CLICK ON THE IMAGERIES BELOW TO GET THEM ENLARGED
JTWC IS ISSUING 6 HOURLY WARNINGS AND 3 HOURLY SATELLITE BULLETINS ON 12W AND ON 14W.
WESTERN PACIFIC: TY 12W(DOLPHIN). WARNING 46 ISSUED BY JTWC @ 07/0900 UTC
PROGNOSTIC REASONING
WDPN31 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 046//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 26.7N 128.1E
INITIAL INTENSITY: 90 KTS
GEOGRAPHIC REFERENCE: 20 NM NORTHEAST OF KADENA AB
MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 09 KTS
SIGNIFICANT WAVE HEIGHT: 40 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL IMAGERY (MSI) DEPICTS TYPHOON (TY) 12W
INTENSIFYING AS IT SCRAPES THE COAST OF NORTHWESTERN OKINAWA.
ANIMATED LONGWAVE INFRARED IMAGERY REVEALS THE INNER CORE HAS
COOLING CLOUD TOPS ASYMMETRICALLY SURROUNDING THE PINHOLE EYE. THE
070422Z AMSR2 MICROWAVE WINDSPEED PRODUCT REVEALS THAT THE
STRONGEST TYPHOON-FORCE WINDS ARE CONFINED TO THE NORTHERN AND
EASTERN QUADRANTS, THOUGH STORM-FORCE WINDS ARE PRESENT IN ALL
QUADRANTS. SURFACE OBSERVATIONS FROM NAGO PEAKED AT 49 KTS
SUSTAINED AT 070600Z, WHILE OBSERVATIONS FROM AMAMI PEAKED AT
070000Z AT 50 KTS SUSTAINED AND GUSTS UP TO 68 KTS. OBSERVATIONS
FROM AMAMI CONTINUE TO REMAIN NEAR 50 KTS SUSTAINED THROUGH
070700Z. THE 070422Z AMSR2 MICROWAVE 91 GHZ IMAGE REVEALS THE TIGHT
INNER CORE WITH A SINGLE LARGE BAND OF DEEP CONVECTION SPIRALING
OUT FROM THE CENTER. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE
ENVIRONMENT, CHARACTERIZED BY LOW (0-5 KTS) VERTICAL WIND SHEAR,
WARM (29-30 C) SEA SURFACE TEMPERATURES (SST), AND GOOD RADIAL
OUTFLOW. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE PINHOLE EYE IN ANIMATED MSI. THE INITIAL INTENSITY OF 90 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE CIMSS AUTOMATED
INTENSITY ESTIMATES AND THE AGENCY DVORAK FIXES LISTED BELOW,
SUPPORTED BY THE AFOREMENTIONED AMSR2 WINDSPEED PRODUCT.
INITIAL WIND RADII BASIS: ADJUSTED WIND RADII USING THE 070100Z
ASCAT DATA.
CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A SUBTROPICAL
RIDGE CENTERED OVER THE SEA OF JAPAN
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.5 - 102 KTS
RJTD: T5.5 - 102 KTS
RCTP: T5.0 - 90 KTS
KNES: T5.5 - 102 KTS
CIMSS SATCON: 102 KTS AT 070610Z
CIMSS ADT: 102 KTS AT 070610Z
CIMSS AIDT: 89 KTS AT 070610Z
CIMSS D-MINT: 76 KTS AT 070504Z
CIMSS D-PRINT: 82 KTS AT 070630Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 0-5 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: HIGH
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: AFTER A BRIEF SOUTHWESTWARD DETOUR, TY 12W
(DOLPHIN) IS FORECAST TO CONTINUE TRACKING WESTWARD WHILE IT
REMAINS UNDER THE INFLUENCE OF THE STR CENTERED OVER THE SEA OF
JAPAN. THE TROUGH CURRENTLY ERODING THE STR IS EXPECTED TO PASS BY
AROUND TAU 36, ALLOWING THE STR TO REORIENT AND BUILD TO THE
NORTHEAST OF THE SYSTEM, DRIVING A GENTLE NORTHWESTWARD CURVE
BEGINNING AROUND TAU 24. LANDFALL IN CHINA IS EXPECTED AROUND TAU
60. REGARDING INTENSITY, 12W HAS INTENSIFIED SLIGHTLY, BOLSTERED BY
ELEVATED OCEAN HEAT CONTENT (OHC) ASSOCIATED WITH THE KUROSHIO
CURRENT. IT IS EXPECTED TO MAINTAIN THIS INTENSITY APPROXIMATELY
FOR THE NEXT 24 HOURS. 12W WILL EXIT THE WARM POOL OF HIGHER OHC
VALUES AROUND TAU 24-36, CONTRIBUTING TO SLIGHT WEAKENING LEADING
UP TO LANDFALL. DOLPHIN IS FORECAST TO RAPIDLY WEAKEN OVER LAND AND
FULLY DISSIPATE BY TAU 96.
MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH LANDFALL AT TAU 60, LENDING HIGH CONFIDENCE TO
THE SHORT-TERM TRACK FORECAST. MODELS DIVERGE SIGNIFICANTLY
POST-LANDFALL, CONTRIBUTING TO UNCERTAINTY SURROUNDING THE TRACK
FORECAST FROM TAU 72-96. AS A RESULT, THE JTWC TRACK FORECAST IS
PLACED WITH HIGH CONFIDENCE FROM TAU 0-72 AND LOW CONFIDENCE FROM
TAU 72-96. RELIABLE INTENSITY AIDS ARE IN STRONG AGREEMENT FOR THE
DURATION OF THE FORECAST PERIOD, SUPPORTING THE JTWC INTENSITY
FORECAST WITH HIGH CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: HIGH
INTENSITY 72-120 HR: HIGH//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 046//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 26.7N 128.1E
INITIAL INTENSITY: 90 KTS
GEOGRAPHIC REFERENCE: 20 NM NORTHEAST OF KADENA AB
MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 09 KTS
SIGNIFICANT WAVE HEIGHT: 40 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL IMAGERY (MSI) DEPICTS TYPHOON (TY) 12W
INTENSIFYING AS IT SCRAPES THE COAST OF NORTHWESTERN OKINAWA.
ANIMATED LONGWAVE INFRARED IMAGERY REVEALS THE INNER CORE HAS
COOLING CLOUD TOPS ASYMMETRICALLY SURROUNDING THE PINHOLE EYE. THE
070422Z AMSR2 MICROWAVE WINDSPEED PRODUCT REVEALS THAT THE
STRONGEST TYPHOON-FORCE WINDS ARE CONFINED TO THE NORTHERN AND
EASTERN QUADRANTS, THOUGH STORM-FORCE WINDS ARE PRESENT IN ALL
QUADRANTS. SURFACE OBSERVATIONS FROM NAGO PEAKED AT 49 KTS
SUSTAINED AT 070600Z, WHILE OBSERVATIONS FROM AMAMI PEAKED AT
070000Z AT 50 KTS SUSTAINED AND GUSTS UP TO 68 KTS. OBSERVATIONS
FROM AMAMI CONTINUE TO REMAIN NEAR 50 KTS SUSTAINED THROUGH
070700Z. THE 070422Z AMSR2 MICROWAVE 91 GHZ IMAGE REVEALS THE TIGHT
INNER CORE WITH A SINGLE LARGE BAND OF DEEP CONVECTION SPIRALING
OUT FROM THE CENTER. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE
ENVIRONMENT, CHARACTERIZED BY LOW (0-5 KTS) VERTICAL WIND SHEAR,
WARM (29-30 C) SEA SURFACE TEMPERATURES (SST), AND GOOD RADIAL
OUTFLOW. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE PINHOLE EYE IN ANIMATED MSI. THE INITIAL INTENSITY OF 90 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE CIMSS AUTOMATED
INTENSITY ESTIMATES AND THE AGENCY DVORAK FIXES LISTED BELOW,
SUPPORTED BY THE AFOREMENTIONED AMSR2 WINDSPEED PRODUCT.
INITIAL WIND RADII BASIS: ADJUSTED WIND RADII USING THE 070100Z
ASCAT DATA.
CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A SUBTROPICAL
RIDGE CENTERED OVER THE SEA OF JAPAN
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.5 - 102 KTS
RJTD: T5.5 - 102 KTS
RCTP: T5.0 - 90 KTS
KNES: T5.5 - 102 KTS
CIMSS SATCON: 102 KTS AT 070610Z
CIMSS ADT: 102 KTS AT 070610Z
CIMSS AIDT: 89 KTS AT 070610Z
CIMSS D-MINT: 76 KTS AT 070504Z
CIMSS D-PRINT: 82 KTS AT 070630Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 0-5 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: HIGH
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: AFTER A BRIEF SOUTHWESTWARD DETOUR, TY 12W
(DOLPHIN) IS FORECAST TO CONTINUE TRACKING WESTWARD WHILE IT
REMAINS UNDER THE INFLUENCE OF THE STR CENTERED OVER THE SEA OF
JAPAN. THE TROUGH CURRENTLY ERODING THE STR IS EXPECTED TO PASS BY
AROUND TAU 36, ALLOWING THE STR TO REORIENT AND BUILD TO THE
NORTHEAST OF THE SYSTEM, DRIVING A GENTLE NORTHWESTWARD CURVE
BEGINNING AROUND TAU 24. LANDFALL IN CHINA IS EXPECTED AROUND TAU
60. REGARDING INTENSITY, 12W HAS INTENSIFIED SLIGHTLY, BOLSTERED BY
ELEVATED OCEAN HEAT CONTENT (OHC) ASSOCIATED WITH THE KUROSHIO
CURRENT. IT IS EXPECTED TO MAINTAIN THIS INTENSITY APPROXIMATELY
FOR THE NEXT 24 HOURS. 12W WILL EXIT THE WARM POOL OF HIGHER OHC
VALUES AROUND TAU 24-36, CONTRIBUTING TO SLIGHT WEAKENING LEADING
UP TO LANDFALL. DOLPHIN IS FORECAST TO RAPIDLY WEAKEN OVER LAND AND
FULLY DISSIPATE BY TAU 96.
MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH LANDFALL AT TAU 60, LENDING HIGH CONFIDENCE TO
THE SHORT-TERM TRACK FORECAST. MODELS DIVERGE SIGNIFICANTLY
POST-LANDFALL, CONTRIBUTING TO UNCERTAINTY SURROUNDING THE TRACK
FORECAST FROM TAU 72-96. AS A RESULT, THE JTWC TRACK FORECAST IS
PLACED WITH HIGH CONFIDENCE FROM TAU 0-72 AND LOW CONFIDENCE FROM
TAU 72-96. RELIABLE INTENSITY AIDS ARE IN STRONG AGREEMENT FOR THE
DURATION OF THE FORECAST PERIOD, SUPPORTING THE JTWC INTENSITY
FORECAST WITH HIGH CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: HIGH
INTENSITY 72-120 HR: HIGH//
NNNN
3 HOUR POSITION UPDATE GRAPHIC
SURFACE OBSERVATIONS
AI Model Track Forecasts
Multiplatform Tropical Cyclone MSLP and Maximum Winds
Digital Dvorak
Bias Correction of Subjective Dvorak
TPPN11 PGTW 070900
A. TYPHOON 12W (DOLPHIN)
B. 07/0830Z
C. 26.90N
D. 128.01E
E. ONE/GK2A
F. T5.0/5.5/D0.5/24HRS STT: W0.5/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 07A/PBO IRREG EYE/ANMTN. OW EYE SURROUNDED BY MG YIELDS
AN E# OF 4.5. ADDED 0.5 EYE ADJUSTMENT FOR B, TO YIELD A DT OF 5.0.
MET YIELDS 5.5. PT YIELDS 5.0. DBO DT.
I. ADDITIONAL POSITIONS:
07/0422Z 26.92N 128.07E AMS2
RUCKER
A. TYPHOON 12W (DOLPHIN)
B. 07/0830Z
C. 26.90N
D. 128.01E
E. ONE/GK2A
F. T5.0/5.5/D0.5/24HRS STT: W0.5/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 07A/PBO IRREG EYE/ANMTN. OW EYE SURROUNDED BY MG YIELDS
AN E# OF 4.5. ADDED 0.5 EYE ADJUSTMENT FOR B, TO YIELD A DT OF 5.0.
