AN AREA OF CONVECTION HAS PERSISTED NEAR 13.5S 170.3W,
APPROXIMATELY 54 NM NORTH-NORTHEAST OF PAGO PAGO, AMERICAN SAMOA.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS FLARING CONVECTION
ASSOCIATED WITH AN ILL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC).
A 270330Z SSMIS REVEALS THE BULK OF THE DEEP CONVECTION OVER THE
NORTHEASTERN QUADRANT WITH FRAGMENTED CONVECTIVE BANDING AROUND THE
LLCC. UPPER-LEVEL ANALYSIS INDICATES THE DISTURBANCE IS LOCATED IN
AN AREA OF LOW VERTICAL WIND SHEAR AND A POINT-SOURCE DIRECTLY
OVERHEAD SUSTAINING THE CONVECTION AND PROVIDING EXCELLENT OUTFLOW.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS LOW
Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Mar 28/0911 UTC 2015 UTC.
TROPICAL DISTRUBANCE 14F CENTER [1006HPA] WAS ANALYSED NEAR 19.1S
167.3W AT 280600UTC. SLOW MOVING. POSITION POOR BASED ON MTSAT IR/EIR
IMAGERY AND PERIPHERAL OBSERVATIONS.
ORGANISATION REMAINS POOR WITH CONVECTION PESISTANT OVER THE SUPPOSED
LLCC IN THE PAST 12 TO 18 HOURS. SYSTEM LIES UNDER A UPPER RIDGE IN A
LOW SHEARED ENVIRONMENT. SST AROUND 29 DEGREE CELSIUS. CYCLONIC
CIRCULATION EXTENDS UPTO 500HPA.
GLOBAL MODELS HAVE PICKED THIS SYSTEM AND MOVE IT SOUTHEASTWARDS WITH
LITTLE INTENSIFICATION.
THE POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN
THE NEXT 24 TO 48 HOURS IS LOW.
NO OTHER SIGNIFICANT TROPICAL DISTURBANCE ANALYSED OR FORECAST IN THE
AREA.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 17.9S
168.7W IS NOW LOCATED NEAR 21.9S 160.9W, APPROXIMATELY 600 NM
SOUTHWEST OF BORA BORA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS FLARING CONVECTION BEING SHEARED SOUTHEAST OF AN ELONGATED
LOW LEVEL CIRCULATION CENTER. AN ASSESSMENT OF RECENT MICROWAVE
IMAGERY, INCLUDING A 290626Z SSMIS 91GHZ COLOR COMPOSITE IMAGE,
SHOWS THAT THE CONVECTION IS LOCATED ALONG THE SOUTHEASTERN
PERIPHERY WITH DRY AIR WRAPPING AROUND THE NORTHWESTERN PERIPHERY
AND INTO THE CENTER. A 290855Z SCATTEROMETER PASS FURTHER SHOWS THE
ELONGATED NATURE OF THE SYSTEM; HOWEVER, THERE ARE 35-40 KNOT WINDS
ALONG THE EASTERN PERIPHERY. UPPER LEVEL ANALYSIS REVEALS THAT THE
SYSTEM IS SOUTH OF THE RIDGE UNDER THE MID-LATITUDE WESTERLY FLOW.
IN ADDITION, THE SYSTEM IS IN AN AREA OF MODERATE TO HIGH (20 TO 30
KNOT) NORTHWESTERLY VERTICAL WIND SHEAR (VWS). THE SYSTEM IS
EXPECTED TO CONTINUE TRACKING EAST-SOUTHEASTWARD, FURTHER INTO THE
BAROCLINIC ZONE AND INCREASED VWS. THIS SYSTEM IS ASSESSED AS
SUBTROPICAL. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 35 TO
40 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 993 MB.
DUE TO THE SUBTROPICAL ASSESSMENT AND DECLINING UPPER LEVEL
ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (SUBTROPICAL SYSTEM) PREVIOUSLY
LOCATED NEAR 21.9S 160.9W IS NOW LOCATED NEAR 22.6S 158.2W,
APPROXIMATELY 510 NM SOUTHWEST OF BORA BORA. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS PERSISTENT DEEP CONVECTION
SHEARED OVER THE SOUTHEAST QUADRANT OF AN EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC). A 300307Z AMSU-B 89 GHZ IMAGE SHOWS
SHALLOW BANDING WRAPPING INTO AN ELONGATED LLCC WITH DEEP CONVECTIVE
BANDING CONFINED TO THE SOUTHEAST QUADRANT. RECENT SCATTEROMETER
IMAGERY INDICATES 25 TO 30 KNOT WINDS OVER THE EASTERN SEMI-CIRCLE.
UPPER-LEVEL ANALYSIS REVEALS AN UNFAVORABLE ENVIRONMENT
CHARACTERIZED BY MODERATE TO STRONG (20 TO 30 KNOTS) VERTICAL WIND
SHEAR (VWS) ASSOCIATED WITH STRONG NORTHWESTERLY FLOW ALOFT. THIS
SYSTEM IS LOCATED POLEWARD OF THE SUBTROPICAL RIDGE AXIS AND IS
EMBEDDED WITHIN THE SUBTROPICAL WESTERLIES WITH MODERATE
BAROCLINICITY. THE SYSTEM IS NOT EXPECTED TO DEVELOP INTO A TROPICAL
SYSTEM AND WILL CONTINUE TRACKING EAST-SOUTHEASTWARD, FURTHER INTO
THE BAROCLINIC ZONE AND INCREASED VWS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 30 TO 35 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 998 MB. DUE TO THE SUBTROPICAL NATURE OF THE
SYSTEM, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.
FMS升熱帶低壓
Tropical Disturbance Summary For area Equator to 25S, 160E to 120W
ISSUED FROM RSMC NADI Mar 30/0136 UTC 2015 UTC.
TROPICAL DEPRESSION 14F CENTRE [1000HPA] WAS ANALYSED NEAR 23.0S
158.8W AT 292100UTC MOVING SOUTHEAST AT 15 KNOTS. POSITION POOR BASED
ON MTSAT VIS IMAGERY AND PERIPHERAL OBSERVATIONS. SST AROUND 29
DEGREES CELSIUS.
ORGANISATION HAS IMPROVED OVER THE PAST 24 HOURS. CONVECTION REMAINS
PESISTANT. SYSTEM LIES UNDER AND UPPER DIFFULENT REGION IN A MODERATE
TO HIGH SHEARED ENVIRONMENT. CYCLONIC CIRCULATION EXTENDS UPTO
700HPA.
GLOBAL MODELS HAVE PICKED THIS 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.
NO OTHER SIGNIFICANT TROPICAL DISTURBANCE ANALYSED OR FORECAST IN THE
AREA.
提升卡
千斤頂
