Tropical Cyclone Report

Hurricane Kenneth

14-30 September 2005

Richard J. Pasch

National Hurricane Center

April 20 2006

Kenneth was a category 4 hurricane on the Saffir-Simpson Hurricane Scale
that had a long track into the Central Pacific hurricane basin. It
dissipated just before reaching the Hawaiian Islands.

a\. Synoptic History

The origin of this long-lived tropical cyclone can possibly be traced
back to a tropical wave that crossed southern Central America and
entered the eastern North Pacific Ocean by 9 September. This system
moved westward within the Intertropical Convergence Zone for several
days, and by 13 September, the associated deep convection started
showing signs of organization. On 14 September, the cloud pattern became
sufficiently well organized to indicate the formation of a tropical
depression about 780 n mi southwest of Cabo San Lucas, Mexico. 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 (best track
data west of 140ºW were furnished by the Central Pacific Hurricane
Center). Kenneth's motion was controlled largely by variations in the
strength of the subtropical ridge to its north. Throughout its life
cycle, the tropical cyclone moved mainly westward to west-northwestward,
but steering currents weakened on a couple of occasions leading to a
slow erratic motion.

After formation, the cyclone strengthened and it became a tropical storm
around 0600 UTC 15 September. Within an environment of weak vertical
shear and sufficiently high sea surface temperatures, Kenneth
strengthened fairly rapidly and became a hurricane by about 0000 UTC 16
September. The hurricane continued to intensify while developing a
well-defined eye, and Kenneth reached its peak intensity of 115 kt
around 1200 UTC 18 September while located about 1500 n mi east of the
Big Island of Hawaii. Gradual weakening began early on 19 September as
north-northeasterly shear began to impact the system. Steering currents
became weak, and the hurricane drifted erratically but generally
southwestward on 19-20 September. Kenneth weakened to a tropical storm
by 1800 UTC 20 September. Stable air and modest northeasterly shear
caused additional slow weakening to an intensity of 45 kt around 1800
UTC 21 September. Kenneth's intensity fluctuated between 45 and 55 kt
over the next several days. The environment, however, eventually became
conducive enough for the cyclone to regain hurricane strength around
0000 25 September. Steering currents again weakened, and Kenneth limped
south-southwestward and entered the Central Pacific Hurricane basin by
0600 UTC 26 September, weakening below hurricane strength shortly
thereafter.

The cyclone turned toward the northwest while continuing to gradually
lose strength in an environment of increasing south-southwesterly shear.
On 29 September, Kenneth turned toward the west and weakened to a
depression as an intensifying upper-level trough in the vicinity of the
Hawaiian Islands created a hostile environment for the tropical cyclone.
Kenneth dissipated as it approached the Big Island of Hawaii on 30
September. The system's remnants moved near or over the Hawaiian Islands
and produced some locally heavy rains there.

b\. Meteorological Statistics

Observations in Kenneth (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 of great value for tracking Kenneth. The
peak intensity of Kenneth at 1200 UTC 18 September is based on a blend
of subjective and objective Dvorak T-numbers.

Kenneth's remnants produced locally heavy rainfall totaling 6 to 12
inches, along with isolated flash floods, over portions of the Hawaiian
Islands.

No ship reports of winds of tropical storm force or greater associated
with Kenneth have been received at the National Hurricane Center (NHC).

c\. Casualty and Damage Statistics

There were no reports of damages or casualties associated with Kenneth.

d\. Forecast and Warning Critique

Tropical Weather Outlooks from the NHC began to describe the area of
disturbed weather that developed into Kenneth only about 19 h prior to
genesis.

Average official (NHC) track errors (with the number of cases in
parentheses) for Kenneth were 28 (46), 50 (46), 69 (46), 86 (46), 106
(46), 119 (46), and 154 (45) n mi for the 12, 24, 36, 48, 72, 96, and
120 h forecasts, respectively. These errors are substantially lower than
the average official track errors for the 10-yr period 1995-2004[^1] of
37, 68, 97, 123, 175, 208, and 259 n mi, respectively. Table 4 lists the
mean errors for selected numerical guidance techniques. The mean
official forecasts were better than any of the numerical guidance except
for BAMM from 12-48 h, CONU for 12 h and GUNA from 12-36 h.

Average official intensity errors for Kenneth were 7, 12, 17, 19, 20,
16, and 14 kt for the 12, 24, 36, 48, 72, 96, and 120 h forecasts,
respectively. These mean wind speed errors are comparable to the average
official intensity errors over the 10-yr period 1995-2004 of 6, 11, 14,
17, 19, 18, and 19 kt, respectively.

Table 1. Best track for Hurricane Kenneth, 14-30 September 2005. Track
west of 140W was provided by the Central Pacific Hurricane Center.

