Charleston high tide flooding
Flooding at high tide on Sunday morning, September 20, in Charleston, South Carolina. (Image credit: Eric Dunphy)

Significant coastal flooding has been affecting much of the Southeast and mid-Atlantic U.S. coast since September 15, during the high “king tide” period associated with the New Moon of September 17. The king tides have been exacerbated by big swells from Hurricane Teddy, high runoff from the heavy rains from Hurricane Sally the previous week, and powerful northeast winds associated with a strong area of high-pressure positioned over New England.

Moderate coastal flooding at high tide has been widespread during the past week from Florida to North Carolina, with a few regions including Charleston, South Carolina, experiencing major flooding during multiple high tide cycles. NOAA indicated that Charleston experienced major flooding during high tides on September 15, 19, and 20, with these events ranking in the top-25 water levels of all-time. The high water did major damage to a $50 million beach renourishment project at nearby Folly Beach, washing much of it away. The tidal flooding has also forced the closure on multiple days of the only highway connecting North Carolina’s Outer Banks to the mainland, NC-12.

NC bridge
Figure 1. Highway NC-12 at the Canal Zone on the Outer Banks of North Carolina, as seen at 10:52 a.m. EDT September 21 from an NCDOT traffic camera. NC-12 was closed on Monday in both directions from just south of the Ocracoke Ferry dock to just north of the Pony Pen beach area, and from the town of Rodanthe to the Bonner Bridge, in light of standing water in the roadway.

How climate change turns minor tidal flooding into a big deal

Disruptive tidal flooding that now affects the U.S. Gulf and Atlantic coastlines on three to six days per year will strike as often as 80 to 180 days a year by the 2040s, according to a 2018 report from NOAA’s National Ocean Service, “Patterns and Projections of High Tide Flooding along the U.S. Coastline Using A Common Impact Threshold” (see PDF). That report built upon projections of global and regional sea-level rise that were released in a separate NOAA report earlier in 2018 (see PDF). The first sentence of the earlier report makes no bones about the situation: “Long-term sea level rise driven by global climate change presents clear and highly consequential risks to the United States over the coming decades and centuries.”

Though it’s often called “nuisance” flooding because it poses little threat to life or limb, high-tide flooding is a fast-growing threat to the economies and the built environment of coastal areas, especially along the Gulf and Atlantic shores. In South Florida alone, hundreds of millions of dollars are being spent to combat both long-term sea level rise and also routine “king tides” that are getting worse. High tide flooding is now accelerating at 75 percent of NOAA tide gauge locations along the East and Gulf Coasts, with nearly all other locations rising, but not yet accelerating. Already, the U.S. annual high tide flooding frequency is more than twice that in the year 2000 as a result of rising relative sea levels.

Figure 2 Figure 2. The number of days per year with at least minor coastal flooding in Charleston, South Carolina, shows a worrisome trend. (Image credit: Charleston National Weather Service)

High-tide flooding is distinct from extreme storm surges related to tropical cyclones and nor’easters, although they can overlap. By definition, high-tide floods happen at predictable points in the tidal cycle, such as the period from late summer into autumn when astronomical tides are at their highest. They can be enhanced by seemingly innocuous weather features, such as strong high pressure offshore that pushes high water toward the coast under sunny skies.

Flooding is the new normal in Miami

 

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Posted on September 21, 2020 (3:39pm EDT)

Topics: Weather Extremes
62 Comments
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Ricardo de Soto
Ricardo de Soto
1 month ago

“$50 million beach renourishment project” Now here’s the ample road to Corruption Hell.
Affluent coastal communities have had themselves built piers as anti-erosion “sand catchments” which does’nt work because refraction from wave action carries the sand away. So they bitch to their congress hacks that property values are affected so please have COE renourish their (private?) beach which turns out to be BILLIONS handed out to COE so COE passes $$$ to their favored contractor after taking their cut (budgetary tool). This is repeated yearly of course.
😉

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Rod
Rod
1 month ago

I wonder if things have reached the threshold where insurers of residential and commercial properties are starting to take a hard look at future coverage. A 30 year mortgage takes us to 2050.

Terry
Terry
1 month ago

x marks the spot?

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ChanceShowerLA
ChanceShowerLA
1 month ago

Pretty neat to see the frontal boundary connecting the GOM and Teddy….looks like Beta getting clamped down again by dry air….

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Jeff
Jeff
1 month ago

Anyone have the link to the wunderground disquis chat blog?

Jeff
Jeff
1 month ago
Reply to  Terry

Thank you!

Dirk
Dirk
1 month ago

Thanks Dr. Jeff for the update.

Terry
Terry
1 month ago

smoke and storm

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Terry
Terry
1 month ago
Reply to  Terry

hmm

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Brian
Brian
1 month ago
Reply to  Terry

Wow, made me go from my west-facing window (clear blue sky) to an east-facing window (sure ’nuff, clouds).