MET YIELDS 5.5. PT YIELDS 5.0. DBO DT.
I. ADDITIONAL POSITIONS:
07/0422Z 26.92N 128.07E AMS2
RUCKER
H-9 @0920 UTC
FY4-B @0700 UTC
@0425 UTC
Radius of Maximum Wind (RMW)
Platform: RCM-2 Acquisition Date: 2026-08-06 21:21:06 UTC
Platform: RCM-2
Acquisition Date: 2026-08-06 21:21:06 UTC
Storm Name: WP122026 / DOLPHIN
Storm ID: WP12
Storm Center Longitude: 129.604
Storm Center Latitude: 27.135
Incidence Angle (Degrees): 38.818
Quadrant 1 NE VMax (kts): 68.65
Quadrant 2 SE VMax (kts): 62.40
Quadrant 3 SW VMax (kts): 66.29
Quadrant 4 NW VMax (kts): 83.54
RMax (nmi): 11.00 - 107.00
Acquisition Date: 2026-08-06 21:21:06 UTC
Storm Name: WP122026 / DOLPHIN
Storm ID: WP12
Storm Center Longitude: 129.604
Storm Center Latitude: 27.135
Incidence Angle (Degrees): 38.818
Quadrant 1 NE VMax (kts): 68.65
Quadrant 2 SE VMax (kts): 62.40
Quadrant 3 SW VMax (kts): 66.29
Quadrant 4 NW VMax (kts): 83.54
RMax (nmi): 11.00 - 107.00
WESTERN PACIFIC: TS 14W(CHAN HOM). WARNING 2 ISSUED BY JTWC @ 07/0900 UTC
PROGNOSTIC REASONING
WDPN33 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (CHAN-HOM) WARNING NR
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 29.7N 160.4E
INITIAL INTENSITY: 40 KTS
GEOGRAPHIC REFERENCE: 475 NM NORTHEAST OF MINAMI TORI SHIMA
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
SIGNIFICANT WAVE HEIGHT: 23 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 14W AS A HIGHLY SHEARED AND FULLY EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC) COMPLETELY DEVOID OF CONVECTION SAVE FOR
A PITIFUL PLUME OF CENTRAL CONVECTION WEAKLY EMANATING FROM THE
LLCC. DRY AIR IS SPIRALING INTO THE CORE FROM THE WEST AND SOUTH.
THE 070709 91 GHZ SSMIS PASS REVEALS THE LOW-LEVEL CLOUD BANDING
AND THE LACK OF DEEP CONVECTION. ADDITIONALLY, THE LARGE AMOUNTS OF
DRY AIR ARE ALSO PRESENT IN THE IMAGE. ENVIRONMENTAL ANALYSIS
REVEALS AN UNFAVORABLE ENVIRONMENT, CHARACTERIZED BY MODERATE TO
HIGH (20-25 KTS) VERTICAL WIND SHEAR (VWS), MARGINALLY WARM (26-27
C) SEA SURFACE TEMPERATURES (SST) AND VERY LOW OCEAN HEAT CONTENT,
WITH POOR OUTFLOW AND LARGE AMOUNTS OF DRY AIR. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE FULLY EXPOSED
LLCC. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE CIMSS AUTOMATED INTENSITY ESTIMATES AND THE
AGENCY DVORAK FIXES LISTED BELOW.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A WESTWARD
EXTENSION OF THE SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.5 - 35 KTS
RJTD: T1.5 - 25 KTS
RCTP: T2.0 - 30 KTS
CIMSS SATCON: 40 KTS AT 070810Z
CIMSS ADT: 45 KTS AT 070810Z
CIMSS AIDT: 36 KTS AT 070810Z
CIMSS D-MINT: 28 KTS AT 070708Z
CIMSS D-PRINT: 27 KTS AT 070810Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 20-25 KTS
SST: 26-27 CELSIUS
OUTFLOW: WEAK POLEWARD
OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
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: TS 14W (CHAN-HOM) IS FORECAST TO CONTINUE
TRACKING NORTHWESTWARD WHILE IT REMAINS UNDER THE STEERING
INFLUENCE OF THE WEAK STR CENTERED TO ITS NORTHEAST. BETWEEN TAU
24-36, A DEEP TROUGH WILL WEAKEN THE RIDGE AND CAUSE 14W TO SLOW
TRACK SPEEDS AND TRACK DUE WESTWARD BETWEEN TAU 24-48. FOLLOWING
THE PASSAGE OF THE TROUGH AROUND TAU 48, THE STR WILL REBUILD AND
DRIVE 14W NORTHWESTWARD THROUGH TAU 96. TOWARDS THE END OF THE
FORECAST PERIOD, A SHALLOW STR OVER THE SEA OF JAPAN WILL BUILD AND
CAUSE 14W TO TRACK DUE WESTWARD AGAIN BETWEEN TAU 96-120. REGARDING
INTENSITY, 14W IS EXPECTED TO GRADUALLY INTENSIFY THROUGH TAU 72 AS
THE ENVIRONMENT SLOWLY BECOMES MORE FAVORABLE. VWS IS EXPECTED TO
EASE SLIGHTLY BY TAU 24 AND ALLOW FOR SLIGHT INTENSIFICATION.
