WDXS31 PGTW 311500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 04S (ALVARO)     
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.4S 39.0E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 127 NM NORTH-NORTHWEST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 04S HAS CONSOLIDATED QUICKLY AS DEPICTED IN
RECENT ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY. EIR
IMAGERY REVEALS A COMPACT, WELL-ORGANIZED CONVECTIVE CORE WITH THE
BULK OF THE DEEP CONVECTION AND DEEP CONVECTIVE BANDING OVER THE
EASTERN SEMICIRCLE. A 311122Z AMSR2 89 GHZ MICROWAVE IMAGE SHOWS
DEEP CONVECTIVE BANDING OVER THE EASTERN SEMICIRCLE WRAPPING
TIGHTLY INTO THE WESTERN QUADRANT WITH A WEAK MICROWAVE EYE FEATURE
EVIDENT. THE AMSR2 37 GHZ IMAGERY INDICATES A BETTER-DEFINED
MICROWAVE EYE FEATURE POSITIONED ABOUT 15 NM EAST-SOUTHEAST OF THE
UPPER-LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON THE AMSR2 IMAGERY. THE INITIAL INTENSITY
OF 35 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE HIGHER
RANGE OF DVORAK INTENSITY ESTIMATES, CONSISTENT WITH THE WEAK,
FORMATIVE MICROWAVE EYE FEATURE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) POSITIONED
TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   FMEE: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: MID- TO UPPER-LEVEL DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 04S IS FORECAST TO TRACK EAST-SOUTHEASTWARD
TO EASTWARD OVER THE NEXT 36 HOURS ALONG THE SOUTHERN PERIPHERY OF
THE NER POSITIONED TO THE NORTH. ENVIRONMENTAL CONDITIONS SHOULD
REMAIN GENERALLY FAVORABLE WITH ENHANCED POLEWARD OUTFLOW INTO THE
SUBTROPICAL JET TO THE SOUTH AND WARM SEA SURFACE TEMPERATURES.
HOWEVER, DRY AIR ENTRAINMENT IS CURRENTLY HINDERING DEVELOPMENT
OVER THE WESTERN SEMICIRCLE AND IS FORECAST TO ENVELOP THE SYSTEM
AFTER TAU 24. THEREFORE, THE INTENSITY IS EXPECTED TO PEAK NEAR 45
KNOTS WITHIN THE NEXT DAY THEN DECREASE AS THE SYSTEM APPROACHES
THE COAST OF MADAGASCAR, WITH LANDFALL NEAR TAU 36. FURTHER
WEAKENING WILL OCCUR AS THE SYSTEM TRACKS OVER THE MOUNTAINOUS
TERRAIN OF MADAGASCAR. AFTER TAU 72, THE REMNANTS WILL RE-EMERGE
OVER THE INDIAN OCEAN WITH GRADUAL REINTENSIFICATION TO ABOUT 35
KNOTS AS THE SYSTEM INTERACTS WITH STRENGHTHENING SUBTROPICAL
WESTERLIES. INCREASING VERTICAL WIND SHEAR (30-40 KNOTS) SHOULD
LIMIT THIS REINTENSIFICATION PHASE. TRACK MOTION SHOULD GENERALLY
BE EAST-SOUTHEASTWARD AS THE STEERING INFLUENCE TRANSITIONS TO A
SUBTROPICAL RIDGE POSITIONED TO THE NORTHEAST.          

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
THROUGH TAU 72 WITH INCREASING CROSS-TRACK SPREAD LENDING MEDIUM
CONFIDENCE TO THE JTWC TRACK FORECAST. AFTER TAU 72, THERE IS A
LARGE SPREAD IN THE GUIDANCE, WITH LOW CONFIDENCE IN THE TRACK
FORECAST. INTENSITY GUIDANCE IS IN POOR AGREEMENT THROUGH TAU 120
LENDING LOW OVERALL CONFIDENCE TO THE JTWC INTENSITY FORECAST.     

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