HadesGodWyvern
HadesGodWyvern
1 month ago

Japan Meteorological Agency
Tropical Cyclone Advisory #13 – 21:00 PM JST September 22 2020
SEVERE TROPICAL STORM DOLPHIN (T2012)
================================================
Sea South of Japan

At 12:00 PM UTC, Severe Tropical Storm Dolphin (975 hPa) located at 29.3N 136.1E has 10 minute sustained winds of 60 knots with gusts of 85 knots. The cyclone is reported as moving north northeast at 12 knots.

Storm Force Winds
==================
45 nm from the center

Gale Force Winds
=================
240 nm from the center in northeastern quadrant
100 nm from the center in southwestern quadrant

Dvorak Intensity: T4.0-

Forecast and Intensity
=========================
24 HRS: 32.1N 137.7E – 60 knots (CAT 2/Severe Tropical Storm) Sea South of Japan
48 HRS: 35.2N 141.0E – 45 knots (CAT 1/Tropical Storm) 60 km south southeast of Choshi (Chiba Prefecture)
72 HRS: 39.5N 143.9E – Extratropical Low offshore east of Sanriku region (Iwate Prefecture)

stormsissy
stormsissy
1 month ago

great! It worked!

stormsissy
stormsissy
1 month ago

Update on Teddy from a nova scotia perspective:

Teddy has finally begun its
expected northwestward turn, with an intial motion toward the nnw at
24 knots. Teddy's intensity is maintained at 85 knots. Buoy 44137
(East Scotian Slope) reported a gust to 56 knots at 11Z and a
significant wave height of 6.8 m. Buoy 44150 (West Scotian Slope)
reported a gust to 52 knots at 11Z and a significant wave height of
7.7 m.

oops, doesn’t want to display unless I highlight the text. I wish there were instructions…..

Guess I’ll post and see. If it doesn’t work, I’ll find another way.

Terry
Terry
1 month ago

“Is that a bad thing or a good thing? Honestly, we don’t know,” she said. “That could be this inequitable situation where we’re targeting these communities for relocation, like people are trying to remove them … or it could be we’re recognizing that the most at-risk communities in the U.S. are communities of color, and then we should be targeting them in order to help them.”

Thanks YCC for the morning read!

ChanceShowerLA
ChanceShowerLA
1 month ago

Morning everyone….past 24 hours rainfall….image should update throughout the day….

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Terry
Terry
1 month ago
Reply to  ChanceShowerLA

morning!

vis0
vis0
1 month ago

comment image

Terry
Terry
1 month ago
Reply to  vis0

huge wow! never seen one like this

Susan Anderson
Susan Anderson
1 month ago
Reply to  Terry

Sandy …

Terry
Terry
1 month ago
Reply to  vis0

wow

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Afrim Alimeti
Afrim Alimeti
1 month ago

Paulette, and remnant of Alpha attempting a reformation in the Mediterranean.comment image

Stevettocs
Stevettocs
1 month ago

Today’s wide view

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Art
Art
1 month ago

CMC also is hinting at it coming thru the islands oct 2nd i think.comment image

weather explorer
weather explorer
1 month ago
Reply to  Art

is that the one that will be in the western Caribbean?

Art
Art
1 month ago

comment image

Art
Art
1 month ago
Reply to  Art

6z gfs run now has it into mexico i think…comment image

Art
Art
1 month ago

yes GFS long term has one coming up from under Cuba and into south Florida on this current run..but its long term and will probably change again..but for myself..at this time of year most Lows in the gulf area tend to come back into Florida huh..at this stage of the TS season i stay extra alert lol.

Art
Art
1 month ago
000
FXUS62 KTBW 220706
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
306 AM EDT Tue Sep 22 2020

.SYNOPSIS...
A deep strong and elongated surface high extends down the
Atlantic coastline while a stalled frontal boundary is located
across the Florida Straits. Aloft, weak west-northwest flow
resides over the Peninsula as we are located on the northeast side
of a weak upper-level anticyclone currently over the Gulf. For
the tropics, Hurricane Teddy is currently northwest of Bermuda,
taking aim at portions of Nova Scotia as it is expected to
transition into a powerful post- tropical cyclone. Meanwhile,
Tropical Storm Beta is right at the coast of Central Texas and
this system is expected to move northeast along the coast over the
next couple of days.

&&
HadesGodWyvern
HadesGodWyvern
1 month ago

Japan Meteorological Agency
Tropical Cyclone Advisory #11 – 15:00 PM JST September 22 2020
SEVERE TROPICAL STORM DOLPHIN (T2012)
================================================
Sea South of Japan

At 6:00 AM UTC, Severe Tropical Storm Dolphin (975 hPa) located at 28.1N 135.4E has 10 minute sustained winds of 60 knots with gusts of 85 knots. The cyclone is reported as moving north at 8 knots.

