WPAC: Ex-Tropical Storm NAMTHEUN (1008/09W)

[supercane]

TXPN23 KNES 300917
SIMWIR
A. 09W (NONAME)
B. 30/0832Z
C. 26.0N
D. 122.6E
E. FIVE/MTSAT
F. T3.0/3.0/D1.5/24HRS
G. IR/EIR/VIS/AMSRE/AMSU
H. REMARKS...LLC HAS BECOME TUCKED UNDER DEEP CONVECTION SHIELD...VIS CDO
METHOD YIELDS 3.0 BASED ON CIRCULAR 1.25 DEGREE DIAMETER HARD CONVECTIVE
CDO. MET IS 3.0. AS IS PT. FT BASED ON CONSENSUS.
I. ADDL POSITIONS
30/0458Z 26.1N 122.7E AMSRE
30/0554Z 25.9N 122.4E AMSU
...GALLINA
=

[P.K.]

WTPQ20 RJTD 301200
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008) UPGRADED FROM TD
ANALYSIS
PSTN 301200UTC 26.2N 122.0E FAIR
MOVE W 06KT
PRES 996HPA
MXWD 035KT
GUST 050KT
30KT 50NM
FORECAST
24HF 311200UTC 25.9N 121.2E 70NM 70%
MOVE ALMOST STATIONARY
PRES 996HPA
MXWD 035KT
GUST 050KT
48HF 011200UTC 25.0N 121.0E 160NM 70% TROPICAL DEPRESSION =

[Chacor]

Wow, wasn't expecting an upgade from JMA at all.

[dexterlabio]

Now this gets my attention. Pretty interesting to see how the three cyclones,hundreds of kilometers apart, could affect each other.

[StormingB81]

man and someone was joking today what if when Kompagu leaves then This one heads NE and hits us from the other side.. I was liek I think the waters would be to churned up for it to intensify any

[Chacor]

Fujiwhara seems more likely to me, hence Namtheun's short forecast lifespan.

[Chacor]

THIS FORECASTS REPRESENTS A
SIGNIFICANT CHANGE FROM THE PREVIOUS ISSUANCE. TS
09W IS NOW EXPECTED TO FURTHER INTENSIFY AND
TRACK TOWARDS THE SOUTHWEST AND EVENTUALLY
BECOME ABSORBED BY TS 07W (LIONROCK) BETWEEN TAU 36 AND 48.

JTWC also upgrades Namtheun to a TS and no longer forecasting DCI with Kompasu, but rather with Lionrock instead.

[StormingB81]

Chacor does that mean that since Kompagu been ramping up quick since it will be moving away it can ramp up even quicker now?

[supercane]

WTPN33 PGTW 301500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 09W (NAMTHEUN) WARNING NR 002
UPGRADED FROM TROPICAL DEPRESSION 09W
03 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
301200Z --- NEAR 26.0N 121.9E
MOVEMENT PAST SIX HOURS - 260 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 26.0N 121.9E
---
FORECASTS:
12 HRS, VALID AT:
310000Z --- 25.6N 120.7E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 220 DEG/ 06 KTS
---
24 HRS, VALID AT:
311200Z --- 24.7N 119.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 215 DEG/ 05 KTS
---
36 HRS, VALID AT:
010000Z --- 23.9N 119.2E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 210 DEG/ 03 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
011200Z --- 23.4N 118.9E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
301500Z POSITION NEAR 25.9N 121.6E.
TROPICAL DEPRESSION (TD) 09W (NINE), LOCATED APPROXIMATELY 60 NM
NORTH-NORTHEAST OF TAIPEI, TAIWAN, HAS TRACKED WESTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. THIS FORECASTS REPRESENTS A SIGNIFICANT
CHANGE FROM THE PREVIOUS ISSUANCE. TS 09W IS NOW EXPECTED TO FURTHER
INTENSIFY AND TRACK TOWARDS THE SOUTHWEST AND EVENTUALLY BECOME
ABSORBED BY TS 07W (LIONROCK) BETWEEN TAU 36 AND 48. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 301200Z IS 8 FEET. NEXT WARNINGS AT
302100Z, 310300Z, 310900Z AND 311500Z. REFER TO TROPICAL STORM 07W
(LIONROCK) WARNINGS (WTPN31 PGTW) FOR SIX-HOURLY UPDATES. REFER TO
TYPHOON 08W (KOMPASU) WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES.
//
NNNN



