WDXS31 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (GOMBE) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.1S 47.6E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 228 NM NORTH OF ANTANANARIVO, MADAGASCAR
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 0 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
MEDIUM-SIZED SYSTEM THAT HAS UNRAVELED AS IT TRACKS OVER NORTHERN
MADAGASCAR. FEEDER BANDS HAVE BECOME WEAK AND FRAGMENTED, ALBEIT
WITH A SEMBLANCE OF ORGANIZATION. THE INITIAL POSITION IS BASED
WITH MEDIUM CONFIDENCE INSIDE THE TERMINATION OF CURVED BANDS. THE
INITIAL INTENSITY OF 30KTS IS DERIVED FROM NEARBY MEAN SEA LEVEL
PRESSURE OBSERVATIONS AND CONSISTENT WITH THE EIR SIGNATURE. 
ANALYSIS INDICATES AN UNFAVORABLE ENVIRONMENT WITH LOW (10-15KT) VWS 
AND MODERATE RADIAL OUTFLOW OFFSET BY LAND INTERACTION WITH 
MADAGASCAR. THE CYCLONE IS TRACKING SLOWLY ALONG THE NORTHERN 
PERIPHERY OF THE STR TO THE SOUTH.

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

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 10-15 KTS
   SST: OVER LAND
   OUTFLOW: MODERATE RADIAL

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: UNDER THE STEERING INFLUENCE OF THE STR TO THE
SOUTH, TC GOMBE WILL EXIT INTO THE MOZAMBIQUE CHANNEL OVER THE NEXT
FEW HOURS, DRIFT WEST-SOUTHWESTWARD, MAKE LANDFALL OVER CENTRAL
MOZAMBIQUE AROUND TAU 66, THEN TRACK SOUTHWARD AFTER TAU 96 AS IT 
ROUNDS THE WESTERN EDGE OF THE STR AXIS. THE WARM SST IN THE 
MOZAMBIQUE CHANNEL PLUS CONTINUED FAVORABLE VWS AND OUTFLOW WILL 
FUEL STEADY INTENSIFICATION TO A PEAK OF 75KTS, POSSIBLY HIGHER WITH 
RAPID INTENSIFICATION, BY TAU 48. AFTERWARD, INCREASING VWS AND LAND 
INTERACTION WILL RAPIDLY WEAKEN THE CYCLONE DOWN TO DISSIPATION BY 
TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT UP TO TAU
72 WITH A GRADUAL AND EVEN SPREAD TO 206NM. AFTERWARD, THE MODELS
SIGNIFICANTLY DIVERGE AS THEY LOSE THE VORTEX OVER LAND. IN VIEW OF
THIS, THERE IS OVERALL MEDIUM CONFIDENCE IN THE JTWC TRACK AND
INTENSITY FORECASTS UP TO TAU 72 THEN LOW CONFIDENCE AFTERWARD. 


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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