Tropical Cyclone Report

Tropical Storm Lee

28 August- 2 September 2005

Lixion A. Avila

National Hurricane Center

7 December 2005

Lee was a tropical storm over the open Atlantic for a short period of
time.

a\. Synoptic History

A vigorous tropical wave that moved off the west coast of Africa on 24
August spawned a low pressure area while it moved westward across the
tropical Atlantic. The shower activity associated with the low became
organized and a tropical depression formed at 1200 UTC 28 August about
midway between Africa and the Lesser Antilles. Because northeasterly
wind shear prevailed, the main center of circulation was removed from
the convection. There were two other smaller circulations embedded
within a larger cyclonic gyre. The depression moved toward the
west-northwest and continued to struggle within the shearing environment
and degenerated into a broad area of low pressure at 1800 UTC 29 August.
The low moved northward and then northeastward around a non-tropical low
located to the north of the system. As the remnant low moved toward the
northeast, the thunderstorm activity increased, some modest convective
banding features developed, and a ring of deep convection was noted on
microwave data. Based on this data, it is estimated that a depression
regenerated at 0600 UTC 31 August, and became Tropical Storm Lee at 1200
UTC on that day. By then, the cyclone was located between Bermuda and
the Azores. Thereafter, Lee weakened to a tropical depression as it
moved northeastward and northwestward around the eastern side of the
non-tropical low. Lee absorbed the non-tropical low and maintained
limited convection. The depression weakened to a broad area of low
pressure at 0600 UTC 2 September and became absorbed by a cold front at
0000 UTC 4 September. The "best track" chart of the tropical cyclone'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.

b.  Meteorological Statistics

    Observations in Lee (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 Lee. Operationally, tropical depression advisories were
    initiated based on NOAA buoy (41041) data that confirmed that a
    surface circulation developed in association with the vigorous
    tropical wave which spawned Lee. An image from the SSM/I pass at
    1018 UTC 31 August shows a ring of deep convection around the center
    (Fig. 4) associated with Tropical Storm Lee.

c\. Casualty and Damage Statistics

There are no reports of casualties or damage associated with Lee.

d\. Forecast and Warning Critique

Lee was difficult to forecast primarily due to the interaction with a
non-tropical low resulting in large average track forecast errors.
However, the sample was small. These errors (with the number of cases in
parentheses) for Lee were 80 (7), 173 (3), 269 (1), 475 (1), 685 (3),
and 729 (2) n mi for the 12, 24, 36, 48, 72, and 96 h forecasts,
respectively. These errors are greater than the average official track
errors for the 10-yr period 1995-2004[^1] of 42, 75, 107, 138, 202, and
236 n mi, respectively).

Average official intensity errors were 2, 7, 10, 5, 3 and 8 kt for the
12, 24, 36, 48, 72, and 96 h forecasts, respectively. For comparison,
the average official intensity errors over the 10-yr period 1995-2004
are 6, 10, 12, 15, 18, and 20 kt, respectively.

Table 1. Best track for Tropical Storm Lee, 28 August- 2 September 2005.

+----------+--------+---------+---------+--------+------------------+
| D        | La     | Lo      | P       | Wind   | Stage            |
| ate/Time | titude | ngitude | ressure | Speed  |                  |
|          |        |         |         |        |                  |
| (UTC)    | (°N)   | (°W)    | (mb)    | (kt)   |                  |
+----------+--------+---------+---------+--------+------------------+
| 28 /     | 14.0   | 45.1    | 1009    | 25     | tropical         |
| 1200     |        |         |         |        | depression       |
+----------+--------+---------+---------+--------+------------------+
| 28 /     | 14.9   | 46.4    | 1007    | 25     | \"               |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 29 /     | 15.7   | 47.6    | 1007    | 25     | \"               |
| 0000     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 29 /     | 17.0   | 48.9    | 1007    | 25     | \"               |
| 0600     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 29 /     | 17.7   | 50.6    | 1008    | 25     | \"               |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 29 /     | 18.5   | 52.5    | 1009    | 20     | Low              |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 30 /     | 20.5   | 53.2    | 1010    | 20     | \"               |
| 0000     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 30 /     | 22.1   | 53.6    | 1010    | 20     | \"               |
| 0600     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 30 /     | 24.2   | 54.2    | 1010    | 20     | \"               |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 30 /     | 25.5   | 53.6    | 1010    | 25     | \"               |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 31 /     | 26.9   | 52.7    | 1010    | 25     | \"               |
| 0000     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 31 /     | 28.0   | 51.6    | 1007    | 30     | tropical         |
| 0600     |        |         |         |        | depression       |
+----------+--------+---------+---------+--------+------------------+
| 31 /     | 29.0   | 50.4    | 1006    | 35     | tropical storm   |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 31 /     | 30.1   | 50.1    | 1007    | 35     | \"               |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 01 /     | 31.1   | 50.3    | 1009    | 30     | tropical         |
| 0000     |        |         |         |        | depression       |
+----------+--------+---------+---------+--------+------------------+
| 01 /     | 31.9   | 51.2    | 1010    | 30     | \"               |
| 0600     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 01 /     | 31.9   | 51.4    | 1010    | 30     | \"               |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 01 /     | 32.3   | 51.5    | 1010    | 30     | \"               |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 02 /     | 32.4   | 52.0    | 1010    | 25     | \"               |
| 0000     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 02 /     | 32.6   | 52.3    | 1010    | 25     | Low              |
| 0600     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 02 /     | 33.2   | 52.3    | 1010    | 25     | \"               |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 02 /     | 33.9   | 52.7    | 1010    | 25     | \"               |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 03 /     | 34.7   | 53.2    | 1010    | 25     | \"               |
| 0000     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 03 /     | 35.5   | 53.9    | 1010    | 25     | \"               |
| 0600     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 03 /     | 36.6   | 54.2    | 1010    | 25     | \"               |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 03 /     | 37.4   | 53.9    | 1010    | 25     | \"               |
| 1800     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+
| 04 /     |        |         |         |        | Absorbed by a    |
| 0000     |        |         |         |        | cold front       |
+----------+--------+---------+---------+--------+------------------+
| 31 /     | 29.0   | 50.4    | 1006    | 35     | minimum pressure |
| 1200     |        |         |         |        |                  |
+----------+--------+---------+---------+--------+------------------+

![](media/image1.wmf){width="6.498611111111111in"
height="5.000694444444444in"}

Figure 1. Best track positions for Tropical Storm Lee, 28 August -2
September, 2005.

![](media/image2.wmf){width="6.497916666666667in"
height="4.438194444444444in"}

Figure 2. Selected wind observations and best track maximum sustained
surface wind speed curve for Lee, 28 August- 2 September, 2005.

![](media/image3.wmf){width="6.497916666666667in"
height="4.438194444444444in"}

Figure 3. Selected pressure observations and best track minimum central
pressure curve for Tropical Storm Lee, 28 August 2 September, 2005.

![](media/image4.jpeg){width="5.5in" height="5.5in"}

Figure 4. Microwave data at 1018 UTC 31 August showing a ring of
convection associated with the center of Tropical Storm Lee. Note the
presence of the non-tropical low to the northwest of Lee.

[^1]: Errors given for the 96 h period are averages over the four-year
    period 2001-4.