WDPN33 PGTW 301500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (NAMTHEUN)
WARNING NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TROPICAL STORM (TS) 09W (NAMTHEUN), LOCATED APPROXIMATELY
60 NM NORTH-NORTHEAST OF TAIPEI, TAIWAN, HAS TRACKED WESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS. THE SYSTEM IS ACCELERATING AND IS
STARTING TO TRACK JUST SOUTH OF DUE WEST IN AN APPARENT BINARY
INTERACTION WITH TS 07W (LIONROCK) IN THE SOUTH CHINA SEA. ANIMATED
INFRARED SATELLITE IMAGERY DEPICTS A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION FLARING TO THE
SOUTHEAST. WATER VAPOR IMAGERY SHOWS THAT THE SYSTEM HAS A STRONG
EQUATORWARD OUTFLOW CHANNEL BUT THE POLEWARD SIDE OF THE SYSTEM IS
STARTING TO BECOME IMPINGED BY A BAROCLINIC ZONE TO THE NORTHWEST. A
301010Z SSMIS IMAGE SHOWS THE EXPOSED LLCC WITH DEEP CONVECTION TO
THE SOUTHEAST ALONG WITH A DEEP CONVECTIVE FEEDER BAND DRAWING INTO
THE CONVECTION FROM THE SOUTH. THE SYSTEM IS ALSO WITHIN RANGE OF
TAIWANESE RADAR, AND THE LLCC IS EVIDENT, BUT THERE IS ONLY WEAK
PRECIPITATION AT THE VALID TIME FOR THE FORECAST. THE CURRENT
INTENSITY IS BASED ON DVORAK ESTIMATES OF 30 TO 45 KNOTS FROM PGTW
AND KNES, POSITION IS BASED ON RADAR AND POSITION FIX FROM PGTW.
3. FORECAST REASONING.
A. THE FORECAST REASONING HAS CHANGED SIGNIFICANTLY SINCE THE
LAST ISSUANCE. THE SYSTEM IS NOW EXPECTED TO TURN TOWARDS THE
SOUTHWEST AND INTERACT WITH TS 07W (LIONROCK).
B. TS 09W IS IN A RELATIVELY COMPLEX STEERING ENVIRONMENT, BUT IS
FORECAST TO CONTINUE ACCELERATING AND START TRACKING MORE TOWARDS
THE SOUTHWEST AS IT BEGINS TO INTERACT WITH TS 07W (LIONROCK).
TYPHOON 08W (KOMPASU) APPEARS TO BE TOO FAR TO EAST TO ASSERT THE
PRIMARY STEERING INFLUENCE, AND THE BAROCLINIC ZONE TO THE NORTHWEST
APPEARS TOO FAR AWAY ALSO. AS THE SYSTEM MOVES TO THE SOUTHWEST IT
WILL CONTINUE TO INTENSIFY SLOWLY IN THE WARM WATERS OF THE TAIWAN
STRAIT, BUT AS IT APPROACHES TS 07W THE OUTFLOW OF THE LATTER WILL
OVERWHELM THE UPPER LEVELS OF TS 09W AND IMPEDE FURTHER
INTENSIFICATION. CONFIDENCE IN THE TRACK IS MODERATE. A VERY LIKELY
ALTERNATE SCENARIO IS THAT TS 09W WILL TURN TO THE SOUTH FASTER THAN
THE MODELS INDICATE AND WILL MAKE LANDFALL IN TAIWAN, OR SKIRT ALONG
THE COAST OF TAIWAN, AND THEN THE MUCH WEAKER REMNANTS WILL BECOME
ABSORBED BY TS 07W. THERE REMAINS THE POSSIBILITY THAT THE SYSTEMS
WILL UNDERGO CAPTURE AND RELEASE AND TS 09W WILL MAKE LANDFALL IN
CHINA NEAR 25.5N AS A DISCRETE SYSTEM. NUMERICAL MODEL GUIDANCE IS
STILL RELATIVELY POOR, BUT THERE IS CLEAR INDICATION THAT IT IS
POINTING TOWARDS BINARY INTERACTION WITH TS 07W. ECMWF, GFDN AND
GFS ALL HAVE THE SYSTEM ON A SIMILAR TRACK TO THIS FORECAST THROUGH
48 HOURS BEFORE BECOMING ERRATIC (PRESUMABLY THEY BECOME ERRATIC
ONCE THE STORM CENTER IS ABSORBED BY TS 07W). NOGAPS CONTINUES DUE
WEST INTO CHINA AND SHOWS NO SIGNS OF INTERACTION AND WBAR, THE
BAROTROPIC MODEL, IS OVER-RESPONDING TO THE BAROCLINIC ZONE AND
TAKING THE SYSTEM DUE NORTH.
NNNN

