Dorian Makes Landfall at Cape Hatteras, North Carolina; Canada is Next

Hurricane Dorian made landfall at 8:35 am EDT Friday as a Category 1 hurricane with 90 mph winds and a pressure of 956 mb at Cape Hatteras, North Carolina. Dorian brought sustained winds of hurricane force to at least three land stations. Dorian's strong winds caused severe storm surge flooding that triggered a flash flood emergency on the North Carolina barrier islands Friday morning.

Hatteras near the Ferry. #Dorian #obx #ncwx pic.twitter.com/PiKAO7HCJm

— Brad Panovich (@wxbrad) September 6, 2019

Two stations on the North Carolina barrier islands measured sustained winds of hurricane force on Friday morning: a Weatherflow station at Avon Sound, NC (sustained 83 mph, gusting to 98 mph), and a Weatherflow station in Buxton, NC at Hatteras High School (77 mph, gusting to 89 mph). In addition, Cape Lookout, NC, reported sustained winds of 81 mph, gusting to 94 mph, early Friday morning.

Figure 1. Radar image of Dorian near the time of landfall at Cape Hatteras, North Carolina: 8:35 am EDT September 6, 2019. Image credit: NOAA/Mark Nissenbaum.

Water levels along the Pamlico Sound side of the barrier islands near Cape Hatteras rose suddenly around 9 am EDT Friday, after the winds switched to onshore during passage of Dorian’s eye. A flash flood emergency was declared in Okracoke, NC, when storm surge flooding suddenly inundated the town.

Figure 2. Water levels at Cape Hatteras, NC, on the Pamlico Sound side of the barrier island. Major coastal flooding occurred suddenly on Friday morning near 9 am EDT, after the winds switched to onshore during passage of Dorian’s eye. The peak water level of 5.93’ ranked as the second highest on record, behind only the 6.38’ mark set by Hurricane Matthew of 2016. Image credit: NOAA.

Heavy rains from Dorian have brought significant inland flooding problems along its path. A few peak rainfall totals as of 11 am EDT Friday:

15.21 inches: Pawleys Island, South Carolina (5.6 miles NE)
13.10 inches: Wilmington, North Carolina (7.3 miles NE)
12.77 inches: Myrtle Beach, South Carolina (5.2 miles SW)
11.86 inches: Conway, South Carolina
10.96 inches: Lumber River, North Carolina
10.83 inches: Near McClellanville, South Carolina
10.45 inches: North Myrtle Beach, North Carolina
10.25 inches: Castle Hayne, North Carolina
9.92 inches: Wilmington, North Carolina
5.68 inches: Near Palm Coast, Florida
5.54 inches: Charleston, South Carolina

Figure 3. Predicted water levels at Sewell’s Point near Norfolk, Virginia. Major coastal flooding is predicted for Friday afternoon. The predicted level of 6.5’ would rank just outside the list of top-ten highest water levels on record and would be 1.5’ below the record set in the 1933 hurricane. Image credit: NOAA.

Major storm surge flooding predicted for Friday afternoon in NC, VA

Dorian’s storm surge is expected to cause major flooding along portions of the North Carolina and Virginia coasts during the Friday high tide cycles. In their 11 am EDT Friday Dorian advisory, NHC called for coastal storm surge flooding of up to 4 – 7 feet above the high tide mark from Salter Path, NC to Duck, NC, and 2 – 4 feet from Duck, NC to Poquoson, VA—including the Norfolk/Hampton Roads region. The storm surge during the Friday afternoon high tide cycle at Sewell’s Point, Virginia near Norfolk is predicted to bring water levels 1.5’ below the all-time record set in the 1933 hurricane (Figure 3).

A swarm of tornadoes ahead of Dorian

Mini-supercells along Dorian’s rainbands dropped tornadoes across coastal North and South Carolina. Since 4 am Thursday, at least 23 tornado reports were received by the NOAA/NWS Storm Prediction Center. The most destructive twister damaged dozens of campers and manufactured homes in the Boardwalk RV Park in Emerald Isle, NC, around 9 am EDT Thursday. 

GOOSEBUMPS. This video is- wow. Just listen to that wind. It's from Jason Sawyer's Ring doorbell and it shows the moment a tornado destroyed his #EmeraldIsle home #HurricaneDorian #wral @WRAL pic.twitter.com/rYaXm77C8t

— Rosalia Fodera (@WRALRosalia) September 5, 2019

On average, hurricanes are responsible for only about 3-4% of all U.S. tornadoes, but in some years, such as the busy Atlantic season of 2004, hurricanes are responsible for a much larger chunk of the annual total. Hurricane Ivan in 2004 produced a record 120 tornadoes, including 38 in Virginia—the most extensive tornado outbreak on record for any mid-Atlantic or Northeastern state. Several other Atlantic hurricanes have generated 60 or more U.S. tornadoes.

Dorian’s stunning sunset in the Northeast U.S.

The thin cirrus cloud shield that was pushed out well to the north of Dorian by the hurricane’s upper-level outflow led to a spectacular sunset across the Northeast on Thursday night. The lack of a strong jet stream and the ample dry air across the region may have both contributed to the thinness of the overcast, which allowed for vivid colors that painted the evening sky from Washington, D.C., to Boston. A few spectacular examples are below.

