ABPW10 PGTW 270600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
SOUTH PACIFIC OCEANS/270600Z-280600ZSEP2016//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/270151ZSEP2016//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY:
(1) AT 270000Z, TYPHOON 20W (MEGI) WAS LOCATED NEAR 23.1N
123.2E, APPROXIMATELY 152 NM SOUTHEAST OF TAIPEI, TAIWAN, AND HAD
TRACKED NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. MAXIMUM
SUSTAINED SURFACE WINDS WERE ESTIMATED AT 100 KNOTS GUSTING TO 125
KNOTS. SEE REF A (WTPN31 PGTW 270300) FOR FURTHER DETAILS.
(2) NO OTHER TROPICAL CYCLONES.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 15.6N
157.9E, IS NOW LOCATED NEAR 14.8N 153.4E, APPROXIMATELY 500 NM EAST
OF ANDERSON AB, GUAM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND A 262346Z AMSU 89 GHZ IMAGE REVEAL A PARTIALLY-EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION ALONG THE SOUTHERN
SEMICIRCLE. A 262301Z ASCAT PASS DEPICTS 20 KNOTS OF GRADIENT
INDUCED WINDS ALONG THE NORTHERN PERIPHERY WITH WEAKER (10 TO 15
KNOTS) WINDS ALONG SOUTHERN PERIPHERY OF THE SYSTEM. UPPER-LEVEL
ANALYSIS INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH WEAK
OUTFLOW AND LIGHT-MODERATE (15 TO 20 KNOTS) VERTICAL WIND SHEAR.
DYNAMIC MODEL GUIDANCE SHOWS LIMITED DEVELOPMENT OF THE SYSTEM OVER
THE NEXT 24 TO 48 HOURS AS THE SYSTEM TRACKS WESTWARD TOWARD GUAM,
AND INTO AN AREA OF UPPER-LEVEL CONFLUENCE. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.
(2) NO OTHER SUSPECT AREAS.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.//
NNNN
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 98W) HAS PERSISTED NEAR
15.6N 157.9E, APPROXIMATELY 780 NM EAST-NORTHEAST OF GUAM. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A WEAK EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION ALONG THE SOUTHERN
PERIPHERY. A 252320Z METOP-B 89GHZ IMAGE DEPICTS ISOLATED CONVECTION
OVER THE SOUTH QUADRANT OF THE LLCC. A 252321Z ASCAT METOP-B IMAGE
SHOWED AN ELONGATED CIRCULATION WITH 20-25 KNOTS OF GRADIENT EAST-
SOUTHEASTERLY WINDS ON THE NORTHEAST QUADRANT WITH 10-15 KNOTS
ELSEWHERE. THE SYSTEM IS LOCATED IN A MARGINAL ENVIRONMENT WITH LOW
TO MODERATE VERTICAL WIND SHEAR AND FAIR DIVERGENCE ALOFT. GLOBAL
MODELS SHOW LIMITED DEVELOPMENT AS THE SYSTEM TRACKS WESTWARD OVER
THE NEXT 2-3 DAYS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1008 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.
