WDPS31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (JASPER)
WARNING NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.6S 157.1E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 209 NM SOUTHWEST OF HONIARA, SOLOMON
   ISLANDS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
TROPICAL CYCLONE (TC) 03P (JASPER) HAVING BRIEFLY EXPOSED A SYMMETRIC 
EYE, FREE OF DISCERNABLE HYDROMETEORS AT 060910Z, BUT THE FEATURE
QUICKLY VANISHED WITH THE ONGOING TROCHOIDAL MOTION OF THE SYSTEM
OVER THE PAST SIX HOURS. SPIRAL BANDING WITH DEEP CONVECTION PERSISTS 
IN THE SOUTHWEST AND NORTHEAST QUADRANTS OF THE SYSTEM, RIDDLED WITH 
LIGHTNING OBSERVATIONS. A 060759Z RCM 1 SYNTHETIC APERTURE RADAR IMAGE 
UNVEILED A TIGHTENING OF MAXIMUM SUSTAINED WINDS TOWARD THE LOW-LEVEL 
CIRCULATION CENTER (LLCC) AND AN OVERALL LARGER
WIND FIELD, EXPANDING NOTABLY FURTHER IN THE WESTERN PERIPHERY THAN
OBSERVED 6 HOURS PRIOR. LOW (5-10 KTS) VERTICAL WIND SHEAR, HIGH
(28-29 C) SEA SURFACE TEMPERATURE (SST), STRONG POLEWARD OUTFLOW,
AND A MOIST ENVIRONMENT CONTRIBUTE TO THE ASSESSMENT OF A HIGHLY
FAVORABLE ENVIRONMENT. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON A 061200Z HIMAWARI-9 INFRARED SATELLITE IMAGE.
THE INITIAL INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM CONFIDENCE 
BASED ON THE SUBJECTIVE AND OBJECTIVE INTENSITY GUIDANCE LISTED BELOW.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: NEAR EQUATORIAL RIDGE (NER) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   ABRF: T4.5 - 77 KTS
   CIMSS SATCON: 70 KTS AT 061100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 FORECAST TO CONTINUE
TRACKING SOUTH-SOUTHWESTWARD OVER THE NEXT 72 HOURS. ALONG-TRACK RAPID 
INTENSIFICATION IS EXPECTED, DRIVING UP THE SYSTEMS INTENSITY TO A 
PEAK OF NEAR 110KTS AROUND TAU 30. AFTER TAU 30, VERTICAL WIND SHEAR 
VALUES ARE FORECAST TO RAMP UP TO 33KTS BY TAU 48 AND WILL LIKELY 
INFLUENCE A WEAKENING TREND TO TRANSPIRE. TANGENTIAL TO THE 
BIFURCATION DISCUSSION BELOW, THE JTWC FORECAST IS SUPPORTED BY THE 
SUSTAINMENT OF THE NEAR EQUATORIAL RIDGE EAST OF THE TC AND EVENTUALLY 
(TAU 72 TO TAU 120) THE BUILDING SUBTROPICAL RIDGE TO THE SOUTH, WHICH 
IS EXPECTED TO STEER THE SYSTEM TO A MORE WESTWARD TRAJECTORY BY TAU 
120. SHOULD THE SOUTHERN RIDGE NOT BUILD IN AND INFLUENCE THE STEERING 
PATTERN, A QUASI-STATIONARY TRACK MAY ONSET BETWEEN TAU 60 AND 72.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE OFFERS A PRIMARY
AND ALTERNATE TRACK SOLUTION. THE MAJORITY OF THE JTWC CONSENSUS
MEMBERS TRACK TC 03P SOUTH-SOUTHWESTWARD, GRADUALLY TURNING THROUGH 
THE FORECAST PERIOD TO A WESTWARD TRACK BY TAU 120. AN ALTERNATE
SOLUTION OCCURS BETWEEN TAU 60 AND TAU 72 IN GALWEM AND UKMET
SOLUTIONS, WHEREBY A QUASI-STATIONARY SCENARIO ARISES AND THE TC
LOITERS THROUGH TAU 120. DUE TO THE NATURE OF THE BIFURCATED
GUIDANCE AND TIMELINE, THE FORECAST CONFIDENCE FOR TRACK IS HIGH
THROUGH TAU 72, AND MEDIUM THEREAFTER. GOOD ALIGNMENT IN INTENSITY
GUIDANCE CONTINUES TO SHOW SIGNIFICANT POSSIBILITY FOR RAPID
INTENSIFICATION TO OCCUR THROUGH TAU 24. DUE TO GOOD AGREEMENT IN
INTENSITY GUIDANCE, THE FORECAST CONFIDENCE FOR INTENSITY MIRRORS
THAT OF THE TRACK FORECAST CONFIDENCE.

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