WunderBlog Archive » Category 6™

Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.

Arthur Nears Hurricane Strength

By: Dr. Jeff Masters, 9:03 PM GMT on July 02, 2014

Tropical Storm Arthur has formed a large, 30-mile diameter eye, and appears destined to be a hurricane by early Thursday morning, as the storm heads towards a rendezvous with the North Carolina coast on Friday. An Air Force hurricane hunter aircraft was in the storm Wednesday afternoon, and measured top surface winds of about 70 mph with their SFMR instrument. Arthur's central pressure was 995 mb at 3:10 pm EDT, then dropped to 992 mb during their second eye penetration an hour later, at 4:04 pm. Radar out of Melbourne, Florida and satellite loops on Wednesday afternoon showed that Arthur had closed off an eye, though portions the northwestern portion of the eyewall had a gap due to infiltration of dry air. Arc-shaped bands of low cumulus clouds are no longer spreading out to Arthur's north, indicating that the storm has walled off its center from dry air. An impressive "hot tower"--a powerful eyewall thunderstorm with a high top--developed along the eastern side of the eye at 4 pm EDT. Wind shear continued to be a light 5 - 10 knots. Water vapor satellite loops showed dry air to the north and west of Arthur, and some of this dry air was still filtering into the circulation.


Figure 1. MODIS satellite image of Tropical Storm Arthur, taken at approximately 16:30 UTC (12:30 pm EDT) on Wednesday, July 2, 2014. Note the arc-shaped lines of low clouds to Arthur's north, caused by dry air at mid-levels of the atmosphere getting ingested into Arthur's heavy thunderstorms, creating strong downdrafts that spread out along the ocean surface. This process robs a tropical storm of moisture and energy. Image credit: NASA.


Figure 2. Melbourne, Florida radar image of Tropical Storm Arthur at 4:37 pm EDT July 2, 2014.

Forecast for Arthur
Now that Arthur has mostly closed off an eye and walled off much of the dry air to its north, we can expect some modest intensification, with perhaps a 20 mph increase in strength by Thursday afternoon. The 18Z Wednesday run of the SHIPS model predicted that wind shear will remain light to moderate, 5 - 15 knots, between now and the time Arthur makes is closest approach to North Carolina on Friday morning. There will still be dry air to the storm's north and west, and the SHIPS model predicted a 17% chance of rapid intensification--a 30 mph increase in winds in 24 hours. I put the odds Arthur becoming a Category 3 or stronger storm at 10%. The four main intensity models used by NHC--the LGEM, SHIPS, GFDL, and HWRF--continue to be in remarkable agreement, predicting that Arthur will reach hurricane strength on Thursday, and peak at maximum sustained winds between 80 - 95 mph about the time Arthur is making its closest pass to the Outer Banks of North Carolina, on Friday morning. The models are also in good agreement on the track of Arthur. A trough of low pressure passing to the north will turn the storm northeastwards by Thursday, and cause Arthur to pick up speed. The Outer Banks of North Carolina will be the land area at greatest risk of a direct hit, and the 5 pm EDT Wednesday wind probability forecast from NHC gave Cape Hatteras a 26% chance of experiencing hurricane-force winds. Given the degree of model unanimity, the cone of uncertainty is likely thinner than presented. The latest 12Z Wednesday runs of our top two track models, the GFS and European (ECMWF), showed the eye of Arthur passing over Cape Hatteras, North Carolina between 5 am - 8 am EDT Friday, July 4.


Figure 3. Screenshot of the experimental NHC Potential Storm Surge Flooding Map for the North Carolina Outer Banks, generated at 11 am EDT Wednesday July 2. Inundation of the land to a depth of 3 - 6 feet (yellow colors) has a 10% chance of occurring near the vulnerable section of Highway 12 near Rodanthe, and at the Bonner Bridge over Oregon Inlet. The bridge was forced to close in December 2013 for 12 days of emergency repairs due to dangerous scouring around the support pillars. The image was generated using using NOAA's Probabilistic Hurricane Storm Surge (P-Surge 2.0) model. P-Surge 2.0 uses multiple runs of the NWS Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model to create an ensemble of possible inundations, by varying the hurricane's landfall location, intensity, size, forward speed, and angle of approach to the coast. The image shows where the storm surge has a 10% chance of inundating the coast at 3, 6, and 9 feet above ground level. The model does not take into account wave action, freshwater flooding from rainfall, and breaching or overtopping of levees.

