TROPICAL DISTURBANCE ADVISORY NUMBER B15 ISSUED FROM RSMC NADI
Dec 161952 UTC.
SEVERE TROPICAL CYCLONE YASA CENTRE 899HPA WAS LOCATED NEAR 15.5S
176.7E AT 161800 UTC. POSITION GOOD BASED ON HR HIMAWARI EIR IMAGERY
AND PERIPHERAL SURFACE REPORTS. CYCLONE MOVING EAST SOUTHEAST AT
ABOUT 11 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE
ESTIMATED AT ABOUT 135 KNOTS.
EXPECT WINDS OVER 63 KNOTS WITHIN 60 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 60 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 35 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 50 NAUTICAL MILES IN NW QUADRANT
EXPECT WINDS OVER 47 KNOTS WITHIN 100 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 100 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 70 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 90 NAUTICAL MILES IN NW QUADRANT
EXPECT WINDS OVER 33 KNOTS WITHIN 200 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 180 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 150 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 150 NAUTICAL MILES IN NW QUADRANT
DEEP CONVECTION WITH CLOUD TOP COOLING CONTINUES TO PERSIST WITH A
WELL DEFINED EYE. ORGANISATION GOOD. TC YASA LIES UNDER AN UPPER
DIFFLUENT REGION IN A LOW SHEARED ENVIRONMENT. YASA IS BEING STEERED
EASTWARD-SOUTHEASTWARDS ALONG THE SOUTHERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE TO THE NORTH. CYCLONIC CIRCULATION EXTENDS UPTO
500HPA. SST IS AROUND 29 DEGREES CELSIUS. DVORAK ANALYSIS BASED ON OW
EYE PATTERN WITH A W SURROUND WITH BANDING FEATURE YIELDING DT OF
7.5. MET 7.5 AND PT 6.0. FT BASED ON DT THUS, YIELDING
T7.5/7.5/D0.5/24HRS.
FORECASTS :
AT 12 HRS VALID AT 170600 UTC 16.6S 178.4E MOV SE AT 10 KT WITH 130
KT CLOSE TO CENTRE
AT 24 HRS VALID AT 171800 UTC 18.0S 179.8E MOV SE AT 10 KT WITH 120
KT CLOSE TO CENTRE
OUTLOOK :
AT 36 HRS VALID AT 180600 UTC 19.4S 179.2W MOV SE AT 09 KT WITH 115
KT CLOSE TO CENTRE
AT 48 HRS VALID AT 181800 UTC 20.8S 178.8W MOV SE AT 09 KT WITH 110
KT CLOSE TO CENTRE
Dec 161952 UTC.
SEVERE TROPICAL CYCLONE YASA CENTRE 899HPA WAS LOCATED NEAR 15.5S
176.7E AT 161800 UTC. POSITION GOOD BASED ON HR HIMAWARI EIR IMAGERY
AND PERIPHERAL SURFACE REPORTS. CYCLONE MOVING EAST SOUTHEAST AT
ABOUT 11 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE
ESTIMATED AT ABOUT 135 KNOTS.
EXPECT WINDS OVER 63 KNOTS WITHIN 60 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 60 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 35 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 50 NAUTICAL MILES IN NW QUADRANT
EXPECT WINDS OVER 47 KNOTS WITHIN 100 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 100 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 70 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 90 NAUTICAL MILES IN NW QUADRANT
EXPECT WINDS OVER 33 KNOTS WITHIN 200 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 180 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 150 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 150 NAUTICAL MILES IN NW QUADRANT
DEEP CONVECTION WITH CLOUD TOP COOLING CONTINUES TO PERSIST WITH A
WELL DEFINED EYE. ORGANISATION GOOD. TC YASA LIES UNDER AN UPPER
DIFFLUENT REGION IN A LOW SHEARED ENVIRONMENT. YASA IS BEING STEERED
EASTWARD-SOUTHEASTWARDS ALONG THE SOUTHERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE TO THE NORTH. CYCLONIC CIRCULATION EXTENDS UPTO
500HPA. SST IS AROUND 29 DEGREES CELSIUS. DVORAK ANALYSIS BASED ON OW
EYE PATTERN WITH A W SURROUND WITH BANDING FEATURE YIELDING DT OF
7.5. MET 7.5 AND PT 6.0. FT BASED ON DT THUS, YIELDING
T7.5/7.5/D0.5/24HRS.
FORECASTS :
AT 12 HRS VALID AT 170600 UTC 16.6S 178.4E MOV SE AT 10 KT WITH 130
KT CLOSE TO CENTRE
AT 24 HRS VALID AT 171800 UTC 18.0S 179.8E MOV SE AT 10 KT WITH 120
KT CLOSE TO CENTRE
OUTLOOK :
AT 36 HRS VALID AT 180600 UTC 19.4S 179.2W MOV SE AT 09 KT WITH 115
KT CLOSE TO CENTRE
AT 48 HRS VALID AT 181800 UTC 20.8S 178.8W MOV SE AT 09 KT WITH 110
KT CLOSE TO CENTRE