WPAC: WIPHA - Post-Tropical

[Nancy Smar]

92W INVEST 190728 0600 16.4N 118.4E WPAC 15 0

[Nancy Smar]

LOW PRESSURE AREA 1006 HPA NEAR 16N 113E ALMOST STATIONARY.

[Nancy Smar]

92W INVEST 190729 0000 16.1N 116.6E WPAC 20 1005

[Hayabusa]

ABPW10 PGTW 290600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/290600Z-300600ZJUL2019//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 92W) HAS PERSISTED NEAR
16.5N 116.2E, APPROXIMATELY 365 NM SOUTH-SOUTHEAST OF HONG KONG.
ANIMATED MULTISPECTRAL IMAGERY DEPICTS DEEP CONVECTION OVER THE
SOUTHERN SEMICIRCLE WRAPPING INTO A BROAD LLC. A 290135Z ASCAT-C
IMAGE REVEALS A DEVELOPING CIRCULATION WITH 20-25 KT WESTERLY WINDS
ALONG THE SOUTHERN QUADRANT AND 10-15 KT SOUTHERLY WINDS OVER THE
EASTERN QUADRANT. A 282239Z WINDSAT 37 GHZ MICROWAVE IMAGE SHOWS
WEAK BANDING WRAPPING INTO A BROAD, ELONGATED CIRCULATION. UPPER
LEVEL ANALYSIS INDICATES BROAD DIFFLUENCE. THE DISTURBANCE IS
CURRENTLY LOCATED IN A MARGINALLY FAVORABLE SHEAR ENVIRONMENT BUT IS
EXPECTED TO TRACK WEST-NORTHWESTWARD INTO A FAVORABLE SHEAR
ENVIRONMENT WITH SIGNIFICANT UPPER LEVEL DIVERGENCE OVER THE NEXT 24-
36 HRS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
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 MEDIUM.

[euro6208]

WTPN21 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 17.0N 116.6E TO 20.0N 113.1E
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 18 TO 23 KNOTS. METSAT
IMAGERY AT 291800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 17.2N 116.3E. THE SYSTEM IS MOVING NORTHWESTWARD AT 05
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 92W) PREVIOUSLY LOCATED
NEAR 16.5N 116.2E, IS NOW LOCATED NEAR 17.2N 116.3E, APPROXIMATELY
381 NM EAST-SOUTHEAST OF HAIKOU, HAINAN. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS FLARING DEEP CONVECTION PRIMARILY TO THE
SOUTH OF A BROAD LOW LEVEL CIRCULATION CENTER (LLCC). A 291314Z
METOP-B ASCAT PASS SHOWS A BROAD, WEAK LLCC WITH A LARGE REGION OF
20 TO 25 KNOT WINDS OVER 100 NM TO THE SOUTHEAST. 92W IS CURRENTLY
IN A MARGINAL ENVIRONMENT WITH GOOD EQUATORWARD OUTFLOW AND WARM (26
TO 27 CELSIUS) SEA SURFACE TEMPERATURE OFFSETTING MARGINAL (15 TO 20
KNOT) VERTICAL WIND SHEAR. GLOBAL MODELS INDICATE 92W WILL TRACK
NORTHWESTWARD TOWARD HAINAN AND INTENSIFY. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1001 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
302100Z.//
NNNN

[1900hurricane]

Looks like it's developed a decent enough circulation, although convection still leaves something to be desired.

[Nancy Smar]

WTPQ20 RJTD 300600

RSMC TROPICAL CYCLONE ADVISORY

NAME TD

ANALYSIS

PSTN 300600UTC 17.5N 114.3E POOR

MOVE ALMOST STATIONARY

PRES 998HPA

MXWD 030KT

GUST 045KT

FORECAST

24HF 310600UTC 19.8N 112.0E 80NM 70%

MOVE NW 08KT

PRES 994HPA

MXWD 035KT

GUST 050KT =

[euro6208]

THE AREA OF CONVECTION (INVEST 92W) PREVIOUSLY LOCATED
NEAR 17.2N 116.3E, IS NOW LOCATED NEAR 17.9N 115.7E, APPROXIMATELY
270 NM SOUTH-SOUTHEAST OF HONG KONG. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS FLARING DEEP CONVECTION PRIMARILY TO THE
SOUTH OF A BROAD LOW LEVEL CIRCULATION CENTER (LLCC). A 291314Z
METOP-B ASCAT PASS SHOWS A BROAD, WEAK LLCC WITH A LARGE REGION OF
20 TO 25 KNOT WINDS OVER 100 NM TO THE SOUTHEAST. 92W IS CURRENTLY
IN A MARGINAL ENVIRONMENT WITH GOOD EQUATORWARD OUTFLOW AND WARM (26
TO 27 CELSIUS) SEA SURFACE TEMPERATURE OFFSETTING MARGINAL (15 TO 20
KNOT) VERTICAL WIND SHEAR. GLOBAL MODELS INDICATE 92W WILL TRACK
NORTHWESTWARD TOWARD HAINAN AND INTENSIFY. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.