HOWEVER, BY AROUND TAU 72, SSTS ARE EXPECTED TO BECOME UNFAVORABLE
AND INDUCE WEAKENING THROUGH THE REMAINDER OF THE FORECAST PERIOD.
14W IS FORECAST TO BEGIN SUBTROPICAL TRANSITION NO LATER THAN TAU
120.
MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH TAU 72, SUPPORTING THE JTWC TRACK WITH HIGH
CONFIDENCE. FOLLOWING TAU 72, TRACK GUIDANCE DIVERGES SIGNIFICANTLY
IN THE CROSS-TRACK DIRECTION, CAUSING UNCERTAINTY WITH THE
LATE-TERM TRACK FORECAST. THE JTWC TRACK FORECAST IS PLACED CLOSE
TO THE MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE FROM TAU 72-120.
RELIABLE INTENSITY AIDS ARE IN STRONG AGREEMENT THROUGHOUT THE
FORECAST, SUPPORTING THE JTWC INTENSITY FORECAST WITH HIGH
CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: HIGH
INTENSITY 72-120 HR: HIGH//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (CHAN-HOM) WARNING NR
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 29.7N 160.4E
INITIAL INTENSITY: 40 KTS
GEOGRAPHIC REFERENCE: 475 NM NORTHEAST OF MINAMI TORI SHIMA
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
SIGNIFICANT WAVE HEIGHT: 23 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 14W AS A HIGHLY SHEARED AND FULLY EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC) COMPLETELY DEVOID OF CONVECTION SAVE FOR
