WDPS32 PGTW 010900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 09P (NINE) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.2S 153.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 439 NM EAST-NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN ELONGATED
LOW LEVEL CIRCULATION (LLC) WITH BURSTS OF INTENSE CONVECTION
OBSCURING THE CENTER AND EXTENSIVE LOW LEVEL CLOUD LINES WRAPPING
INTO THE LLC. A 010617Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS A
DISORGANIZED SYSTEM WITH A WEAKLY DEFINED LLC. TC 09P IS LOCATED
JUST EAST OF AN UPPER-LEVEL POINT SOURCE WITH DIVERGENT FLOW ALONG
A WEST-NORTHWEST TO EAST-SOUTHEAST AXIS, HOWEVER, CONVERGENT FLOW
SOUTH OF THE SYSTEM IS RESTRICTING POLEWARD OUTFLOW. ADDITIONALLY,
THERE IS SIGNIFICANT DRY AIR PRESENT OVER THE SOUTHERN PERIPHERY OF
THE SYSTEM WITH MID-LEVEL DRY AIR ENTRAINMENT. SEA SURFACE
TEMPERATURES (29-30C) AND VERTICAL WIND SHEAR REMAIN FAVORABLE. THE
INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE MSI AND
SSMIS IMAGE. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON AGREEMENT BETWEEN THE PGTW AND ABRF DVORAK
ESTIMATES AND THE CIMSS ADT ESTIMATE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) POSITIONED
TO THE NORTH AND NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   ABRF: T2.5 - 35 KTS
   CIMSS SATCON: 40 KTS AT 010335Z
   CIMSS ADT: 37 KTS AT 010540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK POLEWARD AND EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TC 09P IS FORECAST TO TRACK EASTWARD TO
EAST-SOUTHEASTWARD UNDER THE STEERING INFLUENCE OF THE NER THROUGH
TAU 72. TC 09P WILL MAINTAIN INTENSITY AT 35 KNOTS THROUGH TAU 36
DUE TO DRY AIR ENTRAINMENT AS WELL AS INCREASING MID-LEVEL VERTICAL
WIND SHEAR (VWS). AFTER TAU 36, THE SYSTEM WILL INTENSIFY SLOWLY AS
VWS DECREASES, THE CORE ENVIRONMENT MOISTENS AND POLEWARD OUTFLOW 
IMPROVES. AFTER TAU 72, TC 09P WILL GRADUALLY TURN SOUTHEASTWARD 
ALONG THE WESTERN FLANK OF A BUILDING SUBTROPICAL RIDGE (STR) TO THE 
EAST. TRACK SPEEDS WILL INCREASE AFTER TAU 72 AS THE SYSTEM TRACKS 
WITHIN THE ENHANCED FLOW BETWEEN THE STR AND A BROAD MIDLATITUDE 
TROUGH. THE SYSTEM WILL PEAK AT 55 KNOTS BY TAU 96 AND WILL MAINTAIN 
THIS INTENSITY THROUGH TAU 120, HOWEVER, THIS PORTION OF THE 
INTENSITY FORECAST IS UNCERTAIN DUE TO POSSIBLE DRY AIR ENTRAINMENT 
AND SLIGHTLY COOLER SEA SURFACE TEMPERATURES (27-28C).  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A
220NM SPREAD IN SOLUTIONS AT TAU 72. HOWEVER, THERE IS LARGE SPREAD
AFTER TAU 72. GFS AND AFUM INDICATE A MORE EASTWARD, UNLIKELY TRACK
DIRECTLY INTO THE STR WHILE THE REMAINDER OF THE GUIDANCE TURNS THE
SYSTEM SOUTHEASTWARD TO SOUTHWARD TOWARD NEW CALEDONIA. ECMWF (EPS)
AND GFS (GEFS) ENSEMBLE IMAGERY INDICATE A SIMILAR LARGE SPREAD
WITH THE VAST MAJORITY OF SOLUTIONS RECURVING THE SYSTEM
SOUTHEASTWARD TO SOUTHWARD. BASED ON THE POSITIONAL UNCERTAINTY AND
SPREAD IN MODEL TRACKERS, THERE IS MEDIUM CONFIDENCE IN THE JTWC
TRACK FORECAST.   

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