WDPS31 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (JASPER) WARNING 
NR 029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.3S 147.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 126 NM EAST-NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS CURVED
BANDING WRAPPING INTO AN INCREASINGLY WELL-DEFINED LOW LEVEL
CENTER. A TIMELY 112350Z ASCAT-B PASS PROVIDES EXCELLENT COVERAGE
OF THE COMPLETE CIRCULATION, WHICH COMBINED WITH WILLIS ISLAND
RADAR AND HOLMES REEF OBSERVATION DATA, PROVIDES HIGH CONFIDENCE IN
THE INITIAL POSITION. THE INITIAL INTENSITY WAS ASSESSED AT 55
KNOTS WITH MODERATE CONFIDENCE. THIS VALUE IS SUPPORTED BY THE PGTW
DVORAK FINAL-T OF T3.5 (55 KNOTS), WHICH IS THE HIGHEST OF THE
THREE REPORTING AGENCIES. ADDITIONALLY, OBJECTIVE FIXES REMAIN
ALMOST STUBBORNLY LOW. THE AFOREMENTIONED ASCAT HAD A LARGE SWATH
OF 40 KNOTS, HOWEVER BIAS CORRECTION COULD REASONABLY REACH 50 TO
55 KNOTS. ADDITIONALLY, THERE WERE A PAIR OF COINCIDENT SAR PASSES
MID-CYCLE. WHILE THE PEAK SAR WINDS ARE OVER-ESTIMATED, POSSIBLY
DUE TO ATMOSPHERIC SIGNAL ATTENUATION, THE DATA STILL SUGGESTS
THAT 50 TO 55 KNOTS IS WARRANTED. DEEP LEVEL VERTICAL WIND SHEAR
HAS RELAXED, WITH THE MOST RECENT CIMSS ESTIMATED SHEAR AT 5 TO 10
KNOTS, AND SST REMAINS FAVORABLE. THE LIMITING FACTORS ARE
PERSISTENT WEAK MID-LEVEL RELATIVE HUMIDITY TO SUPPORT SUSTAINED
DEEP CONVECTION AND MARGINAL EQUATORWARD OUTFLOW.

INITIAL WIND RADII BASIS: AVERAGE OF RECENT SCATTEROMETER AND SAR
WIND DATA. 

CURRENT STEERING MECHANISM: MID-LEVEL SUB-TROPICAL RIDGING TO THE
SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T2.5 - 35 KTS
   ABRF: T3.0 - 45 KTS
   CIMSS SATCON: 44 KTS AT 111830Z
   CIMSS ADT: 41 KTS AT 112330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: THE MOST RECENT FRAMES OF MSI SUGGEST THAT THE
TRACK OF TC 03P HAS BEGUN TO FLATTEN OUT AND MOVE MORE WESTERLY
TOWARDS PORT DOUGLAS. CONSENSUS MODEL CROSS TRACK SPREAD ALONG THE
COAST IS ABOUT 45 MILES, EXPANDING TO ABOUT 100 NM BY TAU 48. THE
HAFS-A MODEL APPEARS TO
HAVE A GOOD HANDLE ON THE INITIAL ANALYSIS STRUCTURE. THE MODEL
INDICATES JASPER WILL CONTINUE TO SLOWLY ORGANIZE OVER THE NEXT 24
HOURS. SHEAR CONDITIONS SHOULD REMAIN FAVORABLE, WITH SLOWLY
IMPROVING HUMIDITY AND OUTFLOW ALLOWING ADDITIONAL
REINTENSIFICATION PRIOR TO LANDFALL, AT AROUND 130200Z. THE
FORECAST PEAK IS SET TO 60 KNOTS. JASPER IS EXPECTED TO TRACK
WESTWARD OVER CAPE YORK AND SHOULD DISSIPATE PRIOR BY TAU 48. THE
MOST RECENT RUN OF ECMWF TAKES A MORE NORTHERLY TRACK INTO THE
GULF, ALLOWING FOR A BRIEF PERIOD OF REINTENSIFICATION, WHILE
REMAINING CONSENSUS MEMBERS ARE MORE SOUTHERLY AND DO NOT CALL FOR
REDEVELOPMENT. 

MODEL DISCUSSION: THE COAMPS-TC ENSEMBLE INDICATES A HIGH (80 TO 90
PERCENT) LIKELIHOOD OF JASPER MAKING LANDFALL AS A STRONG TROPICAL
STORM, WITH ONE TO TWO MEMBERS REFLECTING A WEAK TYPHOON
EQUIVALENT. AMONG GFS, ECMWF, AND COAMPS-TC ENSEMBLE GUIDANCE, ONLY
THE ECENS IS INDICATING A POTENTIAL FOR REDEVELOPMENT IN THE GULF,
AT 15-20 PERCENT PROBABILITY. THE FORECAST PERIOD WILL BE EXTENDED
IF CONDITIONS WARRANT. 

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