WDPS31 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (JASPER) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.8S 156.7E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 657 NM EAST-NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 37 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
IMPROVING 15-20NM EYE WITH DEEP CONVECTIVE BANDING IN ALL QUADRANTS
AND PERSISTENT VIGOROUS OUTFLOW TO THE SOUTH. THOUGH THE
CIRCULATION CONTINUES TO IMPROVE ITS VERTICAL ALIGNMENT, A SLIGHT
TROCHOIDAL WOBBLE IS EVIDENT AS 03P GLIDES POLEWARD. A 071451Z
AMSR2 89GHZ MICROWAVE IMAGE INDICATES A CLEARLY DEFINED EYE AND
NEARLY COMPLETE EYE WALL WITH DEEP CONVECTIVE BANDS WRAPPING THE
SOUTHERN SEMICIRCLE OF THE SYSTEM. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON EIR AND AMSR2 IMAGERY. THE INITIAL
INTENSITY OF 105 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
ALL DVORAK INTENSITY ESTIMATES INDICATING 115KTS WHILE CIMSS
AUTOMATED ESTIMATES RANGE FROM 102KTS-124KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: ONGOING TRANSITION FROM A SUBTROPICAL
RIDGE (STR) POSITIONED TO THE EAST TO A STRONGER STR TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T6.0 - 115 KTS
   ABRF: T6.0 - 115 KTS
   CIMSS SATCON: 102 KTS AT 071800Z
   CIMSS ADT: 124 KTS AT 071730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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 03P (JASPER) IS FORECASTED TO CONTINUE
TRACKING GENERALLY SOUTH-SOUTHWESTWARD UNDER THE COMBINED
INFLUENCES OF SUBTROPICAL RIDGING TO THE EAST AND SOUTH. OVER THE
NEXT 24 HOURS, 03P WILL BE FORCED INTO AN INCREASINGLY WESTWARD
COURSE AS STEERING CONTROL IS TRANSFERRED TO THE STR TO THE SOUTH.
AFTER REACHING ITS PEAK INTENSITY NEAR TAU 12 OF 110KTS AND
POSSIBLY SLIGHTLY HIGHER, ENVIRONMENTAL CONDITIONS BEGIN TO
DEGRADE. VERTICAL WIND SHEAR (VWS) INCREASES, COOL DRY AIR BEGINS
TO ENTRAIN INTO THE NORTHERN PERIPHERY OF THE SYSTEM AND UPPER
LEVEL OUTFLOW BEGINS TO DWINDLE. THESE FACTORS WILL RESULT IN A
GRADUAL WEAKENING TREND AND BY TAU 96, 03P WILL BARELY CLING TO
TYPHOON STRENGTH. ALL IS NOT LOST HOWEVER, NEAR TAU 100, VWS IS
FORECASTED TO ONCE AGAIN FALL TO SINGLE DIGITS. REDUCED VWS WHEN
COUPLED WITH IMPROVING MOISTURE CONTENT WITHIN THE CORE OF THE
SYSTEM MAY ALLOW 03P TO SLIGHTLY RE-INTENSIFY THROUGH THE REMAINING
FORECAST PERIOD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH ALL
MEMBERS INDICATING THE SAME GENERAL TRACK FORECAST WITH A FEW
EXCEPTIONS. HWRF AND COAMPS-TC (NVGM VERSION) ARE SLIGHT SOUTHERLY
OUTLIERS AS THE SYSTEM ALTERS COURSE TOWARD EASTERN AUSTRALIA. TRACK 
CONFIDENCE HAS IMPROVED OVER THE LAST SEVERAL CYCLE BUT
OVERALL CONFIDENCE IN THE JTWC FORECAST TRACK REMAINS MEDIUM.
RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT INITIALLY
WITH ALL MEMBERS CONTINUING TO INTENSIFY THE SYSTEM THROUGH TAU 12,
AFTER WHICH GRADUAL DECLINE OCCURS THROUGH TAU 100. THE SPREAD IN THE
MEMBERS IS GREATEST TOWARDS THE END OF THE FORECAST WHICH IS
TYPICAL BUT WHEN COMPOUNDED WITH THE POSSIBILITY OF
RE-INTENSIFICATION, THE SPREAD IS FURTHER EXACERBATED. AS A RESULT
THE JTWC INTENSITY FORECAST IS PLACED INITIALLY WITH MEDIUM
CONFIDENCE AND WITH LOW CONFIDENCE THEREAFTER.

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