Irene has now made its way north of the Mid-Atlantic Bight leaving her mark inshore and along the coast.   RU16 fought the onshore currents associated with the northern edge of the storm until this morning when the currents switched as the eye passed overhead.  The last several surfacing show that the glider is now making much better progress offshore.   The glider is now offshore of the large phytoplankton bloom we were monitoring before Irene’s arrival.   You can follow that event here: (http://maracoos.org/summerbloom/).  The map below shows the bloom location several days before the storm as the color background underneath RU16′s path.

Preliminary data from the glider shows that the impact of Irene was felt deep into the water column.   Before the storm, the ocean had a very warm surface layer above a very cold bottom layer.   The temperature gradient between the two is one of the largest in our global ocean.   You can see the pre-storm conditions in the plot below.  Look at the data collected between August 26 and August 28.

Irene’s influence is see near the left edge of the plot with a rapid cooling of the surface layer from 25 degrees C before the storm to 19 degrees C after the storm.  That is over 11 degrees F!  In addition the surface layer deepened significantly from 15 meters to almost 30 meters.  Irene has doubled the thickness of the mixed layer.

The mixing and deepening of the surface mixed layer is also seen in the dissolved oxygen data.   Relative to before the storm the mixed layer is now slightly lower dissolved oxygen concentrations in the near surface but has now delivered more oxygen rich water deep in the water column.   As with Ernesto 5 years ago, Irene did not mix away the strong stratification in the deeper waters of the mid-shelf.  RU16 will now turn back inshore to see how Irene’s influence was felt in the shallower waters coincident with the highest cell concentrations associated with the pre-storm bloom.

First check in – National Hurricane Center.  Here is the 5 am guidance. Hurricane Watch in the northern Mid Atlantic north to Cape Cod, Tropical Storm watch across the Gulf of Maine past Halifax.

From their discussion, the strength and track pieces:

IRENE IS EXPECTED TO REMAIN NEAR HURRICANE
STRENGTH UNTIL IT MOVES INTO SOUTHERN NEW ENGLAND LATER TODAY..
SLOW WEAKENING IS EXPECTED AFTER LANDFALL AS IRENE BECOMES A
POST-TROPICAL CYCLONE IN ABOUT 24 HOURS.
THE TRACK GUIDANCE
REMAINS TIGHTLY PACKED...BUT HAS SHIFTED A LITTLE TO THE LEFT IN
THE VERY SHORT TERM.  THE NEW NHC TRACK FORECAST HAS BEEN ADJUSTED
IN THAT DIRECTION AND IS CLOSE TO THE ECMWF THROUGH 24 HOURS.
AFTER EXTRATROPICAL TRANSITION THE NHC FORECAST IS A BLEND OF THE
GFS...ECMWF...AND UKMET.
 
Second Check, the global glider fleet.

Antonio reports that they are dealing with a storm in over on the European side of the Atlantic, with Silbo (the yellow ellipse) in it.  After the strong storm they will move Silbo into some strong SW currents towards the Azores.  Follow along on the Challenger Mission blog at http://www.i-cool.org/?cat=77
 

 
On the Pacific side of the U.S., Tina reports flat calm seas  on the R/V Thompson. http://www.i-cool.org/?cat=168     Tina deployed RU25 as part of the NSF Ocean Observing Initiative cruise to Axial Seamount. There is live HD TV from the vent field after a recent eruption.  One of the sites getting the HD feed is the Rutgers COOLroom – you’ll see the photo of the COOLroom in this article.
http://www.nsf.gov/news/news_summ.jsp?cntn_id=121463&org=NSF&from=news
We are getting ready for the recovery of RU25 early on monday, maybe even a view of the RU25 glider from the HD TV on the ROPOS autonomous underwater vehicle.
With everything set in the far corners of the image, lets turn to Irene.
First the three standard overviews.  The clouds from Irene:

And now the rains.  Starting to clear over Cape Hatteras:

And the view of the Mid-Atlantic HF Radar network.  From Cape May north we still have communications.

So lets zoom in to the northern side:

The surface currents are towards the coast from Cape May to Block Island, flowing into both Long Island Sound and New York Harbor. This is the scenario Alan discussed on CNBC on friday.  The currents are coming in, and so is the spring tide forced by the new moon.
So lets check the Stevens NYHOPS website for storm surge
http://hudson.dl.stevens-tech.edu/SSWS/
 

They have Moderate flooding in New York Harbor.  Lets zoom into the Battery

Looks like water levels are 3 feet above the high spring tide. Lets check the current WRF forecast:

Winds will be shifting to alongshore, and that will help with the flooding in the Harbor.  Lets look at mid-afternoon on sunday.

Now the winds are from the coast offshore New Jersey and towards the coast out by Rhode Island and Cape Cod.  For Sunday evening:

We see the stronger winds are along the southern New England coast and in the Gulf of Maine.
 
