WDPS31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05P (CODY) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.6S 175.4E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 227 NM SOUTHWEST OF SUVA, FIJI
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS BANDS OF
GENERALLY SHALLOW CONVECTION WRAPPING INTO A WELL DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC). THE DEEPEST CONVECTION IS LIMITED TO THE
VICINITY OF THE CENTER AND TO THE NORTHWEST. EVEN WITH THE LACK OF
ANY RECENT MICROWAVE IMAGERY, THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE MOSTLY EXPOSED LLCC. DUE TO A LACK OF
SIGNIFICANT CONVECTIVE ACTIVITY TO WRAP, THE DVORAK BASED INTENSITY
ESTIMATES ARE UNRELIABLE AND TOO LOW. THIS FACT IS CONFIRMED BY
100547Z SMOS AND 100642Z SMAP PASSES, WHICH SHOWED A LARGE AREA OF
50KT OR HIGHER WINDS TO THE SOUTH OF THE CENTER, AND 45-50 KNOTS
WRAPPING AROUND TO THE NORTH. THUS THE INITIAL INTENSITY IS
ASSESSED WITH HIGH CONFIDENCE AT 50 KNOTS, ABOVE ALL THE AVAILABLE
AGENCY AND OBJECTIVE DVORAK INTENSITY ESTIMATES, WHICH RANGED
BETWEEN T2.5 TO T3.0. AUTOMATED AND FORECASTER GENERATED PHASE
CLASSIFICATIONS CONSISTENTLY INDICATE THE SYSTEM IS TROPICAL IN
NATURE, THOUGH IT LIES UNDER THE SOUTHEASTERN SIDE OF A 200MB LOW
HEIGHT CENTER AND A 500MB COLD POOL. THUS WHILE THE UPPER LOW IS
BEGINNING TO CUT OFF THE POLEWARD OUTFLOW CHANNEL, THE UPPER COLD
POOL IS SUSTAINING CONVECTION NEAR THE CENTER. A WEDGE OF DRY AIR
IS WRAPPING AROUND FROM THE NORTH NEARLY TO THE CORE OF THE SYSTEM,
BUT WILL STEADILY MOISTEN AS TIME PROGRESSES.

INITIAL WIND RADII BASIS: SMAP DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   PHFO: T2.5 - 35 KTS
   CIMSS ADT: 34 KTS AT 101140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: WHILE THERE IS NO SIGNIFICANT CHANGE
TO THE FORECAST PHILOSOPHY, THE FORECAST HAS BEEN SHORTENED TO 96
HOURS. 

FORECAST DISCUSSION: TC 05P WILL CONTINUE TRACKING WESTWARD ALONG
THE NORTHERN SIDE OF A DEEP STR FOR THE NEXT 12 TO 24 HOURS. DURING
THIS TIME, A STRONG MID-LATITUDE TROUGH WILL PASS FAR TO THE SOUTH,
ERODING AND ULTIMATELY BREAKING THE STR. IN RESPONSE TC 05P WILL
TURN SHARPLY POLEWARD BY TAU 24 AND ACCELERATE INTO THE BREAK IN
THE RIDGE PATTERN. WHILE THE SYSTEM HAS INTENSIFIED OVER THE PAST
12 HOURS, IT HAS LIKELY REACHED ITS NEAR-TERM PEAK INTENSITY. AS
THE SYSTEM IS NOW UNDER AN UPPER LOW, CONVERGENT FLOW ALOFT WILL
CUT THE SYSTEM OFF FROM ANY SIGNIFICANT OUTFLOW. SO WHILE
CONVECTIVE ACTIVITY FED BY THE WARM SSTS AND COLD POOL ALOFT IS
EXPECTED TO CONTINUE, THE SYSTEM WILL STEADILY WEAKEN THROUGH TAU
24. TC 05P WILL MOVE AWAY FROM THE UPPER LOW AFTER TAU 24 AND
REESTABLISH A SOLID POLEWARD OUTFLOW MECHANISM, WHICH WILL OFFSET
GRADUALLY INCREASING VWS, ALLOWING IT TO REINTENSIFY TO A PEAK OF
50 KNOTS BY TAU 48. AFTER TAU 48, THE SYSTEM WILL MOVE UNDER STRONG
MID-LATITUDE NORTHWESTERLY FLOW, AND BY THIS POINT THE SHEAR WILL
COME TO DOMINATE THE OUTFLOW, LEADING TO STEADY WEAKENING THROUGH
THE END OF THE FORECAST. AS TC 05P MOVES SOUTH OF THE 25TH LATITUDE
LINE, IT WILL CROSS THE 26C ISOTHERM AND WILL BEGIN SUBTROPICAL
TRANSITION. THE SUBTROPICAL TRANSITION PROCESS IS EXPECTED TO BE
COMPLETE NO LATER THAN TAU 96. 

MODEL DISCUSSION: TRACK GUIDANCE REMAINS IN GOOD AGREEMENT, WITH
CROSS AND ALONG-TRACK SPREAD DECREASING SINCE THE PREVIOUS RUN. THE
ONLY OUTLIERS WITH THIS RUN ARE THE HWRF AND NAVGEM WHICH PUSH THE
WESTWARD TRACK ABOUT 60NM FURTHER WEST BEFORE TURNING POLEWARD. THE
REMAINDER OF THE GUIDANCE IS IN A TIGHT GROUPING ABOUT THE
CONSENSUS MEAN THROUGH THE REMAINDER OF THE FORECAST. THE JTWC
TRACK LIES CLOSE TO AND SLIGHTLY SLOWER THAN THE CONSENSUS MEAN
WITH HIGH CONFIDENCE. THE BULK OF THE INTENSITY GUIDANCE SUGGESTS
THE SYSTEM WILL MAINTAIN INTENSITY FOR THE DURATION OF THE
FORECAST, THOUGH THE HWRF SHOWS VARIABILITY. THE JTWC FORECAST
TRACKS THE HWRF SOLUTION CLOSELY THROUGH THE FORECAST PERIOD, WITH
MEDIUM CONFIDENCE.  

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