WDPS31 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (JASPER) WARNING 
NR 032//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.6S 147.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 104 NM NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND RADAR
IMAGERY FROM CAIRNS, AUSTRALIA DEPICTS TROPICAL CYCLONE 03P
(JASPER) AS A COILED, COMPACT VORTEX WITH SPIRAL BANDING PRIMARILY
CONFINED SOUTH AND WEST OF THE LOW-LEVEL CIRCULATION CENTER (LLCC).
DEEP CONVECTIVE COVERAGE IS INCREASING A BIT IN THE VICINITY OF THE
LLCC RELATIVE TO THE PAST 12 HOURS AS THE STORM MOVES OVER SLIGHTLY
WARMER COASTAL AUSTRALIAN WATERS OF AROUND 28 DEGREES CELSIUS AND
BEGINS MIXING OUT THE ENVIRONMENTAL DRY AIR THAT WAS WRAPPED INTO
THE CIRCULATION A COUPLE DAYS AGO. UPPER-LEVEL OUTFLOW IS SEEN
EXPANDING EASTWARD BUT IS BEGINNING TO STAGNATE IN THE WESTERN
SEMICIRCLE. THE INITIAL INTENSITY IS SET AT 45 KT BASED ON ASCAT
DATA FROM 121222Z AND AN AMSR2 PASS FROM 121508Z SHOWING 40-45 KT
WINDS 30 TO 50 NM SOUTH OF THE LLCC. JASPER PASSED JUST SOUTH OF
BOUGAINVILLE REEF AT AROUND 121430Z, AND THE REEF IS REPORTING 29
KT NORTHERLY WINDS AS OF 121930Z.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTH AND
SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   ABRF: T3.0 - 45 KTS
   CIMSS ADT: 33 KTS AT 121730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EASTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE 03P (JASPER) IS EXECUTING A
FAIRLY ABRUPT TURN FROM ITS PREVIOUS NORTHWESTWARD MOTION TO A MORE
WEST-SOUTHWESTWARD MOTION FROM NOW UNTIL LANDFALL IN QUEENSLAND IN
A LITTLE OVER 12 HOURS. THIS IS IN RESPONSE TO ANTICYCLOGENESIS
OVER EASTERN QUEENSLAND, LEADING TO A STRENGTHENING DEEP-LAYER
RIDGE CENTERED SOUTHEAST OF JASPER. NUMERICAL MODELS DISAGREE ON
THE DETAILS OF THIS TURN, LEADING TO SOME SIGNIFICANT SPREAD IN THE
LANDFALL LOCATION. THE MULTI-MODEL CONSENSUS HAS SHIFTED A BIT
SOUTHWARD, AND THE JTWC FORECAST FOLLOWS SUIT, NOW LYING 10 TO 15
NM SOUTH OF THE PREVIOUS ONE, WITH LANDFALL OCCURRING ABOUT 60 NM
NORTH OF CAIRNS. HOWEVER, A GROUPING OF MODELS INCLUDING THE GFS,
HAFS-A, AND HWRF PREDICT LANDFALL SIGNIFICANTLY CLOSER TO CAIRNS,
WITHIN 20 NM OF THE CITY, DEPICTING THE SHORT-TERM MOTION
UNCERTAINTY. REGARDING INTENSITY, WHILE JASPER HAD BEEN WEAKENING
DURING THE PAST 24 HOURS, CURRENT SIGNS INDICATE THAT THIS TREND
HAS HALTED, AND JASPER MAY EVEN RESTRENGTHEN SLIGHTLY PRIOR TO
LANDFALL AS DEEP CONVECTION REDEVELOPS AROUND THE CENTER OF THE
STILL COMPACT WIND FIELD. THE JTWC FORECAST SHOWS A SLIGHT INCREASE
TO 50 KT IN 12 HOURS JUST PRIOR TO LANDFALL. DISSIPATION BELOW
WARNING THRESHOLD IS LIKELY TO FOLLOW AS JASPER CROSSES THE CAPE
YORK PENINSULA DURING THE 12 TO 72 HOUR PERIOD. THE VORTEX IS
EXPECTED TO EMERGE OVER THE GULF OF CARPENTARIA BY 72 HOURS AND
WILL BE MONITORED CLOSELY FOR POTENTIAL REGENERATION AS IT
CONTINUES TO MOVE GENERALLY WESTWARD. ENVIRONMENTAL WESTERLY SHEAR
IS EXPECTED TO PICK UP DURING THE OVERLAND PORTION OF THE TRACK,
POTENTIALLY LEAVING THE REMNANTS OF JASPER IN A DISORGANIZED STATE
WHEN THEY EMERGE BACK OVER WATER. THE COMBINED EFFECTS OF THIS
DISORGANIZATION AND THE PRESENCE OF AMBIENT DRY AIR IN THE GULF OF
CARPENTARIA MAY LIMIT THE PACE OF REGENERATION, IF ANY. WARNINGS
WILL BE RESTARTED IF THE REMNANTS REGAIN WARNING CRITERIA OVER
WATER.

MODEL DISCUSSION: THE JTWC TRACK FORECAST IS CLOSE TO THE
MULTI-MODEL CONSENSUS. THE JTWC INTENSITY FORECAST IS ALSO CLOSE TO
THE MULTI-MODEL CONSENSUS, IGNORING SOME OF THE HIGH INTENSITY
OUTLIERS PRIOR TO LANDFALL IN QUEENSLAND, SUCH AS HAFS-A WHICH
SHOWS INTENSIFICATION TO 70-80 KT IN THE NEXT 12 HOURS. THIS IS
DISMISSED AS UNLIKELY DUE TO THE VORTEX BEING INITIALIZED TOO
STRONG IN HAFS-A.

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