What a stunning sunset tonight... pic.twitter.com/AJceNQOWn0

— Only In Boston (@OnlyInBOS) September 6, 2019

https://twitter.com/HowardManges/status/1169767898967171073
https://twitter.com/bjweiss22/status/1169780155583254528
https://twitter.com/RedSox/status/1169770626434969602
https://twitter.com/MegOLeary/status/1169763288462352384\
https://twitter.com/VickiVeltri/status/1169792543028068359
https://twitter.com/stormchaserray/status/1169759225272295426
https://twitter.com/isardasorensen/status/1169790110700904448
https://twitter.com/joekaczmarek/status/1169799030236438529
https://twitter.com/KVG_DC/status/1169760162204311558

Figure 4. Predicted wind speeds (colors) and sea level pressure (black lines) for 5 pm Saturday, September 7, 2019, from the 6Z Friday run of the HWRF model. The model predicted that Dorian would be hitting near Halifax, Nova Scotia as a Category 1 hurricane with 80 mph winds. Image credit: tropicaltidbits.com.

Dorian expected to hit Canada as a Category 1 hurricane

Dorian has one more nation to trouble on its extended tour of the Atlantic—Canada. Canada is no stranger to seeing Category 1 winds from hurricanes (or their extratropical versions, since many hurricanes transform to powerful extratropical storms with hurricane-force winds shortly before reaching Canada).

Dorian was headed northeast at 17 mph late Friday morning, and will accelerate over the coming day, making landfall in Nova Scotia, Canada, as a Category 1 hurricane on Saturday afternoon or evening. Dorian will be undergoing a transition to a powerful extratropical storm with hurricane-force winds as it moves over Nova Scotia and into Newfoundland. This transition will allow the hurricane’s wind field to greatly expand, bringing damaging winds to a large area of the Canadian Maritime Provinces.

We can expect Dorian to cause considerable damage in Nova Scotia and Newfoundland from a combination of wind, flooding from heavy rains of 3 – 5”, and storm surge. The timing of Dorian’s strike on the coast is critical for determining how much storm surge damage occurs, since the range between low tide and high tide is about 1.5 meters in Nova Scotia. If Dorian hits near low tide, which occurs at 10:50 pm ADT Saturday, there will be little or no storm surge damage. But if the hurricane hits at high tide (3:25 pm ADT Saturday), surge damage could be significant.

Dorian’s impact in Nova Scotia may be similar to that of Hurricane Earl of 2010, which hit the province as a Category 1 hurricane, knocking out the power to nearly 1 million people. According to meteorologist Doug Gillham of theweathernetwork.com, the center of Dorian is likely to pass more over eastern Nova Scotia, sparing the more populated central and western portions of the province the hurricane’s worst winds.

It would be hard for Dorian to beat the impact of Hurricane Juan of 2003, though. Juan took a worst-case track and hit Halifax, Nova Scotia as a Category 2 hurricane with 100 mph winds, killing 8 and causing $200 million in damage--Canada’s most expensive hurricane on record. Juan was one of only two hurricanes to get its name retired because of the impact on Canada. The other was Hurricane Igor of 2010, which brought catastrophic flooding to Newfoundland, where it dumped up to ten inches of rain. Igor’s price tag: $200 million (2010 dollars).

Figure 5. Visible satellite image of 94L off the coast of Africa on Friday morning, September 6, 2019. Image credit: NASA Worldview.

A threat to the Lesser Antilles: 94L off the coast of Africa

A tropical wave that residents of the Caribbean definitely need to watch is one that emerged from the coast of Africa on Wednesday. This system was designated 94L by NHC on Thursday evening, and passed through the Cabo Verde Islands Thursday night, bringing thunderstorms and sustained winds of 25 mph.

Satellite images on Friday morning showed that this system had a high amount of spin, but a very limited amount of heavy thunderstorm activity. The meager heavy thunderstorm activity was due to plenty of dry air, as seen on the latest Saharan Air Layer Analysis.

The 6Z run of the SHIPS model predicted that the atmosphere in front of 94L would have favorable conditions for development, with low wind shear, sea surface temperatures of 28 – 29°C (82 – 84°F), and a mid-level relative humidity near 60%. Dry air will continue to inhibit development over the next two days, though, until 94L can generate enough heavy thunderstorm activity to moisten the atmosphere. The low shear will aid this process.

Recent runs of our three top models for predicting tropical cyclone genesis—the GFS, European and UKMET—have all shown support for development, with several runs depicting the wave developing into a long-track Cape Verdes-type hurricane. The wave is predicted to take a west to west-northwest track over the coming week, and 94L could arrive in the Lesser Antilles Islands as a named storm as early as September 14. However, recurvature into the open central Atlantic is also a good possibility. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave this system 2-day and 5-day odds of development of 20% and 70%, respectively. The next name on the Atlantic list of storms is Humberto.

The other tropical systems and threat areas out there—Tropical Storm Gabrielle, Invest 92L, and a disturbance a few hundred miles northeast of the Leeward Islands—are all no threat to land, and not worthy of discussion at this time.

Please consider supporting a disaster relief charity for Dorian relief, such as the Red Cross, Portlight, or Hurriup!

Bob Henson co-wrote this post.