South Pacific: TC 17P(VICKY), Invest 98P:Tropical Cyclone Formation Alert, 96P & 99P: updates

TC 17P(VICKY) SOUTH PACIFIC
As of 00:00 UTC Feb 21, 2020:
Location: 14.8°S 170.8°W
Maximum Winds: 45 kt ( 85km/h)
Gusts: 55 kt ( 100km/h)
Minimum Central Pressure: 996 mb
TPPS11 PGTW 210339
A. TROPICAL CYCLONE 17P (VICKY)
B. 21/0300Z
C. 15.28S
D. 170.95W
E. FIVE/GOES17
F. T3.0/3.0/D2.0/18HRS  STT: S0.0/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 40A/PBO SBC/ANMTN. CNVCTN WRAPS .45 ON LOG10 SPIRAL
YIELDING A DT OF 2.5. MET YIELDS A 2.5 AND PT YIELDS 3.0. DBO
PT.
I. ADDITIONAL POSITIONS: NONE
ELIAS
REMARKS:
210300Z POSITION NEAR 15.2S 170.6W.
21FEB20. TROPICAL CYCLONE (TC) 17P (VICKY), LOCATED APPROXIMATELY
31 NM SOUTH OF PAGO PAGO, AMERICAN SAMOA HAS TRACKED SOUTHEASTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTIPSECTRAL
SATELLITE IMAGERY DEPICTS EXPANSION OF DEEP CONVECTIVE BANDING
WRAPPING INTO A DEFINED LOW LEVEL CIRCULATION CENTER. DESPITE THE
IMPROVEMENT OBSERVED IN VISIBLE IMAGERY, A 210049Z AMSR2 IMAGE
REVEALS POOR OVERALL CONVECTIVE ORGANIZATION.  THE CURRENT INTENSITY
IS HELD AT 45 KNOTS BASED ON DVORAK ESTIMATES OF T2.5 TO T3.0 (35-45
KNOTS), WHICH IS ABOVE AUTOMATED GUIDANCE.  NO RECENT SCATTEROMETRY
IS AVAILABLE TO CONFIRM THE INTENSITY AND WIND RADII ESTIMATES.  TC
17P IS TRACKING SOUTHEASTWARD ALONG THE PERIPHERY OF A SUB-TROPICAL
RIDGE, AND IS CURRENTLY IN A FAVORABLE ENVIRONMENT WITH WARM (27-28
CELSIUS) SEA SURFACE TEMPERATURES, LOW (10-15KTS) VERTICAL WIND
SHEAR (VWS) AND ESTABLISHED POLEWARD OUTFLOW. THE SYSTEM IS EXPECTED
TO BEGIN A GENERALLY SOUTH-SOUTHEASTWARD TRACK AT TAU 12, BECOMING
SOUTHWARD AFTER TAU 24. BETWEEN TAU 24 TO 48, CONDITIONS ARE
EXPECTED TO DEGRADE, WITH INCREASING VWS. NUMERICAL GUIDANCE
SUGGESTS 17P WILL WEAKEN AS IT APPROACHES THE SUB-TROPICAL
CIRCULATION TO THE SOUTH (96P), AND POTENTIALLY BE ABSORBED INTO
THIS AREA AS THE COMBINED ENERGY TRACKS GENERALLY WESTWARD.  
HOWEVER, LIMITED NUMERICAL MODEL SOLUTIONS ARE IN POOR AGREEMENT.
THE COMBINATION OF POTENTIAL SYSTEM INTERACTION AND HIGH DEGREE OF
SPREAD YIELDS LOW CONFIDENCE TO THE OVERALL JTWC FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 210000Z IS 15 FEET. NEXT WARNINGS
AT 210900Z, 211500Z, 212100Z AND 220300Z.


INVEST 98P SOUTH PACIFIC
As of 00:00 UTC Feb 21, 2020:
Location: 12.0°S 176.7°W
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 1003 mb
TPPS12 PGTW 210319
A. TROPICAL DISTURBANCE 98P (NW OF SAMOA)
B. 21/0240Z
C. 12.01S
D. 176.57W
E. FIVE/GOES17
F. T1.0/1.0  STT: S0.0/03HRS
G. IR/EIR/VIS/MSI
H. REMARKS: 40A/PBO SBC/ANMTN. CNVCTN WRAPS .25 ON LOG10 SPIRAL
YIELDING A DT OF 1.0. MET AND PT AGREE. DBO DT.
I. ADDITIONAL POSITIONS: NONE
ELIA
WTPS21PGTW 210230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 11.1S 178.9W TO 13.3S 173.4W
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 27 TO 33 KNOTS. METSAT
IMAGERY AT 210130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.0S 176.7W. THE SYSTEM IS MOVING EAST-SOUTHEASTWARD AT 11
KNOTS.
2. REMARKS:
AN AREA OF CONVECTION (INVEST 98P) HAS PERSISTED NEAR 12.0S 176.7W,
APPROXIMATELY 381 NM WEST-NORTHWESTWARD OF PAGO PAGO, AMERICAN
SAMOA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY, ALONG WITH A
202128Z METOP-B PASS DEPICTS A FORMATIVE LOW LEVEL CIRCULATION
CENTER (LLCC) WITH FRAGMENTED DEEP CONVECTION TO THE NORTHEAST.
ENVIRONMENTAL ANALYSIS REVEALS FAIR CONDITIONS FOR DEVELOPMENT WITH
MODERATE POLEWARD OUTFLOW, WEAK DIFFLUENCE ALOFT, LOW (10 KTS)
VERTICAL WIND SHEAR, AND WARM (29 TO 30 CELSIUS) SEA SURFACE
TEMPERATURES. GLOBAL MODELS INDICATE THAT 98P WILL CONTINUE TO
CONSOLIDATE AND SLIGHTLY INTENSIFY AS IT CONTINUES TO TRACK SOUTH-
SOUTHEASTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27
TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 998
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
220230Z.
//
NNNNS

INVEST 96P SOUTH PACIFIC
As of 00:00 UTC Feb 21, 2020:
Location: 19.7°S 169.7°W
Maximum Winds: 25 kt
Minimum Central Pressure: 1004 mb

INVEST 99P SOUTH PACIFIC
As of 00:00 UTC Feb 21, 2020:
Location: 13.8°S 139.2°E