybrid system we expect to see over the next few days.  Jet winds currently located over the Panhandle/ Mountain West are the final ingredient that will make this storm the monster it will be.  This energy will continue to propagate eastward and will “absorb” Sandy in the next 36-50 hours.

Forecast

Unlike in some systems we will be forecasting this winter which seem to change each and every forecast cycle, this has been a pretty “easy” forecast.  The low pressure center should pass somewhere over New Jersey (likely along the North Jersey Shore) and bring with it VERY strong winds.  Gusts in excess of 75-80 mph along the coast are expected with the potential for record setting low pressure readings.

In more inland locations, winds will be gusting into the 70 mph range while being sustained in the 40′s.  Heavy rainfall will also be a big concern with Sandy, especially on the southern side of the pressure center.  HPC (Hydrometeorologcal Prediction Center) forecasts for the Lehigh Valley are in the 2-5 inch range while locations in Southern Delaware could see rainfall exceeding 1 foot over the next 4-5 days.

Lehigh Valley Impacts

There seems to be confusion as to what inland locations can expect in terms of impacts from this system.  I need to stress that local impacts will vary from one place to the next based on topography, vegetation, and very small scale meteorological phenomena.  Communities along the coast will take the full brunt of this system, and that is where a lot of focus will be in the coming days.

Flooding

With rainfall in excess of 3-4 inches, there is no doubt that flooding will become an issue, but I do not anticipate it being catastrophic   A logical comparison is last year when hurricane Irene impacted the region but I do not anticipate the flooding from this system will match what was felt in late August last year.  August 2011 set an all time monthly rainfall record so many of the rivers were already quite high.  All of the major rivers and tributaries in the region are currently at normal to slightly below “normal” flows right now.

Public enemy number 1 for flooding is loose leaves clogging storm drains.  Moderate to severe street flooding is possible as drains become clogged by the falling leaves around the region.  If you can, please take some time to clear drainage area that become clogged.

Wind

By far, the biggest concern with this system is the strong winds.  Winds in excess of 40 mph and gusting into the 60′s and even some local 70 mph gusts will cause wide spread tree damage.   As is typical, with tree damage comes power outages.  In tiny regions this again would not be a big problem, the trouble comes in with the power companies ability to restore power across their entire service area.  Rural areas could go more than 3-5 days without power, and that is being conservative.  Take care of your power workers in the coming week, they will be working VERY long hours and as we all know, during stressful situations citizens can being to get bossy and mean to these workers.

Closing

I hope to update again tomorrow morning but until then, please take precautions in clearing anything that can blow off your property and have an emergency kit prepared.  Try to remember that as stressed as you are…there are others (my wife is due any day now) out there that could be far more impacted than your minor inconvenience of not being able to watch the latest episode of the Jersey Shore.  Enjoy some time to yourself, and my hopes are that your able to make it through the storm with no property damage or injuries to you or any of your loved ones.

Feel fee to contact me via twitter (@dmodjr) or on facebook (www.facebook.com/den748)

Powder Keg

Although Sandy is weakening, she still threatens to pack a huge punch as she approaches the Eastern Seaboard.  Media outlets have correctly been billing this storm as a hybrid storm because Sandy will lose her tropical characteristics in the next few days as a trough approaches the area.  Upper level energy will move in from the west (see image) and provide a spark for Sandy to explode into a quickly deepening area of low pressure.  Pressure gradients will be very steep which means that a very large area can expect tropical storm force winds with area along the coast experiencing hurricane force gusts.

Upper level winds showing where the energy is coming from

Where and When

Everyone wants to know exactly where and when this event will take place.  Unfortunately there is still a bit of disagreement among the models as to where the storm will be strongest.  American models (GFS, NAM) suggest that the storm will make the greatest impact in Long Island and may even have the storm follow down the Long Island Sound, which would be devastating for some communities along the waterway, especially on the southern half where the sound funnels into New York City.  The every consistent Euro continues to strike Delmarva which could push water up the Delaware River into Philadelphia.  This would also impact greatly the resort towns through Delaware and Maryland.

In either case, weather will start to deteriorate late Sunday into Monday for most of New Jersey and Pennsylvania.  The worst of the storm will likely take place late Monday into Tuesday, especially if the long island sound solution verifies, New York city would take the brunt of the storm on Tuesday.

