WPAC: VAMCO - Post-Tropical

[jaguarjace]

95W INVEST 150910 1800 13.3N 117.6E WPAC 15 1010

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.9N
120.5E IS NOW LOCATED NEAR 17.1N 112.5E, APPROXIMATELY 320 NM SOUTH-
SOUTHWEST OF HONG KONG. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS AN EXPOSED BUT DEFINED LOW-LEVEL CIRCULATION CENTER
(LLCC) EMBEDDED WITHIN THE MONSOON TROUGH. MSI ALSO SHOWS A LARGE
AREA OF PERSISTENT DEEP CONVECTION DISPLACED WELL TO THE SOUTH,
HOWEVER, THIS AREA IS ASSOCIATED WITH THE CONVERGENT WESTERLY FLOW.
THIS IS CLEARLY EVIDENT IN AN 110228Z ASCAT IMAGE, WHICH SHOWS A
WEAK CIRCULATION WITH 10 TO 15 KNOT WINDS AND 20 TO 25 KNOT WINDS
ASSOCIATED WITH THE WESTERLY WIND BURST. UPPER-LEVEL ANALYSIS
INDICATES A MARGINAL ENVIRONMENT WITH MODERATE EASTERLY VERTICAL
WIND SHEAR. NUMERICAL GUIDANCE CALLS FOR THIS AREA TO GRADUALLY
CONSOLIDATE OVER THE NEXT 4 DAYS. MAXIMUM SUSTAINED SURFACE WINDS
ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR THE DEVELOPMENT OF
A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

[1900hurricane]

Guidance seems to be generally latching onto development, although the depictions in the model fields are of a pretty broad and sprawling area of low pressure. Combined with the limited time before it comes ashore Vietnam, the intensity ceiling might be fairly low.

[euro6208]

JMA and NAVGEM at least brings onshore Vietnam a strong LPA/weak TS.

CMC is stronger, 990 mb, as it makes landfall.

EURO is now weaker, only a strong LPA or TD.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 17.1N
112.5E, IS NOW LOCATED NEAR 15.1N 114.1E, APPROXIMATELY 400 NM WEST
OF MANILA, PHILIPPINES. ANIMATED MSI DEPICTS A VERY BROAD AREA OF
TURNING EMBEDDED WITHIN THE MONSOON TROUGH. MSI ALSO SHOWS A LARGE
AREA OF PERSISTENT DEEP CONVECTION DISPLACED WELL TO THE SOUTHWEST
WHICH IS CLEARLY EVIDENT IN AN 120121Z GPM IMAGE. UPPER-LEVEL
ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH 05 TO 10 KNOTS OF VWS
AND GOOD EQUATORWARD OUTFLOW. NUMERICAL GUIDANCE CALLS FOR THIS AREA
TO GRADUALLY CONSOLIDATE OVER THE NEXT 4 DAYS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 15.1N
114.1E, IS NOW LOCATED NEAR 15.5N 112.9E, APPROXIMATELY 310 NM EAST
OF HUE, VIETNAM. ANIMATED MSI DEPICTS A VERY BROAD AREA OF TURNING
WITH INCREASED CONVECTION TO THE NORTHWEST OF AN ELONGATED LLCC. A
130231Z METOP-A ASCAT IMAGE SHOWS PERSISTENT 10 TO 15 KNOTS WINDS
WITH SOME 20 KNOTS WINDS LOCATED IN THE DEEPEST CONVECTION ON THE
NORTHERN PERIPHERY. UPPER-LEVEL ANALYSIS INDICATES A GOOD
ENVIRONMENT WITH 05 TO 10 KNOTS OF VWS AND GOOD EQUATORWARD OUTFLOW.
MODEL GUIDANCE HAS DEVELOPMENT OF THE SYSTEM OUTSIDE OF 36-48
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.

[talkon]

TXPQ23 KNES 130929
TCSWNP

A. TROPICAL DISTURBANCE (95W)

B. 13/0832Z

C. 15.8N

D. 111.5E

E. THREE/MTSAT

F. T2.0/2.0/D1.0/06HRS

G. IR/EIR/VIS/SSMI

H. REMARKS...THE 0725Z SSMI PASS SHOWS SIGNIFICANTLY MORE CURVED
CONVECTIVE BANDING ABOUT THE LLCC THAN THE 0230Z ASMU. SYSTEM IS
DEVELOPING/CONSOLIDATING RAPIDLY. THE 06HR AVERAGE DT IS 2.2. THE CURRENT
DT OF 3.0 IS BASED ON 0.75 BANDING. MET IS 2.0 AND PT IS 2.5. FT IS
BASED ON RAPID INTENSIFICATION.

