WDIO31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01B (MOCHA) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.8N 91.1E
   INITIAL INTENSITY: 130 KTS
   GEOGRAPHIC REFERENCE: 273 NM SOUTH OF CHITTAGONG
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 50 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 01B (MOCHA) IS A MONSTER OF A STORM, WHICH
APPEARS TO HAVE REACHED PEAK INTENSITY OVER THE BAY OF BENGAL AT
134KTS USING A WELL-TIMED BULLS-EYE 131201Z RCM-2 SAR IMAGE.
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A 17NM
ASYMMETRICAL EYE FEATURE WITH CENTER TEMPERATURES WARMING TO -2C,
AS DEEP CONVECTIVE BANDS REMAIN AROUND THE INNER CORE. A SLIGHT
TROCHOIDAL MOTION NOTICED IN THE EIR LOOP LENDS FURTHER EVIDENCE TO
AN INTENSE SYSTEM. THE SLIGHT WOBBLE IS MAKING THE TRACK APPEAR
MORE ERRATIC IN THE JOG TO THE NORTHEAST. THE RADIAL OUTFLOW WITH
THE ROBUST JETMAX OVER SOUTHERN CHINA CONTINUES ENHANCING THE
SYSTEM SIZE AND INTENSITY. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE RECENT EIR IMAGE. THE INITIAL
INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON A BLEND OF
MULTIPLE AGENCY INTENSITY ESTIMATES, ALONG WITH THE OPEN-AIIR
ESTIMATE OF 129 KNOTS. THE SYSTEM CONTINUES TO TRACK NORTH
NORTHEASTWARD ALONG THE NORTHWEST SIDE OF THE SUBTROPICAL RIDGE
(STR). CONDITIONS REMAIN FAVORABLE FOR INTENSIFICATION, WITH LOW TO
MODERATE (10-15 KTS) VWS, WARM (30-31C) SSTS, AND ROBUST RADIAL
OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE. 

CURRENT STEERING MECHANISM: NORTHWEST PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED OVER THE SOUTH CHINA SEA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   KNES: T7.0 - 140 KTS 
   DEMS: T6.0 - 115 KTS
   CIMSS ADT: 122 KTS AT 131730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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: THE SYSTEM HAS SLOWED SLIGHTLY IN THE
NORTHEAST JOG, WHICH IS DUE TO THE SLIGHT WOBBLE PREVIOUSLY
DESCRIBED AND THE INTENSITY INCREASE. HOWEVER, THE SYSTEM WILL
STILL MAKE LANDFALL ALONG THE MYANMAR COAST BETWEEN TEKNAF AND
SITTWE WITHIN THE NEXT 12 TO 18 HOURS. THE SYSTEM WILL RUSH TO THE
NORTHEAST AFTER LANDFALL AS IT WILL BE IN A STRONG STEERING
ENVIRONMENT. THE INTENSITY REMAINS BETWEEN 120 KNOTS AND 125 KNOTS
JUST BEFORE LANDFALL. THE CONDITIONS NEAR LAND INDICATE A MODERATE
INCREASE OF 10 KNOTS OF VWS ALONG AND COASTAL UPWELLING DUE TO THE
SHALLOWING OF THE COASTAL WATERS. THESE FACTORS CAN INHIBIT THE
SYSTEM INTENSITY JUST BEFORE SHORE BREAK. HOWEVER, THE SYSTEM WILL
REMAIN WITH NEAR-OPTIMAL CONDITIONS FOR A FEW MORE HOURS, ALLOWING
IT ANOTHER CHANCE TO INCREASE IN INTENSITY, WHICH CAN COUNTER THE
LATE INHIBITING EFFECTS ALTOGETHER. AFTER THE SYSTEM MAKES
LANDFALL, IT WILL RAPIDLY WEAKEN AS IT ENCOUNTERS HIGHER SHEAR AND
INTERACTS WITH ROUGHER TERRAIN, AND DISSIPATE OVER NORTHEAST
MYANMAR. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE REMAINS IN VERY GOOD
AGREEMENT ON THE NORTHEAST TRACK THROUGH THE FORECAST PERIOD, WITH
LESS THAN 35NM SPREAD NEAR LANDFALL, LENDING HIGH CONFIDENCE TO THE
JTWC FORECAST TRACK. INTENSITY GUIDANCE IS ALSO IN GOOD OVERALL
AGREEMENT, WITH THE MAJORITY OF THE CONSENSUS MEMBERS INDICATING A
STEADY HIGH INTENSITY THROUGH TAU 12, FOLLOWED BY GRADUAL WEAKENING
THROUGH LANDFALL AND THEN DRASTIC WEAKENING THROUGH DISSIPATION.
OVERALL CONFIDENCE IN THE JTWC FORECAST INTENSITY IS MEDIUM. 

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