[euro6208]

[Cunxi Huang]

18Z upgraded to 08W.

08W INVEST 190730 1800 18.2N 113.3E WPAC 30 996

[euro6208]

WDPN31 PGTW 302100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT)
WARNING NR 001//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 08W (EIGHT), LOCATED APPROXIMATELY 451
NM EAST-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD
AT 07 KNOTS (KTS) OVER THE PAST SIX HOURS. THE INITIAL POSITION,
PLACED WITH LOW CONFIDENCE USING ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY WHICH SUGGESTS A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC), IS JUST NORTH OF SUSTAINED CONVECTIVE
BANDING. THE EIR ALSO REVEALS LIMITED CONVECTIVE BANDING TO
THE NORTH OF THE LLCC. THE INITIAL INTENSITY IS BASED ON A 301400Z
METOP-C ASCAT IMAGE WHICH SHOWS 30 KT WINDS IN THE SOUTH, EAST, AND
NORTH QUADRANTS (THE PASS MOSTLY MISSED THE WEST QUADRANT). DVORAK
INTENSITY FIXES ARE T1.5 (25 KTS) AND BELOW. ENVIRONMENTAL
CONDITIONS ARE SOMEWHAT FAVORABLE WITH GOOD EQUATORWARD OUTFLOW AND
WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES, PARTIALLY OFFSET BY
MARGINAL (15-20 KT) VERTICAL WIND SHEAR AND A WEAK UPPER LEVEL LOW
RESULTING IN CONVERGENCE ALOFT JUST NORTH OF THE SYSTEM. TD 08W IS
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE
(STR).
3. FORECAST REASONING.
A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE
FORECAST
PHILOSOPHY.
B. THROUGH TAU 72, TD 08W IS EXPECTED TO CONTINUE TRACKING ALONG
THE PERIPHERY OF THE STR, PASS OVER THE LEIZHOU PENINSULA AROUND TAU
30, ENTER THE GULF OF TONKIN NEAR TAU 36, AND MAKE LANDFALL NEAR
HANOI AROUND TAU 72. THE MARGINAL ENVIRONMENT IS EXPECTED TO LIMIT
INTENSIFICATION TO 35 KTS AT TAU 12. HOWEVER, THERE IS A POSSIBILITY
THE UPPER LEVEL LOW WILL WEAKEN AND ALLOW MORE INTENSIFICATION
BEFORE LANDFALL. BY TAU 24, SIGNIFICANT LAND INTERACTION SHOULD
INHIBIT INTENSIFICATION, BUT SMALL VARIATIONS IN THE ACTUAL TRACK
COULD LEAD TO SIGNIFICANT DIFFERENCES IN THE INTENSITY. NUMERICAL
MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 36. AFTER TAU 36,
THE UKMET MODEL DEVIATES TO THE SOUTH FROM THE OTHER MEMBERS. FOR
THIS PORTION OF THE FORECAST, THE JTWC TRACK FORECAST CLOSELY
FOLLOWS CONSENSUS WITH LOW CONFIDENCE DUE PRIMARILY TO HIGH
UNCERTAINTY IN THE INITIAL POSITION.
C. AFTER TAU 72, TD 08W WILL CONTINUE INLAND AND DISSIPATE. THE
JTWC TRACK FORECAST IS HEDGED NORTH OF CONSENSUS TO OFFSET THE
SOUTHERN OUTLIER (UKMET) WITH LOW CONFIDENCE.//
NNNN

[Nancy Smar]

WTPQ20 RJTD 310000

RSMC TROPICAL CYCLONE ADVISORY

NAME TS 1907 WIPHA (1907) UPGRADED FROM TD

ANALYSIS

PSTN 310000UTC 18.5N 113.4E FAIR

MOVE NNW SLOWLY

PRES 994HPA

MXWD 035KT

GUST 050KT

30KT 270NM EAST 210NM WEST

FORECAST

24HF 010000UTC 20.7N 110.9E 40NM 70%

MOVE NW 08KT

PRES 990HPA

MXWD 040KT

GUST 060KT

48HF 020000UTC 21.0N 108.8E 75NM 70%

MOVE W SLOWLY

PRES 985HPA

MXWD 045KT

GUST 065KT

72HF 030000UTC 20.7N 106.7E 100NM 70%

MOVE W SLOWLY

PRES 990HPA

MXWD 040KT

GUST 060KT =

[euro6208]

EURO has some modest intensification.

