Number range CHAPTERTropical Cyclone Report

Tropical Storm Zeta

30 December 2005 -- 6 January 2006

Richard D. Knabb and Daniel P. Brown

National Hurricane Center

17 March 2006

Zeta was the 27th and final named storm in the Atlantic during 2005,
establishing the record for the most named storms in one year in that
basin. It was the second-latest tropical storm to form in the Atlantic
basin, only six hours earlier than Hurricane Alice (1954) that also
became a tropical storm on 30 December. Zeta and Alice are the only two
Atlantic tropical cyclones on record to cross from one calendar year to
the next. Zeta spent about one week moving erratically in a general
westward direction over the subtropical waters of the central Atlantic,
and it did not affect land.

a.  Synoptic History

    The origins of Tropical Storm Zeta can be traced back to the
    interaction between a weakening frontal boundary and an
    upper-tropospheric trough. By 28 December, the upper-level trough
    had cut off and evolved into an upper-level low centered about 650 n
    mi west-northwest of the Cape Verde Islands. A surface trough, the
    remains of a weakening front, was oriented from southwest to
    northeast and lay beneath the upper-level low. On 29 December, just
    northwest of the center of the upper-level low in an area of
    upper-level difluence, a closed low formed along the surface trough
    about 675 n mi northwest of the Cape Verde Islands. Late on the
    29th, thunderstorm activity increased near the center of this low,
    and it is estimated that the system gained sufficient organization
    to be designated a tropical depression at 0000 UTC 30 December. 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.

    Convective banding quickly developed and wrapped around the
    low-level center early on 30 December, and Zeta became a 40-kt
    tropical storm by 0600 UTC. Initially, Zeta moved slowly
    northwestward around a mid-level low to its southwest. Situated
    beneath weak anticyclonic flow aloft, the tropical storm
    strengthened to 45 kt by 1200 UTC that day. A weak low- to mid-level
    ridge to its north forced Zeta to turn westward on 31 December, but
    upper-level westerlies slowed its forward motion to a 2-kt crawl.
    Although Zeta reached an intensity of 50 kt early that day, westerly
    shear later stripped Zeta of nearly all its deep convection in the
    hours just before the new year. Convection soon rebounded, however,
    and although westerly shear persisted, Zeta was located beneath an
    upper-level diffluent region with stronger shear to the north and
    south. Zeta also was probably too shallow of a system to be
    substantially weakened by shear associated with strong winds in the
    upper troposphere. These factors allowed Zeta to resume a slow
    strengthening trend as it turned toward the southwest on 1 January,
    still moving at a snail's pace. Zeta first reached its peak
    intensity of 55 kt at 1800 UTC that day (Fig. 4) about 900 n mi
    northwest of the Cape Verde Islands.

    Zeta's low-level center became mostly exposed and accelerated
    southwestward early on 2 January, and the storm weakened to 45 kt by
    1200 UTC. However, this tenacious tropical storm began to strengthen
    again and decelerate later that day as a burst of deep convection
    redeveloped over the center. It is estimated that Zeta again reached
    a peak intensity of 55 kt at 0000 UTC 3 January while centered about
    1000 n mi west-northwest of the Cape Verde Islands, and it
    maintained that intensity for the remainder of the day. On 4
    January, the tropical storm turned westward to the south of the deep
    layer ridge over the central Atlantic, and westerly shear
    sufficiently increased to initiate a prolonged but final weakening
    phase. Zeta turned west-northwestward on 5 January and accelerated
    between the western extent of the ridge and an approaching cold
    front. It generated only sporadic bursts of deep convection that
    day, and the circulation gradually spun down. It is estimated that
    Zeta had weakened below tropical storm strength by 0600 UTC 6
    January. The tropical cyclone lost all deep convection and
    degenerated to a remnant low by 1800 UTC that day. The remnant low
    was pulled northwestward around the retreating low-level ridge and
    ahead of the approaching front. The circulation dissipated east of
    the front late on 7 January about 575 n mi southeast of Bermuda.

    b\. Meteorological Statistics

    Observations in Zeta (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 data
    and imagery from National Oceanic and Atmospheric Administration
    (NOAA) satellites, Defense Meteorological Satellite Program (DMSP)
    satellites, and National Aeronautics and Space Administration (NASA)
    satellites including the Tropical Rainfall Measuring Mission (TRMM),
    QuikSCAT, and Aqua were also useful in tracking Zeta. QuikSCAT wind
    speed retrievals were particularly helpful in estimating the
    intensity of Zeta, as there were about a dozen QuikSCAT passes that
    captured most or all of Zeta's circulation. A couple of ships and
    drifting buoys also provided some useful data.