North Carolina's Outer Banks at risk of getting cut off
Hurricane Sandy pummeled the Outer Banks of North Carolina in late October 2012, causing $13 million in damage, and wiping out the protective dunes along a long section of coast. Coastal Highway 12 that connects North Carolina's Outer Banks to the mainland was cut for nearly two months, until repairs were completed in December 2012. Residents of the Outer Banks were forced to take a 2-hour ferry ride to get to the mainland when Highway 12 was cut. Nor'easters and storms repeatedly caused overwash and road damage to NC-12 during the winter of 2012 - 2013, but a temporary barrier was erected in 2013 that has been successful at keeping the road open during the past year (though minor overwash occurred during storms on October 10, 2013 and March 18, 2014, and Tropical Storm Andrea closed the road to all but 4-wheel drive vehicles on June 7, 2013.) Emergency post-Sandy federal funding of $20.8 million was secured to construct a barrier designed to last three years, but the project is up for bid, and has not yet begun.



Figure 4. Top: Coastal Highway 12 in North Carolina, which connects the Outer Banks to the mainland, as seen at 5:43 pm EST on Tuesday, November 13, 2012, near Rodanthe. Hurricane Sandy wiped out most of the protective dunes along the coast, allowing the ocean to directly pound the road during high tide. Bottom: the same view as seen in June 2014, after a temporary repair was made to the beach destroyed by Sandy. Image credit: North Carolina DOT. Live views of Highway 12 road cams are available from the NCDOT web site.

NC 12 is once again in danger of being cut, due to the storm surge and wave action of Arthur. Also at risk is Highway 12's Bonner Bridge over Oregon Inlet on the Outer Banks, which was forced to close for 12 days in December 2013 for emergency repairs, when scans revealed excessive sand erosion (scour) around some of the support columns. With sea level rise steadily increasing the damage that storms like Arthur can do to the vulnerable Highway 12, some very expensive long-term solutions are being studied for keeping Highway 12 open.


Figure 5. A small boy plays with a toy donated by Portlight on September 5, 2012. His home in Pearlington, Mississippi was demolished by Hurricane Isaac. Image credit: Portlight.org.

Portlight disaster relief charity ready to respond during the 2014 Atlantic hurricane season
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, is asking for donations as the 2014 hurricane season gets underway. This year, Portlight has already deployed staff to help victims of the April 27 EF-2 tornado that devastated Quapaw and Baxter Springs, Oklahoma, and is still active in New Jersey in the aftermath of Hurricane Sandy. This hurricane season, they hope to deploy a disaster shelter trailer which will help them assist shelter operators in making their facilities fully accessible to people with all types of disabilities. This will include ramping, railings, cots, dinner- and drinkware, and assistive technologies for those with vision, hearing, cognitive and developmental delays. Check out the Portlight Blog , and consider a donation to Portlight's disaster relief fund at the portlight.org website.

Jeff Masters

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Quoting 1499. washingtonian115:

Arthur seems like he wants to be retired. ?...

His name has been used 6 times already...
we locater at cape romain,have roof
Quoting 1491. OracleDeAtlantis:

We are immune from hurricanes in South Carolina.


Ask folks in Charleston how that kind of thinking worked out for them in 1989.

JeffMasters has created a new entry.
1505. Doss2k
Intensity debate aside (since people are all over the place on that it seems). The more troubling part to me is that while the exact center may stay off shore the models and my eyes tell me this is going to likely be a bit more west. This may put nearly the entire NC coast in the eyewall even with the center staying offshore until the OBX due to the size of the eye.

