Tropical Depression 09F (97P.Invest) - Discussion

[wyq614]

Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Feb 01/2358 UTC 2009 UTC.

TROPICAL DEPRESSION 09F [1000HPA] WAS LOCATED NEAR 15.2S 163.6E AT
012100 UTC. POSITION FAIR AND BASED ON MTSAT/VIS, RECENT QUIKSCAT AND
PERIPHERAL SURFACE OBSERVATIONS. SEA SURFACE TEMPERATURE IS ABOUT 31
DEGREES.

09F IS EMBEDDED IN A MONSOONAL TROUGH, SOUTH OF A DEVELOPING
CONVERGENCE ZONE. LLCC LIES EXPOSED AS STRONG SHEAR OVER THE SYSTEM
HAS DISPLACED DEEP CONVECTION TO THE NORTH. UPPER DIFFLUENCE IS
LIKELY TO INCREASE AS THE 250HPA SUBTROPICAL RIDGE, CURRENTLY TO THE
FAR SOUTH, MOVES NORTH IN THE NEXT 48 HOURS. 09F MAY COME UNDER THE
INFLUENCE OF A RETROGRESSING UPPER TROUGH FROM THE EAST AS WELL.
CIMMS INDICATES DECREASING SHEAR ALONG 09F'S FORECAST MOVEMENT AND
THIS IS LIKELY TO ENHANCE THE DEVELOPMENT OF THE SYSTEM. CURRENTLY, A
SOUTHEAST SURGE EXISTS TO THE SOUTH, WHILE A NORTHWEST SURGE IS
DEVELOPING TO THE NORTHWEST. GLOBAL MODELS HAVE CAPTURED 09F AND MOVE
IT SOUTH OR SOUTHEAST WITH SOME INTENSFICATION.

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

NO OTHER TROPICAL DISTURBANCE ANALYSED OR FORECAST FOR THE AREA.

[HURAKAN]

AN AREA OF CONVECTION HAS PERSISTED NEAR 12.9S 161.1E,
APPROXIMATELY 640 NM NORTH-NORTHWEST OF NOUMEA, NEW CALEDONIA.
ANIMATED METSAT IMAGERY DEPICTS A DEVELOPING LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH FLARING DEEP CONVECTION LOCATED
PRIMARILY OVER THE WESTERN PERIPHERY OF THE DISTURBANCE. A 012222Z
ASCAT PASS SHOWS 10 TO 15 KNOT WINDS NEAR THE CENTER OF THE TIGHT,
BUT ELONGATED, LLCC. THE SYSTEM IS LOCATED IN A REGION OF STRONG
VERTICAL WIND WHICH IS LIMITING DEVELOPMENT AT THIS TIME. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. DUE TO THE STRONG
VERTICAL WIND SHEAR, AND LACK OF PERSISTENT CONVECTION ASSOCIATED
WITH THE LLCC, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS POOR.

[HURAKAN]

[Crostorm]

TROPICAL DISTURBANCE ADVISORY NUMBER A4 ISSUED FROM RSMC NADI
Feb 04/0220 UTC 2009 UTC.

TROPICAL DEPRESSION TD09F [999HPA] CENTRE LOCATED NEAR 19.1S 161.6E
AT 040000 UTC. POSITION POOR, BASED ON MTSAT VIS/EIR WITH ANIMATION
AND RECENT MICROWAVE PASS. DEPRESSION MOVING SOUTH AT 18 KNOTS.
EXPECT CLOCKWISE WINDS 25 TO 30 KNOTS, POSSIBLY INCREASING TO 35
KNOTS IN THE SECTOR 50 TO 180 NAUTICAL MILES OF CENTRE IN THE
NORTHEASTERN SEMICIRCLE IN THE NEXT 12 TO 18 HOURS. AREA OF GALES
MOVING WITH TROPICAL DEPRESSION.

LLCC LOCATED SOUTHWEST OF DEEP CONVECTION. CLOUD TOPS HAVE WARMED IN
THE LAST 6 HOURS BUT THIS MAY BE DUE TO DIURNAL EFFECTS. OUTFLOW GOOD
TO EAST BUT RESTRICTED ELSEWHERE. DVORAK ANALYSIS BASED ON 0.4 WRAP
ON LOG10 SPIRAL YIELDS AN UNREPRESENTATIVE DT=2.5, MET=1.5, PT=2.0.
FT BASED ON PT, THUS, T2.0/2.0/D0.5/24HRS.
SYSTEM LOCATED UNDER A 250 HPA RIDGE IN AN AREA OF DIFLUENCE WITH AN
APPROACHING SHORT WAVE TROUGH AT 500 HPA. SST AROUND 31C. AN UPPER
LEVEL JET LIES TO THE SOUTHWEST. RECENT WATER VAPOR IMAGERY SHOWS DRY
AIR PUSHING IN FROM THE SOUTH. 09F IS EXPECTED TO STEER SOUTHEAST BY
DEEP MONSOONAL NORTHWESTERLIES. CIMMS INDICATES 30 TO 50 KNOT SHEAR
JUST TO THE SOUTH OF THE SYSTEM BUT IS EXPECTED TO DECREASE. MOST
GLOBAL MODELS GENERALLY AGREE ON MOVING 09F SOUTHEAST WITH SOME
INTENSIFICATION.

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

THE NEXT TROPICAL DISTURBANCE ADVISORY ON TD09F WILL BE ISSUED AROUND
040830UTC.