Storm Force Winds
==================
45 nm from the center

Gale Force Winds
=================
240 nm from the center in northeastern quadrant
100 nm from the center in southwestern quadrant

Dvorak Intensity: T4.0-

Forecast and Intensity
=========================
24 HRS: 30.7N 136.2E – 60 knots (CAT 2/Severe Tropical Storm) Sea South of Japan
48 HRS: 33.9N 138.7E – 45 knots (CAT 1/Tropical Storm) 80 km south of Irozaki (Shizuoka Prefecture)
72 HRS: 39.3N 143.0E – Extratropical Low offshore east of Sanriku region (Iwate Prefecture)

HadesGodWyvern
HadesGodWyvern
1 month ago

comment image Tropical Storm Lowell (EP172020) near Clarion island

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Last edited 1 month ago by HadesGodWyvern
HadesGodWyvern
HadesGodWyvern
1 month ago

Japan Meteorological Agency
Tropical Cyclone Advisory #9 – 9:00 AM JST September 22 2020
SEVERE TROPICAL STORM DOLPHIN (T2012)
================================================
Sea South of Japan

At 0:00 AM UTC, Severe Tropical Storm Dolphin (985 hPa) located at 26.9N 135.3E has 10 minute sustained winds of 50 knots with gusts of 70 knots. The cyclone is reported as moving north slowly.

Gale Force Winds
=================
210 nm from the center in northeastern quadrant
100 nm from the center in southwestern quadrant

Dvorak Intensity: T3.5-

Forecast and Intensity
=========================
24 HRS: 29.8N 135.3E – 60 knots (CAT 2/Severe Tropical Storm) Sea South of Japan
48 HRS: 32.9N 137.1E – 50 knots (CAT 2/Severe Tropical Storm) South of Aichi Prefecture
72 HRS: 37.8N 141.6E – Extratropical Low offshore east of Sanriku region (Miyagi Prefecture)

NSAlito
NSAlito
1 month ago

All sea level is local. Let’s see that again: All sea level is local.

Here is an excellent summary of many of the factors that can affect local sea level rise:
https://www.youtube.com/watch?v=RCc3C89qxOM

Susan Anderson
Susan Anderson
1 month ago
Reply to  NSAlito

A classic!

cloudy2
cloudy2
1 month ago

I don’t like this Alpha, Beta, etc.Why not use real Greek names?
Αλέξανδρος (Alexander), Βερενίκη (Berenice)?

Terry
Terry
1 month ago
Reply to  cloudy2

good point .

TampaLurker
TampaLurker
1 month ago

Since we are only just past the midpoint of the Atlantic season and into the Greek alphabet, I feel compelled to ask:

If a tropical system is such that the losses to life and property would have caused the name to be retired if it had been part of the usual naming system but it is say, Hurricane Delta…would they retire the letter?

Storm Master
Storm Master
1 month ago
Reply to  TampaLurker

Here are the rules on geek names from the 2005 season

Retirement[edit]
After the season had ended, the World Meteorological Organization’s hurricane committee retired five names: Dennis, Katrina, Rita, Stan and Wilma and replaced them with Don, Katia, Rina, Sean and Whitney for the 2011 season.[168] This surpassed the previous record for the number of hurricane names retired after a single season, four (held by the 1955, 1995, and 2004 seasons).[169] During the conference, there was considerable discussion on the usage of the Greek alphabet and if those names could be retired if one proved to be particularly damaging or deadly.[168] The committee decided that the usage of the Greek alphabet had a major important political, economic and social impact globally, which might not have happened if a secondary or circular list of names had been used.[168] As a result, the committee decided that the Greek alphabet would be used again if the traditional naming list was exhausted, and that it was not practical to retire a Greek letter. Storms named with Greek letters that would otherwise be eligible for retirement would appear in the retired name list, but have a notation affixed with the circumstances.[168]

Susan Anderson
Susan Anderson
1 month ago
Reply to  Storm Master

Greek geek … good one

TampaLurker
TampaLurker
1 month ago
Reply to  Storm Master

Thanks! I was certain that the possibility had to have been considered but I had no idea where to look.

HadesGodWyvern
HadesGodWyvern
1 month ago

Japan Meteorological Agency
Tropical Cyclone Advisory #7 – 3:00 AM JST September 22 2020
TROPICAL STORM DOLPHIN (T2012)
================================================
Sea South of Japan

At 18:00 PM UTC, Tropical Storm Dolphin (992 hPa) located at 26.1N 135.2E has 10 minute sustained winds of 45 knots with gusts of 65 knots. The cyclone is reported as moving north northeast slowly.

