WDPN31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (KROSA) WARNING NR 
016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.7N 145.4E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 235 NM NORTH OF AGRIHAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
PERSISTENT DEEP CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION
CENTER OF TROPICAL STORM (TS) 12W. THE SYSTEM HAS CONTINUED TO
RESIST THE UNFAVORABLE FEATURES OF DRY AIR AND VERTICAL WIND SHEAR
INDUCED FROM THE UPPER-LEVEL RIDGE TO THE WEST. CURVED CONVECTIVE
BANDS WRAP AROUND THE SOUTHERN PERIPHERY OF THE SYSTEM FROM THE
SOUTHWEST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON A 271128Z METOP-B ASCAT IMAGE REVEALING THE LLCC. THE
INITIAL INTENSITY OF 70 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
THE AFOREMENTIONED SCATTEROMETRY AND IS ACCOMPANIED BY FIXES BELOW.

INITIAL WIND RADII BASIS: 271128Z METOP-B SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 75 KTS AT 271400Z
   CIMSS ADT: 77 KTS AT 271130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 25-30 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 12W WILL CONTINUE TO TRACK NORTHWARD ON A
NEAR EQUATORIAL RIDGE (NER) TO THE EAST. THE SYSTEM WILL ENTER A
COMPETING STEERING ENVIRONMENT BETWEEN TAU 36-72 BETWEEN TWO
RIDGES, THE NEAR EQUATORIAL RIDGE TO THE SOUTHEAST AND THE
SUBTROPICAL RIDGE TO THE NORTHEAST. DURING THIS TIME PERIOD, THE
TRACK MOTION WILL BECOME IRREGULAR AND QUASI-STATIONARY. AFTER TAU
72, THE NEAR EQUATORIAL RIDGE TO THE SOUTHEAST WILL REORIENT ON A
SOUTHWEST-NORTHEAST AXIS, DRIVING THE SYSTEM NORTHEASTWARD FOR THE
REMAINDER OF THE FORECAST PERIOD. THE SYSTEM WILL SLIGHTLY WEAKEN
IN THE NEAR-TERM FORECAST AS THE SYSTEM CONTINUES TO REMAIN
PUMMELED BY THE UPPER-LEVEL TROUGH TO THE NORTHEAST. UPWELLING
BETWEEN TAU 36-72 WILL FURTHER RESULT IN WEAKENING DESPITE A CEASE
OF VERTICAL WIND SHEAR. REINTENSIFICATION IS ANTICIPATED TO OCCUR
AFTER TAU 72 AS THE SYSTEM MOVES INTO WARMER WATERS, LEADING TO AN
INTENSIFICATION OF 60KTS FOR THE REMAINDER OF THE FORECAST PERIOD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT IN THE NEAR TERM FORECAST UNTIL TAU 72, WITH A
CROSS-TRACK SPREAD OF 240NM AT THE END OF THE FORECAST PERIOD. THE
TRACK GUIDANCE REMAINS UNCERTAIN BEYOND TAU 72 AS THE MULTI-MODEL
CONSENSUS SOLUTIONS SPREAD. THE INTENSITY GUIDANCE IS SPLIT IN THE
NEAR-TERM, WITH HWRF AND GFS FORECASTING INTENSIFICATION AND
COAMPS-TC AND HAFS-A FORECASTING WEAKENING. THE INTENSITY GUIDANCE
BEYOND TAU 24 REMAINS CONSISTENT WITH MARGINAL INTENSIFICATION AND
WEAKENING EXCEPT COAMPS-TC, WHICH PEAKS AT 105KTS AT TAU 96 FAR
ABOVE THE REST OF THE CONSENSUS.

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