Tropical Storm Arthur – There Is Nothing Unusual About the Sea Surface Temperatures Off the East Coast of the U.S.

Map 1

UPDATE (July 2, 2014): See the correction at the end of the post.

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This post was prepared in anticipation of the usual nonsense we hear whenever a tropical storm or hurricane forms and is expected to strike the U.S. The map to the right (Map 1) presents the weekly sea surface temperatures (not anomalies) for the Eastern U.S. Coastal Waters from Florida to Massachusetts (26N-42N, 82W-70W), for the week centered on Wednesday June 25,2014. (Please click the map to enlarge it.) Seasonally warmed sea surface temperatures from the east coast of Florida northwards to North Carolina are well above the 26 deg C (79 deg F) value needed to generate and maintain tropical storms and hurricanes.

Before we look at the recent sea surface temperature anomalies, let examine longer-term data to put it in context.

Initial note: The anomalies presented in this post are referenced to the base-year period of 1971-2000, which are the base years used by NOAA for their Reynolds OI.v2 sea surface temperature data through the NOMADS website.


When Hurricane Sandy strolled up the eastern extratropical waters off the east coast of the U.S. back in 2012, we presented sea surface temperature data for its storm track in two posts:

So there should be no surprise that the sea surface temperature anomalies (NOAA’s ERSST.v3b data) for similar coordinates also show cooling since 1938, the year of the Great New England Hurricane—also known as the Yankee Clipper, Long Island Express, or the Great Hurricane. See Figure 1. The coordinates used for this post are 26N-42N, 82W-70W, and they are shown above in Map 1. The ERSST.v3b data are available through the KNMI Climate Explorer.

Figure 1

Figure 1

In anticipation of someone accusing me of cherry-picking the start date, Figure 2 presents the sea surface temperature anomalies and linear trend, for that coastal region, for the past 100 years. Sea surfaces warmed there primarily in the first half of the 20th Century, not the second. The linear trend is basically flat, which means, based on the trend, sea surface temperatures along the east coast of the U.S. have not warmed since 1915.

Figure 2

Figure 2


Let’s switch datasets to NOAA’s Optimum Interpolation (version 2) satellite-enhanced sea surface temperature data, aka Reynolds OI.v2. It is available through NOAA’s NOMADS website in monthly and weekly formats. That monthly data start in November 1981, and, as of today, they run through the preliminary monthly data for June 2014. (The final June 2014 values will be available on Monday, July 7th.) Figure 3 presents the monthly sea surface temperature anomalies for the eastern coastal waters from Florida to Massachusetts, using the same coordinates as above: 26N-42N, 82W-70W. The red horizontal line is not the linear trend; it is the June 2014 value. It was +0.21 deg C. I suspect that value will increase in the final version, but there’s nothing unusual about that value.

Figure 3

Figure 3

Looking at the data on a weekly basis for such a small region leaves us with lots of weather-related noise. As we can see in Figure 4, the sea surface temperatures for that region have increased, cycling higher in the past few weeks, up to almost +1.0 deg C. But even that anomaly has been exceeded in the past.

Figure 4

Figure 4

And referring to the monthly data back to 1915 (Figure 2) anomalies that high were more commonplace in the first half of the 20th Century than in recent decades.


While we’re discussing sea surface temperature anomalies and hurricanes, for information purposes, the next two graphs present the weekly sea surface temperature anomalies through June 25, 2014 for the Atlantic Main Development Region (10N-20N, 80W-20W), Figure 5, and for the Gulf of Mexico (21N-31, 98W-81W), Figure 6. Again, the horizontal lines in these graphs are the values for the week of June 25th, not the linear trends.

Figure 5

Figure 5

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Figure 6

Figure 6

Note: Hurricanes DO NOT CARE about temperature anomalies. The actual sea surface temperatures (absolute) from June to November have and will continue to rise to values capable of spawning hurricanes…a result of the normal seasonal variations in surface temperatures. And while El Niño conditions in the Pacific tend to suppress hurricane development by effectively chopping the tops off the developing hurricanes (the result of wind shear in the tropical North Atlantic caused by an El Niño in the tropical Pacific), hurricanes can still form and will likely continue to do so this season.


