WESTERN NORTH PACIFIC: TD 25W. WARNING 1 ISSUED BY JTWC @09/0300 UTC
TC WARNING GRAPHIC
PROGNOSTIC REASONING
WDPN31 PGTW 090300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR) WARNING
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 8.7N 152.1E
INITIAL INTENSITY: 25 KTS
GEOGRAPHIC REFERENCE: 73 NM NORTH OF CHUUK
MOVEMENT PAST 6 HOURS: WESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 14 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS LOOSELY
ORGANIZED CLOUD BANDS WRAPPING INTO A MID-LEVEL CIRCULATION THAT IS
OFFSET TO THE NORTH-NORTHWEST OF THE ASSESSED LOW-LEVEL CIRCULATION
CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON THE ANIMATED MSI AND SURFACE OBSERVATIONS FROM
CHUUK. THE INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON PARTIAL METOP-B ASCAT PASSES THAT REVEALED
SWATHS OF 20-25 KT WINDS IN THE OUTER EDGES OF THE CIRCULATION, AS
WELL AS AGENCY DVORAK FIXES RANGING FROM T1.0-2.0. THE ENVIRONMENT
IS ASSESSED TO BE FAVORABLE FOR CONTINUED DEVELOPMENT OF 04W, WITH
WARM (28-29 C) SEA SURFACE TEMPERATURES, LOW VERTICAL WIND SHEAR,
ABUNDANT MID-LEVEL MOISTURE AVAILABILITY, AND MODERATE POLEWARD
OUTFLOW ALOFT.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: A WEAK STEERING ENVIRONMENT WITH A
WESTWARD EXTENSION OF A NEAR-EQUATORIAL RIDGE IN THE CENTRAL NORTH
PACIFIC AND THE EASTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE
CENTERED OVER THE LUZON STRAIT.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.0 - 30 KTS
RJTD: T1.0 - 25 KTS
KNES: T2.0 - 30 KTS
CIMSS D-PRINT: 30 KTS AT 080000Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 10-15 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE POLEWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.
FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 04W HAS BECOME
INCREASINGLY ORGANIZED OVER THE PAST 12 HOURS AS IT HAS SLOWLY
TRACKED NORTHWESTWARD. THE TRAJECTORY OF THE SYSTEM IS FORECAST TO
CONTINUE IN A GENERALLY NORTHWESTWARD DIRECTION TOWARD GUAM FOR THE
ENTIRE FORECAST PERIOD. THERE ARE SIGNIFICANT FORECAST CHALLENGES
IN REGARDS TO THE EXACT TRACK THAT IS EXPECTED, AS THERE IS LITTLE
CONSENSUS AMONG FORECAST GUIDANCE ABOUT WHICH OF THE COMPETING
STEERING INFLUENCES WILL ULTIMATELY CONTROL THE SYSTEM TRACK. A
NEAR-EQUATORIAL RIDGE TO THE EAST HAS THE POTENTIAL TO STEER 04W IN
A RECURVING ARC WITH A LARGER NORTHWARD COMPONENT, WHILE A
DEEP-LAYER SUBTROPICAL RIDGE TO THE WEST WOULD MAINTAIN A MORE
NORTHWESTWARD TRACK IF IT IS ABLE TO EXTEND TO THE NORTH OF 04W.
THE JTWC FORECAST TRACK IS PLACED ON A TRAJECTORY THAT FAVORS THE
LATTER STEERING MECHANISM, WHICH TRACKS THE SYSTEM SOUTHWEST OF
GUAM WITH A CPA OF 31 NM SHORTLY BEFORE TAU 120. THERE REMAINS A
HIGH LEVEL OF UNCERTAINTY IN THE TRACK AT THIS TIME, LENDING LOW
CONFIDENCE TO THE FORECAST. THE INTENSITY FORECAST PROJECTS STEADY
INTENSIFICATION THROUGH THE ENTIRE FORECAST PERIOD, UP TO 95 KTS AT
TAU 120. THE CURRENT FAVORABLE ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO DEGRADE IN THE NEAR TERM WITH INCREASING MID-LAYER VWS
THAT WILL PLACE A LIMIT ON THE RATE OF INTENSIFICATION THROUGH
AROUND TAU 60. FURTHER INTENSIFICATION AFTER TAU 60 IS EXPECTED IN
A MORE FAVORABLE SHEAR ENVIRONMENT.
MODEL DISCUSSION: GEFS, ECENS, AND GOOGLE DEEPMIND ENSEMBLE SUITES
PREDICT A VARIETY OF MULTI-MODAL TRACK SOLUTIONS THAT APPEAR TO BE
LARGELY DEPENDENT UPON THE TIMING AND LOCATION OF CYCLONE GENESIS.