							

National Hurricane Center has Irene continuing along its forecast track.  Here are the maps:

The view from MARACOOS:

First the clouds:

The rain:

The radar:

Lots of power out in the southern part of our region.  So we zoom into the northern part:

Currents are toward the coast, so water levels are expected to remain above the normal tidal heights.  Zooming into the Approaches to New York Harbor:

Currents are toward the beach and into the harbor.  Water levels will be one of the first things to check in the morning.  The total water levels may be dropping with the outgoing tide right now, but that will change with high astonomical tide tomorrow morning around 7-8 am combined with the wind driven storm surge.

Here is the animation of the most recent RU-WRF forecasts.  The control buttons are along the bottom. The first time through the loop is slow since it has to load each image.  Subsequent loops are fast.

http://marine.rutgers.edu/cool/weather/RUWRF/animation/6km/wind.html

Present forecast conditions:

The strongest windband is right into the entrance to Delaware Bay.   Wind if now from the west offshore Cape Hatteras, reducing the storm surge.  But the winds are still strong.  North of Delaware Bay, winds are blowing from offshore right at the NJ Coast and New York Harbor.

Now here are the winds at 8 am tomorrow morning, the predicted time of high tide.

The eye is over southern NJ and the winds are still into New York Harbor.  So the winds are forecast to still be sending water into the harbor at the new-moon high tide tomorrow morning.  We’ll check storm surge forecasts after posting this blog.  Here is one from NYHOPS model. It shows water levels at the Battery in New York City.  Forecast is approaching a moderate flood.

More forecasts can be found at:

http://hudson.dl.stevens-tech.edu/SSWS/

Lets also check the measured water levels, this time at Atlantic City where they are reporting lots of power outages.

This is from the NOAA Tides and Currents page.  The measured water level in red is about 2-3 feet above the normal tide level.  This will increase overnight with the winds towards the coast, and as the morning high tide approaches, we’ll likely see some of the highest water levels.

But before cruising the water level websites, first we show the accumulated rainfall from the WRF model:

http://marine.rutgers.edu/cool/weather/RUWRF/animation/6km/accrain.html

For the accumulated rainfall, it looks like 5-10 inches over the Chesapeake and Delware Bays. Delaware and Hudson Rivers are getting even more.

So the coast will get hit with the winds, storm surge and high spring tide. And the inshore side will see significant rain.  The Hudson is getting flooded from both sides.

This just sent in from Laura, our CODAR partner on the West Coast,

concerning the storm surge and New York city.

Here is the web link to a clear, concise interview of Alan Blumberg by CNBC.

http://www.cnbc.com/id/15840232?play=1&video=3000041964

Interview piece is titled, "How Bad Will Irene Be? Alan Blumberg, Phd,

Consortium for Climate, discusses the best and worst case scenarios

of when Hurricane Irene hits New York City"

In summary Alan says it's all about the tide status at time of

hurricane storm surge reaching NY Harbor.

If the storm surge arrives near high tide then big trouble

in lower lying areas.

Ru16 has been heading offshore into deeper water since Wednesday afternoon in anticipation of Irene’s arrival this weekend.  Over that time we were able to get the glider into deeper water so that it can better weather the large seas associated with the storm.  Once the storm passes, the glider will be ready to head back inshore to give us our first look at the post storm water column conditions.

At about 3:00pm local this afternoon Irene started to push back and halt any progress ru16 was making.  The onshore currents associated with the northern edge of the Hurricane are now fighting ru16′s progress offshore.  You can see these strong currents in the above map in the large red vectors heading toward the New Jersey coast.

When we look closer at Ru16′s path we can see each surface event as red circles along its path.  Each point, about 2.5 hours apart, marks the location the glider surfaced when calling back to our mission control center at Rutgers.   Up until the last 4 surface events, the glider was making its way along the line at a rate of about 2 km every 2.5 hour segment.  The last 4 segments however show the effect of the strong onshore currents.  Since the glider is a slow mover and flying right into the onshore flow, the glider is basically standing still with all surface events practically on top of each other.   Irene has successfully turned the glider into a profiling mooring sampling the same part of the ocean with each up and down yo.  The glider will now sample the ocean conditions through the storm as Irene continues to move up the coast.

RU16 and Irene will be locked in this great dual until mid-day tomorrow when the currents will switch offshore and start hitting the glider on the other cheek!

Here is the track.  Hurricane advisories across the entire Mid-Atlantic.  Tropical storm advisories across the Gulf of Maine to Halifax.

First piece extracted from the National Hurricane Center discussion:

A SLOW WEAKENING IS EXPECTED AS IRENE MOVES
ALONG THE COAST OF THE MID-ATLANTIC STATES DUE TO LAND
INTERACTION...COLDER WATERS...DRY AIR ENTRAINMENT...AND INCREASING
SOUTHWESTERLY SHEAR.  BECAUSE THE LARGE WIND FIELD WILL TAKE TIME
TO SPIN DOWN...HOWEVER...IRENE IS STILL EXPECTED TO REACH THE NEW
YORK AREA AT OR NEAR HURRICANE STRENGTH.

