WDXS31 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 12S (DUMAKO) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.7S 53.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 263 NM NORTH-NORTHWEST OF ST DENIS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT SYSTEM WITH DEEP CONVECTION LIMITED TO THE SYSTEM CENTER
AND FRAGMENTED BANDING IN THE PERIPHERY OF THE LOW LEVEL
CIRCULATION CENTER (LLCC). A 141552Z AMSU 89GHZ MICROWAVE IMAGE
SHOWS DEEP CONVECTIVE BANDING IS CONFINED PRIMARILY TO THE SOUTHERN
SEMICIRCLE WITH SHALLOW BANDING OVER THE EASTERN SEMICIRCLE
WRAPPING INTO THE LLCC. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON EIR IMAGERY AND THE AMSU IMAGE. THE INITIAL
INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
THE PGTW AND FMEE DVORAK CURRENT INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) 
POSITIONED TO THE SOUTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS SATCON: 53 KTS AT 141553Z
   CIMSS ADT: 51 KTS AT 141815Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 12S (DUMAKO) IS FORECAST TO TRACK GENERALLY
WESTWARD TOWARDS MADAGASCAR ALONG THE NORTHERN PERIPHERY OF THE
STR THROUGH THE FORECAST PERIOD. ENVIRONMENTAL CONDITIONS REMAIN 
MARGINAL WITH LOW VERTICAL WIND SHEAR (VWS) (10-15KTS) AND MODERATE 
OUTFLOW OFFSET BY SIGNIFICANT DRY AIR ENTRAINMENT IN THE MID LEVELS. 
SEA SURFACE TEMPERATURES REMAIN CONDUCIVE (28-29C), HOWEVER, THERE 
IS A LOW PROBABILITY OF INTENSIFICATION BEFORE LANDFALL DUE TO THE 
DRY AIR ENTRAINMENT. AFTER MAKING LANDFALL NEAR TAU 18, THE SYSTEM 
WILL TRACK OVER MOUNTAINOUS TERRAIN AND WILL RAPIDLY WEAKEN AND 
DISSIPATE BY TAU 36. THE REMNANTS ARE EXPECTED TO TRACK OVER THE 
MOZAMBIQUE CHANNEL AFTER TAU 36 BUT ARE NOT EXPECTED TO REDEVELOP.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A
77NM SPREAD IN SOLUTIONS AT TAU 24 THUS SUPPORTING THE JTWC
FORECAST TRACK WITH MEDIUM CONFIDENCE. THE 140600Z ECMWF ENSEMBLE
(EPS) STRIKE PROBABILITY PRODUCT ALSO SUPPORTS THE JTWC TRACK
PHILOSOPHY. RELIABLE INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH
THE JTWC INTENSITY FORECAST SHOWING A STEADY WEAKENING TREND
THROUGH TAU 12 THEN A SHARPER WEAKENING TREND AFTER THE SYSTEM MAKES
LANDFALL. 

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