THE LIMITED MODEL TRACK GUIDANCE CURRENTLY AVAILABLE LEANS TOWARD A
MORE NORTHWESTWARD TRACK UNDER THE STEERING INFLUENCE OF THE STR TO
THE WEST. THE JTWC TRACK FORECAST IS PLACED NEAR THE MULTI-MODEL
CONSENSUS, ALBEIT WITH LOW CONFIDENCE CONSIDERING THE LEVEL OF
UNCERTAINTY. THERE IS BETTER AGREEMENT AMONG THE MODEL GUIDANCE FOR
INTENSITY AS SIMILAR ENVIRONMENTAL CONDITIONS SHOULD PREVAIL
REGARDLESS OF ANY VARIABILITY IN THE TRACK. HAFS-A IS BY FAR THE
MOST AGGRESSIVE MODEL, SUGGESTING A PEAK INTENSITY OF 125 KTS WHILE
THE REMAINDER OF GUIDANCE IS 90-110 KNOT RANGE. OVERALL, THE JTWC
INTENSITY FORECAST IS PLACED NEAR THE MULTI-MODEL CONSENSUS WITH
MEDIUM CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: LOW
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR) WARNING
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 8.7N 152.1E
INITIAL INTENSITY: 25 KTS
GEOGRAPHIC REFERENCE: 73 NM NORTH OF CHUUK
MOVEMENT PAST 6 HOURS: WESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 14 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS LOOSELY
ORGANIZED CLOUD BANDS WRAPPING INTO A MID-LEVEL CIRCULATION THAT IS
OFFSET TO THE NORTH-NORTHWEST OF THE ASSESSED LOW-LEVEL CIRCULATION
CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON THE ANIMATED MSI AND SURFACE OBSERVATIONS FROM
CHUUK. THE INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON PARTIAL METOP-B ASCAT PASSES THAT REVEALED
SWATHS OF 20-25 KT WINDS IN THE OUTER EDGES OF THE CIRCULATION, AS
WELL AS AGENCY DVORAK FIXES RANGING FROM T1.0-2.0. THE ENVIRONMENT
IS ASSESSED TO BE FAVORABLE FOR CONTINUED DEVELOPMENT OF 04W, WITH
WARM (28-29 C) SEA SURFACE TEMPERATURES, LOW VERTICAL WIND SHEAR,
ABUNDANT MID-LEVEL MOISTURE AVAILABILITY, AND MODERATE POLEWARD
OUTFLOW ALOFT.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: A WEAK STEERING ENVIRONMENT WITH A
WESTWARD EXTENSION OF A NEAR-EQUATORIAL RIDGE IN THE CENTRAL NORTH
PACIFIC AND THE EASTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE
CENTERED OVER THE LUZON STRAIT.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.0 - 30 KTS
RJTD: T1.0 - 25 KTS
KNES: T2.0 - 30 KTS
CIMSS D-PRINT: 30 KTS AT 080000Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 10-15 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE POLEWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.
FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 04W HAS BECOME
INCREASINGLY ORGANIZED OVER THE PAST 12 HOURS AS IT HAS SLOWLY
TRACKED NORTHWESTWARD. THE TRAJECTORY OF THE SYSTEM IS FORECAST TO
CONTINUE IN A GENERALLY NORTHWESTWARD DIRECTION TOWARD GUAM FOR THE
ENTIRE FORECAST PERIOD. THERE ARE SIGNIFICANT FORECAST CHALLENGES
IN REGARDS TO THE EXACT TRACK THAT IS EXPECTED, AS THERE IS LITTLE
CONSENSUS AMONG FORECAST GUIDANCE ABOUT WHICH OF THE COMPETING
STEERING INFLUENCES WILL ULTIMATELY CONTROL THE SYSTEM TRACK. A
NEAR-EQUATORIAL RIDGE TO THE EAST HAS THE POTENTIAL TO STEER 04W IN
A RECURVING ARC WITH A LARGER NORTHWARD COMPONENT, WHILE A
DEEP-LAYER SUBTROPICAL RIDGE TO THE WEST WOULD MAINTAIN A MORE
NORTHWESTWARD TRACK IF IT IS ABLE TO EXTEND TO THE NORTH OF 04W.
THE JTWC FORECAST TRACK IS PLACED ON A TRAJECTORY THAT FAVORS THE
LATTER STEERING MECHANISM, WHICH TRACKS THE SYSTEM SOUTHWEST OF
GUAM WITH A CPA OF 31 NM SHORTLY BEFORE TAU 120. THERE REMAINS A
HIGH LEVEL OF UNCERTAINTY IN THE TRACK AT THIS TIME, LENDING LOW
CONFIDENCE TO THE FORECAST. THE INTENSITY FORECAST PROJECTS STEADY
INTENSIFICATION THROUGH THE ENTIRE FORECAST PERIOD, UP TO 95 KTS AT
TAU 120. THE CURRENT FAVORABLE ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO DEGRADE IN THE NEAR TERM WITH INCREASING MID-LAYER VWS
THAT WILL PLACE A LIMIT ON THE RATE OF INTENSIFICATION THROUGH
AROUND TAU 60. FURTHER INTENSIFICATION AFTER TAU 60 IS EXPECTED IN
A MORE FAVORABLE SHEAR ENVIRONMENT.