So Irene is forecast to remain hurricane intensity across our entire region.  Now the second piece extracted:

IRENE IS FORECAST TO MOVE NORTH-
NORTHEASTWARD ALONG THE MID-ATLANTIC COAST TONIGHT AND OVER NEW
ENGLAND ON SUNDAY. AFTER THE CYCLONE BECOMES EXTRATROPICAL IN 36-48
HOURS IT SHOULD TURN NORTHEASTWARD THEN EAST-NORTHEASTWARD IN THE
MID-LATITUDE WESTERLIES. THE NEW TRACK FORECAST IS UNCHANGED FROM
THE PREVIOUS ADVISORY.

Looks like the extratropical transition occurs after it moves into New England. This is not like Ernesto in 2006.  Now the last piece extracted:

NOTE THAT ESTIMATES OF STORM TOTAL RAINFALL HAVE BEEN INCREASED WITH
THIS ADVISORY...TO 20 INCHES.

20 inches?  It looks like rain will be the story for much of the Mid-Atlantic tomorrow.

Now the MARACOOS view of the offshore.  First the cloud shot:

Now the rain shot:

On to the view of the network, and we see that communications to our southern radar sites are going down.  This is likely due to loss of power.  Some sites are on backup batteries and generators, so they could be operating.  We often find this is the case after a power outage with loss of communications.

So lets zoom into the northern side where the communication network is still up and running.

The currents are now heading towards the coast all the way north to New York Harbor.  So lets zoom in further to the New York Harbor Approaches.  The HF radars in this area where funded by different agencies, but are now operated as part of IOOS.

In the southern side of the shipping lanes, we have the surface currents from the DHS/DoD 13 MHz CODAR network saying all the flow is towards the beach.  In the entrance to New York Harbor, the ONR CODARs are also saying the flow is all into the harbor.

With rain being the story, I’ll move over to the weather forecasts next.  Then I though I would check out the NYHOPS forecasts of storm surge from Stevens Institute of Technology.  You can view all of these yourself by visiting the MARACOOS website:

http://maracoos.org/

Click on the “Web Products” link in the right column. Or try going directly to

http://maracoos.org/data_forecasts

By then the National Hurricane Center should update their advisory.  Looks like they are on a 2-3 hour cycle.

Before we get down to the real work of blogging the present local situation, here is a shot for the glider fans.  It is the North Atlantic Basin Scale view of Irene and Silbo.

It shows the origins of Irene, just west of the Cape Verde Islands off Africa, tracking across the southern side of the North Atlantic Gyre, transitioning to a hurricane as it passes our CaRA IOOS and DHS partners in Puerto Rico.  Irene then continues on its course along the U.S. Eastern Seaboard through the SECOORA, MARACOOS and NERACOOS regions of IOOS, encountering 2 gliders deployed by MARACOOS in the Mid-Atlantic. Irene then tracks by our friends in Halifax, through Canada and across the northern side of the North Atlantic to Iceland.  There it encounters the track of the long-duration glider Silbo launched by our partners at Teledyne Webb Research from their lab in Iceland.  The Silbo is being piloted by scientists and students (mostly students) from PLOCAN and the Universidad de Las Palmas de Gran Canaria in the Canaries and at Rutgers.  You can visit their blog at http://www.i-cool.org/?cat=77 to learn more about this first test flight for the Challenger Mission.  Currently, glider Silbo is on a course to fly by the Azores then on the Canaries for refueling.  From the Canaries we hope to continue south to the Cape Verde Islands, and then across the southern side of the gyre to Puerto Rico, following the yellow line.  If all goes well, Silbo will visit our CaRA partners in Puerto Rico for refueling sometime near the end of 2012.

To our friends in the Canaries, it is unlikely your students will be returning from their summer semester in the COOLroom on Monday.  Flights out of the New York area are being cancelled.  It looks like Irene may get to Europe before they do.  Instead, they are helping us here.

Advisory #30 just released.  here is the now standard overview for the many codar fans on the email traffic.

We have two gliders in the water.  One is crippled and will act as a drifter until recovery after the storm.  The other being coordinated by Rutgers, NJ DEP and the EPA continues to fly well.  Josh has coordinated the glider team to keep flying the RU16 glider offshore.  Josh’s rationale is below

“Lets keep the same offshore waypoint for Ru16.
According to the codar fields the onshore currents associated with the north side of the storm should be hitting the glider within the next couple hours.   The glider will fight these currents through the night then we turn it tomorrow afternoon/evening back inshore.
Josh”

The data from the RU16 glider does not yet show major impacts of the storm’s arrival.  The water column remains strongly stratified with almost a twelve degree gradient in ~1 meter depth change, which makes this shelf one of the more extreme coastal thermal gradients in the global coastal ocean. The sharp thermocline clearly shows the presence of internal waves which will be interesting to follow as Irene tracks up the coast. The strong temperature gradient leads to an extremely stable water column as indicated by the density plot.  The interesting question is whether the hurricane has sufficient energy to overcome the extreme thermal inertia in the water column. Oxygen remains high in the surface waters reflecting the large phytoplankton bloom, check out the summer bloom blog (http://maracoos.org/summerbloom/). The storm should significantly change this oxygen profile and hopefully will increase the oxygen in the bottom waters which remains close to the border where animals can be stressed.