    A QuikSCAT overpass at 0752 UTC 30 December estimated surface winds
    as strong as about 45 kt. Based on these data, it is estimated the
    depression became a 40-kt tropical storm by 0600 UTC 30 December and
    likely had reached tropical storm status a couple of hours earlier.
    Additionally, drifting buoy 62557, although it did not report wind
    data, reported a pressure fall of 11.9 mb during the 20-h period
    ending 0800 UTC 30 December, when it reported a pressure of 1006.7
    mb near the center of circulation. The progression of Zeta's
    convective pattern early on 30 December was so abrupt that Dvorak
    satellite classifications did not begin until 0600 UTC. Due to
    constraints within the Dvorak technique, the Dvorak intensity
    estimates during Zeta's initial development were too low. Dvorak
    "data T-numbers" were likely a better estimate of the intensity for
    the newly-formed tropical storm. At 0600 UTC 30 December, the
    initial Dvorak data T-numbers from the Satellite Analysis Branch
    (SAB) and the Tropical Analysis and Forecast Branch (TAFB)
    corresponded to intensities of 35 and 45 kt, respectively.

    Ship *Liberty Star* (call sign WCBP) provided several reports during
    Zeta, including 34 kt winds about 40 n mi north of the circulation
    center (and within the northern extent of the deep convection) at
    0800 UTC 31 December during which time Zeta's maximum winds were
    estimated at 50 kt.

    The two separate peaks in Zeta's intensity at 55 kt, on 1 and 3
    January, are based in large part on QuikSCAT wind speed estimates.
    The QuikSCAT overpasses at 0840 and 2104 UTC on 1 January both
    suggest Zeta was probably stronger than the Dvorak estimates on that
    day (Fig. 2). The best track intensities lean closer to the QuikSCAT
    solutions since retrieved wind speeds of 50 kt or more from that
    instrument are not as likely to be artificially inflated by rain.
    This is especially the case near the center of an established
    tropical storm, where it is already known that the winds will be of
    tropical storm force and the returned signal from the surface will
    be fairly strong. Further, the convection produced by Zeta that day
    does not appear to have been particularly deep and strong such that
    attenuation by rain would preclude a reasonable estimate of surface
    wind speeds of tropical storm force. The peak intensity on 3 January
    is supported by both QuikSCAT and Dvorak estimates. Both data
    sources are also consistent in indicating that Zeta weakened to
    about 45 kt in the interim on 2 January.

    c\. Casualty and Damage Statistics

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

d\. Forecast and Warning Critique

Tropical Weather Outlooks were not issued by the National Hurricane
Center after 30 November 2005 (the "official" end of the Atlantic
hurricane season), so an assessment of that product in the case of Zeta
is not possible. The abrupt formation of Zeta was not well forecast by
the Tropical Analysis and Forecast Branch (TAFB) at the NHC or by any of
the global models, although TAFB did at times forecast the development
of a low pressure center up to 48 hours in advance. Once the low had
formed, TAFB issued a gale warning at 1030 UTC 30 December, although
this was more than four hours after Zeta is estimated (in this
post-storm analysis) to have become a tropical storm. Since the
convection in Zeta had only persisted a few hours by that time, tropical
cyclone advisories were not initiated by the NHC until 1700 UTC 30
December when the thunderstorm activity had endured for about 18 hours.

