WDPN32 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 15W (FIFTEEN) 
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.8N 153.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 567 NM EAST-SOUTHEAST OF ANDERSEN AFB,
GUAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A
DISORGANIZED, ALBEIT CONSOLIDATING SYSTEM WITH DEEP FLARING
CONVECTION AND SHALLOW FORMATIVE BANDS. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON A NEAR-SURFACE MICROWAVE
NOTCH FEATURE IN THE 070534Z 37GHZ SSMIS IMAGE. THE INITIAL
INTENSITY OF 30KTS IS BASED ON THE HIGH END OF AGENCY DVORAK
ESTIMATES AND REFLECTS THE GRADUAL CONSOLIDATION. ANALYSIS
INDICATES A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE VWS, 
MODERATE POLEWARD OUTFLOW, AND VERY WARM ALONG-TRACK SST.

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

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 32 KTS AT 070321Z
   CIMSS ADT: 30 KTS AT 070530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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: TD 15W WILL TRACK WEST-NORTHWESTWARD THEN
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE
NORTHEAST AND WILL COME TO WITHIN 15NM OF ANDERSEN AFB AS IT TRACKS
BETWEEN GUAM AND ROTA AROUND TAU 72. AFTERWARD, A MID-LATITUDE
TROUGH EXITING JAPAN TO THE NORTHWEST WILL WEAKEN THE STR AND ALLOW
THE SYSTEM TO TRACK MORE NORTHWARD TOWARD IWO TO. THE FAVORABLE
ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO 75KTS AT TAU 72
AS IT APPROACHES GUAM. AFTERWARD, INCREASE POLEWARD OUTFLOW AHEAD
OF THE MID-LATITUDE TROUGH WILL PROMOTE A RAPID INTENSIFICATION,
AND BY TAU 120, REACHING A SUPER TYPHOON INTENSITY OF 130 KTS. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT
WITH A GRADUAL SPREAD TO 198NM BY TAU 72 WITH GFS ON THE LEFT
MARGIN, THEN TO 403NM BY TAU 120 WITH NAVGEM ON THE LEFT MARGIN.
UEMN IS ON THE RIGHT MARGIN FOR THE WHOLE DURATION. GIVEN THE
FORMATIVE NATURE OF THE SYSTEM, THERE IS ONLY MEDIUM CONFIDENCE IN
THE JTWC TRACK FORECAST. 

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