WDXS31 PGTW 171500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY)    
WARNING NR 030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.8S 73.8E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 976 NM EAST-NORTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 43 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
OVER THE PAST 12 HOURS, TROPICAL CYCLONE (TC) 11S HAS CONSOLIDATED
WITH A MORE SYMMETRIC STRUCTURE AND WARMER EYE. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY DEPICTS A SYMMETRIC CORE
SURROUNDING A 20NM DIAMETER ROUND EYE WITH A 17.3C EYE TEMPERATURE.
ALTHOUGH THE SYSTEM MAY APPEAR ANNULAR AT TIMES, IT IS CLEARLY NOT
ANNULAR; CLOUD TOP TEMPERATURES ARE NOT UNIFORM AND A 171248Z SSMIS
91GHZ MICROWAVE IMAGE SHOWS CONVECTIVE BANDING OVER THE WESTERN
SEMICIRCLE. ANIMATED WATER VAPOR IMAGERY CONTINUES TO INDICATE
RADIAL OUTFLOW AND ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE WITH
LOW VERTICAL WIND SHEAR AND WARM (28C) SST VALUES. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON RECENT EWS-G1
SATELLITE IMAGERY AND THE SSMIS 91GHZ IMAGE. THE INITIAL INTENSITY
OF 120 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE SUBJECTIVE
DVORAK ESTIMATES RANGING FROM 115 TO 127 KNOTS AS WELL AS ADT AND
AIDT ESTIMATES OF 122 AND 124 KNOTS. RECENT DMN AND OPEN-AIIR
ESTIMATES ALSO SUPPORT THIS ASSESSMENT AND RANGE FROM 115 TO 120
KNOTS.

INITIAL WIND RADII BASIS: AMSR2 WINDSPEED IMAGE

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T6.5 - 127 KTS
   DEMS: T6.0 - 115 KTS
   FMEE: T6.5 - 127 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: TC 11S WILL CONTINUE TO TRACK WESTWARD THROUGH
TAU 48 ALONG THE NORTHERN PERIPHERY OF THE STR. AFTER TAU 48, THE
SYSTEM WILL TURN WEST-SOUTHWESTWARD AS THE STR REORIENTS TO THE
SOUTHEAST WITH THE APPROACH OF A MAJOR SHORTWAVE TROUGH. THIS
TROUGH IS EXPECTED TO FILL AND PROPAGATE QUICKLY EASTWARD, WHICH
WILL ALLOW TC 11S TO RETURN TO A MORE WESTWARD TRACK NEAR TAU 120.
DESPITE DRY AIR ENTRAINING AROUND THE PERIPHERY OF THE SYSTEM AND
POSSIBLE UPWELLING COOL WATER, TC 11S REMAINS RESILIENT AND
CONTINUES TO TRACK STEADILY WESTWARD AT 14 KNOTS. TC 11S IS
EXPECTED TO WEAKEN SLIGHTLY BY TAU 24 BUT IS EXPECTED TO
REINTENSIFY SLIGHTLY TO 120 KNOTS BY TAU 48. AFTER TAU 72, STEADY 
WEAKENING IS ANTICIPATED AS THE SYSTEM APPROACHES MADAGASCAR NEAR TAU 
96 THEN RAPID WEAKENING AS THE SYSTEM TRACKS OVER MADAGASCAR.

MODEL DISCUSSION: WITH THE EXCEPTION OF AFUM, WHICH RECURVES THE
SYSTEM SOUTHWESTWARD OVER SOUTHERN MADAGASCAR, NUMERICAL MODEL
GUIDANCE IS IN TIGHT AGREEMENT WITH A 60NM TO 115NM SPREAD IN
SOLUTIONS FROM TAU 72 TO TAU 120. THE BULK OF THE EPS AND GEFS
SOLUTIONS INDICATE A HIGH PROBABILITY OF LANDFALL OCCURRING OVER
CENTRAL MADAGASCAR HOWEVER THERE IS A LARGER SPREAD OF SOLUTIONS
THAT EXTEND OVER SOUTHERN MADAGASCAR. THE 170000Z COAMPS-TC
ENSEMBLE INDICATES A 60 TO 70 PERCENT PROBABILITY OF MODERATE
INTENSIFICATION OCCURRING FROM TAU 24 TO TAU 72 AS THE SYSTEM
PASSES NORTH OF PORT MATHURIN AND MAURITIUS. 

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