WPAC: MERBOK - Post-Tropical

[doomhaMwx]

A disturbance currently located over the Visayas islands has been designated as Invest 96W... It is expected to emerge over the South China Sea this coming weekend, where it could gain slight organization/strength as it moves NW-NNW towards southern China within the next 4 days...

[euro6208]

AN AREA OF CONVECTION (INVEST 96W) HAS PERSISTED NEAR
11.3N 121.0E, APPROXIMATELY 195 NM SOUTH OF MANILA, PHILIPPINES.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A POORLY ORGANIZED
LOW LEVEL CENTER CIRCULATION (LLCC) WITH SCATTERED CONVECTION. A
RECENT 090502Z ASCAT (METOP-A) PASS INDICATED A 10-15 KNOT WIND
FIELD ASSOCIATED WITH THE DEVELOPING LLCC. UPPER LEVEL ANALYSIS
REVEALS A MARGINAL ENVIRONMENT, WITH MODERATE (15-20 KNOTS) EASTERLY
VERTICAL WIND SHEAR AND WEAK TO MODERATE OUTFLOW. GLOBAL MODELS
INDICATE SLOW DEVELOPMENT AS THE SYSTEM TURNS POLEWARD OVER THE
SOUTH CHINA SEA DURING THE NEXT FEW DAYS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1008 MB. BECAUSE THE LLCC IS WEAK AND UPPER-
LEVEL CONDITIONS ARE MARGINAL, THE POTENTIAL FOR THE DEVELOPMENT OF
A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

[euro6208]

NAVGEM, CMC, EURO, and GFS develops this with the first three taking it inland near Hong Kong while the fourth takes it to eastern Taiwan.

A TS at best.

[1900hurricane]

I'm not very high on this one. If it does manage to develop, I'm thinking minimum tropical storm at best. Its movement in the low level flow has it at a bad angle relative to the upper level wind vector.

[euro6208]

Seems like the Philippines is flying along with this.

[doomhaMwx]

6/10/17 0100Z

THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED NEAR 11.3N 121.0E, IS NOW LOCATED NEAR 13.3N 119.3E, APPROXIMATELY 125 NM SOUTHWEST OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A MORE ORGANIZED LOW LEVEL CIRCULATION CENTER (LLCC) AND RECENT 092212Z SSMIS 91GHZ MICROWAVE IMAGERY DEPICTED FLARING CONVECTION TO THE SOUTHWEST OF THE DEVELOPING LLCC. UPPER LEVEL ANALYSIS REVEALS A MORE FAVORABLE ENVIRONMENT, WITH LOW (10-15 KNOTS) NORTHEASTERLY VERTICAL WIND SHEAR. OUTFLOW IS RESTRICTED TO THE NORTH BUT IS GOOD ELSEWHERE. GLOBAL MODELS INDICATE DEVELOPMENT WITH THE SYSTEM AS IT TURNS POLEWARD OVER THE SOUTH CHINA SEA DURING THE NEXT 24 TO 36 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.

[euro6208]

96W INVEST 170610 0600 14.0N 118.6E WPAC 15 1010

[euro6208]

While EURO and GFS continues to show a weak TS making landfall, HWRF has a landfalling typhoon.

[euro6208]

JMA has this as a TD 10 min.

[doomhaMwx]

TCFA issued...

REMARKS:
THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED NEAR 13.3N 119.3E, IS NOW LOCATED NEAR 15.0N 118E, APPROXIMATELY 185 NM WEST-NORTHWEST OF MANILA, PHILIPPINES. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS A BROAD LOW LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION LOCATED PRIMARILY TO THE NORTH AND WEST OF THE CENTER. A 101029Z SSMIS 91GHZ MICROWAVE IMAGE CONFIRMS A BROAD CIRCULATION WITH INCREASINGLY SYMMETRICAL DEEP CONVECTIVE BANDING. THE DISTURBANCE IS CURRENTLY LOCATED IN A FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR (5-10 KTS), GOOD EQUATORWARD OUTFLOW TO THE SOUTHWEST, AND VERY WARM SEA SURFACE TEMPERATURES (29-31°C). THERE ARE HIGH LEVELS OF VERTICAL WIND SHEAR LOCATED JUST SOUTH OF THE DISTURBANCE. GLOBAL MODELS ARE IN AGREEMENT THAT THE SYSTEM WILL TRACK TO THE NORTH NORTHWEST OVER THE NEXT FEW DAYS AND DEVELOP WITHIN THE NEXT 24 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.

[1900hurricane]

96W is actually looking better than I was expecting. It may be close to being classified.

[1900hurricane]

Yeah, let's renumber.

[Yellow Evan]

If this isn't classifiable, idk what is.

[euro6208]

04W FOUR 170610 1800 15.5N 117.4E WPAC 20 1007

04W is here.

[1900hurricane]

JMA is progging Tropical Storm Merbok to develop from 04W in 24 hours or so.

