WPAC: MERANTI - Post-Tropical

[1900hurricane]

Trend is shifting more to the west... JMA's forecast track is taking Meranti to Luzon Straight with a bend at the end of the track. STR's been pretty stable in its location for the past few days stretching all the way to Luzon but an approaching trough from Southeastern China should erode the steering ridge leading to a more poleward motion - timing is essential. I'll bet on a Southern Taiwan Landfall

Southern Taiwan is what I'm thinking right now too. At the very least, I think Meranti is more likely to miss Taiwan to the south than to the north.

[dexterlabio]

The active phase of MJO is expected to arrive in this basin last week of September or first week of October. Meranti and a few others brewing in WPAC right now may only be the start..

[1900hurricane]

Hello ASCAT!



IR at the time:

[mrbagyo]

Now on target

[cycloneye]

 https://twitter.com/Adriansweather/status/774660532376862720

[Yellow Evan]

Code: Select all

   WP, 16, 2016091018,   , BEST,   0, 158N, 1364E,  45,  997, TS,  34, NEQ,   70,   70,   60,   60, 1006,  160,  40,   0,   0,   W,   0,    ,   0,   0,    MERANTI, M,

[Yellow Evan]

Honestly with a CDO pattern this is T4.5-T5.0. If not, likely T3.5 ish.

[Yellow Evan]

Code: Select all

10/1430 UTC   15.4N    136.9E       T3.0/3.0         MERANTI -- West Pacific

TPPN11 PGTW 101803

A. TROPICAL STORM 16W (MERANTI)

B. 10/1800Z

C. 16.13N

D. 136.51E

E. FIVE/HMWRI8

F. T3.5/3.5/D1.5/24HRS STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 38A/PBO SBC/ANMTN. .90 WRAP YIELDS A DT OF 3.5. PT
AND MET AGREE. DBO DT.

I. ADDITIONAL POSITIONS:
10/1240Z 15.53N 137.38E MMHS


MARTINEZ

[euro6208]

EURO more left. It keeps the core much longer over water....




GFS 919mb and into Taiwan...

[euro6208]

HWRF agrees with GFS...Taiwan...

[euro6208]

WDPN31 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (MERANTI)
WARNING NR 09//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 16W (MERANTI), LOCATED APPROXIMATELY 391 NM
NORTH-NORTHWEST OF YAP, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS
A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH IMPROVING
CONVECTIVE BANDING AND A PERSISTENT CENTRAL DENSE OVERCAST FEATURE.
HOWEVER, CONVERGENT FLOW OVER THE NORTHWEST QUADRANT OF THE SYSTEM
CONTINUES TO IMPEDE DEVELOPMENT AS REVEALED IN A 101655Z ATMS IMAGE,
WHICH SHOWS AN EXPOSED LLCC ON THE WESTERN EDGE OF THE DEEP
CONVECTIVE SHIELD. OVERALL, THOUGH, OUTFLOW IS GOOD WITH WARM SST
AND HIGH OCEAN HEAT CONTENT VALUES. THE CURRENT INTENSITY IS
ASSESSED AT 50 KNOTS BASED ON AN AVERAGE OF DVORAK INTENSITY
ESTIMATES RANGING FROM 45 TO 55 KNOTS, CONSISTENT WITH A RECENT
SATCON ESTIMATE OF 47 KNOTS. TS 16W IS TRACKING WESTWARD UNDER THE
STEERING INFLUENCE OF THE SUBTROPICAL RIDGE ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 72, TS 16W WILL TRACK GENERALLY WEST-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE DEEP-LAYERED SUBTROPICAL RIDGE
(STR). THIS STR IS DEPICTED IN THE RECENT 500MB ANALYSES AS A BROAD,
STRONG STR EXTENDING WESTWARD, FROM A HIGH CENTERED NEAR 32N 158E,
TO HAINAN ISLAND, CHINA WITH A MAJOR SHORTWAVE TROUGH DIGGING INTO
EASTERN AND SOUTHEASTERN CHINA. DYNAMIC MODEL GUIDANCE IS IN FAIR
AGREEMENT THROUGH TAU 72 WITH A 200-NM SPREAD IN SOLUTIONS AT TAU
72, THEREFORE, SIGNIFICANT UNCERTAINTY REMAINS. AS POLEWARD OUTFLOW
IMPROVES, TS 16W IS FORECAST TO CONTINUE INTENSIFYING AT A NEAR
CLIMATOLOGICAL RATE TO A PEAK INTENSITY OF 115 KNOTS BY TAU 48 TO 72.
C. AFTER TAU 72, DYNAMIC MODEL GUIDANCE DIVERGES WITH TWO
DISTINCT CLUSTERS. THE FIRST CLUSTER OF MODELS (UKMET, GFDN, COAMPS-
TC, JGSM, JENS AND NAVGEM) DEPICTS A MORE WESTWARD TRACK INTO
SOUTHEAST CHINA. ANALYSIS OF AVAILABLE MODEL FIELDS INDICATES THAT
THESE MODELS ARE DRIVING THE SYSTEM INTO THE MAJOR TROUGH RATHER
THAN TRACKING IT POLEWARD TOWARD THE WEAKNESS IN THE STR AS THE
SECOND CLUSTER DEPICTS. THIS SCENARIO IS CURRENTLY ASSESSED AS
UNLIKELY / ERRONEOUS, THEREFORE, THE JTWC FORECAST FAVORS THE RE-
CURVE SCENARIO AS DEPICTED BY THE SECOND CLUSTER OF MODELS (GFS, GFS
ENSEMBLE, ECMWF, ECMWF ENSEMBLE AND HWRF). TS 16W IS FORECAST TO
MAKE LANDFALL ALONG THE EASTERN COAST OF TAIWAN BY TAU 84 AND WILL
WEAKEN RAPIDLY AS IT CROSSES THE MOUNTAINOUS TERRAIN. THE SYSTEM
WILL WEAKEN FURTHER AS IT TRACKS OVER EASTERN CHINA. DUE TO THE
LARGE MODEL SPREAD BEYOND 72 HOURS, THERE IS LOW CONFIDENCE IN THE
JTWC TRACK FORECAST.//
NNNN