[senorpepr]

WTPQ20 RJTD 301500
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008)
ANALYSIS
PSTN 301500UTC 25.8N 121.7E FAIR
MOVE WSW 06KT
PRES 996HPA
MXWD 040KT
GUST 060KT
30KT 50NM
FORECAST
24HF 311500UTC 25.7N 121.0E 70NM 70%
MOVE ALMOST STATIONARY
PRES 996HPA
MXWD 040KT
GUST 060KT
45HF 011200UTC 25.0N 121.0E 160NM 70% TROPICAL DEPRESSION =

[supercane]

Latest IR. Nice view of all three systems:


KNES Dvorak:
TXPN23 KNES 301531
SIMWIR
A. 09W (NAMTHEUN)
B. 30/1332Z
C. 25.9N
D. 121.7E
E. THREE/MTSAT
F. T3.0/3.0/D1.5/24HRS
G. IR/EIR/SSMIS
H. REMARKS...CENTER IS SHEARED LESS THAN FROM DG RESULTING IN A DT
OF 2.5. MET = 2.5 AND PT = 3.0. FT BASED ON PT.
I. ADDL POSITIONS
30/1011Z 26.2N 122.6E SSMIS
...KIBLER
=

Microwave shows the center exposed to the west of the convection, indicating westerly shear:

[supercane]

BTW, here's a schematic of binary interaction from the COMET program:

Fig. 10.76. Centroid-relative track of a pair of interacting tropical cyclones illustrating the four stages of storm-storm interactions: (i) Approach (A) and Capture (C), (ii) Mutual Orbit (O), and either (iii) Merger (M) or (iv) Escape (E).

Looks like we're past the Approach and Capture stage and into Mutual Orbit about a centroid. Namtheun will suffer merger.

[supercane]

WTPQ20 RJTD 301800
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008)
ANALYSIS
PSTN 301800UTC 25.6N 121.3E FAIR
MOVE SW 08KT
PRES 994HPA
MXWD 040KT
GUST 060KT
30KT 60NM
FORECAST
24HF 311800UTC 25.3N 120.7E 85NM 70%
MOVE ALMOST STATIONARY
PRES 994HPA
MXWD 040KT
GUST 060KT
48HF 011800UTC 24.6N 120.7E 160NM 70% TROPICAL DEPRESSION =

[supercane]