[euro6208]

WDPN31 PGTW 310300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (WIPHA)
WARNING NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 08W (WIPHA), LOCATED APPROXIMATELY 234
NM SOUTH-SOUTHWEST OF HONG KONG, HAS TRACKED NORTHWESTWARD AT 06
KNOTS (KTS) OVER THE PAST SIX HOURS. THERE IS FAIR CONFIDENCE IN THE
INITIAL POSITION BASED ON A FULLY EXPOSED, BUT POORLY-DEFINED, LOW
LEVEL CIRCULATION CENTER (LLCC) IN ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI). THE MSI ALSO REVEALS THAT THE OVERALL CONVECTIVE
SIGNATURE HAS IMPROVED SLIGHTLY, WITH MORE DEEP CONVECTION IN THE
WESTERN QUADRANT, BUT THE SYSTEM STILL LACKS CENTRAL CONVECTION. THE
INITIAL INTENSITY IS BEING HELD AT 30 KTS AS THE OVERALL MSI
SIGNATURE IS JUST STARTING TO SHOW SIGNS OF IMPROVEMENT AND DVORAK
INTENSITY ESTIMATES REMAIN AT T1.5 (25 KTS) AND BELOW. ENVIRONMENTAL
CONDITIONS ARE SOMEWHAT FAVORABLE WITH GOOD EQUATORWARD OUTFLOW,
WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE, AND LOW (10-15 KT)
VERTICAL WIND SHEAR. A WEAK UPPER LEVEL LOW JUST NORTH OF THE SYSTEM
IS PROVIDING SUBSIDENCE AND INHIBITING INTENSIFICATION. TD 08W IS
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE
(STR).
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 72, TD 08W IS EXPECTED TO CONTINUE TRACKING ALONG
THE PERIPHERY OF THE STR, PASS OVER THE LEIZHOU PENINSULA AROUND TAU
30, ENTER THE GULF OF TONKIN NEAR TAU 36, AND MAKE LANDFALL NEAR
HANOI AROUND TAU 72. THE SUBSIDENCE FROM THE UPPER LEVEL LOW TO THE
NORTH IS EXPECTED TO LIMIT INTENSIFICATION TO A PEAK OF 35 KTS AT
TAU 12. BY TAU 24, THE UPPER LEVEL LOW SHOULD FILL BUT, BY THAT
TIME, LAND INTERACTION WILL INHIBIT INTENSIFICATION. THE JTWC TRACK
FORECAST FOLLOWS THE CONSENSUS THROUGH TAU 72. BASED ON SPREAD IN
THE NUMERICAL MODEL GUIDANCE BEING ABOUT 185 NM AT TAU 72 (PRIMARILY
DUE TO DIFFERENCES IN ALONG-TRACK SPEED), THERE IS LOW CONFIDENCE
FOR THIS PORTION OF THE JTWC TRACK FORECAST.
C. AFTER TAU 72, TD 08W WILL CONTINUE INLAND AND DISSIPATE. THE
JTWC TRACK FORECAST FOLLOWS CONSENSUS WITH LOW CONFIDENCE BASED ON
LARGE SPREAD IN THE MODEL GUIDANCE.//
NNNN

[euro6208]

Upgraded to a TS.


