WDPN31 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (MALAKAS) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 6.2N 145.7E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 452 NM SOUTH OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE
CENTRAL DENSE OVERCAST (CDO) FEATURE SHEARED OVER THE WESTERN
SEMICIRCLE OF THE SYSTEM DUE TO HIGH MID-LEVEL VERTICAL WIND SHEAR.
A 080910Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS FRAGMENTED DEEP 
CONVECTIVE BANDING OVER THE NORTHERN PERIPHERY WITH A LINEAR BAND OF
CONVECTION ASSOCIATED WITH THE CDO OVER THE WESTERN QUADRANT. THE
LOW-LEVEL CIRCULATION REMAINS BROAD AND WEAKLY-DEFINED IN THE SSMIS
COLOR COMPOSITE IMAGE ALTHOUGH THERE IS SHALLOW BANDING WRAPPING
AROUND AN ELONGATED CENTER JUST EAST OF THE LINEAR BAND. A 081214Z
ASCAT-B IMAGE ALSO SUPPORTS THE INITIAL POSITION ON THE EASTERN
EDGE OF THE CDO, AND SHOWS AN ASYMMETRIC WIND FIELD WITH 35-40
KNOT WINDS OVER THE WESTERN SEMICIRCLE. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON THE ASCAT IMAGE AND THE
SSMIS IMAGE. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE ASCAT DATA, AND DVORAK ESTIMATES RANGING
FROM 35 TO 45 KNOTS. UPPER-LEVEL ANALYSIS INDICATES GENERALLY
FAVORABLE CONDITIONS WITH MODERATE POLEWARD AND EQUATORWARD
OUTFLOW, WARM SST AND HIGH OCEAN HEAT CONTENT OFFSET BY HIGH MID-
LEVEL VERTICAL WIND SHEAR. ADDITIONALLY, THE BROAD NATURE OF THE LOW-
LEVEL CIRCULATION CONTINUES TO SLOW DEVELOPMENT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   CIMSS SATCON: 48 KTS AT 080936Z
   CIMSS ADT: 57 KTS AT 081140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: HIGH MID-LEVEL VERTICAL WIND SHEAR

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING. ALTERNATE SCENARIO POSSIBLE
(SEE BELOW).

FORECAST DISCUSSION: TS 02W CONTINUES TO STRUGGLE TO CONSOLIDATE AS
REVEALED IN THE RECENT EIR IMAGERY AND MICROWAVE IMAGERY DESPITE
THE GENERALLY FAVORABLE ENVIRONMENTAL CONDITIONS. UNCERTAINTY IN
THE INITIAL POSITION COULD LEAD TO RELOCATIONS AND SIGNIFICANT
SHIFTS IN THE SHORT-TERM FORECAST TRACK UNTIL THE LOW-LEVEL
CIRCULATION CENTER BECOMES STRONGER AND BETTER DEFINED. TS 02W IS
FORECAST TO TRACK NORTHWESTWARD ALONG THE SOUTHERN AND SOUTHWESTERN
PERIPHERIES OF THE STR THROUGH TAU 72. AFTER TAU 72, TS 02W WILL
SLOW SLIGHTLY AND TURN NORTHWARD TO NORTH-NORTHEASTWARD AS IT
APPROACHES A BREAK IN THE STR POSITIONED SOUTH OF HONSHU. DUE TO
THE BROAD NATURE OF THE LOW-LEVEL CIRCULATION AND PERSISTENT HIGH
MID-LEVEL VERTICAL WIND SHEAR (VWS), TS 02W WILL INTENSIFY SLOWLY
THROUGH TAU 36 BUT IS FORECAST TO INTENSIFY AT A STEEPER RATE AFTER
TAU 36 AS THE LOW-LEVEL CIRCULATION CONSOLIDATES, VWS DECREASES AND
POLEWARD OUTFLOW IMPROVES. THE PEAK INTENSITY OF 100 KNOTS IS
EXPECTED NEAR TAU 96 THROUGH TAU 120.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE THROUGH TAU 60 IS IN
GOOD AGREEMENT WITH A 130NM SPREAD IN SOLUTIONS AT TAU 60 LENDING
MEDIUM CONFIDENCE TO THE JTWC FORECAST TRACK. HOWEVER, AS MENTIONED
EARLIER, THERE COULD BE SOME SHORT-TERM ADJUSTMENTS TO THE JTWC
FORECAST TRACK OVER THE NEXT 1-2 DAYS AS THE SYSTEM CONSOLIDATES IN
THE LOW-LEVELS. INTENSITY GUIDANCE VARIES CONSIDERABLY WITH
COAMPS-TC (GFS AND NAVGEM VERSIONS) ON THE LOWER END OF THE
GUIDANCE AT TAU 72 (55-65 KNOTS) AND HWRF AT 82 KNOTS AT TAU 72.
THE JTWC INTENSITY FORECAST IS POSITIONED HIGHER (90 KNOTS) THAN
THE JTWC INTENSITY CONSENSUS (ICNW), WHICH HAS A PEAK OF 70 KNOTS
AT TAU 72. AFTER TAU 72, MODEL GUIDANCE DIVERGES WITH TWO DISTINCT
TRACK SCENARIOS: FIRST IS THE SCENARIO CURRENTLY FAVORED BY JTWC,
THE SLOW RECURVE NORTHWARD TO NORTH-NORTHEASTWARD. SECOND, IS THE
ALTERNATE SCENARIO DEPICTED BY ECMWF, WHICH TRACKS THE SYSTEM MORE
WESTWARD WHILE STRONGLY INTERACTING WITH, AND UNDERGOING FUJIWHARA
INTERACTION WITH A DEVELOPING TROPICAL CYCLONE (INVEST 94W) NEAR
THE PHILIPPINES. DUE TO THE COMPLEXITY OF THE EVOLVING SYNOPTIC
ENVIRONMENT, THERE IS LOW CONFIDENCE IN THE 72-120 HOUR JTWC TRACK
AND INTENSITY FORECAST.      

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