Joe Bastardi’s very popular post at WattsUpWithThat Bastardi: ‘potential nightmare.. a tropical cyclone coming at the outer banks on the July 4 weekend’ included a sea surface temperature anomaly map from the NOAA OSPO website. See Map 2.

Map 2

That map is based on the NOAA NESDIS Coral Reef Watch analysis, which excludes daytime satellite observations. See their discussion of sea surface temperature data here. As a result, their maps have a warm bias, which they believe is important for their Coral Reef Watch program. But it also explains the apparent difference between that map and the satellite-based data presented in this post, which include bias-adjusted daytime values.


As blogger “Steve from Seattle” pointed out in his comment on the cross-post at WUWT, the NESDIS data should not have a warm bias. My mistake. It’s the color-scaling of their maps that give them the warm appearance. The NESDIS does not have a range of grey or white near zero (+/- 0.5 deg C for example), as is common with many other maps. (See example here.) The NESDIS starts with the yellows anywhere above a zero anomaly.


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But…but….It’s all worse than we thought….surely?
It’s on the cover of Gorey’s book and everything.
However, I can see the spin already.
There will be an accounting in the not too distant for all this.

Steve in Seattle

Mr. Tisdale :
from your link : data here
Compared with daytime SST and day-night blended SST, nighttime SST provides more conservative and stable estimate of thermal stress conducive to coral bleaching. Nighttime SSTs also compare favorably with in situ SSTs at one meter depth (Montgomery and Strong, 1995).
How do their maps have a warm bias ? What am I missing ?

D. Cohen

Latest track data from the national hurricane center (the 11:00 PM forecast for 7/1/2014) show that Arthur is expected to pass further east of the Carolinas than before.

Bloke down the pub



Situation normal?


Why would anyone worth responding to accuse you of “Cherry Picking” the start date for the first chart when it starts decades before they claim AGW started?


Thanks Bob. As usual just the facts. As usual greatly appreciated.


The sad thing about Hurricaine Hysteria that conditions people to overreact to early season minor storms is that people will stop paying attention to the unpredictable nature of storms and will be fullyunprepared for the next Cat. 3 to Cat 5.

Claude Harvey

All this technical hammering misses the point. The Gods are angry. We must sacrifice something to placate The Gods. It must be something large. Their eyesight isn’t so good. I nominate Al Gore.


You haven’t been around here very long, have you? 😉 “Cherry Picking” is usually one of the first claims made (regardless of it’s validity or even it’s applicability) to try to attack Bob’s credibility (while the accusers ‘cherry pick’ with abandon in making their own case) and dismiss whatever he writes about temperature.
From the projected path it doesn’t look like this potential Hurricane is going to make landfall in the US either.

Joseph Bastardi

Dr Ryan Maues map also shows the well above average temps ( I did not put that map on Anthony did, I should have used Ryans) The water is very warm, but its not unusual for it to be like this in the CLIMATE CYCLE WE ARE IN! MY Point in this article
is this is part of the natural ebb and flow, the end game of the warm AMO, the north atlantic is starting to cool, stacks the warm water near the east coast. RELATIVE TO AVERAGES this is very warm! as warm as the 50s as you will see, but the fact is the water had been much colder in the years the east coast was not in this time.
I am going to show this at Heartland btw to explain why if a bunch of hurricanes show up near the east coast, its not cause of co2, but nature
RYANS MAPS are by far the best in the business ( pardon my bias). This storm has August water to work with in July. Its not because of co2. Its because of everything Bill Gray laid out back in the 1970s. In the end, he was as good as you could be with all this
Here is the sst map link and it makes no bones about widespread warmth. KEEP IN MIND THAT 1/2C IS A MUCH BIGGER DEAL AS FAR AS ENERGY where water is 80 plus, than where its 40 or so.. Huge difference in what it means to the atmosphere
In terms of standard deviation, its probably quite significant.
So in terms of what SHOULD HAPPEN in the course of affairs as far as climate cycles, I agree, this is what should happen. But the end game of the warm amo is to stack the temperature deck near the east coast. Next 5 years could be as active as the 50s.. and we should make sure we do not pooh-pooh what this means
please see if the article makes any sense to you. As you know I am one of your biggest fans but want to point out we cant run from the threat this configuration offers us. It looks like the 1950s!

