SPAC: 08F - Tropical Depression

[Subtrop]

92P INVEST 250218 1800 16.0S 177.5W SHEM 20 1003

[cycloneye]

A SIGNIFICANT TROPICAL DISTURBANCE 08F CENTRE [1003HPA] WAS ANALYSED
NEAR 17.9S 171.9W [S OF SAMOA & NW OF NIUE] AT 192200UTC. SST IS
AROUND 29 DEGREES CELSIUS.
ORGANISATION REMAINS POOR AND CONVECTION IS TO the NORTH OF SUPPOSED
LLCC.
THE SYSTEM IS CURRENTLY UNDER MODERATE SHEAR, STRONG VORTICITY AND
MODERATE UPPER DIVERGENCE.
THE SYSTEM IS BEING STEERED TO THE SOUTHEAST BY THE NORTHWEST DEEP
LAYER MEAN.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT SOUTHEASTWARDS
[CLOSE TO NIUE] WITH SLIGHT INTENSIFICATION.

THE POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN
THE NEXT 24 TO 48 HOURS IS LOW.

[cycloneye]

THE AREA OF CONVECTION (INVEST 92P) PREVIOUSLY LOCATED NEAR
17.2S 171.4W IS NOW LOCATED NEAR 18.4S 169.1W, APPROXIMATELY 61 NM
NORTHEAST OF NIUE. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS INTENSIFYING AND INCREASINGLY CURVED CONVECTION OBSCURING THE
CONSOLIDATING LOW-LEVEL CIRCULATION (LLC) NORTHEAST OF NIUE, ALONG
THE SOUTH PACIFIC CONVERGENCE ZONE (SPCZ). ENVIRONMENTAL ANALYSIS
REVEALS A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH LOW TO MODERATE
VERTICAL WIND SHEAR (VWS) OF 15-20 KNOTS, MODERATE POLEWARD UPPER-
LEVEL OUTFLOW, AND WARM SEA SURFACE TEMPERATURES (SST) OF 28-29 C.
DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT PORTRAYING
STRONG DEVELOPMENT AND A SOUTHEASTWARD TRACK OVER THE NEXT 24 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 997 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO HIGH.

[cycloneye]

TROPICAL DEPRESSION TD08F CENTER [1000HPA] WAS ANALYSED NEAR 17.9S
170.9W AT 202100UTC SLOW MOVING. POSITION POOR BASED ON HIMAWARI-9
VIS IMAGERY AND PERIPHERAL SURFACE OBSERVATIONS. SST IS AROUND 29
DEGREES CELSIUS.

ORGANISATION REMAINS POOR AND THE CENTER REMAINS ELONGATED.
CONVECTION REMAINS PERSISTENT TO THE EAST OF THE LLCC. CYCLONIC
CIRCULATION EXTENDS UP TO 500HPA. THE SYSTEM LIES IN AN AREA OF LOW
TO MODERATE SHEAR AND MODERATE UPPER DIVERGENCE, WHILE GOOD
DIVERGENCE REMAINS TO THE EAST OF THE LLCC. THE SYSTEM IS BEING
STEERED TO THE SOUTHEAST BY THE NEAR-EQUATORIAL RIDGE.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT SOUTHEASTWARDS
WITH SLIGHT INTENSIFICATION.

THE POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN
THE NEXT 24 TO 48 HOURS IS LOW TO MODERATE.

[cycloneye]

TROPICAL DEPRESSION TD08F CENTER [998HPA] WAS ANALYSED NEAR 19.7S
166.6W AT 210600UTC SLOW MOVING. POSITION GOOD BASED ON HIMAWARI-9
VIS/IR IMAGERY AND PERIPHERAL SURFACE OBSERVATIONS. SST IS AROUND 28
DEGREES CELSIUS.

DRY AIR WRAPPING IN FROM THE SOUTHWEST. LLCC DISCERNABLE AS DEEP
CONVECTION WARMS OVER LLCC. ORGANISATION REMAINS POOR. CYCLONIC
CIRCULATION EXTENDS UP TO 500HPA. THE SYSTEM LIES IN AN AREA OF LOW
TO MODERATE SHEAR AND MODERATE UPPER DIVERGENCE, WHILE GOOD
DIVERGENCE REMAINS TO THE EAST OF THE LLCC.
THE SYSTEM IS BEING STEERED TO THE SOUTH-SOUTHEAST BY THE
NEAR-EQUATORIAL RIDGE.
TD08F IS EXPECTED TO ENCOUNTER HIGH SHEAR AND DRY AIR IF IT CONTINUES
IN THIS DIRECTION.

GLOBAL MODELS MOVE TD08F SOUTH-SOUTHEASTWARDS WITH SLIGHT
INTENSIFICATION.

THE POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN
THE NEXT 24 TO 48 HOURS REMAINS LOW TO MODERATE.