Inland Impacts

Cities well inland can expect to see several days of strong gusty winds with some heavy rains.  Areas where leaves have already fallen off of trees should see slightly less impact from the wind but that is not to say there will not be power outages.  Areas with thick foliage will experience more an amplified impact  because of the larger surface area.

Rainfall is also a big concern as the storm moves inland, it would not be out of the question to see areas with rainfall in excess of 10” with wide spread 3”+.  Rivers will rise over their banks with the NWS using the word “historic” in their briefings.  In addition to the river flooding, storm drains will be clogged with loose leaves causing very wide spread street flooding.

Coastal Impacts

Historic. 

This is a place where I can assure you that somewhere between OCMD and Islip (Long Island)  there will be a massive impact from tidal flooding.  Hurricane force winds will drive water well up the coastline causing extensive damage to homes and businesses along the shoreline.  Beach erosion will be epic which is ironic because the storms name is Sandy.  Expect to see most of the Weather Channel team reporting from locations in New Jersey.

Insurance Claims

Billions of dollars in insurance claims will be paid out following this storm.  Wide spread roof damage, water damage, business destruction, and losses relating to loss of electricity.  Although it might not seem much for an insurance company to pay out for some roof damage, multiply that by millions of people and it begins to add up.  More on this will be said after the storm has left the region.

Notice a few of the runs bringing Sandy out to sea. Those are the 00 and 0 on the roulette wheel.

At times we as scientists like to get caught up in the extreme and fail to acknowledge the mundane, and this storm is no different.  Communicating information to the public is dicey at times because people have a tendency to latch on to certain words or phrases.  If I say strong winds will cause massive power outages, and you don’t lose power, suddenly I was wrong; even if half of your state is without power.  Educating a large population on something as fickle as the movement of a tropical cyclone is a monumental task, and it takes on a new level of importance when there is the risk of property damage and harm to a number of humans.

I take the “apologize for overstating a storm” rather than “apologize for you being unprepared”.

Past 24 hours

Sandy has already caused extensive damage to Jamaica, Cuba, and Haiti with several deaths reported in the region.  The storm, unexpectedly, remained quite strong after passing over Hispaniola, remaining a strong cat 1 hurricane.   As of the 2pm NHC advisory, the storm has sustained winds of 105 mph which is a strong category 2 hurricane on the verge of reaching major hurricane status (>110 mph).

The projected path of Sandy from the National Hurricane Center

Forecast

As each model run is processed, meteorologists everywhere get chills thinking about the unprecedented results of a “landfalling” major hybrid hurricane.  Sandy will continue to move northward for the next 2-3 days before making a shift west or even southwestward as the negatively tilted trough from the west approaches.

Major cities along the east coast will be impacted but the degree of damage very much depends on the location of the low pressure center.  The operational GFS has Sandy making a hard left turn when it is about even with New York City and bringing what would be a very large surge of water directly down the Long Island Sound.  The end result would be flooding through lower Manhattan and into Brooklyn.  For Philadelphia, the worst case would be the European solution which has the center coming up the mouth of the Delaware River which in conjunction with the heavy rains would effectively cause a storm surge up the Delaware causing flooding in the city.  Points along the south Jersey shore would also be heavily impacted by this solution as winds will come onshore pushing up an already enhanced high tide.  These are just two of the hundreds of possible outcomes of the storm.

The GFS ensemble is showing a lot of agreement

Impacts

One of the difficulties in being a meteorologist is determining the human impact of weather.  So much goes into how damage is created that is beyond just meteorological phenomena, coastal flooding is heavily dependent on oceanography and the exact timing of the storm, power outages can be impacted by how many leaves are still on a tree or by how well local utilities maintain their energy grid.  Impacts felt by one portion of the population may be totally different than felt by another portion.  So before bemoaning that a storm was “overhyped” take a step back and look at the more regional impact of an event, you might be surprised at how many people have been negatively impacted by an event.

Don’t do this:

With that said here are the impacts, almost unchanged from yesterday:

• Record Coastal Flooding
• Widespread tropical storm force winds
• Heavy rain with localized river flooding
• Restructuring of some shore lines (sounds extreme but happens when major hurricanes hit the coast)
• Very wide spread power outages from Maryland through Maine
• Snow in the Appalachians of West Virginia up into New York

What you can do to prepare

• DO NOT BUY MILK AND EGGS , it is likely that you will lose power so it would be a waste of your money and food
• If you have a generator, make sure to buy fuel
• If you do not have a generator, it is likely too late as many home supply stores are already sold out
• Keep your cell phone charged in case of an emergency
• If you are parked under a large tree, move your car
• Try to keep leaves away from storm drains, it will help to decrease the street flooding
• Have candles and a lighter in a location easy to find, also keep a flashlight close to your bed
• Cancel any air travel early next week
• And try to enjoy the fact that you’re seeing history and there is nothing you can do to change what is happening.  Cuddle up next to a good book and candles and just enjoy your time disconnected from the world.