WTPN33 PGTW 302100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 09W (NAMTHEUN) WARNING NR 003
03 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
301800Z --- NEAR 25.7N 121.5E
MOVEMENT PAST SIX HOURS - 235 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
REPEAT POSIT: 25.7N 121.5E
---
FORECASTS:
12 HRS, VALID AT:
310600Z --- 25.2N 120.6E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 225 DEG/ 04 KTS
---
24 HRS, VALID AT:
311800Z --- 24.6N 119.9E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 215 DEG/ 04 KTS
---
36 HRS, VALID AT:
010600Z --- 23.9N 119.4E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 195 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
011800Z --- 22.9N 119.1E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
302100Z POSITION NEAR 25.6N 121.3E.
TROPICAL STORM (TS) 09W (NAMTHEUN), LOCATED APPROXIMATELY 40 NM
NORTH OF TAIPEI, TAIWAN, HAS TRACKED SOUTHWESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. THE CURRENT POSITION ESTIMATE IS BASED ON A
RECENT PGTW SATELLITE FIX, AN 1825Z AMSU-B MICROWAVE SATELLITE
IMAGE, AND RADAR DATA FROM TAIWAN. THE CURRENT INTENSITY ESTIMATE IS
CONSISTENT WITH A 301800Z SHIP REPORT (SHIP ID A8CG6) OF 40 KNOTS.
TS 09W IS EXPECTED TO TRACK SOUTHWESTWARD DURING THE FORECAST PERIOD
UNDER THE STEERING INFLUENCES OF NORTHEASTERLY MID-LEVEL FLOW
CURRENTLY ANALYZED OVER SOUTHEASTERN CHINA AND DIRECT CYCLONE
INTERACTION WITH TS 07W, AND SHOULD EVENTUALLY MERGE WITH THE
STRONGER TS 07W AROUND TAU 48. EASTERLY VERTICAL WIND SHEAR, WHICH
HAS LEFT THE LLCC OF TS 09W PARTIALLY EXPOSED, WILL PREVENT TS 09W
FROM INTENSIFYING IN THE INTERIM PERIOD. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 301800Z IS 10 FEET. NEXT WARNINGS AT 310300Z, 310900Z,
311500Z AND 312100Z. REFER TO TROPICAL STORM 07W (LIONROCK) WARNINGS
(WTPN31 PGTW) FOR SIX-HOURLY UPDATES. REFER TO TYPHOON 08W (KOMPASU)
WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES.//



737
TCNA20 RJTD 302100 CCB
CCAA 30210 47644 KOMPASU(1007) 10249 11298 122/4 2//// 93112=
LIONROCK(1006) 09206 11174 142/4 2//// 91104=
NAMTHEUN(1008) 11258 11210 132/4 2//// 92709=

[supercane]

Vis with all 3 WP named systems:


DATE/TIME LAT LON CLASSIFICATION STORM
30/2101 UTC 25.9N 120.9E T3.0/3.0 NAMTHEUN
30/1332 UTC 25.9N 121.7E T3.0/3.0 NAMTHEUN

TXPN23 KNES 302126
SIMWIR

A. 09W (NAMTHEUN)
B. 30/2101Z
C. 25.9N
D. 120.9E
E. THREE/MTSAT
F. T3.0/3.0/D1.0/24HRS
G. IR/EIR/SWIR/AMSU
H. REMARKS...DT=3.0 BASED ON SHEAR PATTERN WITH LOW LEVEL CENTER 1/3
DEGREE FROM DEEP CONVECTION. PT=2.0. MET=2.0. FT BASED ON DT.
I. ADDL POSITIONS
30/1825Z 25.5N 121.8E AMSU
...SCHWARTZ



WTPQ20 RJTD 302100
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008)
ANALYSIS
PSTN 302100UTC 25.6N 121.1E FAIR
MOVE WSW 06KT
PRES 994HPA
MXWD 040KT
GUST 060KT
30KT 60NM
FORECAST
24HF 312100UTC 25.3N 120.5E 85NM 70%
MOVE ALMOST STATIONARY
PRES 994HPA
MXWD 040KT
GUST 060KT
45HF 011800UTC 24.6N 120.7E 160NM 70% TROPICAL DEPRESSION =

[supercane]

WTPQ20 RJTD 310000
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008)
ANALYSIS
PSTN 310000UTC 25.6N 120.7E FAIR
MOVE W SLOWLY
PRES 994HPA
MXWD 040KT
GUST 060KT
30KT 60NM
FORECAST
24HF 010000UTC 25.2N 120.5E 85NM 70%
MOVE ALMOST STATIONARY
PRES 994HPA
MXWD 040KT
GUST 060KT
48HF 020000UTC 24.5N 120.8E 160NM 70% TROPICAL DEPRESSION =

[supercane]

