WPAC: SINLAKU - Post-Tropical

[euro6208]

WDPN32 PGTW 010900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (SINLAKU)
WARNING NR 001//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 04W (SINLAKU), LOCATED APPROXIMATELY 174 NM
NORTH OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 15
KNOTS OVER THE PAST SIX HOURS. TS 04W HAS TRANSITIONED FROM A
MONSOON DEPRESSION TO A WARM-CORE TROPICAL CYCLONE. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A PARTIALLY-EXPOSED LOW-
LEVEL CIRCULATION CENTER (LLCC) WITH FORMATIVE BANDING WRAPPING INTO
A BROAD CENTER. HOWEVER, A 010716Z GMI 37GHZ IMAGE INDICATES LOW-
LEVEL BANDING WRAPPING TIGHTLY INTO A DEFINED LLCC. ADDITIONALLY, A
010158Z ASCAT-A IMAGE INDICATED INCREASING GALE-FORCE WINDS OVER THE
NORTHWEST QUADRANT AND SOUTHERN SEMICIRCLE WITH A RADIUS OF MAXIMUM
WINDS (RMW) OF 70-80NM, WHICH, ALONG WITH THE MICROWAVE IMAGE,
PROVIDES SUFFICIENT EVIDENCE THAT THE LLCC HAS CONSOLIDATED AND THAT
THE RMW HAS CONTRACTED. SURFACE OBSERVATIONS FROM BACH LONG VI
(48839), 83NM NNW OF THE CENTER, INDICATE NORTHEASTERLY WINDS AT 23
KNOTS (10-MINUTE AVERAGE) WHILE THE 01/00Z SOUNDING SHOWS 33-45 KNOT
WINDS JUST ABOVE THE SURFACE (500-1800 FEET). BASED ON THE ASCAT
DATA AND UPPER-AIR DATA, THE INITIAL INTENSITY IS ASSESSED AT 35
KNOTS. THE INITIAL POSITION IS BASED ON RECENT MICROWAVE IMAGERY
WITH FAIR CONFIDENCE. TS 04W IS CURRENTLY TRACKING WEST-
NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE LOW- TO MID-
LEVEL SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH.
3. FORECAST REASONING.
A. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE AND SETS THE
FORECAST PHILOSOPHY.
B. TS 04W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD
THROUGH THE FORECAST PERIOD, MAKING LANDFALL OVER VIETNAM NEAR TAU
18. THE SYSTEM IS EXPECTED TO INTENSIFY SLIGHTLY OVER THE WARM
WATERS (29-30C) OF THE GULF OF TONKIN, HOWEVER, PERSISTENT
NORTHEASTERLY VERTICAL WIND SHEAR (20-30 KNOTS) SHOULD LIMIT
INTENSIFICATION TO A PEAK OF 40 KNOTS. AFTER TAU 18, TS 04W WILL
TRACK INLAND AND DISSIPATE OVER MOUNTAINOUS TERRAIN BY TAU 36.
NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT, THEREFORE, THERE IS
MODERATE CONFIDENCE IN THE FORECAST TRACK.//
NNNN

[mrbagyo]

[1900hurricane]

I guess it qualifies as a TC, but man this thing looks rough.

[1900hurricane]

There's a TC in these blobs somewhere.

[NotoSans]

Surface observations suggest a center reformation near the west of Hainan Island between 00Z and 06Z yesterday. ASCAT does show a more well-defined center at 12Z so Sinlaku indeed qualifies as a tropical cyclone, but no gale-force winds detected so the naming is still somehow controversial.

[euro6208]