I. ADDL POSITIONS

13/0725Z 15.8N 111.5E SSMI


...RAMIREZ

[1900hurricane]

Just as the title now says, it looks like we have 19W.

[1900hurricane]

Both JMA and JTWC have 19W briefly becoming a weak tropical storm before coming ashore in about 24 hours. This one won't take long to track.

[cycloneye]

[1900hurricane]

1434Z ASCAT pass had some 35 kt barbs. I'd have a 35 kt tropical storm at 18Z.



*EDIT: to fix image

[Extratropical94]

1434Z ASCAT pass had some 35 kt barbs. I'd have a 35 kt tropical storm at 18Z.

http://www.nrlmry.navy.mil/tcdat/tc15/W ... 3_1200.jpg

19W NINETEEN 150913 1800 14.9N 111.2E WPAC 35 996

Best track is up to TS strength, so JTWC will have TS 19W shortly. Let's see if JMA also decides to upgrade and name it.

[1900hurricane]

JMA has upgraded 19W to Tropical Storm Vamco.

TS 1519 (VAMCO)
Issued at 18:55 UTC, 13 September 2015

<Analyses at 13/18 UTC>
Scale -
Intensity -
Center position N15°40'(15.7°)
E110°50'(110.8°)
Direction and speed of movement W 15km/h(7kt)
Central pressure 1000hPa
Maximum wind speed near the center 18m/s(35kt)
Maximum wind gust speed 25m/s(50kt)
Area of 30kt winds or more NW330km(180NM)
SE280km(150NM)

<Forecast for 14/06 UTC>
Intensity -
Center position of probability circle N15°40'(15.7°)
E109°20'(109.3°)
Direction and speed of movement W 15km/h(7kt)
Central pressure 996hPa
Maximum wind speed near the center 20m/s(40kt)
Maximum wind gust speed 30m/s(60kt)
Radius of probability circle 90km(50NM)

<Forecast for 14/18 UTC>
Intensity -
Center position of probability circle N15°30'(15.5°)
E108°00'(108.0°)
Direction and speed of movement W 10km/h(6kt)
Central pressure 996hPa
Maximum wind speed near the center 20m/s(40kt)
Maximum wind gust speed 30m/s(60kt)
Radius of probability circle 130km(70NM)

<Forecast for 15/18 UTC>
Intensity -
Center position of probability circle N15°00'(15.0°)
E106°10'(106.2°)
Direction and speed of movement WSW Slowly
Central pressure 1000hPa
Maximum sustained wind speed 18m/s(35kt)
Maximum wind gust speed 25m/s(50kt)
Radius of probability circle 300km(160NM)

<Forecast for 16/18 UTC>
Intensity -
TD
Center position of probability circle N14°30'(14.5°)
E104°35'(104.6°)
Direction and speed of movement WSW Slowly
Central pressure 1002hPa
Radius of probability circle 410km(220NM)

[euro6208]

WDPN31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (VAMCO) WARNING NR
02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 19W (VAMCO), LOCATED APPROXIMATELY 180 NM
EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-SOUTHWESTWARD
AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS DEEP CONVECTIVE CURVED BANDING WRAPPING
AROUND THE WESTERN PERIPHERY OF THE LOW LEVEL CIRCULATION CENTER
(LLCC). A 131839Z AMSU-B MICROWAVE IMAGE SHOWS A WELL DEFINED LLCC
WITH DEEP CURVED BANDING AND THE BULK OF THE CONVECTION ALONG THE
WESTERN PERIPHERY. A 131434Z ASCAT PARTIAL PASS SHOWS 35 KNOT WINDS
ALONG THE WESTERN PERIPHERY WHICH SUPPORTS THE INITIAL INTENSITY.
THE CURRENT POSITION IS BASED ON THE AFOREMENTIONED MICROWAVE IMAGE
AND A PGTW SATELLITE FIX WITH GOOD CONFIDENCE. ENVIRONMENTAL
ANALYSIS SHOWS THE SYSTEM HAS EXCELLENT EQUATORWARD OUTFLOW, LOW (10-
15 KNOT) VERTICAL WIND SHEAR, AND SEA SURFACE TEMPERATURES ABOVE 30
CELSIUS. TS 19W IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY
OF A DEEP-LAYERED SUB-TROPICAL RIDGE (STR) ANCHORED TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS VAMCO WILL CONTINUE TO TRACK WESTWARD UNDER THE INFLUENCE
OF THE STEERING STR THROUGHOUT THE FORECAST PERIOD. THE SYSTEM WILL
INTENSIFY DUE TO FAVORABLE ENVIRONMENTAL CONDITIONS PRIOR TO MAKING
LANDFALL OVER CENTRAL VIETNAM IN 18 HOURS. AFTERWARDS, TS 19W WILL
BEGIN TO RAPIDLY WEAKEN DUE TO LAND INTERACTION AS IT TRACKS INLAND.
THE SYSTEM IS FORECAST TO FULLY DISSIPATE BY TAU 48 OR POSSIBLY
SOONER. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD OVERALL AGREEMENT
LENDING TO HIGH CONFIDENCE IN THE JTWC FORECAST.//
NNNN

