WDPN32 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 32W (THIRTYTWO) 
WARNING NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.2N 141.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 77 NM EAST OF SOROL
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD
AND DISORGANIZED CIRCULATION WITH FLARING CONVECTION OBSCURING THE
MID-LEVEL CIRCULATION. THE STRUCTURE REMAINS ELONGATED WITH
CONVECTION PRIMARILY ALONG THE SOUTHEASTERN PERIPHERY. WATER VAPOR
IMAGERY REVEALS DRY AIR TO THE NORTH OF THE CIRCULATION AND A DEEP,
DRY TROUGH. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE
BASED ON BROAD AND WEAK CIRCULATION, LEADING TO SIGNIFICANT
DIFFICULTY IN IDENTIFYING THE LOW-LEVEL CIRCULATION CENTER. THE
INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T1.5 - 25 KTS
   CIMSS SATCON: 37 KTS AT 041617Z
   CIMSS ADT: 34 KTS AT 041730Z
   CIMSS AIDT: 35 KTS AT 041730Z
   CIMSS D-MINT: 22 KTS AT 041617Z
   CIMSS D-PRINT: 24 KTS AT 041800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: RAPID INTENSIFICATION IS LIKELY IN
THE EARLY-TERM FORECAST, LEADING TO A HIGHER PEAK INTENSITY THAN
REFLECTED IN PREVIOUS WARNINGS.

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 32W WILL REMAIN
QUASI-STATIONARY AND STRUGGLE TO CONSOLIDATE FOR THE NEXT 12 HOURS.
BY TAU 24, THE SYSTEM WILL COME UNDER THE STEERING INFLUENCE OF THE
SUBTROPICAL RIDGE TO THE NORTH, INITIALLY DRIVING TY 31W
NORTHWESTWARD FOR THE FIRST 48 HOURS OF THE FORECAST. BETWEEN TAU
48-72, THE STEERING INFLUENCE WILL BECOME COMPLEX INCLUDING A
SUBTROPICAL RIDGE CENTERED OVER THE GULF OF TONKIN, SHIFTING THE
TRACK TO THE WEST-NORTHWEST FOR THE REMAINDER OF THE FORECAST
PERIOD. ONCE THE SYSTEM CONSOLIDATES OVER THE NEXT 12 HOURS, IT IS
ANTICIPATED TO INTENSIFY SIGNIFICANTLY DUE TO UNSEASONABLY HIGH SEA
SURFACE TEMPERATURES AND OCEAN HEAT CONTENT, A POINT SOURCE ALOFT,
AND LOW VERTICAL WIND SHEAR (10-15KTS). THE RAPID INTENSIFICATION
RATE WILL TAPER OFF AFTER TAU 72, RESULTING IN A PEAK INTENSITY OF
120KTS BY TAU 96. SLIGHT WEAKENING IS ANTICIPATED AS TD 32W
APPROACHES THE EASTERN COAST OF LUZON DUE TO UPWELLING AND AN
UPTICK OF VERTICAL WIND SHEAR ABOVE 20KTS.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE HAS A LARGE SPREAD
OF TRACK SOLUTIONS CONTRIBUTING TO LOW CONFIDENCE IN THE TRACK
GUIDANCE THROUGHOUT THE ENTIRETY OF THE FORECAST PERIOD. THERE IS A
346NM CROSS-TRACK SPREAD SPANNING FROM THE APPROACH TO THE LUZON
STRAIT TO CENTRAL LUZON. THE FIRST 12 HOURS OF THE FORECAST
GUIDANCE HAS A CLASSIC 'SQUASHED SPIDER' APPEARANCE AS THE VORTEX
TRACKERS STRUGGLE, MUCH LIKE MYSELF, TO FIND THE CENTER OF THE
CIRCULATION AMIDST THE MESS OF MID-LEVEL AND UPPER-LEVEL CONFLICTING
FLOW. HOWEVER, THE MODEL FIELDS REVEAL SIGNIFICANTLY DIFFERENT
POSITIONS OF THE LOW-LEVEL CENTER BASED ON THE MEAN SEA LEVEL
PRESSURE CENTERS. FOR EXAMPLE, GFS POSITIONS THE PRESSURE CENTER
230NM TO THE NORTHEAST OF THE CURRENT 18Z BEST TRACK POSITION,
WHERE THE FLOW IS DEFINITIVELY EASTERLY AND NOT WITHIN THE
CIRCULATION. ALTERNATELY, ECMWF IS CLOSER TO THE BEST TRACK
POSITION, BUT BROADER AND WEAKER. THE INTENSITY GUIDANCE STRONGLY
INDICATES RAPID INTENSIFICATION BASED ON THE JTWC SHIPS GUIDANCE
AND THE OCEAN-COUPLED MODELS (HAFS-A, HWRF, COAMPS-TC). THE SPREAD
OF INTENSITY GUIDANCE COMES AFTER TAU 60, WHEN COAMPS-TC, HAFS-A,
AND HWRF ALL REACH A PEAK OF 125-135KTS AT TAU 96, WHILE GFS DRAGS
BEHIND PEAKING AT 100KTS. THE JTWC INTENSITY FORECAST CONFIDENCE IS
MEDIUM IN THE NEAR-TERM, AND LOW DUE TO THE SPREAD BETWEEN
DETERMINISTIC AND MESOSCALE MODEL GUIDANCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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