Can't believe anyone is calling this a fish storm, even if the eye never makes direct landfall this thing is still going to cause a lot of problems along the coast and affect many people.
1506. ricderr
Not going to jump the gun too much, but how fast it's intensifying I don't think it's out of the question for it to be a high end cat 2 or higher.

We all need to owe JB an apology xD



first...i think the bastardi one is very smart....i also tthink he's good at marketing....combine those two and you have a supreme hypster....there's nothing at this time that supports a cat 3 hurricane.....but...for bastardi...and many others...it won't matter if he's right or wrong in the eyes of the public...his latest pr move will soon be forgotten...as that is why he makes these hyped statements....as people will only consider his latest...as he will make another and then another
the big wave tour is scheduled to start in a few minutes from pico alto peru. a storm about a week ago in the south pacific has created massive long period swell supposingly its the biggest swell in a few yrs for peru. good luck all participants.
1508. hydrus
I hope the folks along the coast are ready. They may have a significant event, and time for preparation is short.
I am from Nova Scotia and the storm is expected to be just west of me barely. The forward speed of the storm when it gets here is sure to add to those winds a little and we are expecting Hurricane force winds even though it will technically be a tropical storm when it is here. Saturday sure looks fun here in New Scotland! :0
So, what is the estimated time of landfall and where?
Had our first rain band in the Wilmington area about an hour ago; produced steady rainfall and peak gusts of 30-35 mph. Looks like more significant stuff is on the way.

Arthur seems to be on the western side of NHC's cone, which is a bad situation altogether. More impacts for my area (hurricane warnings required?), more significant impacts in the Outer Banks.

Quoting 1490. ncstorm:



actually he made that call before yesterday and was accused of being on crack..I actually agreed as well..so I will be the first to say sorry..LOL


I also said it could become a Cat 3 before yesterday. :p But either way it doesn't matter. Thoughts with those that will be affected.

Just to put things into perspective, Arthur is up to 85mph. The NHC forecast had Arthur being at 80mph at 18z in their 9Z forecast. With 5-6 hours until 18z and more time afterwards before landfall, I wouldn't be surprised if Arthur becomes a 970 mb or lower system with winds of 100-105mph at landfall, perhaps even becoming a major.
Quoting 1487. Jonmeister12:

How would you all (experienced meteorologists) compare Arthur to Irene in intensity and other damaging factors such as storm surge? Thx


I'm not an "experienced meteorologist", but for starters Irene already had a well established history by the time she began approaching the coast. She had been a category three storm as she tracked north of the Caribbean islands. As she approached the Carolinas she weakened to a category one storm (same as Arthur), but she also had begun expanding in area. By the time she was near Arthur's current location, she was already a much larger storm plus she already had the ocean waters in motion from the previous days. . . . so, all that combined gave Irene a much greater surge potential.

THAT BEING SAID. . . each storm poses different hazards, and one should base one's storm preparations on what officials recommend, and not based on one's personal storm history. So, one shouldn't blow-off Arthur just because it's not an Irene sized storm.
1514. beell


Grabbed this early this morning from Recon 10 at the four corners of the flight path. Red numbers represent 850 mb heights. Heights from higher up would be a better indicator. Not a whole lot to infer from this limited amount of data but maybe a slight weakness towards the coast. Similar rookie results from a sampling of last night's NOAA dropsonde mission.

Still some north left in Arthur?
Quoting 1497. hydrus:

Not all. There were people here including the Doc stating that this could become a major hurricane..I said in one of my post that a cat-3 was a real threat, but I was not sure if it would be a three at landfall.


I estimate there's a 20% chance that Arthur makes it to Category 3 strength. Unlikely, but still possible. At this point I think it's more likely than not that Arthur makes it to Category 2 strength. I estimate at least a 60% chance the storm reaches minimal Category 2. it doesn't take much for a storm to increase its windspeed by 15MPH with more than 12 more hours over water. I think that the dry air is still a problem for Arthur and every time he looks like he is really getting going, the eyewall erodes due to dry air intrusion. Then again, every time Arthur looks a little ragged on radar, another burst of convection occurs around the eye and the structure improves again. I guess we will know soon enough.
Erik Fox is now at the shopping center where it is VERY DANGEROUS!

