Advisories

WDIO31 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01B (ONE) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.8N 84.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 380 NM SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 01B COMPLETELY OBSCURED BY MID AND UPPER-LEVEL CLOUD
COVERAGE. ANIMATED COMPOSITE RADAR FROM THE AREA REVEALS A COMPACT
AND SYMMETRICAL CIRCULATION CENTER TRACKING TOWARDS THE INDIAN
COAST. ENVIRONMENTAL ANALYSIS REVEALS A MARGINAL ENVIRONMENT FOR 
DEVELOPMENT, CHARACTERIZED BY WARM (28-29 C) SEA SURFACE TEMPERATURES 
AND MODERATE EQUATORWARD OUTFLOW, OFFSET BY LAND INTERACTION AND
MODERATE TO HIGH VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON ANIMATED RADAR REVEALING THE
CIRCULATION CENTER. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON THE CIMSS AUTOMATED INTENSITY
ESTIMATES AND THE PGTW DVORAK FIX LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: A WEAK MID-LEVEL SUBTROPICAL RIDGE
(STR) CENTERED FAR TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   CIMSS SATCON: 50 KTS AT 231000Z
   CIMSS ADT: 51 KTS AT 231130Z
   CIMSS AIDT: 44 KTS AT 231130Z
   CIMSS D-MINT: 42 KTS AT 231028Z
   CIMSS D-PRINT: 37 KTS AT 231130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: LAND INTERACTION

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 01B IS FORECAST TO CONTINUE TRACKING SLOWLY
NORTHWESTWARD WHILE IT REMAINS IN A WEAK STEERING ENVIRONMENT ON
THE OUTSKIRTS OF A MID-LAYER STR CENTERED FAR TO THE NORTHEAST. 01B
IS FORECAST TO MAKE LANDFALL NORTHEAST OF VISAKHAPATNAM PRIOR TO
TAU 12. REGARDING INTENSITY, 01B IS CURRENTLY AT ITS PEAK
INTENSITY, AS THE SYSTEM APPROACHES THE COAST AND ENCOUNTERS
INCREASED LAND INTERACTION THAT WILL PROHIBIT FURTHER
INTENSIFICATION. DISSIPATION OVER LAND IS EXPECTED NO LATER THEN
TAU 24.

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH TAU 24, SUPPORTING THE JTWC TRACK FORECAST WITH
HIGH CONFIDENCE. LIKEWISE, RELIABLE INTENSITY AIDS ARE IN STRONG
AGREEMENT ON A STEADY WEAKENING TREND THROUGH THE END OF THE
FORECAST PERIOD. AS A RESULT, THE JTWC INTENSITY FORECAST IS
ASSESSED WITH HIGH CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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