WPAC: SINLAKU - Post-Tropical

[Nancy Smar]

91W.INVEST.15kts.1006mb.13.2N.125.8E

[dexterlabio]

So here it is, the potential July buzzer-beater that the models are hyping. Although if this indeed develops into a monsoon gyre, getting a named TS would be difficult, or at least a tropical system with a discernable CoC.

[Nancy Smar]

LOW PRESSURE AREA 1006 HPA NEAR 13N 127E WNW 10 KT.

[euro6208]

91W INVEST
As of 18:00 UTC Jul 28, 2020:

Location: 14.4°N 125.1°E
Maximum Winds: 15 kt
Minimum Central Pressure: 1005 mb

[euro6208]

AN AREA OF CONVECTION (INVEST 91W) HAS PERSISTED NEAR
14.5N 123.6E, APPROXIMATELY 155 NM EAST OF MANILA, PHILIPPINES.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 290055Z METOP-B 89
GHZ MICROWAVE IMAGE DEPICT A BROAD LOW LEVEL CIRCULATION WITH
DISORGANIZED FLARING CONVECTION. ENVIRONMENTAL ANALYSIS REVEALS GOOD
POLEWARD OUTFLOW ALOFT, LOW VERTICAL WIND SHEAR, AND WARM (29-31C)
SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GENERAL AGREEMENT
THAT INVEST 91W WILL CONTINUE TO TRACK WESTWARD ACROSS LUZON AND
INTO THE SCS WHERE IT WILL GRADUALLY INTENSIFY. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS LOW.

[doomhaMwx]

91W is w/in a broader monsoon gyre flow encircling the Philippines.

[euro6208]

Agreement with EURO and GFS.

[doomhaMwx]

This sure is one broad system which appears to be composed of multiple distinct areas of vorticity or smaller disturbances seemingly rotating around each other.

[Nancy Smar]

TD
Issued at 01:15 UTC, 31 July 2020

<Analysis at 00 UTC, 31 July>
Scale -
Intensity -
TD
Center position N16°55' (16.9°)
E113°05' (113.1°)
Direction and speed of movement WNW 20 km/h (10 kt)
Central pressure 1000 hPa
Maximum sustained wind speed 15 m/s (30 kt)
Maximum wind gust speed 23 m/s (45 kt)

<Forecast for 12 UTC, 31 July>
Intensity -
TD
Center position of probability circle N17°25' (17.4°)
E112°00' (112.0°)
Direction and speed of movement WNW 10 km/h (6 kt)
Central pressure 996 hPa
Maximum sustained wind speed 15 m/s (30 kt)
Maximum wind gust speed 23 m/s (45 kt)
Radius of probability circle 110 km (60 NM)

<Forecast for 00 UTC, 1 August>
Intensity -
Center position of probability circle N17°55' (17.9°)
E110°40' (110.7°)
Direction and speed of movement WNW 15 km/h (7 kt)
Central pressure 994 hPa
Maximum sustained wind speed 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
Radius of probability circle 150 km (80 NM)

[euro6208]

THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 15.8N 118.7E IS NOW LOCATED NEAR 16.8N 115.0E, APPROXIMATELY
370 NM NORTHWEST OF MANILA, PHILIPPINES. THE SYSTEM IS BEING
ASSESSED AS A MONSOON DEPRESSION. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY AND A 301322Z METOP-B 89 GHZ MICROWAVE IMAGE DEPICT A VERY
BROAD (>150 NM) LOW LEVEL CIRCULATION (LLC). ASCAT-B DATA FROM THE
301322Z PASS FURTHER DEPICTS WEAK (10-15 KTS) WINDS AROUND THE
CENTER OF THE ELONGATED CIRCULATION WHICH COVERS MOST OF THE SOUTH
CHINA SEA (SCS). THE CONVECTION IS SHALLOW, DISORGANIZED AND
FLARING. ENVIRONMENTAL ANALYSIS REVEALS GOOD POLEWARD OUTFLOW ALOFT,
LOW (<15 KTS) VERTICAL WIND SHEAR, AND WARM (29-31C) SEA SURFACE
TEMPERATURES AND IS CONDUCIVE FOR FURTHER DEVELOPMENT. GLOBAL MODELS
ARE IN GENERAL AGREEMENT THAT INVEST 91W WILL CONTINUE TO TRACK WEST-
NORTHWESTWARD IN THE SCS WHERE IT WILL SLOWLY CONSOLIDATE AND
INTENSIFY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.

