WDXS31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (FABIEN) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 6.2S 76.1E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 221 NM EAST-NORTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 39 FEET

SATELLITE ANALYSIS, INITIAL POSITION, AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS A
COMPACT SYSTEM WITH RAGGED BANDS OF CONVECTION THAT APPEAR TO BE
BREAKING APART COMPARED TO THE PREVIOUS ANALYSIS AS THEY WRAP INTO
THE LOW LEVEL CIRCULATION CENTER (LLCC). A BULLSEYE 152310Z SSMIS
91 GHZ IMAGE SHOWS A RELATIVELY ASYMMETRICAL SYSTEM WITH A BULK OF
THE CONVECTION IN THE WESTERN AND NORTHERN QUADRANTS OUTSIDE OF A
MICROWAVE EYE. EXAMINATION OF THE 152311Z M-PERC EYEWALL
REPLACEMENT TOOL SUGGESTS AN EYEWALL REPLACEMENT CYCLE (ERC) HAS
TAKEN PLACE. TC FABIEN IS IN A FAVORABLE ENVIRONMENT FOR FURTHER
TROPICAL DEVELOPMENT. THESE CONDITIONS ARE CHARACTERIZED BY STRONG
WESTWARD AND POLEWARD OUTFLOW ALOFT, AN IMPRESSIVE 850 MB VORTICITY
SIGNATURE, LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS), AND VERY WARM
(28-29 C) SEA SURFACE TEMPERATURES (SST). THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON MULTI-AGENCY FIXES, AS WELL AS
THE AFOREMENTIONED SSMIS PASS. THE INITIAL INTENSITY OF 90 KNOTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED OFF A BLEND OF MULTI-AGENCY
AND AUTOMATED DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T5.0 - 90 KTS
   FMEE: T4.5 - 77 KTS
   FIMP: T4.5 - 77 KTS
   CIMSS SATCON: 86 KTS AT 152012Z
   CIMSS ADT: 82 KTS AT 160000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG WESTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 19S (FABIEN) IS RIDING THE NORTHWESTERN
PERIPHERY OF THE STR TO THE SOUTHEAST. DURING TAUS 12 THROUGH 24,
TC FABIEN WILL CONTINUE TO TRACK SOUTHWESTWARD AND STEADILY
INTENSIFY TO ITS PEAK INTENSITY OF 100 KTS. BY THIS TIME, THE STR
TO THE SOUTHEAST WILL BEGIN TO RECEDE AND THE STR OVER MADAGASCAR
WILL BECOME THE MAIN STEERING FEATURE. AS A RESULT, TC 19S WILL
CHANGE TO A MORE WESTWARD TRACK BY TAU 48, OVER 100 NM SOUTH OF
DIEGO GARCIA. IN ADDITION, THE INTENSITY WILL BE ON A DECREASING
TREND DUE TO THE SYSTEM ENTERING A MORE HOSTILE ENVIRONMENT. THIS
ENVIRONMENT IS CHARACTERIZED BY DRY AIR ENTRAINMENT FROM THE SOUTH
WRAPPING INTO THE SYSTEM, AN INCREASE IN MID-LEVEL WIND SHEAR, AND
UPWELLING THE STORM WILL BE PRODUCING BRINGING RELATIVELY COOLER
(26 C) SSTS TO THE SURFACE AS INDICATED BY THE 151800Z HWRF MODEL
RUN. BETWEEN TAUS 72 AND 96, THE SYSTEM WILL CHANGE IN TRAJECTORY
TO THE WEST-NORTHWEST AS THE SYSTEM WILL STRUGGLE BETWEEN THE STR
OVER MADAGASCAR AND THE NEAR EQUATORIAL RIDGE (NER) TO THE
NORTHEAST. MOREOVER, THE INTENSITY WILL CONTINUE TO STEADILY
DECREASE TO 70 KNOTS BY TAU 120 AS THE SYSTEM TURNS NORTHWARD. 

MODEL DISCUSSION: THE DETERMINISTIC AND ENSEMBLE MODELS ALL AGREE
THAT TC 19S WILL CONTINUE TO TRACK SOUTHWEST THROUGH TAU 36, THEN
TRACK WESTWARD AFTERWARDS. HOWEVER, BY TAU 72 AND BEYOND THERE IS
SOME UNCERTAINTY IN THE TRACK SOLUTIONS. THE JTWC FORECAST TRACK
CONSENSUS MEMBERS ARE IN GOOD AGREEMENT SHOWING A 27 NM SPREAD AT
TAU 12 THAT GRADUALLY INCREASES TO 93 NM BY TAU 60. NAVGEM IS THE
OUTLIER SHOWING A MORE SOUTHERLY TRACK THAN A BULK OF THE CONSENSUS
MEMBERS. DUE TO THIS, THE JTWC TRACK IS PLACED WITH MEDIUM
CONFIDENCE SLIGHTLY RIGHT OF CONSENSUS THROUGH TAU 72, AND LOW
CONFIDENCE AFTERWARDS DUE TO THE SPORADIC BEHAVIOR OF THE MODELS.
IT SHOULD BE NOTED THAT THE COAMPS-TC AND HWRF TRACK SOLUTIONS SHOW
TC 19S HOOKING NORTHWARD, AND THEN BACK EASTWARD JUST SOUTH OF
DIEGO GARCIA IN THE LATER TAUS. THE JTWC INTENSITY CONSENSUS
MEMBERS ARE NOT IN GOOD AGREEMENT SHOWING A 40 KNOT SPREAD BY TAU
24, MORE THAN LIKELY DUE TO THE SMALL SIZE OF THE SYSTEM. HOWEVER,
THEY DO AGREE WITH A DECREASING SCENARIO AFTER TAU 24. THE JTWC
INTENSITY FORECAST IS SET WITH MEDIUM CONFIDENCE UP TO TAU 72, AND
LOW CONFIDENCE IN THE LATER TAUS DUE TO THE UNCERTAINTY OF TRACK
PROGRESSION.

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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