TD
Issued at 01:15 UTC, 11 June 2017

<Analysis at 00 UTC, 11 June>
Scale -
Intensity -
TD
Center position N16°00' (16.0°)
E116°50' (116.8°)
Direction and speed of movement NNW 15 km/h (7 kt)
Central pressure 1006 hPa
Maximum wind speed near center 15 m/s (30 kt)
Maximum wind gust speed 23 m/s (45 kt)

<Forecast for 12 UTC, 11 June>
Intensity -
TD
Center position of probability circle N18°40' (18.7°)
E116°30' (116.5°)
Direction and speed of movement N 20 km/h (12 kt)
Central pressure 1002 hPa
Maximum wind speed near center 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, 12 June>
Intensity -
Center position of probability circle N21°00' (21.0°)
E116°30' (116.5°)
Direction and speed of movement N 20 km/h (12 kt)
Central pressure 1000 hPa
Maximum wind speed near center 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
Radius of probability circle 200 km (110 NM)

[doomhaMwx]

JTWC Tropical Depression 04W...
Forecast to make landfall as a Tropical Storm over Southern China's Guangdong province, east of HongKong, tomorrow evening(Monday) or early Tuesday local date/time...

[Yellow Evan]

WTPN31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR/101451ZJUN2017//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL DEPRESSION 04W (FOUR) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110000Z --- NEAR 16.1N 116.9E
MOVEMENT PAST SIX HOURS - 320 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 16.1N 116.9E
---
FORECASTS:
12 HRS, VALID AT:
111200Z --- 18.1N 116.3E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 345 DEG/ 11 KTS
---
24 HRS, VALID AT:
120000Z --- 20.3N 115.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 350 DEG/ 10 KTS
---
36 HRS, VALID AT:
121200Z --- 22.2N 115.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 015 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
130000Z --- 23.9N 115.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 070 DEG/ 15 KTS
---
72 HRS, VALID AT:
140000Z --- 26.0N 122.0E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 96 HR POSIT: 075 DEG/ 18 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
150000Z --- 27.6N 130.0E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
110300Z POSITION NEAR 16.6N 116.8E.
TROPICAL DEPRESSION 04W (FOUR), LOCATED APPROXIMATELY 254 NM
WEST-NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 110000Z IS 10 FEET. NEXT WARNINGS AT 110900Z, 111500Z, 112100Z AND
120300Z. THIS CANCELS AND SUPERSEDES REF A (WTPN21 PGTW 101500).//
NNNN

[doomhaMwx]

We now have Tropical Storm "Merbok"...

http://www.jma.go.jp/en/typh/

[euro6208]

WDPN31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR) WARNING
NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 04W (FOUR), LOCATED APPROXIMATELY 254 NM
WEST-NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT
08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS THE SYSTEM HAS STEADILY CONSOLIDATED AS
CONVECTIVE TOPS IN THE CENTRAL DENSE OVERCAST DEEPENED AND FORMATIVE
BANDS BEGAN TO CONSOLIDATE. THE INITIAL POSITION IS BASED ON THE MSI
AND DOPPLER RADAR LOOP FROM PAGASA WITH FAIR CONFIDENCE. THE CENTER
ALSO LINES UP WELL WITH A LOW REFLECTIVITY CIRCULATION FEATURE IN THE
102305Z SSMIS MICROWAVE PASS. THE INITIAL INTENSITY OF 25 KNOTS IS
BASED ON AN OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES,
AND RJTD RANGING FROM T1.0 TO T1.5. UPPER LEVEL ANALYSIS INDICATES TD
04W IS IN AN AREA OF LOW VERTICAL WIND SHEAR (VWS) AND STRONG
EQUATORWARD OUTFLOW. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF THE LOW REFLECTION OF THE SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THIS IS THE INITIAL FORECAST AND SETS THE FORECAST PHILOSOPHY
FOR THIS SYSTEM.
B. TD 04W IS EXPECTED TO CONTINUE ON ITS TRACK AND MAKE LANDFALL
JUST EAST OF HONG KONG SHORTLY AFTER TAU 36, ROUND THE WESTERN EDGE
OF THE STR, EXIT INTO THE YELLOW SEA AND ACCELERATE
EAST-NORTHEASTWARD. THE FAVORABLE UPPER LEVEL DYNAMICS, IN ADDITION
TO THE WARM WATERS OF THE SOUTH CHINA SEA, WILL FUEL GRADUAL
INTENSIFICATION PEAKING AT 50 KNOTS BEFORE LANDFALL. AFTERWARD, LAND
INTERACTION AND INCREASING VWS WILL RAPIDLY ERODE THE SYSTEM.
C. AFTER TAU 72, TD 04W WILL CONTINUE TO DETERIORATE THEN
DISSIPATE OVER WATER JUST NORTHEAST OF OKINAWA. DYNAMIC MODEL
GUIDANCE IS IN GOOD AGREEMENT WITH HWRF AS THE NOTABLE OUTLIER TO
THE RIGHT OF THE MODEL ENVELOPE. THE JTWC TRACK IS LAID JUST TO THE
LEFT OF CONSENSUS TO OFFSET HWRFS UNLIKELY TIGHT TURN AROUND THE
STR. IN VIEW OF THE FORMATIVE NATURE OF THE SYSTEM, THERE IS LOW
CONFIDENCE TO THE INITIAL JTWC FORECAST TRACK.//
NNNN

[1900hurricane]

Looks like Merbok may be dealing with some dry air coming off the Asian mainland shortly. Both the Airmass RGB and Microwave data seem to show a tongue of it beginning to wrap towards the system. I'll also post the 12Z sounding from Hong Kong once it becomes available.