WDPN31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 04W (SINLAKU) WARNING NR 
019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.1N 147.4E
   INITIAL INTENSITY: 150 KTS
   GEOGRAPHIC REFERENCE: 165 NM EAST OF NAVSTA GUAM
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 43 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS SUPER
TYPHOON (STY) 04W (SINLAKU) MAINTAINING A SYMMETRIC STRUCTURE AND
WELL-DEFINED EYE 15 NM IN DIAMETER AND WARMING TO 21 C FROM 18 C
SINCE THE LAST WARNING. ENVIRONMENTAL ANALYSIS REVEALS A RELATIVELY
FAVORABLE ENVIRONMENT WITH WARM (28-29 C) SEA SURFACE TEMPERATURES
(SST), VERY LOW (0-5 KTS) VERTICAL WIND SHEAR (VWS), AND ROBUST
RADIAL OUTFLOW. A 130836Z F16 SSMIS 91 GHZ MICROWAVE IMAGE SHOWS AN
INCREASINGLY SYMMETRICAL AND NEARLY COMPLETE SECONDARY EYEWALL
FORMING WITH THE PRIMARY EYEWALL CURRENTLY STILL INTACT. PREVIOUSLY
FORECAST EYEWALL REPLACEMENT CYCLE (ERC) IS STILL EXPECTED AND
ONGOING. BASED ON THE CLEARLY DISCERNIBLE EYE IN THE VISIBLE
SATELLITE IMAGERY, THE INITIAL POSITION IS FIXED WITH HIGH CONFIDENCE. 
THE INITIAL INTENSITY OF 150 KTS IS ALSO ASSESSED WITH HIGH 
CONFIDENCE, BASED ON THE AGREEMENT OF ALL OBJECTIVE AIDS EITHER 
MAINTAINING OR SHOWING SLIGHT INTENSIFICATION SINCE THE LAST WARNING.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT, WITH AN
EXTENSION OF A NEAR-EQUATORIAL RIDGE (NER) CENTERED TO THE EAST AND
A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.5 - 155 KTS
   RJTD: T7.5 - 155 KTS
   RCTP: T7.5 - 155 KTS
   KNES: T7.0 - 140 KTS 
   CIMSS SATCON: 156 KTS AT 131200Z
   CIMSS ADT: 152 KTS AT 131200Z
   CIMSS AIDT: 149 KTS AT 131200Z
   CIMSS D-MINT: 147 KTS AT 130836Z
   CIMSS D-PRINT: 151 KTS AT 131130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: AS MENTIONED EARLIER, STY 04W IS LIKELY IN THE
PROCESS OF THE ERC, WITH THE SECONDARY EYEWALL NEARLY FULLY WRAPPED
AROUND THE PRIMARY. STY SINLAKU IS THEREFORE CURRENTLY MAINTAINING
ITS INTENSITY AS IT NEARS THE NORTHERN MARIANA ISLANDS. BEYOND THE
BRIEF AND TEMPORARY INTENSIFICATION, THE SYSTEM IS EXPECTED TO
START WEAKENING DUE TO DRY AIR ENTRAINMENT AND A REDUCED NORTHWESTWARD 
OUTFLOW ALOFT. THE FORECAST TRACK HAS SHIFTED SLIGHTLY SOUTHWESTWARD 
AND THE LOW-LEVEL CIRCULATION CENTER IS EXPECTED TO PASS OVER THE 
ISLAND OF TINIAN AROUND TAU 24. AS THE SYSTEM IS APPROACHING THE AXIS 
OF A NER EXTENSION TO THE EAST, STY 04W WILL SLOW DOWN, WHILE SLOWLY 
AND GRADUALLY WEAKENING. PAST THE CPA WITH THE NORTHERN MARIANA 
ISLANDS, STY SINLAKU IS FORECAST TO RECURVE AROUND THE AXIS OF THE NER 
BETWEEN TAUS 48-72 AND CONTINUE NORTH-NORTHEASTWARD BEYOND TAU 72 
UNDER THE SAME STEERING REGIME. CONTINUING PAST TAU 72, STY 04W WILL 
ENCOUNTER COOLER SSTS, FURTHER DRY AIR ENTRAINMENT, AND INCREASED 
SHEAR, ALL OF WHICH WILL CONTRIBUTE TO THE FORECAST WEAKENING. 

MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IN THE SHORT TERM
IS ASSESSED WITH MEDIUM CONFIDENCE, AS THE CROSS-TRACK SPREAD
DURING THE CPA TO THE MARIANAS IS CURRENTLY 46 NM, INCLUDING THE
PRIMARY OUTLIER NAVGEM, WHICH POSITIONS THE TRACK BETWEEN ROTA AND
TINIAN. EXCLUDING NAVGEM WOULD RESULT IN A 12 NM SPREAD, CENTERED
OVER TINIAN. OFFICIAL JTWC TRACK FORECAST IS THEREFORE LAID CLOSE
TO THE MULTI-MODEL CONSENSUS WITH MEDIUM CONFIDENCE. LONG-TERM
TRACK FORECAST IS ASSESSED WITH LOW CONFIDENCE. WHILE ALL MODELS
CONTINUE TO FAVOR THE RECURVATURE SCENARIO, THE CROSS-TRACK AND
ALONG-TRACK SPREAD ARE VERY HIGH, DUE TO DIFFERENT DEPICTIONS OF
THE TIMELINE OF THE SYSTEM ROUNDING THE AXIS OF THE NER. IN REGARDS
TO INTENSITY, JTWC OFFICIAL FORECAST IS LAID WITH MEDIUM CONFIDENCE
AND IN AGREEMENT WITH THE HAFS INTENSITY PREDICTION, BUT ABOVE THE
JTWC MULTI-MODEL CONSENSUS. ALL AVAILABLE CONSENSUS MEMBERS
INDICATE GRADUAL WEAKENING, BUT SOME MODELS, COAMPS-TC AND GFS
PRIMARILY, PREDICT A SIGNIFICANTLY FASTER WEAKENING OVER THE NEXT
24-36 HOURS, WHICH DOES NOT HAVE STRONG SUPPORT IN THE ANALYSIS OF
THE ENVIRONMENT. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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