WDXS31 PGTW 030300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 04S (ALVARO) WARNING 
NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.7S 49.8E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 262 NM SOUTH-SOUTHEAST OF ANTANANARIVO,
MADAGASCAR
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
VIGOROUS CONVECTIVE BURST THAT IS FULLY OBSCURING THE NEWLY FORMED
LLCC. A 030027Z SSMIS 91GHZ MICROWAVE IMAGE INDICATES A LINGERING
DISSONANCE BETWEEN A WELL DEVELOPED UPPER-LEVEL CIRCULATION AND
ASSOCIATED CONVECTION AND A PARTIALLY VISIBLE LOW-LEVEL CIRCULATION
TRAILING SLIGHTLY BEHIND. THE INITIAL POSITION IS PLACED WITH
MEDIUM CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE INITIAL
INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
AUTOMATED AND DVORAK INTENSITY ESTIMATES WHICH INDICATE 35-50KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
NER TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T2.5 - 35 KTS
   FMEE: T3.5 - 55 KTS
   CIMSS ADT: 47 KTS AT 030000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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 04S IS FORECASTED TO TRACK GENERALLY
SOUTHEASTWARD UNDER THE STEERING INFLUENCE OF NER TO THE NORTHEAST.
OVER THE NEXT 12 HOURS, WARM SSTS, MODERATE VERTICAL WIND SHEAR
(VWS) AND FAVORABLE OUTFLOW ALOFT WILL ALLOW 04S TO RE-INTENSIFY TO
45KTS AND POSSIBLY SLIGHTLY HIGHER. AFTER TAU 12, INCREASING VWS,
DRY AIR ENTRAINMENT, COOLING SSTS AND DECREASED OUTFLOW ALOFT WILL
GRADUALLY WEAKEN 04S AS THE SYSTEM QUICKLY ACCELERATES INTO AN
APPROACHING MID-LATITUDE TROUGH. IF 04S IS ABLE TO INTENSIFY BEYOND
THE ANTICIPATED CEILING NEAR 45KTS, THE SYSTEM MAY BE ABLE TO
MAINTAIN STORM FORCE INTENSITY LONG ENOUGH TO BEGIN EXTRATROPICAL
TRANSITION. AT THIS TIME HOWEVER, IT IS UNLIKELY THE SYSTEM WILL
SURVIVE LONG ENOUGH TO ATTAIN ANY MEASURABLE SUB-TROPICAL OR
EXTRA-TROPICAL CHARACTERISTICS.   

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS CLOSELY FOLLOWING THE MULTI-MODEL CONSENSUS. AS A RESULT,
THE JTWC FORECAST TRACK IS PLACED NEAR THE CONSENSUS WITH HIGH
CONFIDENCE. THE SAME CANNOT BE SAID FOR THE SUITE OF RELIABLE MODEL
INTENSITY GUIDANCE WHOSE AGREEMENT IS POOR. GFS AND SHIPS SHOW A
SMALL CLIMB THROUGH TAU 12 BEFORE GRADUALLY WEAKENING THE SYSTEM
THROUGH DISSIPATION WHILE THE REMAINING MEMBERS INTENSIFY 04S TO
NEARLY 60KTS BEFORE BEGINNING TO DISSIPATE. BASED ON THE
ANTICIPATED ENVIRONMENTAL PARAMETERS DISCUSSED ABOVE, THE JTWC
INTENSITY FORECAST IS PLACED BELOW THE MULTI-MODEL CONSENSUS MORE
INLINE WITH GFS AND DECAY-SHIPS ALBEIT WITH LOW CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: LOW//
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