MODEL DISCUSSION: GEFS, ECENS, AND GOOGLE DEEPMIND ENSEMBLE SUITES
PREDICT A VARIETY OF MULTI-MODAL TRACK SOLUTIONS THAT APPEAR TO BE
LARGELY DEPENDENT UPON THE TIMING AND LOCATION OF CYCLONE GENESIS.
THE LIMITED MODEL TRACK GUIDANCE CURRENTLY AVAILABLE LEANS TOWARD A
MORE NORTHWESTWARD TRACK UNDER THE STEERING INFLUENCE OF THE STR TO
THE WEST. THE JTWC TRACK FORECAST IS PLACED NEAR THE MULTI-MODEL
CONSENSUS, ALBEIT WITH LOW CONFIDENCE CONSIDERING THE LEVEL OF
UNCERTAINTY. THERE IS BETTER AGREEMENT AMONG THE MODEL GUIDANCE FOR
INTENSITY AS SIMILAR ENVIRONMENTAL CONDITIONS SHOULD PREVAIL
REGARDLESS OF ANY VARIABILITY IN THE TRACK. HAFS-A IS BY FAR THE
MOST AGGRESSIVE MODEL, SUGGESTING A PEAK INTENSITY OF 125 KTS WHILE
THE REMAINDER OF GUIDANCE IS 90-110 KNOT RANGE. OVERALL, THE JTWC
INTENSITY FORECAST IS PLACED NEAR THE MULTI-MODEL CONSENSUS WITH
MEDIUM CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: LOW
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN
DVORAK ANALYSIS @09/0230 UTC
TPPN10 PGTW 090328
A. TROPICAL DEPRESSION 04W (SE OF GUAM)
B. 09/0230Z
C. 8.15N
D. 151.76E
E. FIVE/GK2A
F. T2.0/2.0/D1.0/18HRS STT: S0.0/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 63A/PBO PRLY ORGNZD LLCC/ANMTN. CNVCTN WRAPS .35 ON
LOG10 SPIRAL YIELDING A DT OF 2.0. MET YIELDS 1.5. PT YIELDS 2.0.
DBO DT.
I. ADDITIONAL POSITIONS: NONE
BALMER
A. TROPICAL DEPRESSION 04W (SE OF GUAM)
B. 09/0230Z
C. 8.15N
D. 151.76E
E. FIVE/GK2A
F. T2.0/2.0/D1.0/18HRS STT: S0.0/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 63A/PBO PRLY ORGNZD LLCC/ANMTN. CNVCTN WRAPS .35 ON
LOG10 SPIRAL YIELDING A DT OF 2.0. MET YIELDS 1.5. PT YIELDS 2.0.
DBO DT.
I. ADDITIONAL POSITIONS: NONE
BALMER
SOUTH PACIFIC: TC 30P(MAILA). WARNING 15 ISSUED BY JTWC 09/0300 UTC
TC WARNING GRAPHIC
PROGNOSTIC REASONING
WDPS31 PGTW 090300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (MAILA) WARNING NR
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 8.5S 155.1E
INITIAL INTENSITY: 100 KTS
GEOGRAPHIC REFERENCE: 741 NM NORTHEAST OF CAIRNS, AUSTRALIA
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 32 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 30P (MAILA) WITH A SLIGHTLY RAGGED 15NM EYE AND PRESSURE
ALONG THE SOUTHEASTERN QUADRANT. THE CULPRIT FOR THE DEFORMATION
WITHIN THE SOUTHEASTERN QUADRANT IS ATTRIBUTED TO THE MODERATE
EASTERLY SHEAR ACTING ON THE SYSTEM. A PARTIAL 082305Z METOP-B
ASCAT PASS CAUGHT THE CENTER OF THE CIRCULATION, LENDING HIGH
CONFIDENCE TO THE INITIAL POSITION AND WESTERN WIND RADII. THE
INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON PERSISTENCE FROM A 081917Z SEN-1 SAR IMAGE SHOWING A VMAX
PEAK OF 103 KTS. AGENCY DVORAK AND CIMSS OBJECTIVE ESTIMATES ARE
ANALYZED TO BE CURRENTLY OVERESTIMATING THE SURFACE WIND FIELD WHEN
COMPARED TO THE SAR OUTPUT. ENVIRONMENTAL ANALYSIS INDICATES THAT
30P IS CURRENTLY IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY MODERATE EQUATORWARD OUTFLOW ALOFT, MODERATE
EASTERLY VERTICAL WIND SHEAR, AND WARM SEA SURFACE TEMPERATURES.
