WPAC: NAMTHEUN - Post-Tropical

[1900hurricane]

Up to 5.0 from JTWC.

TPPN12 PGTW 020316

A. TYPHOON 15W (NAMTHEUN)

B. 02/0250Z

C. 26.73N

D. 130.85E

E. THREE/HMWRI8

F. T5.0/5.0/D3.0/24HRS STT: D0.5/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 11A/PBO RAGGED EYE/ANMTN. DG EYE SURR BY LG (NO ADJ
FOR BLK) YIELDS A DT OF 5.0. PT YIELDS A 4.0 WHILE MET YIELDS A
3.5. DBO DT.

I. ADDITIONAL POSITIONS:
01/2206Z 26.00N 130.83E SSMS
01/2232Z 26.08N 130.81E SSMS
02/0055Z 26.37N 130.80E MMHS


MARTINEZ

[euro6208]

Up to Cat 3.

WDPN31 PGTW 020900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (NAMTHEUN) WARNING NR 08//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 15W (NAMTHEUN), LOCATED APPROXIMATELY 359 NM SOUTH OF
SASEBO, JAPAN, HAS TRACKED NORTHWARD AT 08 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND RECENT RADAR
IMAGERY DEPICT A VERY SMALL SYSTEM WITH A 12-NM EYE, AND ALSO
INDICATE SLIGHT TROCHOIDAL MOTION AS THE SYSTEM TRACKS NORTHWARD. A
020607Z NOAA-19 89GHZ IMAGE SHOWS A SYMMETRIC CORE OF DEEP
CONVECTION OF APPROXIMATELY 70NM DIAMETER. BASED ON THE PLETHORA OF
HIGH RESOLUTION IMAGERY, THERE IS EXCELLENT CONFIDENCE IN THE
CURRENT POSITION. ANIMATED WATER VAPOR IMAGERY INDICATES NEAR-RADIAL
OUTFLOW ENHANCED BY THE MIDLATITUDE SHORTWAVE TROUGH POSITIONED TO
THE NORTH. CONSEQUENTLY, TY 15W HAS RAPIDLY INTENSIFIED AND IS
CURRENTLY ASSESSED AT 100 KNOTS BASED ON DVORAK INTENSITY ESTIMATES
OF T5.5 (102 KNOTS) FROM BOTH KNES AND PGTW. A 020630Z SATCON
ESTIMATE OF 98 KNOTS ALSO SUPPORTS THE CURRENT INTENSITY. TY 15W IS
TRACKING NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STEERING RIDGE
POSITIONED TO THE EAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE. THE JTWC TRACK FORECAST IS HIGHLY
CONSISTENT WITH THE PREVIOUS JTWC WARNING.
B. TY 15W IS FORECAST TO CONTINUE TRACKING NORTHWARD THROUGH TAU
36 ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR). AFTER
TAU 36, THE SYSTEM WILL TURN NORTHEASTWARD AS IT ROUNDS THE STR AXIS
AND SHOULD MAKE LANDFALL ALONG THE WESTERN, CENTRAL COAST OF KYUSHU
NEAR TAU 42. ENVIRONMENTAL CONDITIONS WILL REMAIN FAVORABLE THROUGH
TAU 24 WITH SST NEAR 29C, HIGH OCEAN HEAT CONTENT AND VIGOROUS
POLEWARD OUTFLOW. INITIAL INTERACTION WITH LAND WILL BEGIN TO
GRADUALLY WEAKEN THE SYSTEM AFTER TAU 12 AND INCREASING VERTICAL
WIND SHEAR (VWS) WILL PRODUCE A MORE RAPID DECREASE IN INTENSITY AS
THE SYSTEM APPROACHES THE COAST AND MOVES INLAND OVER THE RUGGED
TERRAIN OF KYUSHU. DYNAMIC MODEL TRACKERS ARE IN GOOD AGREEMENT WITH
A 85-NM SPREAD IN SOLUTIONS AT TAU 48, NEAR SASEBO, THEREFORE, THERE
REMAINS SOME UNCERTAINTY IN THE EXACT TRACK AT CPA. AFTER TAU 48, TY
15W WILL TRACK OVER THE EAST SEA AND BEGIN TO ACCELERATE INTO THE
MIDLATITUDE WESTERLY FLOW, WHICH WILL RAPIDLY WEAKEN THE SYSTEM.
C. IN THE EXTENDED TAUS, TY 15W WILL BEGIN EXTRATROPICAL
TRANSITION (ETT) NEAR TAU 72 AND IS EXPECTED TO COMPLETE ETT BY TAU
96 AS IT BECOMES FULLY EMBEDDED WITHIN THE MIDLATITUDE SHORTWAVE
TROUGH. STRONG VWS AND COOLER SST WILL SERVE TO FURTHER WEAKEN THE
SYSTEM. BASED ON THE GOOD MODEL TRACKER AGREEMENT, THERE IS HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN

