WPAC: 08W - Tropical Storm

[Hayabusa]

95W INVEST 250714 0600 24.7N 140.0E WPAC 15 0

[Hayabusa]

looks like it's going to be 96W huh

[Hayabusa]

Already medium

ABPW10 PGTW 141230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/141230Z-150600ZJUL2025//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/140751ZJUL2025//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/140152ZJUL2025//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REF B IS A SUBTROPICAL
CYCLONE FINAL WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 14JUL25 0600Z, TROPICAL STORM 06W (NARI) WAS LOCATED
NEAR 36.8N 142.6E, APPROXIMATELY 167 NM EAST-NORTHEAST OF YOKOSUKA,
JAPAN, AND HAD TRACKED NORTHWARD AT 27 KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 45 KNOTS GUSTING TO
55 KNOTS. SEE REF A (WTPN31 PGTW 140900) FOR FURTHER DETAILS.
(2) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 95W) HAS PERSISTED NEAR 26.0N
139.5E, APPROXIMATELY 122 NM NORTHWEST OF IWO-TO. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY (EIR) AND A 140901Z SSMIS MICROWAVE IMAGE
DEPICT A SMALL RAPIDLY CONSOLIDATING LOW-LEVEL CIRCULATION (LLC) WITH
PERSISTENT CORE CONVECTION. A RECENT 141048Z ASCAT-B PASS REVEALS A
DEVELOPING CIRCULATION, WITH SHARP CYCLONIC TURNING AND 25-30 KNOT
WINDS ISOLATED OVER THE EASTERN QUADRANT. THIS SMALL SYSTEM IS
FORMING ADJACENT TO AN EXTENSIVE REGION OF 20-30 KNOT SOUTHERLY
WINDS, WHICH EXTENDS POLEWARD AS FAR NORTH AS TS 06W. RECENT
OBSERVATIONS FROM IWO-TO REVEAL SUSTAINED WINDS OF 16-21 KNOTS
GUSTING AS HIGH AS 31 KNOTS WITH A SLP OF 1004MB. ENVIRONMENTAL
ANALYSIS REVEALS LOW TO MODERATE VERTICAL WIND SHEAR (VWS) OF 15-20
KNOTS, GOOD EQUATORWARD UPPER-LEVEL OUTFLOW AND WARM SEA SURFACE
TEMPERATURES (SST) OF 28-29 C. DETERMINISTIC AND ENSEMBLE MODELS ARE
IN AGREEMENT FORECASTING A SMALL RAPIDLY DEVELOPING LLC WITH A
NORTHWARD TRACK. THESE TYPES OF SMALL SYSTEMS HAVE A TENDENCY TO
DEVELOP RAPIDLY AND COULD INTENSIFY TO 40-50 KNOTS OR HIGHER WITHIN
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 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS MEDIUM.
(2) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY:
(1) AT 14JUL25 0000Z, SUBTROPICAL DEPRESSION 07W (SEVEN) WAS
LOCATED NEAR 32.7N 130.8E, APPROXIMATELY 60 NM EAST-SOUTHEAST OF
SASEBO, JAPAN, AND HAD TRACKED NORTHEASTWARD AT 15 KNOTS OVER THE
PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 25
KNOTS GUSTING TO 35 KNOTS. SEE REF B (WTPN32 PGTW 140300) FOR THE
FINAL WARNING ON THIS SYSTEM.
(2) NO OTHER SUBTROPICAL SYSTEMS.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: ADDED MEDIUM AREA IN PARA. 1.B.(1).//
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[Hayabusa]