Joseph Bastardi

By the way Bob, Have I ever told you your my hero. I just dont want to sugar coat it.
Our weatherbell path has always been 30-40 miles offshore. The nightmare is a shift northwest and the intensity ramp up. We had this getting to 85 kts, a blend of my worst fears, which by the way I think are going to be darn close, this gets to a cat 3, and the idea this was no big deal. I see NHC is now very close to the forecast we have had all along I know all of you dont get but the current track and intensity is the map we sent out ON THE WEEKEND. I am not good enough to say I know this wont shift 30 miles, but I would hope as this evolves you see that the ideas I laid out for intensification, the why before the what had merit.
The toughest job in weather from now through Friday are NHC forecasters. Because they will have to deal with the threat that what is a nothing error in skill score ( 30 miles) means the difference between disruptive and destructive. And that is why to a forecaster, this is a night mare. Remember its not June 4 or Oct 4, its July 4

The other Ren

Joe- your map link is restrict

Robert Doyle

I watch Mr. Bastardi’s Weather Bell, Web based, Saturday forecast without fail. As a layman, it’s a welcome learning experience. I admire the fact that, they hang the distant forecasts out there. I’m already thinking next winter is going to hurt.


The NOAA discussions described the “warm sea surface temperatures along the forecast track” as being a factor in their estimate of strengthening. Of course, this says nothing about whether it is unusually warm, but as soon as this is out there – from the NOAA no less – it means everyone will jump up and down and blame it all on increasing sea surface temps.

Mike Maguire

It’s inevitable that the US will eventually get slammed by some major hurricanes. It has always happened and will always happen.
The reaction, will be similar to when we had our first widespread severe drought in the US Cornbelt in 2012.
For years, leading up to the drought, we were setting records for length of time since the previous widespread drought in this region, 1988.
We went 24 consecutive growing seasons, longest since records were kept without a widespread severe drought in this region.
The drought hit, along with the expected blame going to “climate change” and “global warming”.
Funny how 24 years of the best growing weather ever was not “climate change” but 1 year with a drought was.
We have been smashing the record for months and years without a major(cat.3 hurricane to hit the US). You can bet that when we get several of them(we will will 100% certainty), they will all be from “climate change” and the record set for the very lengthy period without them will not be “climate change”

When analyzing the “storm” paths along the East Coast, they seem to be steered by the Gulf Stream. This would make sense. The warm Gulf Stream and cold land or water on each side. This could produce wind events that tend to keep the “storm” centered over the Gulf Stream.
What do you think? [Try not too attack this idea]

Steve in Seattle

Mr. Tisdale, thanks for all your efforts and hard work – I agree with the many others here, your postings are a valued resource.

jlurtz says:
July 2, 2014 at 8:55 am

When analyzing the “storm” paths along the East Coast, they seem to be steered by the Gulf Stream. This would make sense. The warm Gulf Stream and cold land or water on each side. This could produce wind events that tend to keep the “storm” centered over the Gulf Stream.

I haven’t looked into that, but it’s a common enough pattern that I look for it. While there’s a lot else going on, note that both the Gulf Stream and hurricane motion are affected by the Coriolis effect, so if you pick a point where a storm is on the Gulf Stream and has the same heading, that’s one reason to keep them together.
Another reason that might work is the warm Gulf Stream water warms the air at the surface, and convection over the Gulf Stream pulls air in from both sides, that may be one reason why storms like to follow atmospheric troughs. That’s pretty much what you suggested.

P@ Dolan

@ Joseph Bastardi says:
July 2, 2014 at 4:50 am
Does this end of AMO cycle behavior mean that we’re likely to see more tropical cyclones that formed mid-Atlantic/Caribbean, vice Cape Verde types? That seemed to be the pattern last year—