[dexterlabio]

Something still does not look right with this system, perhaps the banding on its western side? The track and timing reminds me a bit of Usagi.

[shah83]

It looks really good to me!

[cycloneye]

JMA upgrades to Severe Tropical Storm:

STS 1614 (Meranti)
Issued at 00:50 UTC, 11 September 2016


<Analysis at 00 UTC, 11 September>
Scale -
Intensity -
Center position N16°25' (16.4°)
E135°50' (135.8°)
Direction and speed of movement WNW 20 km/h (12 kt)
Central pressure 980 hPa
Maximum wind speed near center 30 m/s (55 kt)
Maximum wind gust speed 40 m/s (80 kt)
≥ 50 kt wind area ALL 90 km (50 NM)
≥ 30 kt wind area ALL 220 km (120 NM)

<Forecast for 00 UTC, 12 September>
Intensity Strong
Center position of probability circle N17°50' (17.8°)
E130°20' (130.3°)
Direction and speed of movement WNW 25 km/h (13 kt)
Central pressure 965 hPa
Maximum wind speed near center 35 m/s (70 kt)
Maximum wind gust speed 50 m/s (100 kt)
Radius of probability circle 110 km (60 NM)
Storm warning area ALL 220 km (120 NM)

<Forecast for 00 UTC, 13 September>
Intensity Very strong
Center position of probability circle N19°00' (19.0°)
E125°05' (125.1°)
Direction and speed of movement WNW 25 km/h (13 kt)
Central pressure 945 hPa
Maximum wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of probability circle 200 km (110 NM)
Storm warning area ALL 350 km (190 NM)

<Forecast for 00 UTC, 14 September>
Intensity Very strong
Center position of probability circle N20°40' (20.7°)
E120°50' (120.8°)
Direction and speed of movement WNW 20 km/h (11 kt)
Central pressure 930 hPa
Maximum wind speed near center 45 m/s (90 kt)
Maximum wind gust speed 65 m/s (130 kt)
Radius of probability circle 260 km (140 NM)
Storm warning area ALL 440 km (240 NM)

[1900hurricane]

Structure is looking pretty solid.

[euro6208]

Up to 60 knots.

16W MERANTI 160911 0000 16.3N 135.7E WPAC 60 989

[euro6208]

