WDXS31 PGTW 160900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 07S (BAKUNG) WARNING 
NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.6S 93.1E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 226 NM WEST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 07S (BAKUNG) HAS SHIFTED SOUTH-SOUTHWESTWARD
WITH A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER AS DEPICTED
VIA ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI). SOME DEEP
CONVECTION PERSISTS ESPECIALLY ON THE WESTERN SIDE OF THE
CIRCULATION. THE SYSTEM EXHIBITS MODERATE POLEWARD OUTFLOW. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON
CONVERGING SPIRAL BANDS OF DEEP CONVECTION PRESENT IN THE MSI
IMAGERY. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON A COMBINATION OF OBJECTIVE AIDS AND DVORAK
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: A 152323Z RCM-3 SAR PASS DATA 

CURRENT STEERING MECHANISM: EXTENSION OF A SUBTROPICAL RIDGE
CENTERED TO THE SOUTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   APRF: T3.0 - 45 KTS
   CIMSS ADT: 53 KTS AT 160530Z
   CIMSS AIDT: 43 KTS AT 160530Z
   CIMSS D-MINT: 41 KTS AT 160712Z
   CIMSS D-PRINT: 32 KTS AT 160700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 07S WILL REMAIN IN WEAK
STEERING ENVIRONMENT. AS A RESULT OF A PREVIOUS BINARY INTERACTION
WITH ANOTHER SURFACE-LEVEL VORTICITY MAXIMUM, IT WILL NOW TRACK
GENERALLY NORTHWARD OSCILLATING SLIGHTLY TOWARDS THE EAST AND WEST.
THE SYSTEM HAS SLOWED SIGNIFICANTLY BUT WILL BEGIN TO GAIN SPEED
AGAIN UNDER THE INFLUENCE OF SUBTROPICAL RIDGING CENTERED TO THE
SOUTHWEST. CONTINUED ENTRAINMENT OF THE DRY AIR COMBINED WITH
MODERATE VERTICAL WIND SHEAR WILL CAUSE STEADY WEAKENING OF THE
SYSTEM AS IT PROGRESSES FURTHER NORTH. TC 07S IS FORECAST TO
DISSIPATE OVER WATER BY TAU 36.

MODEL DISCUSSION: THERE IS SIGNIFICANT CROSS TRACK SPREAD AMONG
MODEL GUIDANCE. NAVGEM PUSHES THE CIRCULATION FURTHER TO THE
NORTHWEST BEFORE DISSIPATION WHILE ECMWF DEPICTS A NORTHEASTWARD
TRACK. THE JTWC FORECAST REFLECTS A TRACK BETWEEN THE MULTI MODEL
CONSENSUS AND THE ECMWF DEPICTION WITH MEDIUM CONFIDENCE. INTENSITY
GUIDANCE IS IN BETTER AGREEMENT WITH ALL MODELS DEPICTING A
CONSISTENT DOWNWARD TREND. THE JTWC OFFICIAL FORECAST REFLECTS
CLOSELY THE VALUES OF THE MULTI MODEL CONSENSUS BRINGING THE
INTENSITY BELOW 35 KTS BY TAU 36. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: HIGH//
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