INITIAL WIND RADII BASIS: 082305Z METOP-B ASCAT SCATTEROMETER DATA
CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) POSITIONED OVER NORTHERN AUSTRALIA
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.0 - 115 KTS
KNES: T5.5 - 102 KTS
ABRF: T6.0 - 115 KTS
CIMSS ADT: 115 KTS AT 090000Z
CIMSS AIDT: 110 KTS AT 090000Z
CIMSS D-PRINT: 105 KTS AT 090000Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 15-20 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE EQUATORWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: TRACK SPEEDS HAVE BEEN SLOWED DOWN
COMPARED TO THE PREVIOUS FORECAST TO ACCOUNT FOR THE POSSIBILITY OF
FURTHER SLOW MOVEMENT WITHIN THE SOLOMON SEA OVER THE NEXT 3-4 DAYS
FORECAST DISCUSSION: TC 30P IS FORECAST TO TRACK GENERALLY
WESTWARD, ALONG THE NORTHWESTERN PERIPHERY OF THE STR OVER CENTRAL
AUSTRALIA THROUGH TAU 24. NEAR TAU 24, RIDGING IS EXPECTED TO BUILD
TO THE SOUTHEAST OF THE SYSTEM, DRIVING IT SOUTHWESTWARD THROUGH
TAU 120. A TRACK NEAR THE TIP OF THE PAPUAN PENINSULA IS FORECAST
TO OCCUR NEAR TAU 96. HOWEVER, THERE HAS STARTED TO BE SIGNIFICANT
UNCERTAINTY REVOLVING AROUND THE POTENTIAL FOR FURTHER SLOW
MOVEMENT AND DISSIPATION WITHIN THE SOLOMON SEA. THE SYSTEM IS
CURRENTLY FORECAST TO STEADILY WEAKEN THROUGH TAU 48 DUE TO A TRACK
THROUGH THE POOL OF COLD WATERS THAT WAS LEFT IN THE WAKE OF 30P.
THE TRACK BACK THROUGH THE COLD POOL, ALONG WITH THE PERSISTENT
EASTERLY VERTICAL WIND SHEAR, WILL CAUSE 30P TO WEAKEN. AS
IT STANDS, THE JTWC FORECAST CALLS FOR WEAKENING THROUGHOUT THE
ENTIRE FORECAST PERIOD AND A SLOWER MOVEMENT AFTER TAU 24 AS IT
ATTEMPTS TO TRACK OFF TO THE WEST-SOUTHWEST. THERE IS A POSSIBLITY
THAT THE SYSTEM DISSIPATES EAST OF PAPUA NEW GUINEA IF A
SLOWER TRACK MOVMENT OCCURS OVER THE NEXT 72 HOURS.
MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS NOW IN VERY
POOR AGREEMENT WITH THE ECMWF DETERMINISTIC, ECMWF ENSEMBLE MEAN,
AND THE GOOGLE DEEPMIND ENSEMBLE MEAN ALL NOW SHOWING A TRACK THAT
NEVER ESCAPES THE SLOMON SEA. THIS HAS NOW CAUSED THERE TO BE
EXTREMELY LOW CONFIDENCE IN THE JTWC TRACK FORECAST. THE JTWC TRACK
IS PLACED NEAR THE CONSENSUS THROUGH TAU 48 AND THEN CLOSER TO THE
GFS ENSEMBLE MEAN THROUGH TAU 120. INTENSITY GUIDANCE HAS ONE
REMAINING OUTLIER IN THE COAMPS-TC, WHICH IS NOW THE ONLY MODEL
THAT SUGGESTS FURTHER INTENSIFICATION. OTHER THAN COAMPS-TC, THE
REMAINDER OF GUIDANCE SUGGESTS STEADY WEAKENING THROUGHOUT THE
ENTIRE FORECAST PERIOD. THE JTWC INTENSITY FORECAST IS PLACED NEAR
THE MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE DUE TO THE POSSIBILTY
OF AN EARLIER DISSIPATION TIMELINE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: LOW
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: LOW
INTENSITY 72-120 HR: LOW//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (MAILA) WARNING NR
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 8.5S 155.1E
INITIAL INTENSITY: 100 KTS
GEOGRAPHIC REFERENCE: 741 NM NORTHEAST OF CAIRNS, AUSTRALIA
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 32 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 30P (MAILA) WITH A SLIGHTLY RAGGED 15NM EYE AND PRESSURE
ALONG THE SOUTHEASTERN QUADRANT. THE CULPRIT FOR THE DEFORMATION
WITHIN THE SOUTHEASTERN QUADRANT IS ATTRIBUTED TO THE MODERATE
EASTERLY SHEAR ACTING ON THE SYSTEM. A PARTIAL 082305Z METOP-B
ASCAT PASS CAUGHT THE CENTER OF THE CIRCULATION, LENDING HIGH
CONFIDENCE TO THE INITIAL POSITION AND WESTERN WIND RADII. THE
INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON PERSISTENCE FROM A 081917Z SEN-1 SAR IMAGE SHOWING A VMAX
PEAK OF 103 KTS. AGENCY DVORAK AND CIMSS OBJECTIVE ESTIMATES ARE
ANALYZED TO BE CURRENTLY OVERESTIMATING THE SURFACE WIND FIELD WHEN
COMPARED TO THE SAR OUTPUT. ENVIRONMENTAL ANALYSIS INDICATES THAT
30P IS CURRENTLY IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY MODERATE EQUATORWARD OUTFLOW ALOFT, MODERATE
EASTERLY VERTICAL WIND SHEAR, AND WARM SEA SURFACE TEMPERATURES.