Gale Force Winds
=================
210 nm from the center in northern quadrant
100 nm from the center in southern quadrant

Dvorak Intensity: T2.5

Forecast and Intensity
=========================
24 HRS: 28.6N 134.9E – 55 knots (CAT 2/Severe Tropical Storm) Sea South of Japan
48 HRS: 31.8N 136.2E – 55 knots (CAT 2/Severe Tropical Storm) Sea South of Japan
72 HRS: 31.8N 136.2E – 40 knots (CAT 1/Tropical Storm) 190 km south of Shionomisaki (Wakayama Prefecture)

bagel
bagel
1 month ago

Levi’s site is saying that Paulette is a subtropical storm, which is a very good sign that the NHC will include it in the next batch of advisories.

Since Paulette’s birth, seven (seven!) other named storms have formed: Rene, Sally, Teddy, Vicky, Beta, Wilfred, and Alpha. And in the end, Paulette 2.0 may well outlast them all. That’s got to break at least one record, right?

Stoopid1
Stoopid1
1 month ago
Reply to  bagel

Levi is quick about getting best track data which is a little ahead of official advisories. We might see a special advisory at 8 then since the site has already updated to STS.

jiiski
jiiski
1 month ago

Important and fascinating article, Dr. Masters and Bob Henson.
Thank you so much.

Susan Anderson
Susan Anderson
1 month ago
Reply to  jiiski

Yes! I wish I was in Boston to take a look. Tomorrow evening, I’ll check. Shortly after the new moon time is the majority vote for the highest “normal” tides. Saturday was the peak. Here’s a link:
https://www.boatma.com/tides/Sep/Charlestown-Charles-River-entrance-Boston-Harbor.html

Last edited 1 month ago by Susan Anderson
Big G onMV
Big G onMV
1 month ago
Reply to  Susan Anderson

I’m in Edgartown nowadays (not East Walpole) so will take a look-see tomorrow at the low in-town area which might flood. That coincides with max peripheral winds from Teddy passing off a couple of hundred miles to the east of here. Lots of boats getting hauled out today, and not just because of the onset of Fall.

Stoopid1
Stoopid1
1 month ago

The circulation of ex-Paulette is getting better defined, it’s close to regenerating into a tropical storm. Convection is also organizing further, wrapping around the center better.

Conditions ahead for at least the next few days look to remain largely the same as they are, marginally conducive. Enough for Paulette to persist as a weak to moderate TS. Wouldn’t it be so 2020 if Paulette could shoot the gap of the Strait of Gibraltar? Hmm.

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Terry
Terry
1 month ago
Terry
Terry
1 month ago
Reply to  Terry

Not a good outlook to October ! (photo) ; TropicalTidbits.com

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Terry
Terry
1 month ago
Reply to  Terry

hmm

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Terry
Terry
1 month ago
Reply to  Terry

headache again 🙁

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Terry
Terry
1 month ago
Reply to  Terry

low?

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NW AZ weatherwatcher
NW AZ weatherwatcher
1 month ago
Reply to  Terry

We had blue skies and actual white clouds yesterday for the first time in weeks SW winds the prior 3 days and those 2 swirls that moved through from the Pacific moved all that smoke eastward. And the day before a 2 minute sprinkling here preceeded by a few claps of thunder, but, no measurable amount of precip, only enough to smell the dirt rising into the air momentarily, and about a nice 10 degree temp cooloff (only the second time it rained since April here!)

Missed our usual everyday monsoon storms throughout July and August first time in nearly 25 years! It is bone dry. And no doubt it took another 2 yrs of water useage out of Lake Mead, as it is almost empty now.

NW AZ weatherwatcher
NW AZ weatherwatcher
1 month ago
Reply to  Terry

Pretty normal in the West, we look forward to cooling off right almost annually timely as the usual Trick-or Treeter’s show up at the door! Yes, October 31 each year is a cool off point traditionally. (Sry kids, our place will be dark…Keeping the TrumpVirus at bay this year!

Susan Anderson
Susan Anderson
1 month ago
Reply to  Terry

Alun Hubbard is a “climate hunk”. Hot dam, that’s a good ‘un, thanks for the reminder.

Susan Anderson
Susan Anderson
1 month ago
Reply to  Terry

I understated the importance of that video. Thanks again!

Terry
Terry
1 month ago

Scary trends (“nuisance” flooding) , Thx again for an enlightening read!

PlazaRed
PlazaRed
1 month ago
Reply to  Terry

Tip of the melting icebergs and ice sheets.
Thank you Jeff Masters, for the informative and yet again worrying projections into our near future.

Mags
Mags
1 month ago
Reply to  PlazaRed

Good to see you here!