WDXS31 PGTW 232100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01S (PADDY) WARNING 
NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.9S 106.8E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 215 NM SOUTH-SOUTHEAST OF CHRISTMAS
ISLAND, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING,
DISORGANIZED CONVECTION, SHEARED TO THE SOUTH OF A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). UNFORTUNATELY THERE
HAS BEEN NO RECENT MICROWAVE IMAGERY TO ASSIST WITH PLACING THE
INITIAL POSITION, HOWEVER, ANALYSIS OF THE NORMALIZED RADAR CROSS
SECTION (NRCS) OF A 231454Z ASCAT-C PASS SHOWED THE CENTER OF
CIRCULATION HAD TRACKED SOUTH, THEN CURVED BACK TO THE NORTH OVER
THE PREVIOUS THREE HOURS, AND PROVIDED MEDIUM CONFIDENCE TO THE
INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED AT 40 KNOTS,
WELL ABOVE THE AGENCY FIXES, IN LIGHT OF THE WIND FIELD EVIDENT IN
THE AFOREMENTIONED ASCAT DATA, WHICH SHOWED AN AREA OF 35-40 KNOT
WINDS EXTENDING ACROSS THE SOUTHERN HEMISPHERE OF THE CIRCULATION,
THOUGH WINDS ARE MUCH LIGHTER (LESS THAN 30 KNOTS) ACROSS THE
NORTHERN HEMISPHERE. ENVIRONMENTAL CONDITIONS ARE BECOMING
INCREASINGLY MARGINAL, WITH GOOD POLEWARD OUTFLOW AND LOW SHEAR
BEING OFFSET BY SIGNIFICANT MID-LEVEL DRY AIR AND MARGINALLY
SUPPORTIVE SSTS (26-27C).

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A DEEP LAYER
SUBTROPICAL RIDGE (STR) TO THE SOUTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   APRF: T2.5 - 35 KTS
   CIMSS ADT: 53 KTS AT 231740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: MID-LEVEL DRY AIR

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: OVER THE PAST SIX HOURS, THE AVERAGE MOTION
VECTOR HAS BEEN WESTWARD, HOWEVER, IT IS LIKELY THAT THE SYSTEM
TOOK A SHORT EXCURSION TO THE SOUTH OF THE 14S LATITUDE BASED ON
THE ASCAT NRCS DATA. BY THE 1800Z HOUR HOWEVER, IT APPEARS TO BE
BACK ON THE WESTWARD TRACK, AND THIS MOTION IS EXPECTED TO CONTINUE
THROUGH THE DURATION OF THE FORECAST PERIOD, AS THE RIDGE TO THE
SOUTH PROVIDES A STRONG STEERING MECHANISM. THE SYSTEM IS FORECAST
TO SKIRT THE 26C ISOTHERM FOR THE REMAINDER OF THE FORECAST, WHICH
WILL SERVE TO GENERALLY LIMIT SIGNIFICANT DEVELOPMENT. AT THE SAME
TIME, MID-LEVEL DRY AIR IS EXPECTED TO CONTINUE TO ENCROACH FROM
THE WEST, ULTIMATELY SUFFOCATING THE SYSTEM AND LEADING TO FULL
DISSIPATION NO LATER THAN TAU 36. 

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, WHICH CONTINUES TO
UNREALISTICALLY PUSH THE SYSTEM INTO THE RIDGE TO THE SOUTH, THE
REMAINDER OF THE GUIDANCE PACKAGE IS IN GOOD AGREEMENT THROUGH THE
FORECAST PERIOD, THOUGH THE RECENT MEANDER OF THE CIRCULATION
CENTER DECREASES OVERALL CONFIDENCE IN THE TRACK FORECAST.
INTENSITY GUIDANCE IS IN GOOD AGREEMENT AND LENDS HIGH CONFIDENCE
TO THE INTENSITY FORECAST. 

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