01 December 2000

2000 Tropical Atlantic Activity Report

The hurricane season is officially over, so it's time for the annual Hurricane Season Summary. I sent out about 60 updates to this mailing list (which has grown from a small handful in 1998, to 27 in 1999, to 213 in 2000!) over the past 6 months; now it's time for the final one. I'm going to use the same format as I did last year, so it will look very familiar if you were a subscriber last year. I will keep the same basic outline: 1) the Saffir-Simpson Scale, 2) Lifetimes and Intensities, 3) Climatology, and 4) Landfall.
As usual, my data and typing could contain errors, so if you see a mistake, please point it out to me.

Saffir-Simpson Scale of Tropical Cyclone Intensity

CATEGORY            WINDS (mph)   PRESSURE (millibars)
------------------- ----------    ------------------
depression          23- 39       N/A
tropical storm      40- 73       N/A
1                   74- 95       > 980
2                   96-110       965-979
3                  111-130       945-964
4                  131-155       920-944
5                     >156       < 919

1. Lifetimes and Intensities
        ACTIVITY       (mph)        (mb)
-------- --------------- ------------ -------------
TD1      07 JUN - 08 JUN     25         1008
TD2      24 JUN - 25 JUN     30         1006
ALBERTO  04 AUG - 23 AUG    110          950 (N,H,M)
TD4      09 AUG - 11 AUG     30         1009
BERYL    13 AUG - 15 AUG     45         1007 (N)
CHRIS    18 AUG - 19 AUG     35         1008 (N)
DEBBY    19 AUG - 24 AUG     65          995 (N,H)
ERNESTO  02 SEP - 03 SEP     35         1008 (N)
TD9      09 SEP - 09 SEP     30         1007
FLORENCE 11 SEP - 17 SEP     70          985 (N,H)
GORDON   14 SEP - 18 SEP     65          981 (N,H)
HELENE   15 SEP - 22 SEP     60          986 (N)
ISAAC    21 SEP - 01 OCT    120          943 (N,H,M)
JOYCE    25 SEP - 02 OCT     80          975 (N,H)
KEITH    28 SEP - 06 OCT    115          942 (N,H,M)
LESLIE   05 OCT - 07 OCT     40         1006 (N)
MICHAEL  17 OCT - 20 OCT     85          965 (N,H)
NADINE   19 OCT - 22 OCT     50          999 (N)

In the previous chart, the N, H, and M that follows some storms denote what statistic they contributed to; Named storm (TS+), Hurricane (CAT1+), Major hurricane (CAT3+).
The winds and pressures reflect the most up-to-date best-track data available from the NHC; this is NOT what you may find on many website archives (yet).

2. Climatology and Statistics
The average annual number of tropical disturbances (over the past 54 years) is:
9.9 named storms
5.9 hurricanes
2.5 major hurricanes

This year, the numbers were generally well above that average (which has recently been the trend, except 1997)
14 named storms (12 in 1999)
8 hurricanes (8 in 1999)
3 major hurricanes (5 in 1999)

A fairly unique aspect of the past season was that there were 4 Tropical Depressions that never reached Tropical Storm status. There are typically only one or two such storms per season, so it seems that despite the above-average activity, there was something that inhibited intensification. A common theme for several weeks was vertical wind shear. For some unknown environmental reason, many storms suffered from high shear resulting in a) the large number of unnamed TD's and b) a large number of storms with exposed Low Level Circulation Centers at some point in their lifecycle.

For the second year in a row, the Atlantic Basin never experienced a CAT5 hurricane. In fact, the last CAT5 hurricane in the Atlantic Basin was Mitch in October 1998.

There were a total of 62.75 named storm days (days during which a named storm was present). 31.5 of those days were "hurricane days", and 5.25 of those days were "intense hurricane days". This is 134% of the climatological mean, i.e., this season was about 1/3 more active than the "normal" season. The average numbers (1944-2000) are 46.6 named storm days, 23.9 hurricane days, and 4.7 intense hurricane days.

Here is a summary of highlights (VERY brief):

Alberto not only started the season off, but was also the longest-lived hurricane in August ever (third longest-lived in the basin for all times of year). He had a unique track in that he formed south of the Cape Verde Islands, began recurving at about 59W, completed a giant loop in the north central Atlantic that lasted for one week, then headed off toward Iceland.

Beryl was not too exciting... she formed in the central Gulf of Mexico then headed west into the northern coastal areas of Mexico, causing one death there.

Chris barely made the list... he was weak to start, achieved minimal TS status, then was sheared apart.