INITIAL WIND RADII BASIS: 082305Z METOP-B ASCAT SCATTEROMETER DATA
CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) POSITIONED OVER NORTHERN AUSTRALIA
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.0 - 115 KTS
KNES: T5.5 - 102 KTS
ABRF: T6.0 - 115 KTS
CIMSS ADT: 115 KTS AT 090000Z
CIMSS AIDT: 110 KTS AT 090000Z
CIMSS D-PRINT: 105 KTS AT 090000Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 15-20 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE EQUATORWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: TRACK SPEEDS HAVE BEEN SLOWED DOWN
COMPARED TO THE PREVIOUS FORECAST TO ACCOUNT FOR THE POSSIBILITY OF
FURTHER SLOW MOVEMENT WITHIN THE SOLOMON SEA OVER THE NEXT 3-4 DAYS
FORECAST DISCUSSION: TC 30P IS FORECAST TO TRACK GENERALLY
WESTWARD, ALONG THE NORTHWESTERN PERIPHERY OF THE STR OVER CENTRAL
AUSTRALIA THROUGH TAU 24. NEAR TAU 24, RIDGING IS EXPECTED TO BUILD
TO THE SOUTHEAST OF THE SYSTEM, DRIVING IT SOUTHWESTWARD THROUGH
TAU 120. A TRACK NEAR THE TIP OF THE PAPUAN PENINSULA IS FORECAST
TO OCCUR NEAR TAU 96. HOWEVER, THERE HAS STARTED TO BE SIGNIFICANT
UNCERTAINTY REVOLVING AROUND THE POTENTIAL FOR FURTHER SLOW
MOVEMENT AND DISSIPATION WITHIN THE SOLOMON SEA. THE SYSTEM IS
CURRENTLY FORECAST TO STEADILY WEAKEN THROUGH TAU 48 DUE TO A TRACK
THROUGH THE POOL OF COLD WATERS THAT WAS LEFT IN THE WAKE OF 30P.
THE TRACK BACK THROUGH THE COLD POOL, ALONG WITH THE PERSISTENT
EASTERLY VERTICAL WIND SHEAR, WILL CAUSE 30P TO WEAKEN. AS
IT STANDS, THE JTWC FORECAST CALLS FOR WEAKENING THROUGHOUT THE
ENTIRE FORECAST PERIOD AND A SLOWER MOVEMENT AFTER TAU 24 AS IT
ATTEMPTS TO TRACK OFF TO THE WEST-SOUTHWEST. THERE IS A POSSIBLITY
THAT THE SYSTEM DISSIPATES EAST OF PAPUA NEW GUINEA IF A
SLOWER TRACK MOVMENT OCCURS OVER THE NEXT 72 HOURS.
MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS NOW IN VERY
POOR AGREEMENT WITH THE ECMWF DETERMINISTIC, ECMWF ENSEMBLE MEAN,
AND THE GOOGLE DEEPMIND ENSEMBLE MEAN ALL NOW SHOWING A TRACK THAT
NEVER ESCAPES THE SLOMON SEA. THIS HAS NOW CAUSED THERE TO BE
EXTREMELY LOW CONFIDENCE IN THE JTWC TRACK FORECAST. THE JTWC TRACK
IS PLACED NEAR THE CONSENSUS THROUGH TAU 48 AND THEN CLOSER TO THE
GFS ENSEMBLE MEAN THROUGH TAU 120. INTENSITY GUIDANCE HAS ONE
REMAINING OUTLIER IN THE COAMPS-TC, WHICH IS NOW THE ONLY MODEL
THAT SUGGESTS FURTHER INTENSIFICATION. OTHER THAN COAMPS-TC, THE
REMAINDER OF GUIDANCE SUGGESTS STEADY WEAKENING THROUGHOUT THE
ENTIRE FORECAST PERIOD. THE JTWC INTENSITY FORECAST IS PLACED NEAR
THE MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE DUE TO THE POSSIBILTY
OF AN EARLIER DISSIPATION TIMELINE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: LOW
TRACK 72-120 HR: LOW
INTENSITY 00-72 HR: LOW
INTENSITY 72-120 HR: LOW//
NNNN
Platform: RCM-3
Acquisition Date: 2026-04-08 19:22:10 UTC
Storm Name: SH302026 / MAILA
Storm ID: SH30
Storm Center Longitude: 155.416
Storm Center Latitude: -8.562
Incidence Angle (Degrees): 32.240
Quadrant 1 NE VMax (kts): 98.79
Quadrant 2 SE VMax (kts): 101.05
Quadrant 3 SW VMax (kts): 96.92
Quadrant 4 NW VMax (kts): 103.99
RMax (nmi): 12.00 - 15.00
Acquisition Date: 2026-04-08 19:22:10 UTC
Storm Name: SH302026 / MAILA
Storm ID: SH30
Storm Center Longitude: 155.416
Storm Center Latitude: -8.562
Incidence Angle (Degrees): 32.240
Quadrant 1 NE VMax (kts): 98.79
Quadrant 2 SE VMax (kts): 101.05
Quadrant 3 SW VMax (kts): 96.92
Quadrant 4 NW VMax (kts): 103.99
RMax (nmi): 12.00 - 15.00
DVORAK ANALYSIS @09/0230 UTC
TPPS10 PGTW 090317
A. TROPICAL CYCLONE 30P (MAILA)
B. 09/0230Z
C. 8.38S
D. 154.84E
E. THREE/GK2A
F. T5.5/6.0/S0.0/24HRS STT: W0.5/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 11A/PBO RAGGED EYE/ANMTN. EYE EMBEDDED 60NM IN CDO
YIELDS AN E# OF 6.0. SUBTRACTED 1.0 FOR A RAGGED EYE AND ADDED 0.5
FOR BF TO YIELD A DT OF 5.5. MET YIELDS 6.5. PT YIELDS 6.0. DBO DT.
I. ADDITIONAL POSITIONS: NONE
BALMER
A. TROPICAL CYCLONE 30P (MAILA)
B. 09/0230Z
C. 8.38S
D. 154.84E
E. THREE/GK2A
F. T5.5/6.0/S0.0/24HRS STT: W0.5/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 11A/PBO RAGGED EYE/ANMTN. EYE EMBEDDED 60NM IN CDO
YIELDS AN E# OF 6.0. SUBTRACTED 1.0 FOR A RAGGED EYE AND ADDED 0.5
FOR BF TO YIELD A DT OF 5.5. MET YIELDS 6.5. PT YIELDS 6.0. DBO DT.
I. ADDITIONAL POSITIONS: NONE
BALMER
SOUTH PACIFIC : SS 31P (VAIANU). UPDATED LOCATION AND INTENSITY @09/0000 UTC.
PROGNOSTIC REASONING ISSUED @08/2100 UTC
WDPS32 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 31P (VAIANU) WARNING NR
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 25.4S 178.5E
INITIAL INTENSITY: 60 KTS
GEOGRAPHIC REFERENCE: 438 NM SOUTH OF SUVA, FIJI
MOVEMENT PAST 6 HOURS: SOUTHWARD AT 10 KTS
SIGNIFICANT WAVE HEIGHT: 28 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) THAT HAS DECOUPLED FROM
THE MID-UPPER LEVEL CIRCULATION WHICH HAS BEEN SHEARED TO THE SOUTH
AND EAST AS A RESULT OF STRONG VERTICAL WIND SHEAR (VWS). A 081557Z
F18 SSMIS 91 GHZ MICROWAVE IMAGE REVEALS LITTLE REMAINING DEEP
CONVECTION ASSOCIATED WITH THE LLCC IN THE SOUTHERN PERIPHERY. THE
IMAGE ALSO SHOWS WELL-DEFINED LOW-LEVEL CLOUD LINES WRAPPING
TIGHTLY INTO THE LLCC. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE SSMIS IMAGE AND ANIMATED EIR IMAGERY OF THE
EXPOSED LLCC. THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH LOW
CONFIDENCE DUE TO THE UNDER-ESTIMATION AND LOW BIAS OF THE DVORAK
TECHNIQUE EXPECTED WITH A SYSTEM THAT LACKS CONVECTION NEAR THE
CENTER. THE ENVIRONMENT IS CHARACTERIZED AS UNFAVORABLE FOR FURTHER
TROPICAL DEVELOPMENT WITH VERY HIGH VWS, DRY AIR ENTRAINMENT FROM
THE NORTH, AND COOL SEA SURFACE TEMPERATURES.
