2008 Tropical Cyclones Central North Pacific Jeff Powell table of contents tropical Storm Kika




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2008 Tropical Cyclones Central North Pacific

Jeff Powell

TABLE OF CONTENTS



  • Tropical Storm Kika

TROPICAL STORM KIKA


7-12 August 2008


OVERVIEW. Tropical Depression (TD) 1-C formed far southeast of the main Hawaiian Islands, near 10N 147W, within a small area of convection tracked as Invest 92C since 4 Aug. This system developed sufficiently to warrant a first Central Pacific Hurricane Center (CPHC) bulletin at 0300 UTC 7 Aug, with an initial position at 10.3N 146.9W and an initial strength of 30 kt. Movement was generally towards the west within 27C sea surface temperatures (SST) and weak shear (around 6-8 kt). After achieving nominal tropical storm (TS) strength as Kika with the second bulletin at 0900 UTC 7 Aug, movement continued toward the west with no additional strengthening. TS Kika was not a well-organized system when, between the 1500 UTC and 2100 UTC 8 Aug bulletins, the system center reformed 90 to 100 miles to the south as noted in first visible imagery that day. Since this new position was separated from associated deep convection, Kika was downgraded to a depression with the 2100 UTC 8 Aug bulletin issuance. Subsequently moving towards the west at 10 to 15 kt, Kika slowly regained strength and was upgraded to a TS again with the 0900 UTC 9 Aug bulletin issuance. TS Kika continued moving toward the west, within 26.5C to 27.0C SSTs and less than 10 kt of shear. Shear across the system began to relax as Kika began to move over slightly cooler water south of the main Hawaiian Islands over the next few days, keeping Kika at minimal TS strength through 2100 UTC 10 Aug. Convection, always fluctuating in intensity, lost sufficient organization to prompt the final downgrading of Kika to a TD at 0300 UTC 11 Aug while this system was about 900 miles southwest of the main Hawaiian Islands. Kika continued to weaken within steadily increasing shear, with the last CPHC bulletin issued at 0900 UTC 12 Aug. The remnants of Kika crossed the dateline out of the CPHC area of responsibility around 0000 UTC 14 Aug and became too weak for CPHC to classify after 1200 UTC 14 Aug.

SYNOPTIC HISTORY. When the first CPHC bulletins were issued for TD 01C, then TS Kika, a strong high northeast of the main Hawaiian Islands and a ridge extending to the west of the high provided deep easterly trade wind steering flow. UW-CIMMS assessed favorable system development based on about 8 kt of southeasterly shear. Initial forecasts were for gradual system strengthening to 45 kt by 120 hours. Little change was expected with the strength and orientation of the ridge and, indeed, little change occurred. Shear remained in the 6 to 8 kt range, with favorable development conditions assessed by UW-CIMMS, as the system center reformed between 1500 UTC and 2100 UTC 8 Aug. Convection was persistent around the initial low level circulation center (LLCC) from TD designation through this reformation. After center reformation, convection was initially robust but began fluctuating within 24 hours after the shift. Shear decreased to 4 kt or less after 1200 UTC 9 Aug, increasing back into the 6 to 8 kt range after 1800 UTC 10 Aug. In short, Kika passed over 26.5 to 27.0C water through its lifecycle, with fluctuating but always favorable shear, yet could not sustain enough deep convection long enough after 2100 UTC 8 Aug to develop beyond minimal TS strength.

IMPACTS. There were no impacts since TS Kika, never a large system, passed well south of the main Hawaiian Islands.

Table 1. Best Track Data

Date/Time
(UTC)


Latitude
(°N)


Longitude
(°W)


Pressure
(mb)


Wind Speed
(kt)


Stage/Notes

05/1200

10.2

140.7

1009

20

Disturbance

05/1800

9.8

141.8

1010

20

"

06/0000

9.7

142.5

1008

25

"

06/0600

9.9

143.6

1011

25

"

06/1200

10.1

144.8

1011

25

"

06/1800

10.1

145.9

1011

25

"

07/0000

10.2

146.3

1010

30

Tropical Depression

07/0600

10.4

147.2

1008

35

Tropical Storm

07/1200

10.6

147.9

1008

35

"

07/1800

11.0

149.3

1007

35

"

08/0000

11.2

150.6

1007

35

"

08/0600

11.3

151.6

1008

35

"

08/1200

9.9

152.4

1008

35

"