WDPN31 PGTW 310900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (WIPHA)
WARNING NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 08W (WIPHA), LOCATED APPROXIMATELY 207 NM
SOUTH-SOUTHWEST OF HONG KONG, HAS TRACKED NORTHWESTWARD AT 10 KNOTS
OVER THE PAST SIX HOURS. THERE IS FAIR CONFIDENCE IN THE INITIAL
POSITION BASED ON A PARTIALLY OBSCURED, BUT POORLY-DEFINED, LOW LEVEL
CIRCULATION CENTER (LLCC) IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI). THE MSI LOOP ALSO REVEALS THAT THE OVERALL CONVECTIVE
SIGNATURE HAS IMPROVED SLIGHTLY, WITH MORE DEEP CONVECTION IN THE
NORTHWESTERN QUADRANT, BUT THE SYSTEM STILL LACKS CENTRAL CONVECTION.
THE INITIAL INTENSITY HAS INCREASED SLIGHTLY TO 35 KNOTS BASED ON A
310232Z METOP-C ASCAT PASS SHOWING A BROAD SWATH OF 30-35 KNOT WIND
BARBS AROUND AN OBLONG LLCC. THIS AGREES WITH A 310740Z ADT ESTIMATE
OF 33 KNOTS. ENVIRONMENTAL CONDITIONS ARE SOMEWHAT FAVORABLE WITH
FAIR EQUATORWARD OUTFLOW, WARM (29-30 CELSIUS) SEA SURFACE
TEMPERATURE, AND LOW (10-15 KT) VERTICAL WIND SHEAR. A WEAK UPPER
LEVEL LOW JUST TO THE EAST OF THE SYSTEM IS PROVIDING SUBSIDENCE AND
INHIBITING INTENSIFICATION. TS 08W IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 72, TS 08W IS EXPECTED TO CONTINUE TRACKING ALONG
THE SOUTHWESTERN PERIPHERY OF THE STR, PASS OVER THE LEIZHOU
PENINSULA AROUND TAU 18, ENTER THE GULF OF TONKIN NEAR TAU 24, AND
MAKE LANDFALL EAST OF HANOI AROUND TAU 48. THE SUBSIDENCE FROM THE
UPPER LEVEL LOW TO THE EAST AND LAND INTERACTION ARE EXPECTED TO
LIMIT INTENSIFICATION TO A PEAK OF 35 KNOTS. THE JTWC TRACK FORECAST
FOLLOWS JUST AHEAD OF THE CONSENSUS THROUGH TAU 72. BASED ON ALONG
TRACK SPREAD IN THE NUMERICAL MODEL GUIDANCE, THERE IS LOW CONFIDENCE
FOR THIS PORTION OF THE JTWC TRACK FORECAST.
C. AFTER TAU 72, TS 08W WILL CONTINUE INLAND AND DISSIPATE. THE
JTWC TRACK FORECAST FOLLOWS CONSENSUS WITH LOW CONFIDENCE BASED ON
LARGE SPREAD IN THE MODEL GUIDANCE.//
NNNN

[doomhaMwx]

Rainbands presently affecting parts of Guangdong Province, including HongKong and Macau.

[doomhaMwx]

The center of Wipha is yet to make landfall over the Leizhou Peninsula as the system has jogged northward off the peninsula's coast in the last few hours.



Rainbands are rotating towards a circulation center that has become more apparent/defined on satellite as well as radar images in the last few hours.

[euro6208]