[doomhaMwx]

CMA on board with a TS too.

ZCZC
WTPQ20 BABJ 310900
SUBJECTIVE FORECAST
TD 02 INITIAL TIME 310900 UTC
00HR 17.0N 113.0E 998HPA 15M/S
MOVE WNW 20KM/H
P+12HR 17.6N 110.9E 998HPA 15M/S
P+24HR 18.5N 109.1E 995HPA 15M/S
P+36HR 19.3N 107.1E 992HPA 18M/S
P+48HR 20.1N 106.0E 998HPA 15M/S=
NNNN

[euro6208]

THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 17.4N 114.1E IS NOW LOCATED NEAR 17.4N 112.6E, APPROXIMATELY
200 NM SOUTHEAST OF HAIKOU, CHINA. THIS DISTURBANCE IS CURRENTLY
ASSESSED AS A MONSOON DEPRESSION. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY AND A 310153Z METOP-B 89 GHZ MICROWAVE IMAGE DEPICT A VERY
BROAD LOW LEVEL CIRCULATION (LLC). RECENT ASCAT DATA FURTHER
INDICATE THAT THE STRONGEST (25-30 KTS) WINDS ARE DISPLACED FAR TO
THE NORTHEAST OF THE CIRCULATION CENTER AND ONLY 10-15 KNOT WINDS
ARE PRESENT WITHIN THE CORE OF THE CIRCULATION. CONVECTION IS
SHALLOW, DISORGANIZED AND FLARING. ENVIRONMENTAL ANALYSIS REVEALS
EQUATORWARD OUTFLOW ALOFT, LOW (<15 KTS) VERTICAL WIND SHEAR, AND
WARM (29-31C) SEA SURFACE TEMPERATURES, ALL CONDUCIVE FOR FURTHER
DEVELOPMENT. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST 91W
WILL SLOWLY CONSOLIDATE AND INTENSIFY AS IT TRACKS WEST-
NORTHWESTWARD THROUGH THE SCS. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 999 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

[doomhaMwx]

Looking better and "more tropical" late this night after a burst of deep convection closer to the center in the last few hours, indicative of strengthening. Let's see if this prompts JMA to upgrade it into a TS within the remaining hours of July (in UTC), though an ASCAT pass about a couple of hours ago shows it still lacks ≥35kt winds near the center.

[Hayabusa]

Finally a TCFA

WTPN21 PGTW 311830
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 17.3N 112.8E TO 20.0N 107.1E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 20 TO 25 KNOTS. METSAT
IMAGERY AT 311200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 17.2N 112.0E. THE SYSTEM IS MOVING WESTWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 17.4N 112.6E IS NOW LOCATED NEAR 17.2N 112.0E, APPROXIMATELY
191 NM SOUTH-SOUTHEAST OF HAIKOU, HAINAN. THIS DISTURBANCE IS
CURRENTLY ASSESSED AS A MONSOON DEPRESSION. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS A BROAD LOW LEVEL CIRCULATION
(LLC) WITH PERSISTENT DEEP CONVECTION ALONG THE SOUTHERN SEMICIRCLE
AND FRAGMENTED DEEP CONVECTION EXTENDING EASTWARD. A 311326Z METOP-B
ASCAT PASS SHOWS THAT 91W HAS BEGUN TO CONSOLIDATE AND REVEALS A
GENERALLY ASYMMETRIC LLC WITH A BAND OF 20 TO 25 KNOT WINDS TO THE
SOUTHWEST AND WEAKER WINDS TO THE NORTH. 91W IS CURRENTLY IN A
FAVORABLE ENVIRONMENT WITH EXCELLENT EQUATORWARD OUTFLOW, LOW (5-10
KNOT) VERTICAL WIND SHEAR, AND VERY WARM (31 CELSIUS) SEA SURFACE
TEMPERATURES. GLOBAL MODELS ARE IN VERY GOOD AGREEMENT THAT 91W WILL
CONTINUE TO TRACK WEST-NORTHWESTWARD INTO THE GULF OF TONKIN WHILE
CONTINUING TO CONSOLIDATE, POTENTIALLY REACHING WARNING THRESHOLD
WITHIN THE NEXT 36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
011830Z.//
NNNN

