
WDPN31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 32W (KAI-TAK)
WARNING NR 10//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 32W (KAI-TAK), LOCATED APPROXIMATELY 334 NM
EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS THE SYSTEM HAS ONCE AGAIN UNDERGONE A DEEP
CONVECTIVE MAXIMUM CYCLE CHARACTERIZED BY OVERSHOOTING CLOUD TOPS.
THE FIRST HALF OF THE MSI LOOP SHOWED AN EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC) BEFORE IT WAS OBSCURED BY THE DEEP
CONVECTION. THE INITIAL POSITION IS BASED ON A LOW REFLECTIVITY
CIRCULATION FEATURE IN THE 152222Z SSMIS MICROWAVE PASS WHICH LINED
UP WELL WITH THE LLCC IN THE MSI LOOP. THE INITIAL INTENSITY OF 45
KNOTS IS BASED ON AN OVERALL ASSESSMENT OF AGENCY AND SATCON DVORAK
ESTIMATES AND REFLECTS THE SLIGHT INTENSIFICATION OF THE SYSTEM.
UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT
WITH STRONG (30 TO 35 KNOT) EASTERLY VERTICAL WIND SHEAR (VWS) OFFSET
BY STRONG DIFFLUENCE ALOFT. TS 32W IS TRACKING ALONG THE SOUTHWEST
PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS 32W WILL FLATTEN TO A WESTWARD THEN WEST-SOUTHWESTWARD TRACK
AS THE STR TO THE NORTHWEST ASSUMES STEERING. THE UPPER LEVEL
DYNAMICS WILL PREVAIL, HOWEVER, INTERACTION WITH THE VISAYAN ISLANDS
WILL WEAKEN THE SYSTEM DOWN TO 40 KNOTS BY TAU 24. AFTER TAU 48, THE
CYCLONE WILL EXIT INTO THE SOUTH CHINA SEA (SCS) WEST OF PALAWAN AND
RE-INTENSIFY SLIGHTLY TO 45 KNOTS BY TAU 72 AS IT INTERACTS WITH A
STRONG NORTHEASTERLY SURGE EVENT IN THE SCS. THE WIND SURGE WILL ALSO
EXPAND THE 35-KNOT WIND RADII.
C. AFTER TAU 72, THE STEERING STR IS FORECAST TO BUILD AND DRIVE
TS KAI-TAK TO A MORE SOUTHWESTWARD TRAJECTORY. DISSIPATION IS
EXPECTED AFTER TAU 120 AS THE SYSTEM BECOMES EMBEDDED WITHIN THE
STRONG NORTHEAST FLOW AND STRONG VWS PERSISTS. DYNAMIC MODEL TRACKERS
REMAIN IN EXCEPTIONALLY TIGHT AGREEMENT, HOWEVER, THERE ARE SOME
DIFFERENCES IN THE SPEED OF ADVANCE. OVERALL, THERE IS FAIR
CONFIDENCE IN THE JTWC TRACK FORECAST.//
NNNN