WDPN31 PGTW 010900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (WIPHA)
WARNING NR 07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 08W (WIPHA), LOCATED APPROXIMATELY 287 NM
EAST OF HANOI, VIETNAM, HAS TRACKED NORTH-NORTHWESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS A COMPACT, WELL-DEFINED LOW-LEVEL CIRCULATION CENTER
(LLCC) WITH FRAGMENTED DEEP CONVECTIVE BANDING. A 010530Z AMSR2
89GHZ IMAGE DEPICTS SHALLOW BANDING WRAPPING INTO A WELL-DEFINED
LLCC, WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. A
010245Z ASCAT IMAGE REVEALS A DEFINED CENTER WITH 30 TO 35 KNOT
WINDS OVER THE SOUTH AND EAST QUADRANTS, WHICH SUPPORTS THE INITIAL
INTENSITY ASSESSMENT OF 35 KNOTS. THE ASCAT AMBIGUITY ANALYSIS,
AMSR2 IMAGE, MSI AND A 010716Z GPM 89GHZ IMAGE ALL PROVIDE EVIDENCE
OF AN ABRUPT NORTH-NORTHWESTWARD TURN OVER THE PAST 5-6 HOURS, WHICH
HAS ALLOWED THE SYSTEM TO REMAIN OVER FAVORABLE SST (28-29C) WITH AN
IMPROVED CONVECTIVE SIGNATURE. HOWEVER, THE SYSTEM IS STILL EXPECTED
TO TURN GRADUALLY WESTWARD OVER THE NEXT 12 TO 24 HOURS. UPPER-LEVEL
ANALYSIS INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH LOW TO
MODERATE VERTICAL WIND SHEAR OFFSET BY GOOD POLEWARD AND EQUATORWARD
OUTFLOW. TS 08W IS POSITIONED WEST AND SOUTH OF A LOW- TO MID-LEVEL
SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 08W HAS TRACKED NORTH-NORTHWESTWARD IN THE SHORT-TERM DUE
TO AN EXTENSION OF THE STR TO THE EAST, HOWEVER, THE SYSTEM WILL
GRADUALLY TURN WESTWARD AS IT TRACKS UNDER THE DOMINANT STEERING
INFLUENCE OF THE STR ENTRENCHED TO THE NORTH. THERE IS SOME
UNCERTAINTY IN THE TIMING OF THIS INEVITABLE WESTWARD TURN, WHICH
INTRODUCES SOME UNCERTAINTY IN THE INTENSITY FORECAST AND EXACT
TRACK OVER THE GULF OF TONKIN. THE CURRENT JTWC FORECAST TRACK
SKIRTS THE SOUTHERN COAST OF CHINA WITH LANDFALL ALONG THE NORTHEAST
COAST OF VIETNAM NEAR TAU 42 AND DISSIPATION BY TAU 48 NEAR HANOI.
DYNAMIC MODEL GUIDANCE REFLECTS THIS UNCERTAINTY WITH SOME SOLUTIONS
FURTHER NORTH OVER THE COAST, WHICH COULD LEAD TO GREATER WEAKENING.
DUE TO THIS UNCERTAINTY, THERE IS MODERATE CONFIDENCE IN THE JTWC
FORECAST TRACK.//
NNNN

[euro6208]

WDPN31 PGTW 020900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (WIPHA)
WARNING NR 11//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 08W (WIPHA), LOCATED APPROXIMATELY 170 NM
EAST OF HANOI, VIETNAM, HAS TRACKED NORTHWESTWARD AT 04 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND RADAR IMAGERY DEPICT A CONSOLIDATING LOW-LEVEL CIRCULATION WITH
IMPROVED DEEP CONVECTIVE BANDING WRAPPING INTO A WELL-DEFINED
CENTER. A 020613Z AMSR2 89GHZ IMAGE DEPICTS A COMPACT CORE WITH AN
OBLONG MICROWAVE EYE FEATURE, WHICH SUPPORTS THE INITIAL POSITION
WITH GOOD CONFIDENCE. BASED ON THE IMPROVED CONVECTIVE STRUCTURE,
THE INITIAL INTENSITY IS ASSESSED AT 40 KNOTS, HEDGED ABOVE THE
PGTW/RJTD SUBJECTIVE DVORAK INTENSITY ESTIMATES OF T2.0 (30 KNOTS).
UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT
WITH MODERATE VERTICAL WIND SHEAR AND FAIR OUTFLOW. TS 08W HAS
TRACKED SOMEWHAT ERRATICALLY BUT APPEARS TO BE SLOWLY TRACKING
WESTWARD OVER THE PAST TWO HOURS UNDER THE STEERING INFLUENCE OF THE
LOW-LEVEL SUBTROPICAL RIDGE POSITIONED TO THE NORTH.
3. FORECAST REASONING.
A. THERE HAS BEEN NO SIGNIFICANT CHANGE TO THE FORECAST
PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE, HOWEVER,
THE FORECAST DURATION HAS BEEN CUT TO 36 HOURS.
B. TS 08W IS FORECAST TO GRADUALLY ACCELERATE WEST-SOUTHWESTWARD
THROUGH THE FORECAST PERIOD ALONG THE COAST OF CHINA AND VIETNAM.
THE SYSTEM SHOULD MAKE LANDFALL OVER NORTHEAST VIETNAM NEAR TAU 24
AND IS EXPECTED TO DISSIPATE BY TAU 36. DYNAMIC MODEL GUIDANCE
REMAINS IN FAIR AGREEMENT WITH UNCERTAINTY IN THE EXACT TRACK, WHICH
COULD AFFECT THE INTENSITY FORECAST. THE SYSTEM IS FORECAST TO
MAINTAIN AT 40 KNOTS THROUGH TAU 12 BUT SHOULD WEAKEN STEADILY AS IT
SKIRTS THE COAST AND TRACKS FURTHER INLAND. OVERALL, THERE IS
MODERATE CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN

[doomhaMwx]

Impressive radar presentation.