TCFA

WTPN21 PGTW 141930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 95W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 26.9N 139.5E TO 39.7N 141.1E
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 071930Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 27.2N 139.6E. THE SYSTEM IS MOVING NORTHWARD AT 12 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 95W) PREVIOUSLY LOCATED NEAR
26.0N 139.5E IS NOW LOCATED NEAR 27.2N 139.6E, APPROXIMATELY 505 NM
SOUTH OF TOKYO, JAPAN. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
(EIR) DEPICTS A COMPACT AREA OF DEEP CORE CONVECTION BUILT OVER THE
CENTER OF THE SYSTEM. A 141048Z ASCAT-B PASS REVEALED A SHARP CUSP
FEATURE AND 25-30 KNOT WINDS ISOLATED ALONG THE EASTERN QUADRANTS. THIS
SMALL SYSTEM IS FORMING WITHIN AN EXTENSIVE SWATH OF ELEVATED (20-30
KNOTS) SOUTHERLY WINDS TRAILING IN THE WAKE OF 06W. ENVIRONMENTAL
ANALYSIS REVEALS A FAVORABLE ENVIRONMENT MOVING FORWARD WITH LOW
VERTICAL WIND SHEAR OF 10-15 KNOTS, GOOD EQUATORWARD OUTFLOW ALOFT AND
WARM (28-29 C) SEA SURFACE TEMPERATURES. DETERMINISTIC MODELS SHOW THE
SYSTEM FAILING TO CLOSE OFF INTO A DEFINED CIRCULATION AS IT QUICKLY
TRACKS TO THE NORTH, BUT WITH ENHANCED WINDS CONFINED TO THE EASTERN
SEMICIRCLE. TRACK GUIDANCE IN GOOD AGREEMENT REGARDING THE TRAJECTORY OF
THE SYSTEM WITH MINIMAL SPREAD IN ENSEMBLE MEMBERS.
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
151930Z.
//
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[Hayabusa]

Jtwc 1st warning is TS

[Hayabusa]

