WDPS31 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22P (TWENTYTWO) WARNING 
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.8S 154.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 520 NM EAST-NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A SMALL
CONSOLIDATING SYSTEM IN THE CORAL SEA THAT HAS DEEPENED AND BEGUN
TO FORM SHORT CURVED BANDS AROUND AN OBSCURED UPPER-LEVEL CIRCULATION
(LLC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED
ON A RAGGED BUT DEFINED MICROWAVE LLC FEATURE IN THE 101726Z SSMIS
IMAGE SUITE. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE
BASED ON AGENCY DVORAK ESTIMATES AND RECENT SCATTEROMETER DATA THAT
ARE CONSISTENT WITH THE IMPROVEMENT IN THE CONVECTIVE STRUCTURE.
ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH THE
SYSTEM ON THE NORTHERN EDGE OF MODERATE (15-20 KNOTS) WESTERLY
VERTICAL WIND SHEAR THAT IS OFFSETTING THE WARM SST AND MODERATE
POLEWARD OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

CURRENT STEERING MECHANISM: NEAR EQUATORIAL RIDGE ORIENTED NW-SE
AND ANCHORED TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS IS THE INITIAL PROGNOSTIC REASONING 
BULLETIN AND SETS THE FORECAST PHILOSOPHY. 

FORECAST DISCUSSION: TC 22P IS EXPECTED TO BECOME QUASI-STATIONARY
(QS) AS THE NER RECEDES EASTWARD AND A SUBTROPICAL RIDGE BUILDS
(STR) TO THE SOUTHWEST, RESULTING IN A STEERING IMPASSE. AFTER TAU
36, THE STR IS FORECAST TO DOMINATE AND DRIVE THE CYCLONE
WEST-NORTHWESTWARD. THE CYCLONE IS NOT EXPECTED TO DEVELOP MUCH
WHILE IN QS MOTION AND UNDER MODERATE VWS, INTENSIFYING MODESTLY TO
40KTS. AFTER IT STARTS MOVING WESTWARD, THE RELATIVE VWS WILL ONLY
GET WORSE AS IT TRACKS DIRECTLY AGAINST THE UPPER-LEVEL WIND FLOW,
STIFLING ANY INTENSIFICATION AND SUSTAINING AN INTENSITY OF 35
KNOTS FOR THE REMAINDER OF THE FORECAST, AT BEST. 

MODEL DISCUSSION: GIVEN THE FORMATIVE NATURE OF THE SYSTEM AND THE
COMPETING STEERING MECHANISMS DOWN THE TRACK, THERE IS LOW
CONFIDENCE IN THE WHOLE OF JTWC FORECAST TRACK. THESE VARIABLES
ALSO LEND ONLY MEDIUM CONFIDENCE TO THE INTENSITY FORECAST UP TO
TAU 72 THEN LOW CONFIDENCE AFTERWARD. 

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