Number range CHAPTERTropical Cyclone Report

Hurricane Vince

8-11 October 2005

James L. Franklin

National Hurricane Center

22 February 2006

Vince was a category 1 hurricane (on the Saffir-Simpson Hurricane Scale)
that became the first known tropical cyclone to reach the Iberian
Peninsula. It also became a hurricane farther east than any other known
Atlantic basin tropical cyclone.

a.  Synoptic History

    Vince originated from an occluded deep-layer frontal low that moved
    southeastward across the Azores Islands on 6 October. Over the next
    couple of days, the frontal structure gradually dissipated and
    banded convection became more concentrated near the circulation
    center. It is estimated that this convection became sufficiently
    persistent and organized to designate the cyclone as a subtropical
    storm near 0600 UTC 8 October, when the system was centered about
    500 n mi southeast of Lajes in the Azores. Although by this time the
    core convective signature and surface wind field resembled a fully
    tropical cyclone, the system still had a very prominent cold-core
    cyclonic circulation in the upper-troposphere -- hence the
    subtropical designation.

    The "best track" chart of Vince's path is given in Fig. 1, with the
    wind and pressure histories shown in Figs. 2 and 3, respectively.
    The best track positions and intensities are listed in Table 1. The
    subtropical storm moved little over the next day or so, but then
    began to move slowly northeastward on 9 October. An AMSU overpass at
    1527 UTC that day showed that a mid- to upper-level warm core was
    forming, and it is estimated that Vince became a tropical storm near
    1200 UTC while over sea-surface temperatures of 23-24°C. Later on 9
    October a banding eye developed, and Vince became a hurricane near
    1800 UTC about 135 n mi northwest of Funchal in the Madeira Islands.

    Vince began to weaken almost immediately after becoming a hurricane,
    as strong westerly shear ahead of an approaching frontal trough
    began to impinge upon the cyclone. Vince weakened back to a tropical
    storm at 0000 UTC 10 October and then accelerated
    east-northeastward. With convection diminishing and limited to its
    eastern semicircle, Vince weakened rapidly on 10 October as it
    approached southern Portugal. Vince weakened to a tropical
    depression at 0000 UTC 11 October, about 135 n mi west-southwest of
    Faro, Portugal, although it still maintained some banding structure
    (Fig. 4). The center of circulation passed just south of Faro around
    0700 UTC that day, and made landfall in Spain near Huelva around
    0900 UTC. Vince continued moving rapidly east-northeastward over
    southern Spain and the circulation dissipated after 1200 UTC 11
    October.

b.  Meteorological Statistics

    Observations in Vince (Figs. 2 and 3) include satellite-based Dvorak
    technique intensity estimates from the Tropical Analysis and
    Forecast Branch (TAFB), the Satellite Analysis Branch (SAB) and
    the U. S. Air Force Weather Agency (AFWA). Microwave satellite
    imagery from NOAA polar-orbiting satellites, the NASA Tropical
    Rainfall Measuring Mission (TRMM), the NASA QuikSCAT, and Defense
    Meteorological Satellite Program (DMSP) satellites were also useful
    in tracking Vince. The estimated peak intensity of 65 kt is based on
    Dvorak classifications.

    Two reports of tropical-storm-force winds were received in the
    southwest quadrant of the circulation, 90-120 n mi from the center,
    late on 10 October (Table 2). There is some question as to the
    validity of these reports, as they are at odds with the QuikSCAT
    passes at 0612 UTC 10 October and 0548 UTC 11 October, as well as
    with a WindSat pass at 2318 UTC 10 October, all of which failed to
    show tropical storm force winds in this portion of the circulation.
    The analysis adopted here favors the scatterometer data over the
    ship reports.

    Tropical-storm-force gusts were observed at a number of locations in
    Spain. At the coastline, the Naval Air Station at Rota reported a
    gust to 42 kt with sustained winds (10-min average) of 25 kt at 0930
    UTC 11 October. At Moron, an inland station at 87 m elevation, a
    gust to 40 kt was observed with a sustained wind of 28 kt. Sustained
    winds of 31 kt were reported at Jerez (elevation 27 m) at 1130 UTC,
    with a gust to 42 kt. It is unclear what effects the local terrain
    may have had on these observations, as a cluster of ship reports
    just offshore at 1200 UTC were in the 23-28 kt range.

    The rain in Spain was mainly less than 2 inches, although 3.30
    inches fell in the plain at Cordoba.

c.  Casualty and Damage Statistics

    There were no reports of damage or casualties associated with Vince.

d.  Forecast and Warning Critique

    Atlantic Tropical Weather Outlooks did not discuss the non-tropical
    precursor disturbance to Vince until it had begun to acquire
    subtropical characteristics.

