WDXS31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 12S (DUMAKO) WARNING 
NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.7S 58.3E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 270 NM NORTH-NORTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING
CONVECTION OVER AN INCREASINGLY DEFINED LOW LEVEL CIRCULATION
CENTER EVIDENT IN A 131730Z METOP-B ASCAT PASS. THE INITIAL
POSITION, INTENSITY AND WIND RADII ARE ALL SET WITH HIGH CONFIDENCE
BASED ON THE AFOREMENTIONED ASCAT PASS AND COMPANION WIND SPEEDS
CALCULATED WITH THE ULTRA HIGH RESOLUTION ALGORITHM. THE
WIND STRUCTURE IS HIGHLY ASYMMETRIC, WITH GALE FORCE WINDS CONFINED
TO THE SOUTHERN SEMICIRCLE OF THE LOW LEVEL CIRCULATION.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGING TO THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS SATCON: 42 KTS AT 131539Z
   CIMSS ADT: 41 KTS AT 131815Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: NEAR-TERM INTENSITIES HAVE BEEN
INCREASED FROM THE PREVIOUS WARNING BASED ON THE OBSERVED
INTENSIFICATION TREND.

FORECAST DISCUSSION: TC 12S WILL CONTINUE TO TRACK GENERALLY 
WESTWARD TOWARD THE NORTHEASTERN COAST OF MADAGASCAR ALONG THE 
NORTHERN PERIPHERY OF SUBTROPICAL RIDING OVER THE NEXT 48 HOURS. THE 
STORM TRACK WILL DIP SLIGHTLY POLEWARD OVER THE NEXT 12 TO 24 HOURS 
BEFORE SUBSEQUENTLY TURNING SLIGHTLY EQUATORWARD AS BUILDING RIDGING 
REPLACES A WEAKNESS CURRENTLY SITUATED TO THE SOUTH. THE ENVIRONMENT 
IS GENERALLY FAVORABLE FOR CONTINUED INTENSIFICATION IN THE NEAR-
TERM, WITH VERY WARM OCEAN TEMPERATURES AND LOW VERTICAL WIND SHEAR. 
LIMITED UPPER-LEVEL OUTFLOW APPEARS TO BE THE MAIN LIMITING FACTOR 
FOR INTENSIFICATION OVER THE NEXT 12 TO 24 HOURS. BY TAU 36, 
INCREASING EASTERLY VERTICAL WIND SHEAR ASSOCIATED WITH A 
REORIENTING UPPER-LEVEL PATTERN SHOULD ARREST THE INTENSIFICATION 
TREND. SLOW WEAKENING IS EXPECTED AS TC 12S APPROACHES LANDFALL IN 
NORTHEASTERN MADAGASCAR AROUND TAU 48. PERSISTENT SHEAR AND LAND 
INTERACTION WILL RAPIDLY WEAKEN THE SYSTEM TO DISSIPATION BY TAU 72.

MODEL DISCUSSION: NUMERICAL MODEL TRACK FORECASTS ARE IN EXCELLENT
AGREEMENT THROUGH TAU 24, BUT DIVERGE THEREAFTER DUE TO DIFFERING
DEPICTIONS OF THE EVOLVING STEERING RIDGE TO THE SOUTH AND STORM
STRUCTURE. HOWEVER, A MAJORITY OF THE CONSENSUS MODELS ARE CLUSTERED 
AROUND THE CURRENT FORECAST TRACK, BRACKETED BY THE NAVGEM SOLUTION 
TO THE NORTH AND THE GALWEM AND UKMET GLOBAL MODEL SOLUTIONS TO THE 
SOUTH. GIVEN NOTED MODEL SPREAD, CONFIDENCE IN THE TRACK FORECAST IS 
MEDIUM. NUMERICAL MODEL INTENSITY FORECASTS ARE GENERALLY FLAT IN 
THE NEAR TERM, WHILE SHIPS INTENSITY GUIDANCE CAPTURES THE MORE 
LIKELY INTENSIFICATION SCENARIO GIVEN FAVORABLE ENVIRONMENTAL 
CONDITIONS AND THE OBSERVED TREND. THERE IS BROADER AGREEMENT 
REGARDING WEAKENING AND DISSIPATION IN THE LONGER RANGE. BASED ON 
NEAR-TERM UNCERTAINTY, CONFIDENCE IN THE INTENSITY FORECAST IS 
MEDIUM.

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