WDPN31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (MERANTI)
WARNING NR 10//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 16W (MERANTI), LOCATED APPROXIMATELY 431 NM
NORTH-NORTHWEST OF YAP, HAS TRACKED WEST-NORTHWESTWARD AT 14 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A RAPIDLY-CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH TIGHTLY-CURVED BANDING WRAPPING INTO A WELL-DEFINED CENTER. A
102224Z SSMIS IMAGE DEPICTS DEEP CONVECTIVE BANDING WRAPPING INTO
THE WELL-DEFINED CENTER, WHICH SUPPORTS THE CURRENT POSITION WITH
HIGH CONFIDENCE. OVERALL, OUTFLOW HAS IMPROVED, ESPECIALLY OVER THE
NORTHWEST QUADRANT, WITH WARM SST AND HIGH OCEAN HEAT CONTENT
VALUES. THE CURRENT INTENSITY IS ASSESSED AT 60 KNOTS BASED ON AN
AVERAGE OF DVORAK INTENSITY ESTIMATES RANGING FROM 55 TO 65 KNOTS.
TS 16W IS TRACKING WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE
OF THE SUBTROPICAL RIDGE ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 72, TS 16W WILL TRACK GENERALLY WEST-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE DEEP-LAYERED SUBTROPICAL RIDGE
(STR). THIS STR IS DEPICTED IN THE RECENT 500MB ANALYSES AS A BROAD,
STRONG STR EXTENDING WESTWARD, FROM A HIGH CENTERED NEAR 32N 158E,
TO HAINAN ISLAND, CHINA WITH A MAJOR SHORTWAVE TROUGH DIGGING INTO
EASTERN AND SOUTHEASTERN CHINA. DYNAMIC MODEL GUIDANCE IS IN FAIR
AGREEMENT THROUGH TAU 72 WITH A 210-NM SPREAD IN SOLUTIONS AT TAU
72, THEREFORE, SIGNIFICANT UNCERTAINTY REMAINS. TS 16W IS FORECAST
TO CONTINUE INTENSIFYING AT A NEAR CLIMATOLOGICAL RATE TO A PEAK
INTENSITY OF 120 KNOTS BY TAU 48.
C. AFTER TAU 72, DYNAMIC MODEL GUIDANCE DIVERGES WITH TWO
DISTINCT CLUSTERS. THE FIRST CLUSTER OF MODELS (UKMET, GFDN, COAMPS-
TC, JGSM, NAVGEM) DEPICTS A MORE WESTWARD TRACK INTO SOUTHEAST
CHINA. ANALYSIS OF AVAILABLE MODEL FIELDS INDICATES THAT
THESE MODELS ARE DRIVING THE SYSTEM INTO THE MAJOR TROUGH RATHER
THAN TRACKING IT POLEWARD TOWARD THE WEAKNESS IN THE STR AS THE
SECOND CLUSTER DEPICTS. THIS SCENARIO IS CURRENTLY ASSESSED AS
UNLIKELY / ERRONEOUS, THEREFORE, THE JTWC FORECAST FAVORS THE RE-
CURVE SCENARIO AS DEPICTED BY THE SECOND CLUSTER OF MODELS (GFS, GFS
ENSEMBLE, ECMWF, ECMWF ENSEMBLE AND HWRF, JGSM ENSEMBLE). TS 16W IS
FORECAST TO MAKE LANDFALL ALONG THE EASTERN COAST OF TAIWAN BY TAU
78 AND WILL WEAKEN RAPIDLY AS IT CROSSES THE MOUNTAINOUS TERRAIN.
THE SYSTEM WILL WEAKEN FURTHER AS IT TRACKS OVER EASTERN CHINA. DUE
TO THE LARGE MODEL SPREAD BEYOND 72 HOURS, THERE IS LOW CONFIDENCE
IN THE JTWC TRACK FORECAST.//
NNNN

[euro6208]

TPPN11 PGTW 110311

A. TROPICAL STORM 16W (MERANTI)

B. 11/0300Z

C. 16.65N

D. 135.00E

E. FIVE/HMWRI8

F. T4.0/4.0/D1.5/24HRS STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 40A/PBO SBC/ANMTN. 1.05 WRAP YIELDS A DT OF 4.0. PT
AND MET AGREE. DBO DT.

I. ADDITIONAL POSITIONS:
10/2150Z 16.22N 136.27E SSMS
10/2224Z 16.25N 136.18E SSMS


MARTINEZ

[euro6208]

TXPQ25 KNES 110254
TCSWNP

A. 16W (MERANTI)

B. 11/0230Z

C. 16.6N

D. 135.2E

E. THREE/HIMAWARI-8

F. T4.0/4.0/D1.5/24HRS

G. IR/EIR/VIS/WINDSAT/SSMIS

H. REMARKS...DT=4.0 BASED ON CDO THAT AVERAGES 1.75
DG. PT=4.0. MET=4.0. FT IS BASED ON DT. NASCENT EYE APPARENT IN VISIBLE
IMAGERY.

I. ADDL POSITIONS

10/2054Z 16.1N 136.5E WINDSAT
10/2224Z 16.0N 136.1E SSMIS


...SCHWARTZ

[euro6208]

TPPN11 PGTW 110619

A. TROPICAL STORM 16W (MERANTI)

B. 11/0550Z

C. 16.96N

D. 134.35E

E. FIVE/GOES15

F. T4.5/4.5/D2.0/24HRS STT: D0.5/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: /PBO . CNVCTN WRAP OF 1.10 ON LOG10 SPIRAL YIELDS A CF
OF 4.0. ADDED .5 FOR WHITE TO YIELD A DT OF 4.5. PT AGREES. MET
YIELDS A 4.0. DBO DT.

I. ADDITIONAL POSITIONS: NONE

DREW