WDXS32 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 25S (JUDE) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.0S 44.6E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 400 NM SOUTH-SOUTHWEST OF ANTANANARIVO,
MADAGASCAR
   MOVEMENT PAST 6 HOURS: EASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 25S (JUDE) TRANSITING OVER SOUTHERN PORTION OF 
MADAGASCAR. THE VERTICAL WIND SHEAR (VWS) REMAINS AS HIGH AS 40+ KTS 
FROM THE NORTHWEST, RESULTING IN ALL ASSOCIATED DEEP CONVECTION BEING 
CONTAINED WITHIN THE SOUTHERN SEMICIRCLE OF THE CIRCULATION. THE 
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE 
ANIMATED SHORTWAVE IR LOOP SHOWING A LOW-LEVEL CYCLONIC FLOW OVER THE 
WESTERN AND NORTHERN PORTIONS OF TC 25S. THIS ASSESSMENT IS CONSISTENT 
WITH THE ANALYSIS OF THE MULTI-MODEL (GFS, ECMWF, UKMET) PRESSURE 
FIELDS AND LOCAL SURFACE OBSERVATIONS. AS A LONGWAVE TROUGH APPROACHES 
TO THE SOUTH OF THE SYSTEM, STRONG POLEWARD OUTFLOW REMAINS IN PLACE. 
THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE 
BASED ON PERSISTENT CONVECTION AND MINIMAL LAND INTERACTION, AS TC 25S 
RETAINS MAJORITY OF ITS MOMENTUM THROUGHOUT THE PASSAGE OVER SOUTHERN 
MADAGASCAR.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   KNES: T3.5 - 55 KTS
   CIMSS D-MINT: 41 KTS AT 150250Z
   CIMSS D-PRINT: 50 KTS AT 150530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 40+ KTS
   SST: OVER LAND
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 25S IS FORECAST TO CONTINUE TRACKING
EAST-SOUTHEASTWARD AND RE-EMERGE OVER SOUTHERN INDIAN OCEAN WATER
WITHIN THE NEXT 6-12 HOURS. THE SYSTEM WILL REMAIN UNDER THE
PRIMARY INFLUENCE OF A DEEP-LAYER STR TO THE NORTHEAST.
SIMULTANEOUSLY, A LONGWAVE TROUGH AXIS WILL APPROACH THE SYSTEM AS 
SOON AS TAU 12, INITIATING A SUBTROPICAL TRANSITION (STT). TC JUDE IS 
FORECAST TO MAINTAIN INTENSITY THROUGH TAU 24, ASSISTED BY AN 
INJECTION OF WARM (27-28 C) WATER AND STRONG POLEWARD OUTFLOW, OFFSET 
BY AN INCREASING VWS. BY TAU 36 THE SYSTEM IS FORECAST TO BECOME FULLY 
SUBTROPICAL AND SLOWLY WEAKEN TO 45 KTS, DUE TO RAPIDLY COOLING SEA 
SURFACE TEMPERATURES, DRY AIR ENTRAINMENT FROM THE WEST AND FURTHER 
INCREASING VWS.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 24, WITH CROSS-TRACK OF 75 NM. THE GUIDANCE
UNCERTAINTY INCREASES AFTERWARDS, AS TRACKS BEGIN TO SPLIT BETWEEN
MAJORITY OF THE MODELS FOLLOWING A SOUTHEASTWARD PATH AND
DETERMINISTIC GFS TRACKER RAPIDLY TURNING NORTHEASTWARD. GFS GUIDANCE 
PAST TAU 36 APPEARS TO BE DRIVEN BY A DEVELOPING AND COMPETING STR TO
THE NORTHWEST OF THE SYSTEM AND CALLS FOR DISSIPATION BY TAU 48.
JTWC TRACK GUIDANCE IS THEREFORE ASSESSED WITH MEDIUM CONFIDENCE
THROUGHOUT THE FORECAST PERIOD AND THE JTWC TRACK IS PLACED
SLIGHTLY TO THE SOUTH OF THE MULTI-MODEL CONSENSUS. JTWC INTENSITY
FORECAST IS ALSO ASSESSED WITH MEDIUM CONFIDENCE, BASED ON THE
UNCERTAINTY ASSOCIATED WITH THE STT TIMELINE AND SOME POTENTIAL FOR 
DISSIPATION PRIOR TO OR JUST AFTER THE TRANSITION COMPLETION, AS 
INDICATED BY THE GFS GUIDANCE.

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