Debby was also fairly weak, but lasted a bit longer. She formed out at 45W to the east of Barbados, then passed over the Greater Antilles. The journey near the mountainous islands there was her downfall... she dissipated near the southeast tip of Cuba.

Ernesto was basically an insignificant storm. He was short-lived, never reached hurricane strength, and never got close to land. His entire track was located to the east and northeast of the Lesser Antilles.

Florence was the first of three storms to develop along a mid-latitude trough this season. She formed 400 miles SSE of Cape Hatteras, almost completed a small loop, then was forced northeast, eventually passing just east of Newfoundland where she caused 2 deaths.

Gordon formed on the east coast of the Yucatan Peninsula (causing 19 deaths in Guatemala), crossed over the tip of the peninsula, then headed NNE toward Florida. He made landfall at the northwest tip of the Florida Peninsula, but caused no deaths in the US.

Helene formed out at 54W to the east of Gaudeloupe. She dissipated before reaching the Leeward Islands, then reformed just south of Cuba. She then continued to travel northward, destined to make landfall on the panhandle of Florida.

Isaac formed south of the Cape Verde Islands and followed Alberto's track very closely (except the loop). Like Alberto, Isaac also became a major hurricane and did not threaten land at all.

Joyce formed in the eastern Atlantic and headed west. She made a very unusual dip to the south before reaching the Windward Islands, passed over Tobago, then dissipated just off the South American coast.

Keith formed just off the coast of Honduras and began to head WNW toward Belize. During that short journey, he intensified very quickly to a CAT4 storm. Unfortunately, it was at that point that he stalled right over the Belize coast. After sitting there for over two days, he moved inland over the Yucatan Peninsula, entered the Bay of Campeche, then made landfall again near Tampico, Mexico. Keith caused 17 deaths in several countries.

Leslie was the second storm to form along a mid-latitude trough. She formed off the northeast coast of the Florida Peninsula and immediately moved away from the coast. The disturbance that was pre-Leslie caused 3 deaths in southern Florida due to flooding.

Michael was the third storm to form along a mid-latitude trough. He formed southeast of Bermuda and was also whisked toward the northern Atlantic by the trough. He made direct landfall on Newfoundland as a CAT1, but caused no deaths there.

Finally, Nadine was very much like Ernesto in that she did not last long, was weak, and was never near any land. Her track covered an area to the east of Bermuda.

On 19Aug, there were three named storms... Alberto, Chris, and Debby. Tied for simultaneous activity was mid-September. From Sep15 to Sep17, there were three named storms in the Atlantic again, Florence, Gordon, and Helene. Not too outstanding, but these were the most active time frames of the season. There were many examples of two named storms being present at the same time. It is also interesting to note that there were no named storms during June, July, or November.

3. Landfall
There were 8 landfalling storms this year... only 3 of which made landfall on the US. Compare this to last year, when 5 of 10 landfalling storms made landfall on the US. It is also interesting to note that only LA and FL were hit, leaving the other 16 coastal (Gulf, Atlantic) US states unscathed. Also, there were no landfalls on the east coast of the US.

The first column is the storm name, second column is the date of landfall, third column is the approximate universal (UTC) time of landfall, fourth column is max winds (kts) at landfall, and the fifth column is the nearest location to landfall.

BERYL    8/15    0600  45  La Luz, Tamaulipas, Mexico
DEBBY    8/22    0600  65  Barbuda
         8/22    1000  65  St. Martin, St. Barthelemy
         8/22    1500  65  British Virgin Islands
TD9       9/9    0600  30  Cameron, LA, USA
GORDON   9/18    0300  60  Cedar Key, FL, USA
HELENE   9/20    1300  25  Cabo Corrientes, Pinar del Rio, Cuba
         9/22    1000  45  Navarre, FL, USA
JOYCE    10/1    1000  35  Roxborough, Tobago
KEITH    10/3    0300  60  Ambergris Cay, Belize ##
         10/5    1800  80  Lomas del Real, Tamaulipas, Mexico
MICHAEL 10/19    2300  80  Francois, Newfoundland, Canada

## A note about Keith's first landfall: Although the intensity at official landfall was fairly weak, the storm stalled for 24+ hours just miles off the coast of Belize as a CAT4 storm with 115kt winds. The 80kt winds at landfall is not representative of the damage and deaths he caused.

New this past season was a Tropical Atlantic Satellite Sector webpage I created (www.mcwar.org/gallery/tropics/sectors.html). Thanks to all who tested it during the laborious construction phases. I know it came in handy for me, and I received several kind comments from other tropical enthusiasts during the past few months.
Hurricane Season 2001 begins June 1, the first names in the lineup are Allison, Barry, and Chantal.

Please visit my tropical Atlantic headquarters.

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