WDIO31 PGTW 251500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03B (THREE) WARNING 
NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.3N 88.4E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 258 NM SOUTH OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
CONSOLIDATING SYSTEM WITH A SMALL CENTRAL CORE OF FLARING
CONVECTION HAVING DEVELOPED OVER THE PAST FEW HOURS. A 251049Z
SSMIS 89GHZ MICROWAVE IMAGE SHOWED A BAND OF FAIRLY INTENSE
CONVECTION WRAPPING IN FROM THE NORTHWEST, ALONG THE SOUTHERN SIDE
OF THE CIRCULATION. THE COLORIZED VERSION OF THE SAME MICROWAVE
IMAGE SHOWED WHAT APPEARED TO BE A WEAK MICROWAVE EYE, THOUGH THIS
FEATURE WAS VERY CLEARLY NOT EVIDENT IN THE LOWER 36GHZ IMAGERY.
ANALYSIS OF THE LOW LEVEL SPIRAL BANDS EVIDENT IN THE COLORIZED
89GHZ IMAGE LENT MEDIUM CONFIDENCE TO THE INITIAL POSITION. THE
INITIAL INTENSITY IS ASSESSED AT 40 KNOTS WITH MEDIUM CONFIDENCE,
HEDGED SLIGHTLY ABOVE THE PGTW CURRENT INTENSITY ESTIMATE OF T2.5
(35 KNOTS) IN LIGHT OF THE HIGHER ADT AND SATCON ESTIMATES, WHICH
HOWEVER HAVE BEEN RUNNING MUCH HIGHER OVER THE PAST 24 HOURS WHEN
COMPARED TO SCATTEROMETER DATA. THE ENVIRONMENT IS MARGINALLY
FAVORABLE FOR INTENSIFICATION, WITH MODERATE WESTWARD, DIVERGENT
OUTFLOW AND WARM SSTS. HOWEVER, THE SHARP UPSTREAM EDGE OF THE
CONVECTIVE STRUCTURE IN BOTH THE EIR AND THE MICROWAVE IMAGERY
SUGGESTS SOME MODERATE EAST-NORTHEAST SHEAR, THOUGH THE CIMSS
ANALYSIS INDICATES ONLY 10-15 KNOTS OF SHEAR.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF AN EXTENSION OF A
DEEP SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   CIMSS SATCON: 50 KTS AT 250726Z
   CIMSS ADT: 53 KTS AT 250915Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TROPICAL CYCLONE 03B IS FORECAST TO CONTINUE
TRACKING WESTWARD THROUGH THE DURATION OF THE FORECAST PERIOD,
ALONG THE SOUTHERN PERIPHERY OF THE EXTENSION OF THE DEEP STR TO
THE NORTH. THE SYSTEM IS EXPECTED TO MAKE LANDFALL ALONG THE INDIAN
COASTLINE NORTH OF VISHAKHAPATNAM AROUND TAU 30. WHILE AN
UPPER-LEVEL CYCLONE OVER MYANMAR CONTINUES TO RUN INTERFERENCE FOR
THE SYSTEM, BLOCKING THE STRONGEST OF THE NORTHEASTERLY FLOW ALOFT,
THE SYSTEM IS STILL HAVING TO BATTLE SOME LOW TO MODERATE VWS.
CURRENTLY, THE MODERATELY STRONG DIVERGENT OUTFLOW TO THE WEST IS
OFFSETTING THE SHEAR, AND THIS GENERAL PATTERN IS EXPECTED TO
CONTINUE FOR THE NEXT 24 HOURS OR SO. THIS WILL ALLOW FOR SLOW BUT
STEADY INTENSIFICATION TO A PEAK OF 50 KNOTS BY LANDFALL. ONCE
ASHORE, THE SYSTEM WILL RAPIDLY DISSIPATE OVER THE RUGGED TERRAIN
TO THE NORTHWEST OF VISHAKHAPATNAM. 

MODEL DISCUSSION: TRACK GUIDANCE HAS COME INTO BETTER AGREEMENT
OVER THE PREVIOUS RUN, WITH ALL MODELS EXCEPT THE UKMET AND
ENSEMBLE CONVERGING AROUND A DUE WEST TRACK WITH LANDFALL IN 24-30
HOURS. THE JTWC FORECAST LIES WITHIN THE TIGHTEST GROUPING OF
MODELS, CLOSE TO THE CONSENSUS MEAN WITH HIGH CONFIDENCE. THE
INTENSITY GUIDANCE REMAINS MIXED, WITH HWRF AND GFS INDICATING A
STEADY WEAKENING TREND FROM TAU 00 WHILE THE SHIPS AND COAMPS-TC
GUIDANCE INDICATE INTENSIFICATION THROUGH TAU 24 WITH MARKED
WEAKENING THEREAFTER. THE JTWC FORECAST LIES ABOVE THE CONSENSUS
MEAN, CLOSE TO THE SHIPS GUIDANCE WITH MEDIUM CONFIDENCE. 

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