WDPS31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11P (DOVI) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.8S 166.2E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 963 NM NORTH-NORTHWEST OF WELLINGTON, NEW
ZEALAND
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TC 11P (DOVI) IS IN THE EARLY STAGES OF EXTRATROPICAL TRANSITION
(ETT). ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS
EXTENSIVE STRATOCUMULUS CLOUDS, ASSOCIATED WITH COOLER, DRIER, MORE
STABLE AIR, ADVECTING OVER THE WESTERN PERIPHERY OF THE SYSTEM.
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
DETERIORATION OF THE CONVECTIVE STRUCTURE OVER THE WESTERN
PERIPHERY AS CONVERGENT, WESTERLY TO NORTHWESTERLY WINDS ASSOCIATED
WITH THE MIDLATITUDE UPPER-LEVEL TROUGH BEGIN TO INTERACT WITH THE
SYSTEM. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON A RAGGED 20NM EYE IN EIR IMAGERY. A 110544Z SSMIS 91GHZ IMAGE
REVEALS A LARGER, 40NM ROUND MICROWAVE EYE FEATURE. THE INITIAL
INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A
110306Z AMSR2 WINDSPEED IMAGE SHOWING A SWATH OF 70-75 KNOT WINDS
OVER THE EASTERN SEMICIRCLE WITH A SMALL POCKET OF 80-83 KNOT
WINDS, AND SIGNIFICANTLY LOWER WINDS OVER THE WESTERN SEMICIRCLE.
ALTHOUGH DVORAK CURRENT INTENSITY (CI) ESTIMATES REMAIN HIGHER AT
110600Z (5.0 TO 5.5), THE 110830Z PGTW FINAL-T ESTIMATE HAS 
DECREASED TO T4.0 (65 KNOTS) WITH A CI OF 5.0 (90 KNOTS) REFLECTING 
THE STEADY WEAKENING TREND AND DECAYING CONVECTIVE STRUCTURE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.0 - 90 KTS
   ABRF: T5.0 - 90 KTS
   NZKL: T5.5 - 102 KTS
   CIMSS ADT: 105 KTS AT 110700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 11P (DOVI) IS FORECAST TO RAPIDLY
DETERIORATE FROM A WARM CORE TROPICAL CYCLONE TO A COLD CORE
EXTRATROPICAL LOW BY TAU 36. OVER THE NEXT TWELVE HOURS, TC 11P
WILL TRACK SOUTHWARD, FURTHER INTERACTING WITH AN EASTWARD
PROPAGATING MIDLATITUDE UPPER-LEVEL TROUGH AND STRONG BAROCLINIC
ZONE. MARGINAL SEA SURFACE TEMPERATURES (SST) (24-26C) AND MODERATE
VERTICAL WIND SHEAR (VWS) (15-20KTS) WILL BE OFFSET BY INCREASING
POLEWARD OUTFLOW AND CONTINUES TO DECREASE IN INTENSITY. AFTER
TAU 12, TC 11P WILL RECURVE SOUTH-SOUTHEASTWARD TO SOUTHEASTWARD
AND ENCOUNTER STRONG VWS (30-40KTS) AND COOLER SST VALUES (21-23C).
BY TAU 36, THE SYSTEM WILL COMPLETE ETT AS IT BECOMES EMBEDDED IN
THE BAROCLINIC ZONE NEAR THE JET AND WILL GAIN CLEAR FRONTAL
CHARACTERISTICS. AFTER COMPLETING ETT, THE SYSTEM IS EXPECTED TO
REMAIN A STORM-FORCE LOW AS IT TRACKS OVER NORTH ISLAND, NEW
ZEALAND.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT THROUGH TAU 36 WITH A 90NM SPREAD IN SOLUTIONS AT TAU 36
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. THE 110000Z
ECMWF ENSEMBLE (EPS) STRIKE PROBABILITY OUTPUT SUPPORTS THE JTWC
TRACK PHILOSOPHY WITH A HIGH PROBABILITY OF LANDFALL OCCURRING JUST
SOUTH OF AUCKLAND. JTWC INTENSITY GUIDANCE IS IN GOOD AGREEMENT ON
THE STEADY WEAKENING TREND AND BOLSTERS THE JTWC INTENSITY FORECAST
WITH MEDIUM CONFIDENCE. 
  
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
NNNN