WDPS31 PGTW 080300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (JASPER) WARNING NR 
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.2S 156.6E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 645 NM EAST-NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WELL-
DEFINED, ROUGHLY 25NM EYE WITH TIGHTLY WRAPPING SPIRAL BANDS OF
DEEP CONVECTION IN ALL QUADRANTS. A RECENT 072253Z TROPICS-6 91GHZ
MICROWAVE IMAGE REVEALS A WELL-DEFINED AND SYMMETRIC 25NM MICROWAVE
EYE WITH DEEP CONVECTION PRIMARILY TO THE SOUTH OF THE LLCC. A
071914Z RCM3 SYNTHETIC APERTURE RADAR (SAR) PASS REVEALED LARGER
WIND RADII IN ALL QUADRANTS AND A VMAX OF 120KTS. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON SAR, MSI AND
MICROWAVE IMAGERY. THE INITIAL INTENSITY OF 120 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON SAR DATA FURTHER REINFORCED BY
AUTOMATED INTENSITY ESTIMATES, ALL OF WHICH INDICATE 120-127KTS.

INITIAL WIND RADII BASIS: SAR DATA 

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: 120 KTS AT 071926Z
   CIMSS ADT: 127 KTS AT 072320Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY 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.
HAVING MOST LIKELY REACHED ITS PEAK INTENSITY OF 120KTS,
ENVIRONMENTAL CONDITIONS ARE FORECASTED TO GRADUALLY 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 72, 03P WILL HAVE WEAKENED TO ROUGHLY 70KTS. ALL
IS NOT LOST HOWEVER, NEAR TAU 96, 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 IS NOW THE SOLE SOUTHERLY OUTLIER AS THE SYSTEM
ALTERS COURSE TOWARD EASTERN AUSTRALIA. ALONG TRACK CONFIDENCE HAS
IMPROVED OVER THE LAST SEVERAL CYCLES BUT OVERALL CONFIDENCE IN THE
JTWC FORECAST TRACK REMAINS MEDIUM. RELIABLE MODEL INTENSITY
GUIDANCE IS IN GOOD AGREEMENT INITIALLY WITH ALL MEMBERS STAGNATING
THE SYSTEM OR SLIGHTLY WEAKENING IT THROUGH TAU 12, AFTER WHICH
GRADUAL DECLINE OCCURS THROUGH TAU 72. 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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