WDXS31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 17S (FILIPO)    
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.3S 37.3E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 198 NM NORTHWEST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
CONSOLIDATING SYSTEM WITH A CENTRAL DENSE OVERCAST (CDO) FEATURE
AND IMPROVED DEEP CONVECTIVE BANDING. A PARTIAL 110226Z SSMIS 91
GHZ MICROWAVE IMAGE REVEALS TIGHTLY-CURVED BANDING OVER THE
SOUTHEASTERN QUADRANT REFLECTING THE RAPID CONSOLIDATION OF THE
LOW-LEVEL CIRCULATION OVER THE PAST SIX HOURS. THE IMPROVED
BANDING, WITH INTENSE CONVECTIVE BURSTS OVER THE WESTERN QUADRANT,
EVIDENT IN THE ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. ENVIRONMENTAL
CONDITIONS ARE FAVORABLE WITH RADIAL OUTFLOW AND ENHANCED POLEWARD
OUTFLOW, LOW VERTICAL WIND SHEAR (VWS) AND WARM SST VALUES (29-30
C). HOWEVER, FRICTIONAL EFFECTS ARE BEGINNING TO NEGATIVELY IMPACT
THE OUTER BANDING ALONG THE WESTERN PERIPHERY OF THE SYSTEM. THE
INITIAL INTENSITY IS ASSESSED AT 45 KNOTS BASED ON THE PGTW, KNES,
AND FMEE DVORAK ESTIMATES, SLIGHTLY HIGHER THAN THE UW-CIMSS
OBJECTIVE INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: OTHER 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED OVER SOUTH AFRICA, EXTENDING EASTWARD TO ABOUT 50E
LONGITUDE. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS SATCON: 44 KTS AT 110130Z
   CIMSS ADT: 39 KTS AT 110530Z
   CIMSS AIDT: 38 KTS AT 110530Z
   CIMSS DPRINT: 41 KTS AT 110600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: INITIAL INTERACTION WITH LAND OVER THE WESTERN
                  PERIPHERY.

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 17S IS FORECAST TO TRACK
GENERALLY WEST-SOUTHWESTWARD THROUGH TAU 24 ALONG THE NORTHWESTERN
PERIPHERY OF THE STR, WITH LANDFALL OVER THE MOZAMBIQUE COAST NEAR
TAU 20. AFTER TAU 24, THE SYSTEM WILL RECURVE AROUND THE WESTERN
PERIPHERY OF THE STR AND BEGIN INTERACTING WITH THE SUBTROPICAL
WESTERLIES AND ASSOCIATED LONGWAVE TROUGH BY TAU 48. AFTER TAU 48,
THE SYSTEM WILL RE-EMERGE OVER WATER AND BEGIN TO REINTENSIFY WHILE
UNDERGOING SUBTROPICAL AND THEN EXTRATROPICAL TRANSITION (ETT)
THROUGH INTERACTION WITH THE MIDLATITUDE WESTERLIES AND THE
BAROCLINIC ZONE. TC 17S WILL COMPLETE ETT BY TAU 96 AS IT TRACKS
UNDER THE POLAR FRONT JET AND GAINS FRONTAL CHARACTERISTICS.    

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT THROUGH THE FORECAST PERIOD, WITH AN 80 NM CROSS-TRACK
SPREAD AT TAU 72 AND 160NM AT TAU 96. RELIABLE INTENSITY GUIDANCE
SUPPORTS THE JTWC FORECAST WITH MEDIUM CONFIDENCE AND INDICATES
SIGNIFICANT INTENSIFICATION AS THE SYSTEM TRANSITIONS TO A
COLD-CORE STORM-FORCE MIDLATITUDE LOW. 

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