WTPN33 PGTW 310300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 09W (NAMTHEUN) WARNING NR 004
03 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
310000Z --- NEAR 25.6N 121.0E
MOVEMENT PAST SIX HOURS - 260 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
REPEAT POSIT: 25.6N 121.0E
---
FORECASTS:
12 HRS, VALID AT:
311200Z --- 25.3N 120.4E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 235 DEG/ 03 KTS
---
24 HRS, VALID AT:
010000Z --- 24.9N 119.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 36 HR POSIT: 220 DEG/ 03 KTS
---
36 HRS, VALID AT:
011200Z --- 24.4N 119.3E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 48 HR POSIT: 205 DEG/ 04 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
020000Z --- 23.6N 118.9E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
310300Z POSITION NEAR 25.5N 120.9E.
TROPICAL STORM (TS) 09W (NAMTHEUN), LOCATED APPROXIMATELY 45 NM
NORTHWEST OF TAIPEI, TAIWAN, HAS TRACKED WESTWARD AT 05 KNOTS OVER
THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 310000Z IS 10
FEET. NEXT WARNINGS AT 310900Z, 311500Z, 312100Z AND 010300Z.
REFER TO TROPICAL STORM 07W (LIONROCK) WARNINGS (WTPN31 PGTW) FOR
SIX-HOURLY UPDATES. REFER TO TYPHOON 08W (KOMPASU) WARNINGS (WTPN32
PGTW) FOR SIX-HOURLY UPDATES.//

[supercane]

WTPQ20 RJTD 310600
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008)
ANALYSIS
PSTN 310600UTC 25.3N 120.2E FAIR
MOVE WSW SLOWLY
PRES 996HPA
MXWD 035KT
GUST 050KT
30KT 50NM
FORECAST
24HF 010600UTC 24.6N 118.5E 85NM 70% TROPICAL DEPRESSION =

[supercane]

WTPN33 PGTW 310900
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 09W (NAMTHEUN) WARNING NR 005
03 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
310600Z --- NEAR 25.3N 120.1E
MOVEMENT PAST SIX HOURS - 255 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 25.3N 120.1E
---
FORECASTS:
12 HRS, VALID AT:
311800Z --- 24.8N 119.3E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 220 DEG/ 03 KTS
---
24 HRS, VALID AT:
010600Z --- 24.3N 118.8E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 225 DEG/ 05 KTS
---
36 HRS, VALID AT:
011800Z --- 23.6N 118.1E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
310900Z POSITION NEAR 25.2N 119.9E.
TROPICAL STORM (TS) 09W (NAMTHEUN), LOCATED APPROXIMATELY
80 NM WEST OF TAIPEI, TAIWAN, HAS TRACKED WEST-SOUTHWESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER
(LLCC). THE INITIAL POSITION IS BASED ON THIS PARTIALLY EXPOSED LLCC
WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS BASED ON PGTW AND
RJTD DVORAK ESTIMATES RANGING FROM 30 TO 35 KNOTS. THE LLCC REMAINS
PARTIALLY EXPOSED DUE TO AN UPPER LEVEL TROUGH TO THE NORTH CAUSING
SUBSIDENCE AND HIGHER VERTICAL WIND SHEAR DUE TO THE OUTFLOW FROM
07W. TS 09W IS TRACKING ALONG THE NORTHEASTERLY MID-LEVEL FLOW
ANALYZED ALONG SOUTHERN CHINA AND UNDER THE INFLUENCE OF DIRECT
CYCLONE INTERACTION WITH TS 07W. TS 09W IS FORECAST TO CONTINUE
TRACKING TOWARD TS 07W AND MERGE BY TAU 36. BECAUSE TS 07W IS BETTER
DEVELOPED AND UPPER LEVEL CONDITIONS ARE MORE CONDUCIVE TO SUSTAINED
DEVELOPMENT, IT IS EXPECTED TO REMAIN THE DOMINANT CIRCULATION AS
THE TWO CYCLONES INTERACT. THE NUMERICAL MODEL TRACKERS ARE IN FAIR
AGREEMENT WITH THE CURRENT TRACK FORECAST, ALTHOUGH SEVERAL OF THE
TRACKERS SEEM TO WEAKEN AND LOSE THE LLCC BY TAU 24. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 310600Z IS 10 FEET. NEXT WARNINGS AT
311500Z, 312100Z, 010300Z AND 010900Z. REFER TO TROPICAL STORM 07W
(LIONROCK) WARNINGS (WTPN31 PGTW) FOR SIX-HOURLY UPDATES. REFER TO
TYPHOON 08W (KOMPASU) WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY
UPDATES.//
NNNN



WTPQ20 RJTD 311200
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1008 NAMTHEUN (1008)
ANALYSIS
PSTN 311200UTC 25.1N 119.9E FAIR
MOVE SW SLOWLY
PRES 998HPA
MXWD 035KT
GUST 050KT
30KT 40NM
FORECAST
24HF 011200UTC 24.6N 118.3E 85NM 70% TROPICAL DEPRESSION =

