WDPN31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (MALAKAS) WARNING 
NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.5N 136.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 270 NM NORTH-NORTHWEST OF YAP
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
MEDIUM-SIZED SYSTEM THAT HAS EXPANDED BUT MAINTAINED DEEP CENTRAL
CONVECTION THAT HAS DEVELOPED A RAGGED FORMATIVE EYE. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE FORMATIVE
EYE IN THE MSI LOOP. THE INITIAL INTENSITY OF 60KTS IS BASED ON THE
HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE
SUSTAINED 6-HR CONVECTIVE SIGNATURE. ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH LIGHT VWS, MODERATE RADIAL OUTFLOW, AND WARM SST
OVER THE PHILIPPINE SEA. THE CYCLONE IS TRACKING ALONG THE
SOUTHWESTERN PERIPHERY OF THE STR TO THE
NORTHEAST.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   CIMSS ADT: 59 KTS AT 110540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS MALAKAS WILL CONTINUE TO TRACK
NORTH-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR BUT
WILL SLIGHTLY SLOW DOWN. DUE TO A WEAK BINARY INTERACTION WITH A
SECONDARY CYCLONE (TD 03W) TO THE WEST OVER THE CENTRAL PHILIPPINE
ISLANDS. AFTER TAU 12, IT WILL TRACK MORE POLEWARD AS IT BEGINS TO
ROUND THE STR AXIS THEN RECURVE NORTHEASTWARD. THE FAVORABLE
ENVIRONMENT WILL PREVAIL AND FUEL A STEADY THEN RAPID
INTENSIFICATION TO A PEAK OF 10KTS BY TAU 36 AS THE CYCLONE
ACCELERATES ON THE POLEWARD SIDE OF THE STR AXIS WHERE DECREASED
VWS AND INCREASED POLEWARD OUTFLOW DUE TO THE INITIAL EXPOSURE INTO
THE PREVAILING WESTERLIES, WILL ENHANCE THE FAVORABLE DYNAMICS.
AFTER TAU 36, VWS WILL ONCE AGAIN INCREASE. THIS PLUS THE INFLUX OF
COOL DRY AIR AND COOLING SST WILL RAPIDLY ERODE THE SYSTEM AND BY
TAU 120 WILL BE REDUCED TO 45KTS. CONCURRENTLY BY TAU 96, TS 02W
WILL BEGIN EXTRA-TROPICAL TRANSITION AS IT ENTERS THE BAROCLINIC
ZONE AND BY TAU 120, WILL BECOME A STRONG GALE-FORCE COLD-CORE LOW.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
A GRADUAL AND EVEN SPREAD TO 166NM BY TAU 120, LENDING HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST.  


FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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