It's great weather now...but tonight...that spot IS A DEATH ZONE!

I slept in that parking lot during Earl. It floods...and the intercoastal is just two blocks to the rear.
Erik Fox is in Buxton, NC at this hour.

Ground Zero...very dangerous later tonight!
Next recon flight (enroute) should be interesting.

When should the wind shear start to increase?
1520. FOREX
Looks like the trough is not doing its job.
1521. obxrox
Quoting 1516. CycloneOz:

Erik Fox is now at the shopping center where it is VERY DANGEROUS!

It's great weather now...but tonight...that spot IS A DEATH ZONE!

I slept in that parking lot during Earl. It floods...and the intercoastal is just two blocks to the rear.


That's a bit dramatic.

Buxton does have above ground structures that can sustain hurricane force winds. The highway just north of town floods and washes over frequently. This storm isn't anything they can't handle.
1522. LargoFl
1523. LargoFl
Quoting 1520. FOREX:

Looks like the trough is not doing its job.
I sure hope folks in SC/NC are preparing for a hurricane and NOT thinking oh its just going to pass us by...no need to worry....
1524. LargoFl
Quoting 1511. TropicalAnalystwx13:

Had our first rain band in the Wilmington area about an hour ago; produced steady rainfall and peak gusts of 30-35 mph. Looks like more significant stuff is on the way.

Arthur seems to be on the western side of NHC's cone, which is a bad situation altogether. More impacts for my area (hurricane warnings required?), more significant impacts in the Outer Banks.


hunker down and stay safe ok,hope all your preps are finished and supplies gotten.
1525. LargoFl
NHC should use their new storm surge maps for This storm..would be a great trial run for it.
1526. LargoFl
HURRICANE ARTHUR LOCAL STATEMENT
NATIONAL WEATHER SERVICE WAKEFIELD VA
835 AM EDT THU JUL 3 2014

...ARTHUR STRENGTHENS...

.NEW INFORMATION...
A HURRICANE WARNING HAS BEEN ADDED FOR COASTAL NORTHEAST NORTH
CAROLINA. A TROPICAL STORM WARNING IS NOW IN EFFECT FOR ATLANTIC
COASTAL WATERS FROM THE NC/VA BORDER TO FENWICK ISLAND.

.AREAS AFFECTED...
THIS LOCAL STATEMENT PROVIDES IMPORTANT INFORMATION AND
RECOMMENDED ACTIONS FOR PEOPLE AND MARINE INTERESTS IN SELECT
LOCATIONS AND COASTAL WATERS OF SOUTHEAST VIRGINIA...NORTHEAST
NORTH CAROLINA...INCLUDING THE ATLANTIC COASTAL WATERS AND
CURRITUCK SOUND.

.WATCHES/WARNINGS...
A HURRICANE WARNING CONTINUES FOR THE FOLLOWING LOCATIONS...
PASQUOTANK...CAMDEN...INLAND CURRITUCK AND OUTER BANKS CURRITUCK.

A TROPICAL STORM WARNING CONTINUES FOR THE FOLLOWING LOCATIONS...
BERTIE...CHOWAN...PERQUIMANS...NORFOLK/PORTSMOUTH ...CHESAPEAKE
AND VIRGINIA BEACH.

FOR MARINE INTERESTS...A HURRICANE WARNING CONTINUES FOR
THE CURRITUCK SOUND...AND ADJACENT NORTH CAROLINA COASTAL WATERS.
A TROPICAL STORM WARNING CONTINUES FOR THE COASTAL WATERS
ADJACENT TO SOUTHEAST VIRGINIA AND THE LOWER EASTERN SHORE.

A FLASH FLOOD WATCH IS IN EFFECT FOR PORTIONS OF CENTRAL AND
EASTERN VIRGINIA...NORTHEAST NORTH CAROLINA...AND THE LOWER
EASTERN SHORE. PLEASE LISTEN CLOSELY FOR ANY FLOOD WARNINGS THAT
MIGHT BE IN EFFECT FOR YOUR AREA.

