WDPN32 PGTW 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 32W (THIRTYTWO) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.6N 142.9E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 249 NM SOUTH-SOUTHWEST OF NAVSTA GUAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A NEARLY
FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) ASSOCIATED WITH
TROPICAL DEPRESSION (TD) 32W. THE INITIAL POSITION IS PLACED WITH
MEDIUM CONFIDENCE BASED ON THE ANALYSIS OF VISIBLE SATELLITE
IMAGERY LOOPS IN CONJUNCTION WITH A 040244Z OCEANSAT-3 OSCAT PASS.
WHILE THE SATELLITE DATA HELPS IDENTIFY THE LLCC POSITION, THE
LATTER REVEALS AN ELONGATED NATURE OF THE CIRCULATION, CONTRIBUTING
TO THE UNCERTAINTY ASSOCIATED WITH THE POSITION ASSESSMENT, AS WELL
AS INITIAL TRACK FORECAST. ADDITIONALLY, FLARING CONVECTION CAN BE
OBSERVED ALONG THE PERIPHERY OF THE CIRCULATION, AS WELL AS ALONG
THE SLIGHTLY DETACHED SOUTHERN BANDING. THE INITIAL INTENSITY OF 25
KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
OSCAT PASS SHOWING 20-25 KT MAXIMUM WINDS TO THE NORTH OF THE LLCC, AS 
WELL AS THE AGENCY DVORAK ESTIMATES LISTED BELOW. ADDITIONAL 
ENVIRONMENTAL ANALYSIS REVEALS CONDITIONS FAVORABLE FOR DEVELOPMENT, 
INCLUDING WARM (30-31 C) SEA SURFACE TEMPERATURES (SST), LOW (5-10 
KTS) VERTICAL WIND SHEAR (VWS), MODERATE EQUATORWARD OUTFLOW, OFFSET 
ONLY BY MODERATELY DRY AIR TO THE NORTH AND NORTHWEST.

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

CURRENT STEERING MECHANISM: WESTERN EXTENSION OF A SUBTROPICAL
RIDGE (STR) CENTERED TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.0 - 25 KTS
   CIMSS D-PRINT: 19 KTS AT 040600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TD 32W IS FORECAST TO CONTINUE CONSOLIDATING
AND INTENSIFYING THROUGHOUT THE FORECAST PERIOD AS IT TRACKS
TOWARD THE NORTHERN PHILIPPINES. INITIALLY, THE SYSTEM IS EXPECTED
TO REMAIN WITHIN A WEAK STEERING ENVIRONMENT, DOMINATED BY A
NORTHEASTERLY LOW-LEVEL FLOW TO THE NORTH OF THE LLCC, AS WELL AS A
WESTERN EXTENSION OF A STR CENTERED TO THE NORTHEAST. AS A RESULT,
TD 32W IS EXPECTED TO SLOWLY TRACK SOUTHWESTWARD OR REMAIN
QUASI-STATIONARY. AS THE DEEP CONVECTION CONTINUES TO DEVELOP, THE
EXTENSION OF THE STR WILL RETROGRADE EASTWARD, ALLOWING THE SYSTEM
TO TURN NORTHWESTWARD AND TRANSIT ALONG THE SOUTHWESTERN PERIPHERY
OF THE RIDGE THROUGHOUT THE CURRENT FORECAST PERIOD. IN TERMS OF
INTENSITY, TD 32W IS EXPECTED TO REACH TYPHOON LEVEL MAXIMUM WINDS
WITHIN THE NEXT 48 HOURS AND CONTINUE STRENGTHENING UTILIZING 
FAVORABLE ENVIRONMENT, AS SOON AS THE VORTEX BECOMES FULLY SHIELDED 
FROM THE ENTRAINING DRY AIR.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR
AGREEMENT THROUGHOUT THE CURRENT FORECAST PERIOD AND THE JTWC
OFFICIAL TRACK IS LAID WITH MEDIUM CONFIDENCE. INITIAL POSITION AND
TRACK UNCERTAINTY ARE A RESULT OF QUITE SIGNIFICANT DISCREPANCY
BETWEEN THE GLOBAL DETERMINISTIC MODELS. GFS PORTRAYS THE LLCC
CONSOLIDATING SOUTHEAST OF THE CURRENTLY ASSESSED POSITION, WHILE
ECMWF AND ECMWF ENSEMBLE (ECENS) ARE MORE IN LINE WITH THE
MULTI-MODEL CONSENSUS. ADDITIONALLY, ECMWF IS CURRENTLY
INITIALIZING BETTER, AS CONFIRMED BY SCATTEROMETRY AND SATELLITE
IMAGERY, THEREFORE JTWC TRACK FORECAST IS LAID CLOSE TO THE
MULTI-MODEL CONSENSUS, BUT LEANING CLOSER TO THE SOLUTIONS OFFERED
BY ECMWF AND ECENS. INITIAL CROSS-TRACK GUIDANCE SPREAD AT TAU 12
IS ESTIMATED AT 50 NM, EXPANDING TO 150 NM BY TAU 120. ALONG-TRACK
SPREAD HOWEVER IS AS HIGH AS 450 NM AT THE END OF THE CURRENT
FORECAST PERIOD, RESULTING IN OVERALL MEDIUM TRACK FORECAST
CONFIDENCE. INTENSITY GUIDANCE IS ALSO IN FAIR AGREEMENT, AS ALL
AVAILABLE DATA INDICATES STEADY INTENSIFICATION, HOWEVER MULTIPLE
RAPID INTENSIFICATION (RI) AIDS ARE ALSO TRIGGERING, INDICATING
UNCERTAINTY ASSOCIATED WITH THE SPEED OF CONSOLIDATION FOR TD 32W.
JTWC INTENSITY FORECAST IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS
AND IS ASSESSED WITH MEDIUM CONFIDENCE THROUGHOUT THE FORECAST
PERIOD.

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