[euro6208]

WDPN31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (VAMCO) WARNING NR
04//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 19W (VAMCO), LOCATED APPROXIMATELY 86 NM EAST-
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT
06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MSI SHOWS A PARTIALLY
EXPOSED LLCC WITH THE DEEP CONVECTION OVER VIETNAM AND ON THE
NORTHERN SIDE OF THE LLCC. THE POSITION IS LAID WITH GOOD CONFIDENCE
BASED ON THE EXPOSED LLCC. THE INTENSITY HAS BEEN MAINTAINED AT 35
KNOTS BASED ON DVORAK INTENSITY ESTIMATES FROM RJTD. UPPER LEVEL
ANALYSIS CONTINUES TO INDICATE 20 TO 30 KNOTS OF NORTHEASTERLY VWS
PUSHING THE DEEP CONVECTION AHEAD OF THE LLCC AS WELL AS GOOD
EQUATORWARD OUTFLOW. TS 19W IS TRACKING ALONG THE SOUTHERN PERIPHERY
OF A DEEP-LAYERED STR TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS VAMCO WILL CONTINUE TO TRACK GENERALLY WESTWARD UNDER THE
INFLUENCE OF THE STEERING STR THROUGH THE END OF THE FORECAST
PERIOD. WHILE SOME SLIGHT INTENSIFICATION IS POSSIBLE, IT IS
UNLIKELY TO OCCUR PRIOR TO LANDFALL IN CENTRAL VIETNAM. AS THE
SYSTEM CONTINUES TO INTERACT WITH THE TERRAIN OF SOUTHERN LAOS FROM
TAU 12 THROUGH TAU 36, EXPECT COMPLETE DISSIPATION OF THE SYSTEM.
MODEL GUIDANCE IS IN VERY TIGHT AGREEMENT LEADING TO HIGH CONFIDENCE
IN THE JTWC FORECAST TRACK, WHICH IS LAID SLIGHTLY NORTH OF THE
MULTI-MODEL CONSENSUS.//
NNNN

[euro6208]

Burst of convection near the center...

[1900hurricane]

It fired convection over the center just in time to move inland. Looks to be landfalling right now.

[talkon]

Is this strengthening inland? I think it looks better now than at landfall.

[euro6208]

WTPN31 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 19W (VAMCO) WARNING NR 005
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
141200Z --- NEAR 15.6N 108.9E
MOVEMENT PAST SIX HOURS - 275 DEGREES AT 08 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: 15.6N 108.9E
---
FORECASTS:
12 HRS, VALID AT:
150000Z --- 15.3N 106.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 24 HR POSIT: 250 DEG/ 08 KTS
---
24 HRS, VALID AT:
151200Z --- 14.7N 105.2E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
141500Z POSITION NEAR 15.5N 108.3E.
TROPICAL STORM (TS) 19W (VAMCO), LOCATED APPROXIMATELY 42 NM
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 08 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED IR IMAGERY DEPICTS THE
MAJORITY OF THE CONVECTION OVER CENTRAL VIETNAM AND NORTH OF THE
SYSTEM. THE POSITION IS LAID WITH MODERATE CONFIDENCE AS THE LLCC
APPEARS TO BE WITHIN 10NM OF THE VIETNAM COASTLINE. THE INTENSITY
HAS BEEN MAINTAINED AT 35 KNOTS DUE TO DVORAK INTENSITY ESTIMATES
AND LIMITED COASTAL OBSERVATIONS. OVER THE NEXT 24 HOURS, TS VAMCO
WILL TRACK THROUGH THE RUGGED TERRAIN OF VIETNAM AND LAOS AND
COMPLETELY DISSIPATE. MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT
LEADING TO HIGH CONFIDENCE IN THE FORECAST TRACK. THIS IS THE FINAL
WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI.
THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 141200Z IS 12 FEET.//
NNNN

[1900hurricane]

Vamco has apparently caused some flooding issues across portions of Southeast Asia. Not too surprising considering its slow motion and enhancement from the monsoon, but tragic nonetheless.

Post from WPac Wx on the subject