WDPN32 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (EIGHT) WARNING NR
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 32.7N 140.7E
INITIAL INTENSITY: 40 KTS
GEOGRAPHIC REFERENCE: 164 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
MOVEMENT PAST 6 HOURS: NORTHWARD AT 33 KTS
SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS A FURTHER
ACCELERATING, NOW NEARLY FULLY OBSCURED LOW-LEVEL CIRCULATION
CENTER (LLCC) ASSOCIATED WITH TROPICAL STORM (TS) 08W. THE INITIAL
POSITION IS DETERMINED WITH MEDIUM CONFIDENCE BASED ON THE
LOW-LEVEL CLOUD TRACING, PARTICULARLY THE EXTRAPOLATION OF NORTHERN
SEMICIRCLE CONVECTIVE BANDING LOCATION. THE INITIAL INTENSITY
ESTIMATE OF 40 KTS IS ALSO ASSIGNED MEDIUM CONFIDENCE BASED ON
PERSISTING TRAIL OF CENTRAL CONVECTION PRESENT IN THE MSI, AS WELL
AS THE LATEST AGENCY DVORAK AND THE AUTOMATED INTENSITY ESTIMATES
LISTED BELOW. TS 08W HAS ACCELERATED SIGNIFICANTLY SINCE THE LAST
WARNING AND IS ASSESSED TO BE TRANSITING NORTH AT 33 KTS, STILL
FOLLOWING THE SYNOPTIC TRAIL OF TS 06W. ENVIRONMENTAL ANALYSIS
INDICATES A MARGINAL THERMODYNAMIC AND DYNAMIC REGIME, CHARACTERIZED
BY LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS), SUFFICIENTLY WARM SEA
SURFACE TEMPERATURES (SST) RANGING FROM 27 TO 28 C, AND MODERATE
EQUATORWARD UPPER-LEVEL OUTFLOW ENHANCED BY A TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) CELL LOCATED TO THE SOUTHEAST.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: STRONG SUBTROPICAL RIDGE (STR) TO THE
EAST-NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.0 - 30 KTS
KNES: T2.0 - 30 KTS
CIMSS ADT: 37 KTS AT 150600Z
CIMSS AIDT: 41 KTS AT 150700Z
CIMSS D-PRINT: 28 KTS AT 150700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
VWS: 10-15 KTS
SST: 27-28 CELSIUS
OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: THE VORTEX OF TS 08W IS TRACKING NORTHWARD AT
VERY HIGH TRANSLATIONAL VELOCITY AND IS EXPECTED TO MAKE PROXIMAL
APPROACH TO THE JAPANESE COAST WITHIN THE NEXT 6-12 HOURS. CURRENT
MOTION IS DICTATED BY STEERING FLOW ASSOCIATED WITH A BROAD,
DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST-NORTHEAST,
POSITIONED AHEAD OF A MID-LATITUDE LONGWAVE TROUGH OVER SOUTH
KOREA. CURRENT TRACK GUIDANCE INDICATES THAT TS 08W WILL TRANSIT
JUST EAST OF SOUTHERN HONSHU, IN THE VICINITY OF THE BOSO
PENINSULA. SIMULTANEOUSLY, A SLIGHT REORIENTATION OF THE STR AXIS
IS EXPECTED TO INDUCE A NORTHEASTWARD TRACK ALONG THE NORTHWESTERN
PERIPHERY OF THE STR. TRACK GUIDANCE ALSO INDICATES LANDFALL OVER
NORTHEASTERN HONSHU TO OCCUR AROUND TAU 12, PRIOR TO SECONDARY
LANDFALL OVER SOUTHERN CENTRAL HOKKAIDO. OF NOTE, NEARLY ALL OF THE
GALE FORCE WINDS ARE LOCATED THROUGHOUT THE EASTERN SEMICIRCLE OF THE
STORM, AS WITNESSED BY RELATIVELY CALM (10-15 KTS) WINDS REPORTED AT
HACHIJOJIMA WMO STATION, JUST WEST OF THE TRACK. IN TERMS OF
INTENSITY, TS 08W IS CURRENTLY APPROACHING OR HAS ALREADY REACHED ITS
PEAK OF APPROXIMATELY 40 KTS AND AS ITS WIND FIELD BEGINS TO INTERACT
WITH LAND, IT IS FORECAST TO START WEAKENING. ADDITIONALLY, THE SYSTEM
WILL ENCOUNTER RAPIDLY DETERIORATING ENVIRONMENTAL CONDITIONS,
INCLUDING ENHANCED VWS AND RAPIDLY COOLING SST. DISSIPATION OF THE
LOW-LEVEL VORTEX IS EXPECTED BETWEEN TAUS 24 AND 36.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE EXHIBITS FAIR AGREEMENT
IN THE NEAR TERM, THOUGH NOT ALL DYNAMIC MODELS HAVE FULLY
INITIALIZED THE LLCC. AMONG THE AVAILABLE GUIDANCE, CROSS-TRACK
SPREAD IS RELATIVELY MINIMAL (APPROXIMATELY 20 NM AT LANDFALL),
REFLECTING HIGH AGREEMENT ON THE SHORT-TERM TRACK. HOWEVER, MODEL
DIVERGENCE INCREASES SUBSTANTIALLY IN THE POST-LANDFALL PERIOD,
WITH CROSS-TRACK SPREAD EXPANDING TO OVER 300 NM BY TAU 36. THE
JTWC TRACK FORECAST IS THEREFORE ASSESSED WITH MEDIUM CONFIDENCE.
INTENSITY GUIDANCE ALSO SUPPORTS A MEDIUM CONFIDENCE LEVEL, AS ALL
AVAILABLE GUIDANCE INDICATES MORE OR LESS ABRUPT WEAKENING DUE TO
STRONG SHEAR AND LAND INTERACTION. TIMELINE OF THE DISSIPATION
REMAINS UNCERTAIN, BUT IT IS CONTAINED WITHIN THE 24-36
HOUR ENVELOPE AMONG ALL AVAILABLE GUIDANCE.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM//
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