Today, much like 1991, there is a Hurricane forecast to move northward and it could phase with a trough forecast to dig into the US.  Of course, no two storms are exactly alike and there are many differences between the two events.  Regardless, it is fun to look back at such a historical event and draw similarities based on that past event.

Forecast

As conservative as I tend to be with my forecasts, especially 5 days out, this storm has many of the models in a relative consensus.  There is high confidence that a very strong storm will impact the eastern seaboard and will make “landfall” somewhere between the Chesapeake Bay and the coast of Maine early next week (Late Sunday through Tuesday).  Landfall in the case of a nor’easter takes on a diminished role compared to a tropical system as tropical systems tend to be compact with the areas of strongest wind while a nor’easter will have a wide spread wind pattern.

ECMWF 120 hour forecast

Current model output has some areas receiving rainfall amounts of >6”, which in conjunction with the strong winds could cause a large number of uprooted trees, and the associated power outages.  This heavy rainfall could also lead to inland river flooding while the coastal regions will be heavily impacted regardless of whether the storm stays out to sea due to the full moon on Sunday and an agitated ocean.

As time goes on and new information becomes available, expect an update from me on this page and also on my twitter account (@dmodjr).

Impacts

The exact positioning of the storm will have a great impact on where the worst is felt but, assuming Sandy does not go out to sea, there will be the following impacts.

• Widespread Power Outages
• Tree and large branches falling
• MASSIVE Coastal Flooding
• High Winds
• Mountain snowfall
• Localized River Flooding
• Heavy Beach Erosion
• Billion Dollar Insurance Potential

First and foremost, my winter forecast for the area around Southeastern Pennsylvania!

If you read part 3 of my winter forecast, you noticed that I think that the predominant storm path will come from the south and up the east coast.  My snow mongering friends will hear that and get really excited..but as Lee Corso says..Not so fast my friend!

It is true that some of our strongest winter storms have taken this path up the coast, and with the anomalously warm water temperatures, a fantastic baroclinic zone will set up (an area with a large temperature gradient), which is one of the ingredients for explosive cyclogenesis (storm creation).  Typically with these storms, a battle line is set up where the warm ocean air and the cool continental air collide and we see a changeover to snow/rain.  Often this line is difficult to predict, and can move as the storm progresses.  My forecast is based on the assumption that the line will set up somewhere between Philadelphia and Allentown for almost all the storms while the Lehigh Valley remains all snow during most events.

Forecast Numbers

What is Needed for the Forecast to Come to Fruition?

For my forecast to end up being correct, I need some help from Mother Nature.  First off, a slight El Nino must remain in place to give the proper storm path.  Although I mentioned that there is little correlation to precipitation with El Nino, there is some evidence that shows that snowfall is increased during years with a slight to moderate El Nino.  It is possible to have increased snowfall but have a decrease in precipitation, but that is a subject for a different day.  In addition to the slight El Nino, there needs to be some blocking downstream which implies a negative NAO.  This blocking will help keep storms close enough to the coast as well as push them through the baroclinic zone so that they can strengthen.  Both of these ingredients are crucial for a snowy winter in the Lehigh Valley.  Finally, the AO needs to be negative to allow some of that very cold air to seep down from the arctic.

If all of this happens, then I think my forecast has a fantastic shot at verifying.  The danger is in my assumption that Philadelphia remains in the warm sector and is deprived of snowfall.  A single large storm could completely derail my entire forecast.

What is next?

Now that you all have read the most amazing winter forecast available on the interwebs, you need not have to go anywhere else.

Don’t believe that, I was lying to you.  Almost every forecast issued on the web has some scientific backing to it.  Throw 10 meteorologists in a room and ask them to make a forecast, and you will likely get 5 different forecasts for 10 different reasons.  I will not try to hide other forecast from my readers, in fact I will show you all of them and even link to them so you can see why they made that forecast in the final part of this exciting series. Expect it in the coming week!