WDPS31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11P (DOVI) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.9S 166.0E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 648 NM NORTHWEST OF AUCKLAND, NEW ZEALAND
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 21 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TC 11P (DOVI) IS UNDERGOING EXTRATROPICAL TRANSITION (ETT) AS IT 
ACCELERATES SOUTHWARD AND, AS INDICATED IN ANIMATED WATER VAPOR 
IMAGERY AND UW-CIMSS MID-UPPER LEVEL FEATURE TRACK WINDS, IS 
EMBEDDED WITHIN AN EXTENSIVE REGION OF ENHANCED, ROBUST POLEWARD 
OUTFLOW ALONG THE EASTERN PERIPHERY OF A DEEP UPPER-LEVEL TROUGH. 
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAPIDLY 
DETERIORATING SYSTEM WITH ERODING DEEP CONVECTION OVER THE SOUTHERN 
SEMICIRCLE DUE TO DRY AIR ENTRAINMENT AND HIGHLY ASYMMETRIC 
CONVECTIVE STRUCTURE. DESPITE THE LOSS OF THE RAGGED EYE IN EIR, THE 
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 
FORTUITOUS 111122Z ASCAT-B IMAGE WHICH SHOWS A WELL-DEFINED 
CIRCULATION CENTER. THE SYSTEM IS CURRENTLY LOCATED 100NM WEST OF 
NORFOLK ISLAND (94996), WHICH IS REPORTING NORTHEASTERLY WINDS AT 27 
KNOTS AND SLP NEAR 992.4MB. THE INITIAL INTENSITY OF 70 KTS IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF FINAL-T 
ESTIMATES (T4.0, 65 KNOTS) AND THE DVORAK CURRENT INTENSITY 
ESTIMATES (4.5 TO 5.0). THE 111122Z ASCAT-B IMAGE SHOWS A SMALL 
SWATH OF 60-65 KNOT WINDS IN THE SOUTHEASTERN QUADRANT.  

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T5.0 - 90 KTS
   ABRF: T5.0 - 90 KTS
   NZKL: T4.5 - 77 KTS
   CIMSS ADT: 92 KTS AT 111310Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   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 11P (DOVI) IS FORECAST TO CONTINUE ITS
RAPID DECLINE FROM A WARM CORE TROPICAL CYCLONE TO A COLD CORE
EXTRATROPICAL LOW BY TAU 24. OVER THE NEXT TWELVE HOURS, TC 11P
WILL BEGIN TO RECURVE SOUTH-SOUTHEASTWARD AS ITS INTERACTION WITH
THE UPPER LEVEL MIDLATITUDE TROUGH INCREASES AND DEEP CONVECTION 
SHEARS POLEWARD AND DECOUPLES FROM THE LLCC. MARGINAL SEA SURFACE 
TEMPERATURES (SST) (23-25C) AND MODERATE-HIGH VERTICAL WIND SHEAR 
(VWS) WILL BE PARTIALLY OFFSET BY VIGOROUS POLEWARD OUTFLOW AS
THE SYSTEM CONTINUES TO DECREASE IN INTENSITY. A SIGNIFICANT AMOUNT
OF DRY AIR WILL CONTINUE TO ENTRAIN THROUGHOUT ALL LEVELS OF THE
SYSTEM FURTHER DETERIORATING ITS TROPICAL CHARACTERISTICS. AFTER
TAU 12, TC 11P WILL RECURVE SOUTHEASTWARD AS IT ENCOUNTERS STRONGER 
VWS (35-40KTS) AND LOWER SST VALUES (21-23C). BY TAU 24, 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 TIGHT
AGREEMENT WITH A 56NM SPREAD IN SOLUTIONS AT TAU 24 LENDING HIGH 
CONFIDENCE TO THE JTWC TRACK FORECAST. THE 110600Z 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 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//
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