PLEASE CHECK THE LATEST PUBLIC AND MARINE FORECASTS FOR DETAILED
INFORMATION ABOUT ADDITIONAL HAZARDS.

.STORM INFORMATION...
AT 8 AM EDT...THE CENTER OF HURRICANE ARTHUR WAS LOCATED NEAR
LATITUDE 31.8N...LONGITUDE 78.7W. THIS WAS ABOUT 490 MILES
SOUTH-SOUTHWEST OF OCEAN CITY MD...OR ABOUT 380 MILES
SOUTH-SOUTHWEST OF NORFOLK VA. STORM MOTION WAS NNE OR 15 DEGREES
AT 9 MPH. STORM INTENSITY WAS 80 MPH.

.SITUATION OVERVIEW...
HURRICANE ARTHUR IS EXPECTED TO MOVE JUST OFFSHORE OF COASTAL
NORTH CAROLINA LATE TODAY...BEFORE ACCELERATING AND SHIFTING
NORTHEAST AS IT PASSES ALONG THE NORTH CAROLINA COAST LATE
TONIGHT INTO FRIDAY. MAIN FORECAST CONCERN WITH THE TRACK OF
ARTHUR CONTINUES TO RELATE TO THE POTENTIAL FOR HEAVY RAINFALL AND
ASSOCIATED MINOR FLOODING.

.PRECAUTIONARY/PREPAREDNESS ACTIONS...
PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR THOSE UNDER A WARNING...NOW IS THE TIME TO RUSH TO COMPLETION
PREPARATIONS FOR THE PROTECTION OF LIFE AND PROPERTY. EVACUATE IF
DIRECTED TO DO SO BY LOCAL OFFICIALS...OR IF YOUR HOME IS
VULNERABLE TO HIGH WINDS OR FLOODING.

FOR INTERESTS AT PORTS...DOCKS...AND MARINAS...URGENTLY COMPLETE
PRESCRIBED PREPARATIONS ACCORDING TO YOUR EMERGENCY OPERATIONS
PLAN FOR TROPICAL CYCLONES. IF YOU LIVE ON A BOAT...MAKE FINAL
PREPARATIONS FOR SECURING YOUR CRAFT BEFORE LEAVING IT. BE SURE
TO ACCOUNT FOR THE POSSIBLE CLOSURE OF BRIDGES AND CAUSEWAYS.

REGARDING ANY COASTAL WATERS UNDER A WARNING...SMALL CRAFT SHOULD
REMAIN IN PORT AND WELL SECURED.

FOR ADDITIONAL PRECAUTIONARY AND PREPAREDNESS INFORMATION...
PLEASE REFER TO THE DETAILED RECOMMENDATIONS RELATIVE TO YOUR
LOCATION AS FURTHER DESCRIBED BY YOUR LOCAL NATIONAL WEATHER
SERVICE OFFICE AND LOCAL EMERGENCY MANAGEMENT.

&&

Quoting obxrox:


That's a bit dramatic.

Buxton does have above ground structures that can sustain hurricane force winds. The highway just north of town floods and washes over frequently. This storm isn't anything they can't handle.


That particular location is a death zone tonight. I stand by my comment. Been there...done that.
Quoting 1474. MrstormX:



In many ways, although Arthur is moving so much faster. These fast moving Cat 1/2 hurricanes often crash into Nova Scotia causing extreme damage. I'm getting worried about that scenario for sure.


It will not be a hurricane when it makes its way to Nova Scotia. Possibly a very, very weak category 1. Zero chance of a strong 1 or 2 though. Too much cold water.
1529. MsAddie
While perusing some fishing info, I noticed water temps in Duck and Nags Head have plummeted from the 70s and 80s, down into the 50s. Is this an effect of the storm, or something which may affect it?
Quoting 1527. CycloneOz:



That particular location is a death zone tonight. I stand by my comment. Been there...done that.

Judge for yourself, the whole Earl archive is here:
http://www.1packerfan.com/streams/earl2010.htm

Makes for a good pregame Arthur show