+---------+---------+---------+---------+-----------+----------------+
| Da      | L       | Lo      | P       | Wind      | Stage          |
| te/Time | atitude | ngitude | ressure | Speed     |                |
|         |         |         |         |           |                |
| (UTC)   | \(N\)   | \(W\)   | (mb)    | (kt)      |                |
+---------+---------+---------+---------+-----------+----------------+
| 14 /    | 12.3    | 118.0   | 1009    | 30        | tropical       |
| 1800    |         |         |         |           | depression     |
+---------+---------+---------+---------+-----------+----------------+
| 15 /    | 12.8    | 118.7   | 1006    | 30        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 15 /    | 12.9    | 119.3   | 1002    | 40        | tropical storm |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 15 /    | 12.9    | 119.8   | 997     | 50        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 15 /    | 12.9    | 120.4   | 994     | 55        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 16 /    | 13.0    | 121.3   | 987     | 65        | hurricane      |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 16 /    | 12.9    | 122.2   | 979     | 75        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 16 /    | 13.0    | 123.0   | 979     | 75        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 16 /    | 13.0    | 124.0   | 979     | 75        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 17 /    | 13.2    | 124.7   | 975     | 85        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 17 /    | 13.5    | 125.5   | 956     | 105       | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 17 /    | 13.6    | 126.3   | 952     | 110       | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 17 /    | 13.9    | 127.2   | 952     | 110       | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 18 /    | 14.1    | 127.9   | 952     | 110       | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 18 /    | 14.2    | 128.6   | 951     | 110       | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 18 /    | 14.2    | 129.2   | 947     | 115       | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 18 /    | 14.2    | 129.6   | 948     | 115       | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 19 /    | 14.1    | 130.1   | 949     | 115       | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 19 /    | 13.7    | 130.4   | 952     | 110       | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 19 /    | 13.5    | 130.5   | 956     | 105       | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 19 /    | 13.4    | 130.6   | 970     | 90        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 20 /    | 13.4    | 130.8   | 979     | 80        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 20 /    | 13.4    | 130.9   | 983     | 70        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 20 /    | 13.3    | 131.0   | 987     | 65        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 20 /    | 13.2    | 131.2   | 994     | 55        | tropical storm |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 21 /    | 13.4    | 131.4   | 994     | 55        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 21 /    | 13.9    | 132.0   | 997     | 50        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 21 /    | 14.3    | 132.5   | 997     | 50        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 21 /    | 14.6    | 133.2   | 1000    | 45        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 22 /    | 14.9    | 133.9   | 1000    | 45        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 22 /    | 15.1    | 134.7   | 997     | 50        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 22 /    | 15.4    | 135.5   | 994     | 55        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 22 /    | 15.7    | 135.7   | 994     | 55        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 23 /    | 15.9    | 136.0   | 994     | 55        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 23 /    | 16.0    | 136.4   | 994     | 55        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 23 /    | 16.0    | 136.8   | 994     | 55        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 23 /    | 16.0    | 137.2   | 997     | 50        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 24 /    | 16.0    | 137.7   | 997     | 50        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 24 /    | 16.0    | 138.1   | 1000    | 45        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 24 /    | 16.1    | 138.4   | 996     | 50        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 24 /    | 16.2    | 138.9   | 994     | 55        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 25 /    | 16.4    | 139.3   | 990     | 65        | hurricane      |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 25 /    | 16.5    | 139.4   | 987     | 65        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 25 /    | 16.3    | 139.6   | 987     | 65        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 25 /    | 15.9    | 139.7   | 987     | 65        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 26 /    | 15.7    | 139.9   | 987     | 65        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 26 /    | 15.3    | 140.1   | 988     | 65        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 26 /    | 14.8    | 140.2   | 995     | 60        | tropical storm |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 26 /    | 14.4    | 140.5   | 1000    | 55        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 27 /    | 14.2    | 140.9   | 1000    | 55        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 27 /    | 14.3    | 141.4   | 1000    | 55        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 27 /    | 14.6    | 141.8   | 1003    | 50        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 27 /    | 15.2    | 142.4   | 1005    | 45        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 28 /    | 16.0    | 143.1   | 1005    | 45        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 28 /    | 16.7    | 143.9   | 1005    | 45        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 28 /    | 17.4    | 144.7   | 1006    | 45        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 28 /    | 18.0    | 145.5   | 1008    | 40        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 29 /    | 18.4    | 146.5   | 1010    | 35        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 29 /    | 18.7    | 147.6   | 1010    | 35        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 29 /    | 18.9    | 148.7   | 1012    | 30        | tropical       |
| 1200    |         |         |         |           | depression     |
+---------+---------+---------+---------+-----------+----------------+
| 29 /    | 19.0    | 149.8   | 1012    | 30        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 30 /    | 19.1    | 150.9   | 1012    | 30        | \"             |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 30 /    | 19.2    | 152.0   | 1013    | 25        | \"             |
| 0600    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 30 /    | 19.3    | 153.1   | 1013    | 25        | \"             |
| 1200    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 30 /    | 19.4    | 154.2   | 1013    | 25        | \"             |
| 1800    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 31 /    |         |         |         |           | dissipated     |
| 0000    |         |         |         |           |                |
+---------+---------+---------+---------+-----------+----------------+
| 18 /    | 14.2    | 129.2   | 947     | 115       | minimum        |
| 1200    |         |         |         |           | pressure       |
+---------+---------+---------+---------+-----------+----------------+

Table 2. Preliminary forecast evaluation (heterogeneous sample) for
Hurricane Kenneth, 14-30 September 2005. 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.

