Jacksonville, FL – Talking the Tropics With Mike will be updated daily through November 30th, the end of the Atlantic hurricane season. The next month or so will likely continue to be active – more in the previous “BB” * here *.
While much has been reported on how active the Atlantic has been this season (for the second year in a row), a good measure of global activity is ACE – Accumulated Cyclone Energy. The definition from the Climate Prediction Center:
“The term“ total seasonal activity ”refers to the combined intensity and duration of Atlantic storms and hurricanes that occur during the season. The measure of total seasonal activity used by NOAA is the
Accumulated cyclone energy: The ACE index is a wind energy index, defined as the sum of the squares of the maximum sustained surface wind speed (knots) measured every six hours for all named storms as long as they have at least tropical storms. “
So – worldwide – was the ACE below average. The one basin above is the Atlantic Basin, although the number there too is not astronomical. So we (Atlantic) had a lot of storms, but most of them were short-lived and, despite 8 US landfalls, there was so far a lack of power. Of course there was remarkable Exceptions – Henri & especially Ida.
The next two pictures from CSU & Dr. Phil Klotzbach:
Welcome to the fall equinox! The hottest temps. of the year are behind us, but believe me, we still have to endure far too high humidity before we can get sustained cooler air. I always like to say “wait until Halloween”. But the last week of September will be nice and mild – overnight.
Since 1970, Jacksonville has endured about 7 more above average. Days per year (last 50 years):
Remember that the seasons in the Northern Hemisphere are dictated by the tilt of the earth towards (summer) or away (winter) from the sun:
It looks like the arctic sea ice reached its seasonal minimum on September 16. From NASA:
“Satellite-based passive microwave images of sea ice have been a reliable tool for continuously monitoring changes in Arctic ice since 1979. Each summer, the Arctic ice cap melts to what scientists call its “minimum” before colder weather begins to cause an ice sheet to increase. Analysis of satellite data from NASA and the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder shows that the 2021 minimum extent, which was likely to be reached on September 16, was 1.82 million square miles (4.72 million square kilometers) fraud ).
In an animation – click here – The daily change in Arctic sea ice and seasonal land cover progresses over time, from the annual maximum ice extent on March 21, 2021 to its minimum on September 16, 2021. Above the water, the Arctic sea ice changes from day to day with a running 3-day minimum sea ice concentration in the region where the concentration is more than 15%. The bluish-white color of the sea ice is derived from a 3-day minimum of the AMSR2 89 GHz brightness temperature. The yellow border shows the minimum extent, averaged over the 30-year period from 1981 to 2010. Above the area, the monthly data of the seasonal Blue Marble Next Generation slowly fade from month to month. The faint circle that appears periodically near the pole is an artifact of the visualization process and is not a real feature.
Arctic sea ice appears to have hit its annual minimum on September 16, after having decreased in the northern hemisphere’s spring and summer in 2021. The daylight saving time extension is the one supported by NASA, according to scientists National Snow and Ice Data Center and NASA.
That year, the minimum extent of Arctic sea ice decreased to 4.72 million square kilometers (1.82 million square miles). The sea ice extent is defined as the total area in which the ice concentration is at least 15%.
The average minimum size in September record shows significant decreases since satellite measurements began in 1978. The last 15 years (2007 to 2021) are the lowest 15 minimum extents in the 43-year satellite record.”
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