Average official track errors (with the number of cases in parentheses)
for Zeta were 36 (25), 66 (21), 102 (17), 143 (15), and 264 (3) n mi for
the 12, 24, 36, 48, and 72 h forecasts, respectively. The corresponding
average official track errors for the 10-yr period 1995-2004 are 42, 75,
107, 138, and 202 n mi, respectively (Table 4). No verification
statistics are available at 96 and 120 h, and very few 72-h forecasts
were made, since in general the official forecasts anticipated Zeta
would dissipate much more quickly than it did. In fact, the early
forecasts predicted that Zeta would only survive as a tropical storm for
about 36 h due to increasing westerly shear. The official errors through
36 h are generally less than the 10-yr averages, but the 48- and 72-h
errors are larger than the 10-yr averages. The official forecasts in
general had smaller errors out to 72 h than most of the guidance, with
exceptions being the interpolated NOGAPS (NGPI), the BAMM medium-depth
trajectory model, and the CONU consensus.

Average official intensity forecast errors were 8, 15, 17, 17, and 5 kt
for the 12, 24, 36, 48, and 72 h forecasts, respectively. The errors are
generally larger than the corresponding average official intensity
errors over the 10-yr period 1995-2004 of 6, 10, 12, 15, and 18 kt,
respectively. As is the case of the official track forecasts, no
verification statistics are available at 96 and 120 h and very few 72-h
forecasts were made for Zeta. Clearly, however, Zeta lasted much longer
and was much stronger at 72-120 h than expected at the time most of the
forecasts were issued. The sub-par intensity forecasts can be attributed
to the difficulty in forecasting the impacts of the vertical wind shear
that plagued Zeta throughout its life span. While westerly shear
certainly limited Zeta's intensity, the tropical storm was less affected
by shear than the official forecast or the SHIPS guidance anticipated.
One probable reason is that Zeta was more shallow than most tropical
storms, and calculating vertical shear between the 850 and 200 mb levels
(as is done in the SHIPS model) was probably too deep of a layer to be
representative. Indeed, model analyses suggest that winds at slightly
lower levels (i.e., 300-500 mb) were weaker than at 200 mb during Zeta.
Second, the vertical wind shear in the immediate vicinity of Zeta's
core, based on satellite imagery and model analyses, appeared at times
to be weaker than the shear in its broader environment to the north and
south. This scenario might have resulted in the SHIPS model
overestimating the shear magnitude since it calculates shear over a
large area between 200 and 800 km from the circulation center. These
factors were considered in real time by the official forecasts, which
did not indicate quite as much weakening as the SHIPS model and
therefore had smaller errors than SHIPS.

No coastal watches or warnings were required in association with Zeta.

Number range CHAPTERTable 1. Best track for Tropical Storm Zeta, 30
December 2005 -- 6 January 2006.