    Vince's short life cycle resulted in just a handful of forecasts to
    verify. The average official track errors for Vince were 46, 131,
    and 220 n mi for the 12, 24, and 36 h forecasts, respectively, with
    the number of forecasts ranging from 7 at 12 h to only 3 at 36 h.
    These errors are greater than the average long-term official track
    errors. The official forecasts had a northwestward bias that likely
    resulted from a presumption that Vince's low-level circulation would
    be pulled more northward ahead of the approaching frontal system. In
    fact, Vince was able to maintain just enough convection to have its
    motion affected by the upper-level westerlies.

    Average official intensity errors were 6, 15, and 17 kt for the 12,
    24, and 36, h forecasts, respectively. For comparison, the average
    official intensity errors over the 10-yr period 1995-2004 are 6, 10,
    and 12 kt, respectively.

Acknowledgments

Information on the effects of Vince in Spain was provided by the
Instituto Nacional de Meteorologia. Timothy Garner of NASA provided
additional observations and helpful descriptions of the local
topography.

Number range CHAPTERTable 1. Best track for Hurricane Vince, 8-11
October 2005.

+--------+--------+--------+---------+---------+---------------------+
| Dat    | La     | Lon    | P       | Wind    | Stage               |
| e/Time | titude | gitude | ressure | Speed   |                     |
|        |        |        |         |         |                     |
| (UTC)  | (°N)   | (°W)   | (mb)    | (kt)    |                     |
+--------+--------+--------+---------+---------+---------------------+
| 08 /   | 32.9   | 20.6   | 1001    | 40      | subtropical storm   |
| 0600   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 08 /   | 33.0   | 20.3   | 1000    | 45      | \"                  |
| 1200   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 08 /   | 33.1   | 20.1   | 1000    | 45      | \"                  |
| 1800   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 09 /   | 33.2   | 20.0   | 999     | 45      | \"                  |
| 0000   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 09 /   | 33.4   | 19.6   | 998     | 50      | \"                  |
| 0600   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 09 /   | 33.8   | 19.3   | 995     | 55      | tropical storm      |
| 1200   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 09 /   | 34.1   | 18.9   | 988     | 65      | hurricane           |
| 1800   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 10 /   | 34.3   | 18.3   | 990     | 60      | tropical storm      |
| 0000   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 10 /   | 34.5   | 17.2   | 992     | 50      | \"                  |
| 0600   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 10 /   | 34.7   | 15.3   | 995     | 45      | \"                  |
| 1200   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 10 /   | 35.4   | 12.8   | 998     | 35      | \"                  |
| 1800   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 11 /   | 36.1   | 10.5   | 1000    | 30      | tropical depression |
| 0000   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 11 /   | 36.7   | 8.3    | 1002    | 30      | \"                  |
| 0600   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 11 /   | 37.7   | 6.0    | 1003    | 30      | \"                  |
| 1200   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 11 /   |        |        |         |         | dissipated          |
| 1800   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+
| 11 /   | 37.2   | 7.1    | 1002    | 30      | Landfall near       |
| 0900   |        |        |         |         | Huelva, Spain       |
+--------+--------+--------+---------+---------+---------------------+
| 09 /   | 34.1   | 18.9   | 988     | 65      | minimum pressure    |
| 1800   |        |        |         |         |                     |
+--------+--------+--------+---------+---------+---------------------+

Number range CHAPTERTable 2. Selected ship reports with winds of at
least 34 kt for Hurricane Vince, 8-11 October 2005.

+-----------+-----------+-----------+-----------+-----------+-----------+
| Date/Time | Ship call | Latitude  | Longitude | Wind      | Pressure  |
| (UTC)     | sign      |           |           |           |           |
|           |           | (°N)      | (°W)      | dir/speed | (mb)      |
|           |           |           |           | (kt)      |           |
+-----------+-----------+-----------+-----------+-----------+-----------+
| 10 / 1800 | ZCBD3     | 33.5      | 15.0      | 260 / 35  | 1011.4    |
+-----------+-----------+-----------+-----------+-----------+-----------+
| 10 / 2100 | V2ON3     | 34.7      | 13.7      | 270 / 41  | 1009.0    |
+-----------+-----------+-----------+-----------+-----------+-----------+

Number range CHAPTER

Number range CHAPTER![](media/image1.wmf){width="7.745138888888889in"
height="5.99375in"}

Number range CHAPTERFigure 1. Best track positions for Hurricane Vince,
8-11 October 2005.

![](media/image2.wmf){width="7.152777777777778in"
height="4.819444444444445in"}

Number range CHAPTERFigure 2. Selected wind observations and best track
maximum sustained surface wind speed curve for Hurricane Vince, 8-11
October 2005.

![](media/image3.wmf){width="7.152777777777778in"
height="4.819444444444445in"}

Number range CHAPTERFigure 3. Selected pressure observations and best
track minimum central pressure curve for Hurricane Vince, 8-11 October
2005.

.

![](media/image4.png){width="5.875in" height="5.875in"}

Figure 4. Radar image of Vince at 0300 UTC 11 October from Instituto de
Meteorologia of Portugal.