Mid-July 2013 Hurricane Development Region Sea Surface Temperature Anomalies

Other than the following maps, this post presents the weekly and monthly satellite-era sea surface temperature anomalies for the hurricane development regions—plus the extratropical waters off the east coast of the U.S. We’re including the extratropical waters off the east coast of the U.S. because it was part of Sandy’s storm track last year and people are interested in it. For additional discussions of the sea surface temperatures and anomalies of Sandy’s storm track, refer to the blog posts here and here.

For illustrations and discussions of the longer-term data, including the lack of a warming trend in the sea surface temperatures of the Main Development Region from 1930 to 1995, refer to this year’s first post on this subject here.


The first illustration is an animation of sea surface temperature (not anomaly) maps. One map presents the sea surface temperatures for the week centered on July 10, 2013. The other presents the climatology for the same week, which is based on the average sea surface temperatures for that week during the period of 1971-2000. To determine the anomalies for July 10, 2013, the 30-year average (the climatology) is subtracted from the observed values for the past week.

Animation 1

North Atlantic SST Animation

I presented the sea surface temperature maps for two reasons: First, to show that the sea surface temperatures for much of the Main Development Region (10N-20N, 80W-20), for much of the extratropical U.S. east coast waters (24N-40N, 80W-70W), for the Caribbean (10N-20N, 84W-60W) and for the Gulf of Mexico (21N-31N, 98W-81W) are above 26 deg C, which is considered the threshold for tropical storm development. Refer to the discussion here. The second reason: to show that the sea surface temperatures in those regions are not unusually warm. And we’ll confirm that with the following graphs.


The following four graphs of weekly sea surface temperature anomalies since January 1990 also include horizontal lines in red depicting the July 10, 2013 values. Of the four regions presented in Figures 1 to 4, the Main Development Region had the highest sea surface temperature anomaly of +0.24 deg C last week, but that is not unusual there. At the other end of the spectrum, the sea surface temperature anomalies for the Gulf of Mexico were below the 1971-2000 average—and that also isn’t unusually cool.

Fig 1 Weekly MDR

Figure 1


Fig 2 Weekly Gulf of Mexico

Figure 2


Fig 3 Weekly Caribbean

Figure 3


Fig 4 Weekly East Coast

Figure 4


While we should be interested in the most recent values (the weekly data), there are likely some readers interested in the monthly data for those four regions, so I’ve presented them in Figures 5 through 8.

Fig 5 Monthly MDR

Figure 5


Fig 6 Monthly Gulf of Mexico

Figure 6


Fig 7 Monthly Caribbean

Figure 7


Fig 8 Monthly East Coast

Figure 8


The sea surface temperatures for most of the hurricane development regions are above the temperatures required for tropical storm development, but they are not unusually warm.

Also, there is nothing in the ocean heat content records or satellite-era sea surface temperature data to indicate greenhouse gases were responsible for their warming. That is, the data indicate the oceans warmed naturally. If that topic is new to you, refer to the illustrated essay “The Manmade Global Warming Challenge” [42MB].


The Sea Surface Temperature anomaly data used in this post is available through the NOAA NOMADS website:




About Bob Tisdale

Research interest: the long-term aftereffects of El Niño and La Nina events on global sea surface temperature and ocean heat content. Author of the ebook Who Turned on the Heat? and regular contributor at WattsUpWithThat.
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3 Responses to Mid-July 2013 Hurricane Development Region Sea Surface Temperature Anomalies

  1. tchannon says:

    Bob, Slightly off topic, I don’t know if the following El Nino facility is new to you. I’ve popped up a quick blog item, link is here JAXA/EORC: El Nino Watch

    Tim (co-mod Tallblokes)

  2. Bob Tisdale says:

    Thanks for the link, Tim. I’ve seen that webpage before but didn’t have it stored in my favorites. Now I do. Thanks.

    And I’ve got an ENSO-related link for you from the JMA in return:
    They also have one for their “Indian Ocean Basin Wide” SSTa index:
    And one for their “NINO west” SSTa index:


  3. tchannon says:

    JAXA etc, seem to be a new kid on the block on a number of things, a lot revolving around flying the replacement AMSU-E instrument in the A-train. Those who switched to WindSat when the old instrument failed aboard a NASA satellite, the move itself an interesting departure, may switch back when things fully stabilise.

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