WDIO31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01B (MOCHA) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.8N 92.5E
   INITIAL INTENSITY: 135 KTS
   GEOGRAPHIC REFERENCE: 155 NM SOUTH-SOUTHEAST OF CHITTAGONG
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 54 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
HAVING CONTINUED TO RAPIDLY INTENSIFY THROUGH THE MORNING HOURS, TC
01B (MOCHA) LIKELY REACHED PEAK INTENSITY AT OR NEAR 140000Z, AND
HAS SUBSEQUENTLY WEAKENED AS IT APPROACHES LANDFALL.
ANALYSIS OF A 132346Z SMAP PASS SHOWED A MAXIMUM 10-MIN WIND OF 152
KNOTS, OR 163 KNOTS 1-MIN AND A NEAR-COINCIDENT RCM-2
SAR PASS AT 132355Z SHOWED A LARGE AREA OF WINDS BETWEEN 145-152
KNOTS IN THE EYEWALL. FINALLY, OPEN-AIIR AND DEEP MICRONET
ESTIMATES AT 140000Z WERE IN THE 145-148 KNOT RANGE. TAKING THESE
ESTIMATES INTO ACCOUNT, THE 140000Z INTENSITY HAS BEEN REVISED TO
150 KNOTS AND MARKS THE PEAK INTENSITY OF TC 01B. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) AND ENHANCED INFRARED (EIR)
IMAGERY CURRENTLY DEPICT AN ERODING EYE FEATURE WHICH HAS RAPIDLY 
FILLED IN, AS WELL AS SIGNIFICANTLY WARMER CLOUD TOP TEMPERATURES, 
INDICATIVE OF A RAPID WEAKENING TREND. THE INITIAL POSITION IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED PRIMARILY ON ANALYSIS OF MET-9, 
HIM-9 AND GK2A EYE POSITIONS AND AGENCY FIX POSITIONS, AND 
INTERMITTENT RADAR DATA FROM BANGLADESH. THE INITIAL INTENSITY IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF AGENCY CURRENT 
INTENSITY ESTIMATES OF T7.0 AND DATA-T NUMBERS AT T6.5 AND THE OPEN-
AIIR ESTIMATE OF 137 KNOTS. THE ENVIRONMENT IS QUICKLY TRANSITIONING 
TO UNFAVORABLE, MID-LEVEL SHEAR HAVING INCREASED SHARPLY, DRY AIR 
BEGINNING TO BE ENTRAINED INTO THE NORTHWEST SIDE OF THE CORE, AND 
DECREASING SSTS.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: NORTHWEST PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   KNES: T7.0 - 140 KTS 
   CIMSS ADT: 119 KTS AT 140530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 20-25 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE NORTH-NORTHWEST

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: TC 01B WILL MAKE LANDFALL WITHIN THE NEXT
COUPLE OF HOURS JUST NORTH OF SITTWE, MYANMAR. THEREAFTER IT WILL
TRACK QUICKLY INLAND OVER THE RUGGED INTERIOR OF MYANMAR. FURTHER
WEAKENING IS ANTICIPATED PRIOR TO THE EYE CROSSING THE COAST,
HOWEVER THE SYSTEM WILL STILL BE A POWERFUL TROPICAL CYCLONE WITH
MAXIMUM WINDS AT OR NEAR 130 KNOTS WHEN IT COMES ASHORE. BY TAU 12,
THE SYSTEM WILL HAVE WEAKENED SIGNIFICANTLY UNDER THE COMBINED
INFLUENCES OF DRAMATICALLY HIGHER SHEAR, WHICH WILL DECAPITATE THE
VORTEX, AND THE FRICTIONAL EFFECTS DUE TO TERRAIN INTERACTION. THE
SYSTEM IS EXPECTED TO FULLY DISSIPATE OVER NORTHERN MYANMAR NO LATER
THAN TAU 36. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN STRONG AGREEMENT THROUGH THE
FORECAST PERIOD, THOUGH THE EUROPEAN MODELS DISSIPATE THE VORTEX
MORE QUICKLY, AND TURN THE REMNANTS TO THE SOUTH, INTO EASTERN
MYANMAR. HOWEVER, THE JTWC FORECAST TRACK REMAINS CONSISTENT WITH
THE PREVIOUS FORECASTS AND TRACKS THE SYSTEM INTO NORTHERN MYANMAR
WITH HIGH CONFIDENCE. INTENSITY FORECAST IS ALSO IN GOOD AGREEMENT,
WITH ALL MODELS INDICATING DISSIPATION NO LATER THAN TAU 36, AND
POTENTIALLY A BIT EARLIER, LENDING HIGH CONFIDENCE TO THE JTWC
FORECAST. 

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