+----------+--------+----------+----------+-----------+---------------+
| D        | La     | L        | Pressure | Wind      | Stage         |
| ate/Time | titude | ongitude |          | Speed     |               |
|          |        |          | (mb)     |           |               |
| (UTC)    | (°N)   | (°W)     |          | (kt)      |               |
+----------+--------+----------+----------+-----------+---------------+
| 30 /     | 23.9   | 35.6     | 1009     | 30        | tropical      |
| 0000     |        |          |          |           | depression    |
+----------+--------+----------+----------+-----------+---------------+
| 30 /     | 24.2   | 36.1     | 1005     | 40        | tropical      |
| 0600     |        |          |          |           | storm         |
+----------+--------+----------+----------+-----------+---------------+
| 30 /     | 24.7   | 36.6     | 1002     | 45        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 30 /     | 25.2   | 37.0     | 1000     | 45        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 31 /     | 25.6   | 37.3     | 1000     | 45        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 31 /     | 25.7   | 37.6     | 997      | 50        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 31 /     | 25.7   | 37.9     | 997      | 50        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 31 /     | 25.7   | 38.1     | 1000     | 45        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 01 /     | 25.6   | 38.3     | 997      | 50        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 01 /     | 25.4   | 38.4     | 997      | 50        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 01 /     | 25.2   | 38.5     | 997      | 50        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 01 /     | 25.0   | 38.6     | 994      | 55        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 02 /     | 24.6   | 38.9     | 994      | 55        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 02 /     | 24.3   | 39.7     | 997      | 50        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 02 /     | 23.8   | 40.4     | 1000     | 45        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 02 /     | 23.6   | 40.8     | 997      | 50        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 03 /     | 23.4   | 41.0     | 994      | 55        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 03 /     | 23.3   | 41.3     | 994      | 55        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 03 /     | 23.2   | 41.6     | 994      | 55        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 03 /     | 23.0   | 42.1     | 994      | 55        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 04 /     | 22.6   | 42.4     | 994      | 55        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 04 /     | 22.1   | 42.9     | 997      | 50        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 04 /     | 21.9   | 43.6     | 1000     | 45        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 04 /     | 21.7   | 44.6     | 1002     | 40        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 05 /     | 21.7   | 45.6     | 1005     | 35        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 05 /     | 21.9   | 46.6     | 1005     | 35        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 05 /     | 22.2   | 47.3     | 1006     | 35        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 05 /     | 22.7   | 47.9     | 1007     | 35        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 06 /     | 23.0   | 48.4     | 1007     | 35        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 06 /     | 23.1   | 49.0     | 1007     | 30        | tropical      |
| 0600     |        |          |          |           | depression    |
+----------+--------+----------+----------+-----------+---------------+
| 06 /     | 23.1   | 49.6     | 1008     | 30        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 06 /     | 23.3   | 50.2     | 1009     | 25        | remnant low   |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 07 /     | 23.7   | 51.4     | 1009     | 25        | \"            |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 07 /     | 24.2   | 52.7     | 1012     | 25        | \"            |
| 0600     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 07 /     | 24.8   | 54.2     | 1014     | 25        | \"            |
| 1200     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 07 /     | 26.3   | 55.7     | 1016     | 25        | \"            |
| 1800     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 08 /     |        |          |          |           | dissipated    |
| 0000     |        |          |          |           |               |
+----------+--------+----------+----------+-----------+---------------+
| 01 /     | 25.0   | 38.6     | 994      | 55        | minimum       |
| 1800     |        |          |          |           | pressure      |
+----------+--------+----------+----------+-----------+---------------+