[supercane]

WTPN33 PGTW 311500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 09W (NAMTHEUN) WARNING NR 006
03 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
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WARNING POSITION:
311200Z --- NEAR 25.2N 119.9E
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 25.2N 119.9E
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FORECASTS:
12 HRS, VALID AT:
010000Z --- 24.8N 119.3E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 230 DEG/ 03 KTS
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24 HRS, VALID AT:
011200Z --- 24.4N 118.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 36 HR POSIT: 230 DEG/ 02 KTS
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36 HRS, VALID AT:
020000Z --- 24.1N 118.4E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
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REMARKS:
311500Z POSITION NEAR 25.1N 119.8E.
TROPICAL STORM (TS) 09W (NAMTHEUN), LOCATED APPROXIMATELY 160 NM
NORTH OF KAOHSIUNG, TAIWAN, HAS TRACKED WEST-SOUTHWESTWARD AT 03
KNOTS OVER THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
311200Z IS 10 FEET. NEXT WARNINGS AT 312100Z, 010300Z, 010900Z AND
011500Z. REFER TO TROPICAL STORM 07W (LIONROCK) WARNINGS (WTPN31
PGTW) FOR SIX-HOURLY UPDATES. REFER TO TYPHOON 08W (KOMPASU)
WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES.//
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WDPN33 PGTW 311500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (NAMTHEUN) WARNING
NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TROPICAL STORM (TS) 09W (NAMTHEUN), LOCATED APPROXIMATELY 160
NM NORTH OF KAOHSIUNG, TAIWAN, HAS TRACKED WEST-SOUTHWESTWARD AT 03
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
SHOWS CENTRAL CONVECTION HAS DEVELOPED OVER THE LOW LEVEL
CIRCULATION CENTER (LLCC) WITHIN THE PAST 6 HOURS AND THE LLCC SEEMS
TO BE QUASI-STATIONARY. THE CURRENT POSITION IS BASED ON A PGTW AND
RJTD SATELLITE FIX AND RADAR DATA FROM TAIWAN WITH POOR CONFIDENCE.
THE CURRENT INTENSITY ESTIMATE OF 35 KNOTS IS BASED ON DVORAK
ESTIMATES FROM PGTW, KNES, AND RJTD RANGING FROM 30 TO 35 KNOTS.
SHIP OBSERVATIONS 15 NM TO THE SOUTHEAST OF THE LLCC INDICATE 25
KNOT WINDS AND 998 MB. TS 09W IS TRACKING UNDER THE INFLUENCE OF
EASTERLY TO NORTHEASTERLY STEERING FLOW ANALYZED OVER SOUTHEASTERN
CHINA AND DIRECT CYCLONE INTERACTION (DCI) WITH TS 07W. AN UPPER
LEVEL TROUGH TO THE NORTH IS CAUSING SUBSIDENCE ON THE NORTHERN
PERIPHERY OF THE LLCC AND INHIBITING DEVELOPMENT.
3. FORECAST REASONING.
A. THE FORECAST PHILOSOPHY HAS NOT CHANGED SIGNIFICANTLY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 09W IS EXPECTED TO TRACK UNDER THE INFLUENCE OF
NORTHEASTERLY LOW TO MID-LEVEL STEERING FLOW OVER SOUTHEASTERN CHINA
AND DCI WITH TS 07W. THIS
MOTION WILL CARRY 09W TOWARD TS 07W AND SHOULD RESULT IN A MERGING
OF THE TWO CIRCULATIONS AROUND TAU 36. BECAUSE TS 07W IS BETTER
DEVELOPED, TS 07W IS EXPECTED TO REMAIN THE DOMINANT CIRCULATION AS
THE TWO CYCLONES INTERACT. AN ALTERNATE SCENARIO IS WHERE TS 09W
DISSIPATES OVER LAND BEFORE THE TWO SYSTEMS ARE ABLE TO MERGE. THE
NUMERICAL MODEL TRACKERS ARE SPREAD AND MODELS ANALYZE TS 09W AS TOO
WEAK TO CONTINUE TO TRACK.//
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