WDXS32 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 25S (JUDE) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.1S 39.5E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 77 NM NORTH-NORTHWEST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
QUICKLY CONSOLIDATING SYSTEM, WITH DEEP CONVECTIVE CELLS FORMING
PRIMARILY TO THE SOUTH AND EAST OF THE LOW LEVEL CIRCULATION CENTER
(LLCC), BUT SO FAR UNABLE TO WRAP UPSHEAR. A 131814Z ASCAT-B
BULLSEYE PASS REVEALS A WELL-DEFINED LLCC WITH A SMALL RMW OF ABOUT
25NM AND AN EXTENSIVE GALE-FORCE WIND FIELD, PARTICULARLY LARGE IN
THE SOUTHEASTERN QUADRANT. THE ACCOMPANYING AMSU-B 89GHZ MICROWAVE
IMAGE DEPICTS A HIGHLY ASYMMETRIC SYSTEM, WITH A DISTINCT
COMMA-SHAPED ARC OF CONVECTION ACROSS THE SOUTHERN HEMISPHERE OF
THE ROTATION, WITH A TAIL OF SHALLOW BANDING FEATURES EXTENDING TO
THE NORTH ALONG THE EASTERN EDGE OF THE CIRCULATION. THE INITIAL
POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE ASCAT DATA
NOTED ABOVE. THE INITIAL INTENSITY IS ASSESSED WITH HIGH
CONFIDENCE, HEDGED HIGHER THAN THE BULK OF THE OBJECTIVE AND
SUBJECTIVE ESTIMATES NOTED ABOVE (THE PRIMARY EXCEPTION BEING THE
FMEE T3.0 ESTIMATE), IN LINE WITH THE 40-45 KNOT WINDS OBSERVED IN
THE ASCAT DATA. THE ENVIRONMENT REMAINS FAVORABLE FOR ADDITIONAL
DEVELOPMENT, WITH LOW NORTHWESTERLY DEEP-LAYER SHEAR, WARM SSTS,
AND ROBUST POLEWARD OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER NEAR
EQUATORIAL RIDGE (NER) TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   DEMS: T2.5 - 35 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS SATCON: 38 KTS AT 131730Z
   CIMSS ADT: 32 KTS AT 131800Z
   CIMSS AIDT: 33 KTS AT 131800Z
   CIMSS D-MINT: 35 KTS AT 131550Z
   CIMSS D-PRINT: 36 KTS AT 131800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 25S IS FORECAST TO
CONTINUE TRACKING TOWARDS THE SOUTHEAST, ALONG THE SOUTHERN SIDE OF
A NER CENTERED TO THE NORTH FOR THE NEXT 24 HOURS. LANDFALL ALONG
THE SOUTHWEST COAST OF MADAGASCAR, NEAR THE TOWN OF TOLIARA, IS
EXPECTED AROUND TAU 24. THE SYSTEM WILL THEN CONTINUE TRACKING
EASTWARD, MOVING QUICKLY OVER THE SOUTHERN PORTION OF MADAGASCAR,
AND REEMERGING OVER WATER BETWEEN TAU 36 AND TAU 48. TRACK SPEEDS
ARE EXPECTED TO SLOW SOMEWHAT AS THE SYSTEM CROSSES MADAGASCAR BUT
PICK UP SPEED ONCE AGAIN AFTER MOVING INTO THE SOUTHERN INDIAN
OCEAN. ONCE BACK OVER OPEN WATERS, THE SYSTEM IS EXPECTED TO BEGIN
SUBTROPICAL TRANSITION (STT) AS IT BECOMES EMBEDDED INTO THE
EQUATORWARD END OF A FRONTAL BOUNDARY. IN TERMS OF INTENSITY, THE
SYSTEM IS EXPECTED TO INTENSIFY QUICKLY OVER THE NEXT 12 HOURS AS
IT TAKES ADVANTAGE OF THE WARM SSTS, ROBUST POLEWARD OUTFLOW
CHANNEL AND RELATIVELY LOW SHEAR VALUES. PEAK INTENSITY IS EXPECTED
TO BE REACHED JUST PRIOR TO LANDFALL, BETWEEN TAU 18 AND TAU 24,
AND COULD BE SLIGHTLY HIGHER THAN THE DISCRETE FORECAST VALUES
INDICATE. SIMULTANEOUSLY WITH LANDFALL, SHEAR IS EXPECTED TO
RAPIDLY INCREASE, ACCOMPANIED BY AN INFLUX OF DRY MID-LEVEL AIR,
WHICH COMBINED WITH PASSAGE OVER LAND WILL RESULT IN A VERY SHARP
WEAKENING AS THE SYSTEM MOVES ACROSS MADAGASCAR. THE CIRCULATION
THAT EMERGES BACK OVER WATER IS CURRENTLY EXPECTED TO RETAIN
GALE-FORCE WINDS AS IT MOVES EAST, AND MERGES WITH THE BAROCLINIC
ZONE ALREADY IN-PLACE. HOWEVER, THE SYSTEM MAY IN FACT DISSIPATE
PRIOR TO FULL STT, DEPENDENT UPON THE STRENGTH OF THE CIRCULATION
THAT MOVES BACK OVER WATER AFTER TAU 36. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT
THROUGH LANDFALL, WITH MINIMAL CROSS- OR ALONG-TRACK SPREAD. MODELS
BEGIN TO DIVERGE AFTER LANDFALL WITH CROSS-TRACK SPREAD OPENING UP
TO ABOUT 115NM AT TAU 36, INCREASING EVEN MORE THROUGH THE
REMAINDER OF THE FORECAST. GFS AND GEFS HAVE NOW SHIFTED TO REFLECT
THE REST OF THE CONSENSUS MEMBERS IN DEPICTED A GENERALLY
SOUTHEASTWARD TRACK, AT LEAST THROUGH THE END OF THE FORECAST,
THOUGH THEY DO START TO TURN NORTHWARD BY TAU 72. THE REMAINDER OF
THE GUIDANCE PACKAGE IS CONSISTENT WITH THE JTWC FORECAST TRACK,
SHOWING A TRACK TO THE EAST THAT STEADILY SLOWS DOWN AS RIDGING
DEVELOPS TO THE EAST AND SOUTH AFTER TAU 48. INTENSITY GUIDANCE IS
IN GOOD AGREEMENT THAT THE SYSTEM WILL INTENSIFY OVER THE NEXT 12
TO 18 HOURS, REACHING PEAK INTENSITY BETWEEN 50-55 KNOTS PRIOR TO
LANDFALL, FOLLOWED BY A SHARP WEAKENING OVER LAND AND GENERALLY
STEADY-STATE THEREAFTER DURING STT. THE COAMPS-TC AND HAFS-A ARE
THE SIGNIFICANT OUTLIERS IN THIS SCENARIO HOWEVER, DEPICTING THE
SYSTEM MAINTAINING 50 KNOT OR HIGHER INTENSITY THROUGH TAU 96,
WHICH IS ON THE FACE OF IT HIGHLY UNLIKELY. THE JTWC FORECAST
TRACES THE HWRF, GFS, AND DECAY SHIPS GUIDANCE WITH MEDIUM
CONFIDENCE. 

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