WDPN32 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 32W (THIRTYTWO) 
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.1N 143.4E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 51 NM NORTHWEST OF WOLEAI
   MOVEMENT PAST 6 HOURS: EASTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTIVE BANDING
WRAPPING AROUND THE BROAD AND EXPANSIVE TROPICAL DEPRESSION (TD).
DRY AIR REVEALS THE LOW-LEVEL CLOUD BANDS NOW EVIDENT IN DAYLIGHT.
WATER VAPOR IMAGERY REVEALS DRY AIR TO THE NORTHWEST OF THE
CIRCULATION AND TO THE SOUTHEAST. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON A 042342 METOP-C ASCAT IMAGE
DEPICTING AN ELONGATED CIRCULATION ON A WEST-EAST AXIS. THE INITIAL
INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
AFOREMENTIONED SCATTEROMETRY AND THE AGENCY AND OBJECTIVE FIXES
LISTED BELOW, NOTING THE 5-10KT LOW BIAS OF METOP-C.

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

CURRENT STEERING MECHANISM: THE SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 33 KTS AT 042100Z
   CIMSS ADT: 34 KTS AT 042030Z
   CIMSS AIDT: 34 KTS AT 042030Z
   CIMSS D-MINT: 23 KTS AT 042215Z
   CIMSS D-PRINT: 19 KTS AT 050020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THE TRACK FORECAST FOR TD 32W WILL REMAIN
COMPLEX AS THE SYSTEM CONTINUES TO CONSOLIDATE OVER THE NEXT 12
HOURS, AND DURING THAT TIME IRREGULAR MOTION CAN BE ANTICIPATED
DURING A QUASI-STATIONARY PERIOD. ONCE WELL-DEFINED AND COMPACT,
THE SYSTEM WILL COME UNDER THE PRIMARY STEERING INFLUENCE OF THE
SUBTROPICAL RIDGE TO THE NORTH, TRACKING NORTHWESTWARD FOR THE NEXT
48 HOURS. THE STEERING ENVIRONMENT WILL SHIFT SLIGHTLY DUE TO
INFLUENCE OF A WEAKENING RIDGE OVER THE SOUTH CHINA SEA, CAUSING TD
32W TO TRACK WEST-NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST
PERIOD, MAKING LANDFALL ON LUZON IMMEDIATELY PRIOR TO TAU 120. IN
THE EARLY-TERM, THE SYSTEM WILL STRUGGLE TO INTENSIFY DUE TO DRY
AIR EMBEDDED WITHIN THE CIRCULATION CENTER, HOWEVER AS THE SYSTEM
CONSOLIDATES AND MOISTENS, RAPID INTENSIFICATION IS ANTICIPATED DUE
TO FAVORABLY LOW VERTICAL WIND SHEAR, WARM SEA SURFACE
TEMPERATURES, AND EXPANSIVE OUTFLOW, ALLOWING FOR A PEAK INTENSITY
OF 120KTS BY TAU 96. SLIGHT WEAKENING WILL OCCUR BY TAU 120 DUE TO
TOPOGRAPHIC INTERACTION WITH MAINLAND LUZON.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE CONTINUES TO HAVE A
LARGE SPREAD THROUGHOUT THE FORECAST PERIOD SPANNING APPROXIMATELY
300NM BY TAU 120. THE CROSS-TRACK SPREAD HAS CLOSED SLIGHTLY SINCE
THE PREVIOUS WARNING, HOWEVER THE LOW CONFIDENCE IN THE TRACK
FORECAST REMAINS THE SAME. THE UNCERTAINTY OF EXACTLY WHERE THE
SYSTEM WILL DEVELOP IS DIRECTLY CORRELATED TO THE MODEL
DISAGREEMENT, BUT THERE IS MORE CERTAINTY IN THE 00Z POSITION AND
INTENSITY WHICH WILL ALLOW FOR BETTER CONTRAST AND COMPARISON WITH
THE MODEL SOLUTIONS. GFS CONTINUES TO GIVE THE FALSE APPEARANCE
THAT THERE IS A VORTICITY MAXIMUM TO THE NORTHEAST OF THE BEST
TRACK POSITION WHILE OTHER MODELS, SUCH AS ECMWF, AND REAL-TIME
DATA, SUCH AS THE AFOREMENTIONED 042342Z METOP-C ASCAT IMAGERY,
DISAGREE. THE INTENSITY GUIDANCE IS IN MODERATE AGREEMENT,
INDICATING PEAK INTENSITIES BETWEEN 110-130KTS AT TAU 84. RAPID
INTENSIFICATION GUIDANCE FROM JTWC SHIPS STRONGLY SUGGESTS RAPID
INTENSIFICATION TO OCCUR THROUGH TAU 36-48. 

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