INITIAL WIND RADII BASIS: PERSISTENCE FROM EARLIER SAR DATA WITH
ADJUSTMENTS BASED ON THE OBJECTIVE BEST TRACK
CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A
NEAR-EQUATORIAL RIDGE (NER) CENTERED TO THE NORTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
PHFO: T3.0 - 45 KTS
CIMSS SATCON: 49 KTS AT 081610Z
CIMSS ADT: 35 KTS AT 081800Z
CIMSS AIDT: 43 KTS AT 081800Z
CIMSS D-MINT: 50 KTS AT 081556Z
CIMSS D-PRINT: 40 KTS AT 081800Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 35-40 KTS
SST: 24-25 CELSIUS
OUTFLOW: STRONG POLEWARD
OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE NORTH
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: LOW
INITIAL WIND RADII: LOW
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: TRUNCATED FORECAST TO 48 HOURS
FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 31P (VAIANU) IS FORECAST
TO CONTINUE ON A SOUTHWARD TRAJECTORY THROUGH TAU 36 UNDER THE
STEERING INFLUENCE OF THE NER TO THE NORTHEAST. A SOUTH-SOUTHWESTWARD
TRACK TOWARD THE NORTH ISLAND OF NEW ZEALAND IS ANTICIPATED AS THE
SYSTEM INTERACTS WITH AN EXTENSION OF DEEP-LAYER RIDGING TO THE EAST.
TC 31P IS FORECAST TO TRACK UNDER AN UPPER-LEVEL JET STREAK AND WILL
BE LOCATED POLEWARD OF THE JET AROUND TAU 24. A GRADUAL WEAKENING
TREND IS FORECAST THROUGH THE ENTIRE FORECAST PERIOD UNDER COMPETING
DYNAMICAL FORCING. COOL SEA SURFACE TEMPERATURES, DRY AIR ENTRAINMENT,
AND HIGH VWS THROUGH TAU 24 ARE OFFSET BY EXCELLENT POLEWARD OUTFLOW
ALOFT IN THE PRESENCE OF THE JET STREAK. AFTER TAU 24, THE VWS IS
EXPECTED TO ABATE WHILE A JET STREAK TO THE SOUTH CONTINUES TO SUPPORT
ROBUST POLEWARD OUTFLOW. THE COMBINATION OF SYNOPTIC FORCING WILL
ALLOW TC 31P TO MAINTAIN A BROAD WIND FIELD AND INTENSITIES OF 50
KNOTS THROUGH TAU 48. THIS SYNOPTIC SETUP WILL INITIATE SUBTROPICAL
TRANSITION AROUND TAU 36, WHICH IS EXPECTED TO BE COMPLETE BY TAU 48
AS THE SYSTEM DEVELOPS BAROCLINICITY AND TRACKS OVER COLD (22-23 C)
SEA SURFACE TEMPERATURES.
MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT ABOUT
THE SOUTHWARD TRACK AND TIMING OF A SHIFT TOWARD THE SOUTH-SOUTHWEST,
WITH CROSS-TRACK SPREAD OF 80 NM AT TAU 48. THE JTWC TRACK FORECAST IS
PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.
REGARDING INTENSITY, THE GUIDANCE IS IN GENERALLY GOOD AGREEMENT WITH
THE GRADUAL WEAKENING TREND THROUGHOUT THE ENTIRE FORECAST PERIOD. THE
JTWC INTENSITY FORECAST IS ALSO PLACED CLOSE TO THE MULTI-MODEL
CONSENSUS WITH HIGH CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
INTENSITY 00-72 HR: HIGH//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 31P (VAIANU) WARNING NR
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 25.4S 178.5E
INITIAL INTENSITY: 60 KTS
GEOGRAPHIC REFERENCE: 438 NM SOUTH OF SUVA, FIJI
MOVEMENT PAST 6 HOURS: SOUTHWARD AT 10 KTS
SIGNIFICANT WAVE HEIGHT: 28 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) THAT HAS DECOUPLED FROM
THE MID-UPPER LEVEL CIRCULATION WHICH HAS BEEN SHEARED TO THE SOUTH
AND EAST AS A RESULT OF STRONG VERTICAL WIND SHEAR (VWS). A 081557Z
F18 SSMIS 91 GHZ MICROWAVE IMAGE REVEALS LITTLE REMAINING DEEP
CONVECTION ASSOCIATED WITH THE LLCC IN THE SOUTHERN PERIPHERY. THE
IMAGE ALSO SHOWS WELL-DEFINED LOW-LEVEL CLOUD LINES WRAPPING
TIGHTLY INTO THE LLCC. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE SSMIS IMAGE AND ANIMATED EIR IMAGERY OF THE
EXPOSED LLCC. THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH LOW
CONFIDENCE DUE TO THE UNDER-ESTIMATION AND LOW BIAS OF THE DVORAK
TECHNIQUE EXPECTED WITH A SYSTEM THAT LACKS CONVECTION NEAR THE
CENTER. THE ENVIRONMENT IS CHARACTERIZED AS UNFAVORABLE FOR FURTHER
TROPICAL DEVELOPMENT WITH VERY HIGH VWS, DRY AIR ENTRAINMENT FROM
THE NORTH, AND COOL SEA SURFACE TEMPERATURES.