08/1800

9.6

153.4

1010

30

Tropical Depression

09/0000

9.8

154.6

1010

30

"

09/0600

10.0

155.9

1008

35

Tropical Storm

09/1200

10.1

157.2

1008

35

"

09/1800

10.2

158.2

1008

35

"

10/0000

10.2

159.3

1008

35

"

10/0600

10.0

160.3

1008

35

"

10/1200

9.8

161.5

1009

35

"

10/1800

9.8

162.4

1009

35

"

11/0000

10.1

164.2

1010

30

Tropical Depression

11/0600

10.3

165.6

1010

30

"

11/1200

10.4

166.9

1010

30

"

11/1800

10.7

168.2

1010

30

"

12/0000

10.8

169.6

1011

25

"

12/0600

11.0

170.4

1011

25

"

12/1200

11.0

171.5

1011

25

Disturbance

12/1800

11.0

172.8

1011

25

"

13/0000

10.9

174.2

1011

25

"

13/0600

10.9

175.3

1011

25

"

13/1200

10.9

176.6

1010

25

"

13/1800

11.0

177.8

1011

25

"

14/0000

10.6

179.3

1011

25

"

14/0600

10.0

179.4E

1011

20

Tropical Depression

14/1200

9.6

178.0E

1011

20

"

14/1800

9.5

176.6E

1011

20

"

15/0000

9.4

175.1E

1011

20

"

15/0600

9.4

174.4E

1011

20

"

15/1200

9.3

173.7E

1011

20

"

15/1800

9.1

173.0E

1010

15

Disturbance

16/0000

9.1

172.3E

1010

15

Tropical Depression

16/0600

9.1

171.4E

1010

15

"

Table 2. Track Verification Table entries are track forecast errors, measured in nautical miles. Values in parentheses indicate the number of forecasts. Values in bold represent guidance forecast errors equal to or less than the office CPHC forecast.

Forecast

12-hr

24-hr

36-hr

48-hr

72-hr

96-hr

120-hr

CPHC

42 (20)

61 (18)

79 (16)

102 (14)

156 (10)

220 (6)

248 (2)

CLP5

47 (20)

77 (18)

102 (16)

119 (14)

187 (10)

275 (6)

307 (2)

BAMD

37 (20)

62 (18)

90 (16)

121 (14)

194 (10)

295 (6)

321 (2)

BAMM

40 (19)

55 (17)

79 (15)

106 (13)

154(9)

228 (5)

216 (2)

BAMS

42 (19)

66 (17)

93 (15)

122 (13)

190 (9)

288 (5)

331 (2)

GFDL

40 (19)

58 (17)

71 (15)

97 (14)

176 (10)

256 (6)

325 (2)

AVNO

57 (17)

68 (17)

79 (16)

98 (14)

124 (10)

160 (6)

n/a

NOGAPS

116 (1)

123 (1)

196 (1)

283 (1)

385 (1)

n/a

n/a

Image 1. TS Kika 2125 UTC 10 Aug 2008


ACRONYMS that may have been used in this report.

Acronym

Full Spelling/Definition

AOR

Area of Responsibility

AVNO

Operation global forecast system model

BAMD

Deep Layer Beta Advection Model (mean layer averaged between 850 hPa and 250 hPa)

BAMM

Medium Layer Beta Advection Model (mean layer averaged between 850 hPa and 400 hPa)

BAMS

Shallow Layer Beta Advection Model (mean layer averaged between 850 hPa and 700 hPa)

CLIP

Climatology and Persistence

CPHC

Central Pacific Hurricane Center

GFDL

Geophysical Fluid Dynamics Laboratory model

hPa

Hectopascal (formerly millibar)

ITCZ

Inter-tropical Convergence Zone

JTWC

Joint Typhoon Warning Center

kts

knots

LBAR

Barotropic limited area sine transform

mb

millibars

NA

Not Available

NGPS

NOGAPS (Navy Operational Global Atmospheric Prediction System) Vortex Tracking Routine

NHC

National Hurricane Center

nm

nautical miles

P91E

Pacific Statistical Dynamic Model (adapted from NHC90 for the Eastern Pacific)

SHIFR

Statistical Hurricane Intensity Forecast

SHIP

Statistical Hurricane Intensity Prediction

SST

Sea Surface Temperature

TD

Tropical Depression

TPC

Tropical Prediction Center, Miami, FL

TUTT

Tropical Upper Tropospheric Trough

UTC

Universal Time Coordinated

WFO

Weather Forecast Office


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