A PITIFUL PLUME OF CENTRAL CONVECTION WEAKLY EMANATING FROM THE
LLCC. DRY AIR IS SPIRALING INTO THE CORE FROM THE WEST AND SOUTH.
THE 070709 91 GHZ SSMIS PASS REVEALS THE LOW-LEVEL CLOUD BANDING
AND THE LACK OF DEEP CONVECTION. ADDITIONALLY, THE LARGE AMOUNTS OF
DRY AIR ARE ALSO PRESENT IN THE IMAGE. ENVIRONMENTAL ANALYSIS
REVEALS AN UNFAVORABLE ENVIRONMENT, CHARACTERIZED BY MODERATE TO
HIGH (20-25 KTS) VERTICAL WIND SHEAR (VWS), MARGINALLY WARM (26-27
C) SEA SURFACE TEMPERATURES (SST) AND VERY LOW OCEAN HEAT CONTENT,
WITH POOR OUTFLOW AND LARGE AMOUNTS OF DRY AIR. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE FULLY EXPOSED
LLCC. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE CIMSS AUTOMATED INTENSITY ESTIMATES AND THE
AGENCY DVORAK FIXES LISTED BELOW.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A WESTWARD
EXTENSION OF THE SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.5 - 35 KTS
RJTD: T1.5 - 25 KTS
RCTP: T2.0 - 30 KTS
CIMSS SATCON: 40 KTS AT 070810Z
CIMSS ADT: 45 KTS AT 070810Z
CIMSS AIDT: 36 KTS AT 070810Z
CIMSS D-MINT: 28 KTS AT 070708Z
CIMSS D-PRINT: 27 KTS AT 070810Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 20-25 KTS
SST: 26-27 CELSIUS
OUTFLOW: WEAK POLEWARD
OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
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: TS 14W (CHAN-HOM) IS FORECAST TO CONTINUE
TRACKING NORTHWESTWARD WHILE IT REMAINS UNDER THE STEERING
INFLUENCE OF THE WEAK STR CENTERED TO ITS NORTHEAST. BETWEEN TAU
24-36, A DEEP TROUGH WILL WEAKEN THE RIDGE AND CAUSE 14W TO SLOW
TRACK SPEEDS AND TRACK DUE WESTWARD BETWEEN TAU 24-48. FOLLOWING
THE PASSAGE OF THE TROUGH AROUND TAU 48, THE STR WILL REBUILD AND
DRIVE 14W NORTHWESTWARD THROUGH TAU 96. TOWARDS THE END OF THE
FORECAST PERIOD, A SHALLOW STR OVER THE SEA OF JAPAN WILL BUILD AND
CAUSE 14W TO TRACK DUE WESTWARD AGAIN BETWEEN TAU 96-120. REGARDING
INTENSITY, 14W IS EXPECTED TO GRADUALLY INTENSIFY THROUGH TAU 72 AS
THE ENVIRONMENT SLOWLY BECOMES MORE FAVORABLE. VWS IS EXPECTED TO
EASE SLIGHTLY BY TAU 24 AND ALLOW FOR SLIGHT INTENSIFICATION.
HOWEVER, BY AROUND TAU 72, SSTS ARE EXPECTED TO BECOME UNFAVORABLE
AND INDUCE WEAKENING THROUGH THE REMAINDER OF THE FORECAST PERIOD.
14W IS FORECAST TO BEGIN SUBTROPICAL TRANSITION NO LATER THAN TAU
120.
MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH TAU 72, SUPPORTING THE JTWC TRACK WITH HIGH
CONFIDENCE. FOLLOWING TAU 72, TRACK GUIDANCE DIVERGES SIGNIFICANTLY
IN THE CROSS-TRACK DIRECTION, CAUSING UNCERTAINTY WITH THE
LATE-TERM TRACK FORECAST. THE JTWC TRACK FORECAST IS PLACED CLOSE
TO THE MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE FROM TAU 72-120.
RELIABLE INTENSITY AIDS ARE IN STRONG AGREEMENT THROUGHOUT THE
FORECAST, SUPPORTING THE JTWC INTENSITY FORECAST WITH HIGH
CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: HIGH
INTENSITY 72-120 HR: HIGH//
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WESTERN PACIFIC: INVEST 97W. ADVISORY ISSUED BY JTWC @ 07/0600 UTC
THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED NEAR 19.9N 108.1E IS NOW LOCATED NEAR 19.8N 108.1E, APPROXIMATELY 27 NM SOUTHEAST OF BACH LONGVI. ANIMATED ENHANCED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS PERSISTENT CONVECTION BUILDING OVER A LOW-LEVEL CIRCULATION CENTER (LLCC). A 061430Z ASCAT-C IMAGE REVEALS A CLOSED CIRCULATION WITH 15-20 KNOT WINDS ALONG THE NORTHWEST PERIPHERY. ONLY A SLIGHT IMPROVEMENT IN STRUCTURE WOULD NECESSITATE THE INITIATION OF WARNINGS. THE ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (5-10 KTS), GOOD EQUATORWARD OUTFLOW ALOFT, AND WARM SEA SURFACE TEMPERATURE ALOFT (29-30C). WHILE GLOBAL DETERMINISTIC MODELS ARE NOT IN SUPPORT OF DEVELOPMENT, GLOBAL ENSEMBLE MODELS SHOW SLIGHT DEVELOPMENT OVER THE NEXT 6 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 12 TO 18 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.
WESTERN PACIFIC: INVEST 98W.
