WDPS32 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 09P (NINE) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.3S 153.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 471 NM EAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
DISORGANIZED, ELONGATED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
FLARING CONVECTIVE ACTIVITY CURRENTLY OBSCURING THE CENTER. TC 09P
LIES ALONG A STRONG MOISTURE GRADIENT WITH SIGNIFICANT MID-LEVEL
DRY AIR MOVING NORTH OVER TOP OF THE LLCC. THE SYSTEM ALSO LIES IN
AN AREA OF CONVERGENT FLOW ALOFT, JUST WEST OF A SHARP UPPER-LEVEL
TROUGH AXIS. THESE INHIBITING FACTORS ARE CURRENTLY DOMINATING THE
OTHERWISE FAVORABLE SSTS AND LOW SHEAR, AND LIMITING CONVECTIVE
DEVELOPMENT AND CONSOLIDATION. THE INITIAL POSITION IS ASSESSED
WITH LOW CONFIDENCE USING A 011748Z SSMIS 37GHZ MICROWAVE IMAGE
WHICH SUGGESTS A VERY WEAK LOW LEVEL CIRCULATION ON THE SOUTHEAST
SIDE OF A CONVECTIVE FLARE UP. THE INITIAL INTENSITY IS HELD AT A
GENEROUS 35 KNOTS WITH LOW CONFIDENCE. THE ONLY AGENCY STILL FIXING
ON THE SYSTEM IS KNES THOUGH THE FIX WAS TOO WEAK TO CLASSIFY.
HOWEVER, THE OBJECTIVE ADT, AIDT, AND SATCON CONTINUE TO RETURN
HIGHER ESTIMATES RANGING FROM 39-44 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWEST PERIPHERY OF A
NEAR-EQUATORIAL RIDGE (NER) TO THE NORTH-NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS SATCON: 44 KTS AT 011532Z
   CIMSS ADT: 43 KTS AT 011740Z

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: OVER THE PAST SIX TO TWELVE HOURS, TC 09P HAS
SLOWLY DRIFTED ONTO A MORE WESTWARD TRACK AS THE STEERING RIDGE
ORIENTS TO A MORE EAST-WEST AXIS. THIS TREND IS EXPECTED TO
CONTINUE THROUGH THE NEXT 24 HOURS AND TC 09P WILL TRACK JUST SOUTH
OF WEST THROUGH TAU 24. AFTER THIS POINT, THE NER WILL BUILD AND
REORIENT TO A MORE NORTHWEST-SOUTHEAST AXIS, PUSHING TC 09P ONTO A
SOUTHEASTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD.
TRACK SPEEDS WILL INCREASE DURING THIS TIME FRAME AS THE SYSTEM
RIDES THE TIGHT GRADIENT BETWEEN THE NER AND A STRONG MID-LATITUDE
TROUGH TO THE SOUTH. THE SYSTEM WILL CONTINUE TO STRUGGLE AGAINST
DRY AIR ENTRAINMENT AND A NEUTRAL TO UNFAVORABLE OUTFLOW
ENVIRONMENT FOR THE NEXT 24 HOURS, AND WILL LIKELY DIP DOWN TO 30
KNOTS DURING THIS TIME FRAME. A SLOW BUT STEADY INTENSIFICATION
TREND IS EXPECTED TO START BY TAU 36 AS THE SYSTEM MOVES INTO AN
INCREASINGLY MOIST ENVIRONMENT AND THE UPPER-LEVEL OUTFLOW
IMPROVES. THE SYSTEM IS FORECAST TO PEAK AT 55 KNOTS EAST OF NEW
CALEDONIA AT TAU 96, THEN SLOWLY WEAKEN DUE PRIMARILY DUE TO
DECREASING SSTS. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN FAIR
AGREEMENT, WITH THE MAJORITY OF MEMBERS TRENDING TOWARDS A CLOSER
GROUPING ABOUT THE CONSENSUS MEAN. THE UKMET AND UKMET ENSEMBLE ARE
THE PRIMARY OUTLIERS ON THE POLEWARD SIDE, CONTINUING TO TRACK THE
SYSTEM SOUTH OF NEW CALEDONIA. THE GFS AND NAVGEM ARE ON THE
EQUATORWARD EDGE OF THE ENVELOPE. DISCOUNTING THE UKMET, THE
REMAINDER OF THE GUIDANCE PACKAGE EXHIBITS A SPREAD OF 100NM AT TAU
72, BUT INCREASES TO 400NM AT TAU 120 AS THE MODELS DIVERGE IN THE
AMOUNT OF INTERACTION THE SYSTEM WILL HAVE WITH THE MID-LATITUDE
TROUGH PASSING TO THE SOUTH. THE JTWC FORECAST LIES ON THE SOUTH
SIDE OF THE ENVELOPE THROUGH TAU 36, THEN CLOSE TO BUT SLOWER THAN,
THE CONSENSUS MEAN THROUGH TAU 120. CONFIDENCE IS MEDIUM IN THE
NEAR TERM, TRENDING TO LOW IN THE EXTENDED FORECAST PERIOD.
INTENSITY GUIDANCE REMAINS MIXED WITH THE DECAY-SHIPS STILL
INSISTING ON A PEAK ABOVE 75 KNOTS BY TAU 120, WHILE THE REMAINDER
OF THE PACKAGE IS CLUSTERED BETWEEN A 45-55 KNOT PEAK. THE JTWC
FORECAST LIES BELOW THE GUIDANCE THROUGH TAU 24, THEN TRACKS CLOSE
TO THE HWRF SOLUTION THROUGH THE REMAINDER OF THE FORECAST.
CONFIDENCE IS LOW THROUGHOUT. 

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