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WDPN31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (NAMTHEUN) WARNING NR 10//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 15W (NAMTHEUN), LOCATED APPROXIMATELY 281 NM SOUTH OF
SASEBO, JAPAN, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
COMPACT SYSTEM THAT HAS MAINTAINED DEEP CONVECTIVE SIGNATURE AND A
10-NM EYE. THE INITIAL POSITION IS BASED ON THE EYE FEATURE IN THE
EIR LOOP AND ON COMPOSITE RADAR REFLECTIVITY LOOP FROM THE JAPAN
METEOROLOGICAL AGENCY WITH GOOD CONFIDENCE. THE INITIAL INTENSITY OF
100 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF OBJECTIVE AND AGENCY
FIXES RANGING FROM T5.0 TO T5.5. FAVORABLE ENVIRONMENTAL CONDITIONS
WITH SSTS NEAR 29C, HIGH OCEAN HEAT CONTENT, AND STRONG POLEWARD
OUTFLOW ARE BEING OFFSET BY INCREASING VERTICAL WIND SHEAR (VWS). THE
CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY 15W IS FORECAST TO CONTINUE TRACKING NORTHWARD ALONG THE
WESTERN PERIPHERY OF THE STR MAKING LANDFALL ALONG THE WESTERN,
CENTRAL COAST OF KYUSHU SOUTH OF SASEBO NEAR TAU 30. AFTER TAU 36,
THE SYSTEM WILL TURN NORTHEASTWARD AS IT ROUNDS THE STR AXIS, WITH
CLOSEST POINT OF APPROACH TO SASEBO AT APPROXIMATELY 26 NM.
INCREASING VWS THEN LAND INTERACTION WILL GRADUALLY WEAKEN THE
SYSTEM, HOWEVER, IT WILL STILL BE AT TYPHOON INTENSITY AT TAU 36 AS
IT APPROACHES SASEBO. RAPID DECAY WILL COMMENCE ONCE THE SYSTEM GOES
BACK OVER COLDER WATER (LESS THAN 25C)IN THE SEA OF JAPAN, IN
ADDITION TO VERY STRONG VWS (GREATER THAN 40 KNOTS). BY TAU 72, TY
15W WILL BEGIN EXTRA-TROPICAL TRANSITION.
C. IN THE EXTENDED TAUS, TY NAMTHEUN WILL ACCELERATE
NORTHEASTWARD AND DEEPER INTO THE COLD BAROCLINIC ZONE, BECOMING A
COLD-CORE LOW WITH MODERATE GALE-FORCE WINDS BY TAU 96. NUMERIC MODEL
GUIDANCE IS IN TIGHT AGREEMENT WITH NAVGEM ON THE EXTREME LEFT OF THE
PACK IN THE NEAR TERM THEN CROSSING THE ENVELOPE TO THE EXTREME RIGHT
IN THE LONG TERM. THE JTWC TRACK FORECAST HAS BEEN ADJUSTED TO
COMPENSATE THIS ERRATIC VORTEX MOTION. OVERALL, CONFIDENCE IN THE
JTWC FORECAST REMAINS HIGH.//
NNNN

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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 02 SEP 2016 Time : 201000 UTC
Lat : 28:42:41 N Lon : 130:37:40 E


CI# /Pressure/ Vmax
5.1 / 955.6mb/ 92.4kt


Final T# Adj T# Raw T#
4.7 5.3 5.3

Estimated radius of max. wind based on IR :N/A km

Center Temp : -34.4C Cloud Region Temp : -66.5C

Scene Type : EYE

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 51km
- Environmental MSLP : 1005mb

Satellite Name : HIM-8
Satellite Viewing Angle : 35.3 degrees

****************************************************

[euro6208]

Rolling along...