[Hayabusa]

Still remains a TD on the last 07/31 TC warning, phew.

TD
Issued at 22:05 UTC, 31 July 2020
<Analysis at 21 UTC, 31 July>
Scale -
Intensity -
TD
Center position N18°00' (18.0°)
E110°50' (110.8°)
Direction and speed of movement NW 15 km/h (9 kt)
Central pressure 996 hPa
Maximum sustained wind speed 15 m/s (30 kt)
Maximum wind gust speed 23 m/s (45 kt)

[euro6208]

TPPN11 PGTW 010020

A. TROPICAL DISTURBANCE 91W (E OF VIETNAM)

B. 01/0000Z

C. 17.43N

D. 110.52E

E. FIVE/HMWRI8

F. T1.0/1.0 STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 40A/PBO SBC/ANMTN. CNVCTN WRAPS .25 ON LOG10 SPIRAL
YIELDING A DT OF 1.0. MET AND PT AGREE. DBO DT.

I. ADDITIONAL POSITIONS: NONE


RICHARDSON

[euro6208]

THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 17.2N 112.0E IS NOW LOCATED NEAR 17.8N 110.4E, APPROXIMATELY
133 NM SOUTH OF HAIKOU, HAINAN. THIS DISTURBANCE IS CURRENTLY
ASSESSED AS A MONSOON DEPRESSION. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY CONTINUES TO DEPICT A VERY BROAD LOW LEVEL CIRCULATION (LLC)
ALMOST ENTIRELY OBSCURED BY DISORGANIZED DEEP CONVECTION. A 312315Z
MHS NOAA-19 89GHZ MICROWAVE IMAGE REVEALS GENERAL, DISORGANIZED
FRAGMENTED DEEP CONVECTION IN THE VICINITY OF THE LLC. 91W IS
CURRENTLY IN A FAVORABLE ENVIRONMENT WITH EXCELLENT EQUATORWARD
OUTFLOW, LOW (5 TO 15 KNOT) VERTICAL WIND SHEAR, AND WARM (31
CELSIUS) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN VERY GOOD
AGREEMENT THAT 91W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD INTO
THE GULF OF TONKIN WHILE CONTINUING TO CONSOLIDATE, POTENTIALLY
REACHING WARNING THRESHOLD WITHIN THE NEXT 24 HOURS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 996 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS HIGH.

[Ed_2001]

TS 2003 (Sinlaku)
Issued at 07:15 UTC, 1 August 2020

<Analysis at 06 UTC, 1 August>
Scale Large
Intensity -
Center position N18°30' (18.5°)
E108°35' (108.6°)
Direction and speed of movement WNW 15 km/h (7 kt)
Central pressure 994 hPa
Maximum sustained wind speed 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
≥ 30 kt wind area SE 1100 km (600 NM)
NW 440 km (240 NM)

[Ed_2001]

[doomhaMwx]

It took a long time and it's certainly not the most impressive system out there but Sinlaku is finally here.

JTWC has also renumbered to 04W.

04W FOUR 200801 0600 18.9N 108.4E WPAC 35 995