WDXS31 PGTW 161500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (FABIEN) 
WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 7.3S 75.1E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 155 NM EAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS THE TERMINATOR LINE SWEEPS OVER THE SYSTEM, THE LAST REMAINING
FRAMES OF ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICT A
HIGHLY CONSOLIDATED TROPICAL CYCLONE WITH A WELL FORMED AND SYMMETRIC 
13NM EYE. A FORTUITOUS 161206Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS A 
COMPACT SYSTEM WITH A SINGLE EYE WALL AND DEEP CONVECTIVE BANDS 
WRAPPING INTO THE CENTER FROM THE SOUTH. AN ANALYSIS OF BRIGHTNESS 
TEMPERATURES REVEALS THE EYE HAS WARMED FROM -12C TO +5C OVER THE PAST 
SIX HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED 
ON MSI AND SSMIS IMAGERY. THE INITIAL INTENSITY OF 100KTS IS ASSESSED 
WITH HIGH CONFIDENCE BASED ON AGENCY DVORAK INTENSITY ESTIMATES 
OVERWHELMINGLY INDICATING T5.5 WHICH IS MATCHED BY CIMSS ADT AT 99KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   DEMS: T5.5 - 102 KTS
   FMEE: T5.0 - 90 KTS
   FIMP: T5.0 - 90 KTS
   CIMSS ADT: 99 KTS AT 161200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 19S (FABIEN) IS FORECAST TO CONTINUE
TRACKING SOUTHWESTWARD UNDER THE FADING INFLUENCE OF THE STR TO THE
SOUTHEAST. IT IS IMPORTANT TO MENTION THE STR SEEMS TO BE BREAKING
DOWN SLIGHTLY FASTER THAN ORIGINALLY ANTICIPATED WHICH HAS THANKFULLY 
OPENED THE CPA TO DIEGO GARCIA SLIGHTLY. THROUGH TAU 12, 19S IS 
FORECAST TO REMAIN IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY WARM 
SSTS, LOW VERTICAL WIND SHEAR (VWS) AND MODERATE OUTFLOW ALOFT WHICH 
IS ANTICIPATED TO PEAK THE SYSTEM NEAR 105KTS. FOLLOWING TAU 12, DRY 
AIR ENTRAINMENT IS FORECAST TO BEGIN TO DEGRADE THE ENVIRONMENT WHICH 
WILL RESULT IN SLIGHT WEAKENING THROUGH TAU 36. BY THIS TIME, 19S WILL 
BEGIN TO TRANSITION PRIMARY STEERING INFLUENCE TO THE STR BUILDING 
OVER MADAGASCAR. AS THIS TAKES PLACE, 19S WILL STEADY UP ON A 
GENERALLY WESTWARD COURSE AS THE SYSTEM CONTINUES TO SLOWLY WEAKEN. BY 
TAU 72, A NEAR-EQUATORIAL RIDGE (NER) BUILDING JUST SOUTH OF INDIA 
WILL HALT MOST OF THE SYSTEMS FORWARD MOMENTUM. BY TAU 96 AND THROUGH 
THE FORECAST PERIOD, HAVING WEAKENED TO 70KTS, 19S WILL BE IN A 
COMPLEX AND COMPETING STEERING ENVIRONMENT BETWEEN THE STR TO THE 
SOUTHWEST AND NER TO THE NORTH WHICH IS FORECAST TO TURN THE SYSTEM 
EQUATORWARD AND EVENTUALLY QUASI-STATIONARY.

MODEL DISCUSSION: WITH THE EXCEPTION OF COAMPS-TC AND AFUM,
NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH TAU 72, WITH ALL
OTHER MEMBERS SHOWING A SOUTHWESTERLY TRACK, SOUTH OF DIEGO GARCIA
AFTER WHICH GENERALLY WESTWARD. BY TAU 72, AS THE NER BUILDS TO THE
NORTH AND THE TWO DOMINANT RIDGES FIGHT FOR CONTROL, ALL BETS ARE
OFF WITH VARIOUS MEMBERS RECURVING THE SYSTEM NORTHWARD AND SOUTHWARD. 
COAMPS-TC AND AFUM QUICKLY RECURVE THE SYSTEM EQUATORWARD AFTER TAU 36 
AND TRANSIT EASTWARD STILL SOUTH OF DIEGO GARCIA THROUGH THE FORECAST 
PERIOD. AS A RESULT, THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-
MODEL CONSENSUS WITH MEDIUM CONFIDENCE THROUGH TAU 72 AND WITH LOW 
CONFIDENCE IN THE EXTENDED TRACK FORECAST. RELIABLE MODEL INTENSITY 
GUIDANCE IS IN FAIR AGREEMENT WITH A BULK OF THE MEMBERS SHOWING 
MARGINAL INTENSIFICATION THROUGH TAU 12 AFTER WHICH ALL MEMBERS 
GRADUALLY WEAKEN THROUGH THE FORECAST PERIOD. HWRF IS A NOTABLE 
EXCEPTION TO THIS TREND, SHOWING IMMEDIATE AND PERSISTENT WEAKENING 
THROUGH THE FORECAST PERIOD. FOR THESE REASONS THE JTWC INTENSITY 
FORECAST IS PLACED WITH MEDIUM CONFIDENCE.

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