WDPN32 PGTW 012100 COR
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (SINLAKU) WARNING
NR 003A CORRECTED//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 04W (SINLAKU), LOCATED APPROXIMATELY 138
NM SOUTH-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WESTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS FRAGMENTED DEEP CONVECTIVE BANDING OVER THE WESTERN
SEMICIRCLE WITH A BROAD LOW-LEVEL CIRCULATION CENTER (LLCC). THE
INITIAL INTENSITY IS SET AT 35 KNOTS BASED ON SUBJECTIVE AND
OBJECTIVE DVORAK INTENSITY ESTIMATES RANGING FROM T1.5 TO T2.7 (25
TO 39 KNOTS) AND A 011421Z PARTIAL ASCAT-B PASS WHICH REVEALS A
SMALL SWATH OF 30-34 KT WINDS TO THE SOUTH OF THE LLCC. WIND RADII
HAVE BEEN UPDATED BASED ON RECENT ASCAT DATA. THE ENVIRONMENT IS
MARGINALLY FAVORABLE WITH HIGH (>25 KTS) NORTHEASTERLY VERTICAL WIND
SHEAR (VWS) OFFSETTING THE WARM SEA SURFACE TEMPERATURES AND GOOD
UPPER LEVEL OUTFLOW. TS 04W IS CURRENTLY TRACKING WESTWARD ALONG THE
PERIPHERY OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE IN FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
B. TS 04W IS FORECAST TO TRACK WEST-NORTHWESTWARD THROUGHOUT THE
FORECAST PERIOD, MAKING LANDFALL OVER VIETNAM PRIOR TO TAU 12. AS
THE SYSTEM TRANSITS OVER THE WARM WATERS (29-30 CELSIUS) OF THE GULF
OF TONKIN, TS 04W IS EXPECTED TO SLOWLY WEAKEN DUE TO PERSISTENT
NORTHEASTERLY VERTICAL WIND SHEAR (25-30 KTS). PRIOR TO TAU 12, THE
SYSTEM WILL BEGIN TO INTERACT WITH LAND AND STEADILY WEAKEN. THEN
THE SYSTEM WILL TRACK INLAND AND DISSIPATE OVER MOUNTAINOUS TERRAIN
BY TAU 36. NUMERICAL MODEL GUIDANCE IS IN STRONG AGREEMENT, PLACING
GOOD CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED NEAR THE
MULTI-MODEL CONSENSUS.
4. JUSTIFICATION FOR CORRECTION: CORRECTED INCORRECT STORM NUMBER IN
PARA 3.B.//
NNNN

[doomhaMwx]

TS 2003 (Sinlaku)
Issued at 07:10 UTC, 2 August 2020

<Analysis at 06 UTC, 2 August>
Scale Very large
Intensity -
Center position N19°20' (19.3°)
E105°35' (105.6°)
Direction and speed of movement W 15 km/h (7 kt)
Central pressure 992 hPa
Maximum sustained wind speed 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
≥ 30 kt wind area S 1300 km (700 NM)
N 560 km (300 NM)

<Forecast for 18 UTC, 2 August>
Intensity -
TD
Center position of probability circle N20°05' (20.1°)
E102°50' (102.8°)
Direction and speed of movement WNW 25 km/h (14 kt)
Central pressure 996 hPa
Radius of probability circle 85 km (45 NM)

<Forecast for 06 UTC, 3 August>
Intensity -
TD
Center position of probability circle N20°10' (20.2°)
E100°35' (100.6°)
Direction and speed of movement W 20 km/h (10 kt)
Central pressure 998 hPa
Radius of probability circle 120 km (65 NM)

04W SINLAKU 200802 0600 19.7N 105.8E WPAC 35 994

[doomhaMwx]

Undoubtedly a TS at landfall.

[euro6208]

WTPN32 PGTW 020900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FINAL WARNING//
RMKS/
1. TROPICAL STORM 04W (SINLAKU) WARNING NR 005
02 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
020600Z --- NEAR 19.7N 105.8E
MOVEMENT PAST SIX HOURS - 295 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND SYNOPTIC DATA
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.7N 105.8E
---
FORECASTS:
12 HRS, VALID AT:
021800Z --- 20.1N 103.9E
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: 280 DEG/ 10 KTS
---
24 HRS, VALID AT:
030600Z --- 20.5N 101.9E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
020900Z POSITION NEAR 19.8N 105.3E.
02AUG20. TROPICAL STORM (TS) 04W (SINLAKU), LOCATED APPROXIMATELY 78
NM SOUTH OF HANOI, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY INDICATES THAT THE SYSTEM HAS MADE LANDFALL ALONG THE COAST
OF VIETNAM AND IS TRACKING INLAND WITH A PARTIALLY-EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC) AND FLARING DEEP CONVECTION. A 020625Z
AMSR2 89GHZ COMPOSITE IMAGE SUPPORTS THE INITIAL POSITION WITH GOOD
CONFIDENCE AND ALSO SHOWS SHALLOW BANDING WRAPPING INTO THE LLCC
WITH WEAK, FRAGMENTED BANDS OVER THE SOUTHWEST AND NORTHEAST
QUADRANTS. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON A
020252Z ASCAT-B IMAGE SHOWING 30-35 KNOT WINDS OVER THE EASTERN
SEMICIRCLE. TS 04W IS FORECAST TO CONTINUE TRACKING WEST-
NORTHWESTWARD THROUGH THE FORECAST PERIOD AND WILL DISSIPATE BY TAU
24. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT, THEREFORE, THERE
IS MODERATE CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS
POSITIONED NEAR THE MULTI-MODEL CONSENSUS. 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. REFER TO
TROPICAL STORM 03W (HAGUPIT) WARNINGS (WTPN31 PGTW) FOR SIX-HOURLY
UPDATES.//
NNNN