[euro6208]

WDPN31 PGTW 030900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (NAMTHEUN) WARNING NR 12//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 15W (NAMTHEUN), LOCATED APPROXIMATELY 187 NM SOUTH
OF SASEBO, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A SIGNIFICANT WEAKENING IN THE CONVECTIVE STRUCTURE AND THE
DISSIPATION OF THE EYE FEATURE. THE KYUSHU RADAR LOOP AND A 030511Z
GPM 89GHZ MICROWAVE IMAGE SHOW THAT ALL THE DEEP CONVECTION HAS
BEEN FORCED TO THE NORTHERN SIDE OF THE SYSTEM DUE TO INCREASING
VERTICAL WIND SHEAR (VWS). HOWEVER, THE 36GHZ IMAGE FROM THE SAME
GPM PASS SHOWS A COMPACT MICROWAVE EYE STILL EVIDENT AND SUPPORTS
THE CURRENT POSITION WITH HIGH CONFIDENCE. THE INITIAL INTENSITY HAS
BEEN DECREASED TO REFLECT THE CHANGE IN CONVECTIVE STRUCTURE AND IS
SUPPORTED BY DECREASING DVORAK CURRENT INTENSITY ESTIMATES RANGING
FROM T4.5 TO T5.0 (77-90 KNOTS) AND A SATCON INTENSITY ESTIMATE OF
71 KNOTS. THE UPPER LEVEL ENVIRONMENT IS QUICKLY DETERIORATING AS
THE TYPHOON MOVES CLOSER TO THE UPPER LEVEL TROUGH POSITIONED TO THE
NORTHWEST. THE MODERATE TO HIGH (25-30 KNOT) VWS IS NOW OFFSETTING
THE ENHANCED POLEWARD OUTFLOW THAT THE TROUGH IS PROVIDING. THE
CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY NAMTHEUN IS FORECAST TO CONTINUE TRACKING NORTH-
NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE STR AND WEAKEN AS
IT GAINS LATITUDE DUE TO INCREASING VWS. THE WEAKENING RATE COULD
BECOME EXACERBATED DUE TO INCREASED LAND INTERACTION IF THE CYCLONE
TRACKS CLOSER TO THE SOUTHWESTERN COAST OF KYUSHU. JUST BEFORE TAU
36, TY 15W WILL MAKE LANDFALL NEAR TYPHOON INTENSITY ALONG THE
WESTERN COAST OF KYUSHU, JUST SOUTH OF SASEBO. AFTERWARDS THE SYSTEM
WILL ROUND THE STR AXIS AND ACCELERATE TO THE NORTHEAST WITH THE MID-
LATITUDE WESTERLY FLOW. RAPID DECAY WILL BEGIN ONCE THE SYSTEM MOVES
OVER COLD WATER (LESS THAN 25C) IN THE SEA OF JAPAN. CONCURRENTLY,
TY 15W WILL BEGIN TO UNDERGO EXTRA-TROPICAL TRANSITION (ETT) NEAR
TAU 48.
C. IN THE EXTENDED FORECAST, TY NAMTHEUN WILL CONTINUE
ACCELERATING NORTHEASTWARD AND DEEPER INTO THE COLD BAROCLINIC ZONE,
BECOMING A COLD-CORE LOW BY TAU 96. NUMERIC MODEL GUIDANCE REMAINS
IN FAIRLY GOOD AGREEMENT WITH NAVGEM AND EGRR TAKING A WIDER TURN
BEFORE MAKING LANDFALL. THE JTWC TRACK FORECAST IS LAID SLIGHTLY TO
THE EAST OF CONSENSUS TO OFFSET THE LESS LIKELY WIDE TURN PROPOSED
BY NAVGEM AND EGRR. THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK; HOWEVER, ANY EASTWARD WOBBLE IN THE STORM MOTION WILL RESULT
IN A MUCH WEAKER SYSTEM MAKING LANDFALL DUE TO THE AFOREMENTIONED
LAND INTERACTION.//
NNNN