WDPS31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (RUBY) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.2S 165.5E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 64 NM NORTH-NORTHWEST OF NOUMEA, NEW
CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
DISORGANIZED AREA OF CONVECTION ON THE EAST SIDE OF NEW CALEDONIA,
EMBEDDED WITHIN A LARGER, SOMEWHAT RAGGED CIRCULATION. DRY AIR
INTRUSION IS REVEALED BY THE STRATOCUMULUS FIELD TO THE WEST AND
THE EROSION OF THE CONVECTIVE STRUCTURE ON THE WESTERN SIDE OF THE
SYSTEM. THERE HAS BEEN NO RECENT MICROWAVE IMAGERY BUT THANKS TO
THE NEW CALEDONIA RADAR NETWORK AND SURFACE OBSERVATIONS, THERE IS
GOOD INSIGHT TO THE INITIAL POSITION AND STRUCTURE OF THE LOW LEVEL
CIRCULATION. THE RADAR DATA SHOWED A VERY CLEAR CENTER OR EYE
FEATURE TRACKING DOWN THE EASTERN COAST OF THE ISLAND BETWEEN
132000Z TO 140000Z AND BY 140200Z THE CENTER LIES JUST NORTHWEST OF
THIO. SO WHILE THE MSI IS VERY DISORGANIZED, THE RADAR DATA LENDS
HIGH CONFIDENCE TO THE INITIAL POSITION. DUE TO BEING OVERLAND, ALL
AGENCY FIX POSITIONS LACKED INTENSITY, MAKING AN INTENSITY
ASSESSMENT VERY DIFFICULT. SURFACE OBSERVATIONS FROM TOUHO
AERODROME SAVED THE DAY HOWEVER, AND RECORDED A MINIMUM MSLP OF
984MB AS THE EYE PASSED OVER THE STATION. USING THE CKZ WIND
PRESSURE RELATIONSHIP, 984MB RESULTS IN A WIND ESTIMATE OF 55
KNOTS. WHILE SUSTAINED WINDS WERE MEASURED AT 39 KNOTS (10MIN), THE
PRESSURE READING LENDS MEDIUM CONFIDENCE TO THE INITIAL INTENSITY
OF 55 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS SATCON: 69 KTS AT 132307Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST. 

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: AFTER TRANSITING THE LENGTH OF NEW CALEDONIA,
TC 03P IS EXPECTED TO DIVE INTO THE WARM WATERS OF THE SOUTH
PACIFIC ONCE MORE WITHIN THE NEXT SIX HOURS. ONCE THERE, THE
FORECAST CALLS FOR THE SYSTEM TO ACCELERATE TOWARDS THE SOUTHEAST
ALONG THE STRENGTHENING GRADIENT BETWEEN THE STR TO THE EAST AND A
HIGH-AMPLITUDE TROUGH TO THE WEST THROUGH THE REMAINDER OF THE
FORECAST PERIOD. OVER THE NEXT 24 HOURS, SHEAR IS FORECAST TO
REMAIN AT MODERATE LEVELS WHICH WILL OFFSET THE STRONG POLEWARD
OUTFLOW AND ALLOW FOR THE SYSTEM TO MAINTAIN ITS CURRENT INTENSITY.
TC 03P SHOULD CROSS THE 26C ISOTHERM NEAR TAU 24, AND AT THE SAME
TIME WILL START TO FEEL THE IMPACT OF THE STRONG MID-LATITUDE
WESTERLIES ALOFT AS WELL AS INCREASING VWS, MARKING THE START OF
SUBTROPICAL TRANSITION. THE SYSTEM WILL STEADILY WEAKEN AFTER TAU
24 AS IT TRANSITIONS TO A SUBTROPICAL, STORM-FORCE LOW TO THE
NORTHEAST OF NEW ZEALAND BY TAU 48. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN VERY GOOD AGREEMENT WITH
MINIMAL CROSS-TRACK SPREAD THROUGH THE FORECAST PERIOD, LENDING
HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. INTENSITY GUIDANCE IS
ALSO IN GOOD AGREEMENT, WITH ALL GUIDANCE INDICATING A STEADY
INTENSITY TREND FOLLOWED BY STEADY WEAKENING AFTER TAU 24, LENDING
HIGH CONFIDENCE TO THE JTWC INTENSITY FORECAST. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
NNNN