+-----------+-------+-------+-------+-------+-------+-------+-------+
| Forecast  | For   |       |       |       |       |       |       |
| Technique | ecast |       |       |       |       |       |       |
|           | P     |       |       |       |       |       |       |
|           | eriod |       |       |       |       |       |       |
|           | (h)   |       |       |       |       |       |       |
+===========+=======+=======+=======+=======+=======+=======+=======+
|           | 12    | 24    | 36    | 48    | 72    | 96    | 120   |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CLP5      | 35    | 69    | 107   | 144   | 213   | 271   | 327   |
|           | (46)  | (46)  | (46)  | (46)  | (46)  | (46)  | (45)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFNI      | 33    | 69    | 101   | 122   | 176   | 228   | 267   |
|           | (43)  | (43)  | (43)  | (43)  | (41)  | (41)  | (40)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFDI      | 36    | 72    | 113   | 155   | 238   | 319   | 388   |
|           | (44)  | (44)  | (44)  | (44)  | (44)  | (44)  | (43)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GFSI      | 37    | 76    | 119   | 161   | 240   | 294   | 315   |
|           | (45)  | (45)  | (45)  | (45)  | (45)  | (45)  | (44)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| AEMI      | 41    | 91    | 142   | 190   | 268   | 313   | 318   |
|           | (45)  | (45)  | (45)  | (45)  | (45)  | (45)  | (42)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NGPI      | 37    | 69    | 97    | 117   | 156   | 205   | 262   |
|           | (44)  | (44)  | (44)  | (44)  | (44)  | (44)  | (43)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| UKMI      | 40    | 74    | 108   | 144   | 240   | 289   | 362   |
|           | (44)  | (44)  | (44)  | (44)  | (44)  | (42)  | (39)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMD      | 30    | 51    | 75    | 98    | 156   | 217   | 270   |
|           | (46)  | (46)  | (46)  | (46)  | (46)  | (46)  | (45)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMM      | 30    | *     | *     | *     | 136   | 198   | 253   |
|           | (45)  | *46** | *64** | *83** | (45)  | (45)  | (45)  |
|           |       | (45)  | (45)  | (45)  |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| BAMS      | 38    | 77    | 117   | 153   | 214   | 277   | 329   |
|           | (44)  | (44)  | (44)  | (44)  | (44)  | (44)  | (44)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| CONU      | *     | 50    | 75    | 94    | 126   | 152   | 184   |
|           | *27** | (45)  | (45)  | (45)  | (45)  | (45)  | (44)  |
|           | (45)  |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| GUNA      | *     | *     | *     | 88    | 117   | 132   | 162   |
|           | *26** | *44** | *67** | (42)  | (42)  | (40)  | (37)  |
|           | (42)  | (42)  | (42)  |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| FSSE      | 28    | 54    | 86    | 116   | 132   | 158   | 180   |
|           | (44)  | (44)  | (42)  | (42)  | (41)  | (32)  | (28)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| OFCL      | 28    | 50    | 69    | 86    | 106   | 119   | 154   |
|           | (46)  | (46)  | (46)  | (46)  | (46)  | (46)  | (45)  |
+-----------+-------+-------+-------+-------+-------+-------+-------+
| NHC       | 37    | 68    | 97    | 123   | 175   | 208   | 259   |
| Official  | (     | (     | (     | (     | (     | (355) | (224) |
|           | 2654) | 2378) | 2096) | 1829) | 1386) |       |       |
| (         |       |       |       |       |       |       |       |
| 1995-2004 |       |       |       |       |       |       |       |
| mean)     |       |       |       |       |       |       |       |
+-----------+-------+-------+-------+-------+-------+-------+-------+

![](media/image1.wmf){width="6.925694444444445in"
height="5.495833333333334in"}

Figure 1. Best track positions for Hurricane Kenneth, 14-30 September
2005. Track west of 140ºW was provided by the Central Pacific Hurricane
Center.

![](media/image2.wmf){width="8.097916666666666in"
height="5.498611111111111in"}

Figure 2. Selected wind observations and best track maximum sustained
surface wind speed curve for Hurricane Kenneth, 14-30 September 2005.
Objective Dvorak estimates represent linear averages over a three-hour
period centered on the nominal observation time. Best track wind speeds
after 0000 UTC 26 Sept were provided by the Central Pacific Hurricane
Center.

![](media/image3.wmf){width="8.097916666666666in"
height="5.498611111111111in"}

Figure 3. Selected pressure observations and best track minimum central
pressure curve for Hurricane Kenneth, 14-30 September 2005. Objective
Dvorak estimates represent linear averages over a three-hour period
centered on the nominal observation time. Best track pressures after
0000 UTC 26 Sept were provided by the Central Pacific Hurricane Center.

[^1]: Errors given for the 96 and 120 h periods are averages over the
    four-year period 2001-4.