INITIAL WIND RADII BASIS: PERSISTENCE FROM EARLIER SAR DATA WITH
ADJUSTMENTS BASED ON THE OBJECTIVE BEST TRACK
CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A
NEAR-EQUATORIAL RIDGE (NER) CENTERED TO THE NORTHEAST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
PHFO: T3.0 - 45 KTS
CIMSS SATCON: 49 KTS AT 081610Z
CIMSS ADT: 35 KTS AT 081800Z
CIMSS AIDT: 43 KTS AT 081800Z
CIMSS D-MINT: 50 KTS AT 081556Z
CIMSS D-PRINT: 40 KTS AT 081800Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 35-40 KTS
SST: 24-25 CELSIUS
OUTFLOW: STRONG POLEWARD
OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE NORTH
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: LOW
INITIAL WIND RADII: LOW
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: TRUNCATED FORECAST TO 48 HOURS
FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 31P (VAIANU) IS FORECAST
TO CONTINUE ON A SOUTHWARD TRAJECTORY THROUGH TAU 36 UNDER THE
STEERING INFLUENCE OF THE NER TO THE NORTHEAST. A SOUTH-SOUTHWESTWARD
TRACK TOWARD THE NORTH ISLAND OF NEW ZEALAND IS ANTICIPATED AS THE
SYSTEM INTERACTS WITH AN EXTENSION OF DEEP-LAYER RIDGING TO THE EAST.
TC 31P IS FORECAST TO TRACK UNDER AN UPPER-LEVEL JET STREAK AND WILL
BE LOCATED POLEWARD OF THE JET AROUND TAU 24. A GRADUAL WEAKENING
TREND IS FORECAST THROUGH THE ENTIRE FORECAST PERIOD UNDER COMPETING
DYNAMICAL FORCING. COOL SEA SURFACE TEMPERATURES, DRY AIR ENTRAINMENT,
AND HIGH VWS THROUGH TAU 24 ARE OFFSET BY EXCELLENT POLEWARD OUTFLOW
ALOFT IN THE PRESENCE OF THE JET STREAK. AFTER TAU 24, THE VWS IS
EXPECTED TO ABATE WHILE A JET STREAK TO THE SOUTH CONTINUES TO SUPPORT
ROBUST POLEWARD OUTFLOW. THE COMBINATION OF SYNOPTIC FORCING WILL
ALLOW TC 31P TO MAINTAIN A BROAD WIND FIELD AND INTENSITIES OF 50
KNOTS THROUGH TAU 48. THIS SYNOPTIC SETUP WILL INITIATE SUBTROPICAL
TRANSITION AROUND TAU 36, WHICH IS EXPECTED TO BE COMPLETE BY TAU 48
AS THE SYSTEM DEVELOPS BAROCLINICITY AND TRACKS OVER COLD (22-23 C)
SEA SURFACE TEMPERATURES.
MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT ABOUT
THE SOUTHWARD TRACK AND TIMING OF A SHIFT TOWARD THE SOUTH-SOUTHWEST,
WITH CROSS-TRACK SPREAD OF 80 NM AT TAU 48. THE JTWC TRACK FORECAST IS
PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.
REGARDING INTENSITY, THE GUIDANCE IS IN GENERALLY GOOD AGREEMENT WITH
THE GRADUAL WEAKENING TREND THROUGHOUT THE ENTIRE FORECAST PERIOD. THE
JTWC INTENSITY FORECAST IS ALSO PLACED CLOSE TO THE MULTI-MODEL
CONSENSUS WITH HIGH CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
INTENSITY 00-72 HR: HIGH//
NNNN
DVORAK ANALYSIS @09/0230 UTC
TPPS11 PGTW 090323
A. TROPICAL CYCLONE 31P (VAIANU)
B. 09/0230Z
C. 26.46S
D. 178.69E
E. THREE/HMWRI9
F. ST3.5/3.5
G. IR/EIR/VIS/MSI
H. REMARKS: 19A/PBO XPSD LLCC/ANMTN. SUBTROPICAL CYCLONE
CLASSIFICATION TECHNIQUE YIELDS ST3.5.
I. ADDITIONAL POSITIONS:
08/2125Z 25.42S 178.53E MMHS
BALMER
A. TROPICAL CYCLONE 31P (VAIANU)
B. 09/0230Z
C. 26.46S
D. 178.69E
E. THREE/HMWRI9
F. ST3.5/3.5
G. IR/EIR/VIS/MSI
H. REMARKS: 19A/PBO XPSD LLCC/ANMTN. SUBTROPICAL CYCLONE
CLASSIFICATION TECHNIQUE YIELDS ST3.5.
I. ADDITIONAL POSITIONS:
08/2125Z 25.42S 178.53E MMHS
BALMER