Number range CHAPTERNumber range CHAPTERNumber range CHAPTERTable 2.
Preliminary forecast evaluation (heterogeneous sample) for Tropical
Storm Zeta, 30 December 2005 -- 6 January 2006. Forecast errors (n mi)
are followed by the number of forecasts in parentheses. Errors smaller
than the NHC official forecast are shown in bold-face type. Verification
includes the depression stage, but does not include the remnant low
stage.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Number    | For   |       |       |       |       |       |       |
| range     | ecast |       |       |       |       |       |       |
| CHAPTE    | P     |       |       |       |       |       |       |
| RForecast | eriod |       |       |       |       |       |       |
| Technique | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CLP5      | 46    | 94    | 152   | 195   | 386   | 623 ( | 878 ( |
|           | (25)  | (21)  | (17)  | (15)  | (11)  | 7)    | 3)    |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFNI      | 42    | 66    | **98  | 143   | **261 | 544 ( | 1194  |
|           | (16)  | (13)  | (     | (13)  | (     | 7)    | ( 3)  |
|           |       |       | 13)** |       | 11)** |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDI      | **34  | 67    | 126 ( | 187 ( | **229 | 467 ( | 938 ( |
|           | (     | (11)  | 8)    | 6)    | (     | 2)    | 2)    |
|           | 15)** |       |       |       | 2)**  |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDL\*    | **33  | **49  | **88  | **139 | 264   | 369 ( | 638 ( |
|           | (     | (     | (     | (     | (11)  | 7)    | 3)    |
|           | 25)** | 21)** | 17)** | 15)** |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDN\*    | 42    | **57  | **73  | **110 | **220 | 436 ( | 934 ( |
|           | (17)  | (     | (     | (     | (     | 6)    | 3)    |
|           |       | 12)** | 11)** | 11)** | 11)** |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSI      | 42    | 89    | 151 ( | 243 ( | 455 ( |       |       |
|           | (15)  | (11)  | 9)    | 7)    | 2)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSO\*    | 38    | 68    | 117   | 186   | 453 ( |       |       |
|           | (24)  | (20)  | (14)  | (11)  | 3)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| AEMI      | 47 (  | 76 (  | 113 ( | 206 ( |       |       |       |
|           | 4)    | 2)    | 2)    | 2)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPI      | **33  | **49  | **83  | **133 | **217 | 451 ( |       |
|           | (     | (     | (     | (     | (     | 1)    |       |
|           | 22)** | 19)** | 17)** | 15)** | 11)** |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPS\*    | 36    | **46  | **65  | **115 | **210 | 171 ( |       |
|           | (23)  | (     | (     | (     | (     | 1)    |       |
|           |       | 19)** | 17)** | 15)** | 10)** |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKMI      | 68    | 118   | 153   | 192   | 300 ( |       |       |
|           | (16)  | (14)  | (12)  | (10)  | 2)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKM\*     | 68 (  | 128 ( | 165 ( | 205 ( | 268 ( |       |       |
|           | 9)    | 8)    | 7)    | 6)    | 2)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| A98E      | 44    | 87    | 161   | 241   | 412   | 554 ( | 675 ( |
|           | (25)  | (21)  | (17)  | (15)  | (11)  | 7)    | 3)    |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| A9UK      | 43    | 92 (  | 187 ( | 301 ( | 577 ( |       |       |
|           | (11)  | 9)    | 7)    | 6)    | 4)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMD      | 115   | 229   | 357   | 468   | 522   | 586 ( | 535 ( |
|           | (25)  | (21)  | (17)  | (15)  | (11)  | 7)    | 3)    |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMM      | **35  | **62  | **94  | **133 | **201 | 292 ( | 343 ( |
|           | (     | (     | (     | (     | (     | 7)    | 3)    |
|           | 25)** | 21)** | 17)** | 15)** | 11)** |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMS      | 50    | 89    | 131   | 180   | 267   | 347 ( | 564 ( |
|           | (25)  | (21)  | (17)  | (15)  | (11)  | 7)    | 3)    |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CONU      | **35  | **63  | **94  | **131 | **179 | 445 ( | 992 ( |
|           | (     | (     | (     | (     | (     | 3)    | 2)    |
|           | 23)** | 19)** | 17)** | 15)** | 11)** |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GUNA      | 36    | 73 (  | 138 ( | 234 ( |       |       |       |
|           | (10)  | 8)    | 6)    | 4)    |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 36    | 66    | 102   | 143   | 264 ( |       |       |
|           | (25)  | (21)  | (17)  | (15)  | 3)    |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NHC       | 42    | 75    | 107   | 138   | 202   | 236   | 310   |
| Official  |       |       |       |       |       |       |       |
|           | \(3   | \(3   | \(2   | \(2   | \(2   | \(    | \(    |
| (         | 400\) | 116\) | 848\) | 575\) | 117\) | 649\) | 535\) |
| 1995-2004 |       |       |       |       |       |       |       |
| mean)^1^  |       |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+

^1^ Errors given for the 96 and 120 h periods are averages over the
four-year period 2001-04.

![](media/image1.wmf){width="8.333333333333334in" height="6.5in"}

Number range CHAPTERFigure 1. Best track positions for Tropical Storm
Zeta, 30 December 2005 -- 6 January 2006.

![](media/image2.wmf){width="8.25in" height="5.74375in"}

Number range CHAPTERFigure 2. Selected wind observations and best track
maximum sustained surface wind speed curve for Tropical Storm Zeta, 30
December 2005 -- 6 January 2006.

![](media/image3.wmf){width="8.375in" height="5.83125in"}

Number range CHAPTERFigure 3. Selected pressure observations and best
track minimum central pressure curve for Tropical Storm Zeta, 30
December 2005 -- 6 January 2006.

![](media/image4.png){width="8.989583333333334in"
height="5.822916666666667in"}

Figure 4. GOES-12 infrared image of Tropical Storm Zeta at 1815 UTC 1
January 2006, near the time when it first reached its peak intensity of
55 kt.Number range CHAPTER The Leeward Islands are located in the
southwestern portion of the image.