WDPN31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 04W (SINLAKU) WARNING NR 
022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.6N 146.0E
   INITIAL INTENSITY: 130 KTS
   GEOGRAPHIC REFERENCE: 84 NM NORTHEAST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SUPER
TYPHOON 04W BEARING DOWN ON THE NORTHERN MARIANA ISLANDS, THOUGH
SLOWING TO 03 KTS OVER THE PAST 03 HOURS. THE POWERFUL TYPHOON
MAINTAINS A CIRCULAR, 15 NM WIDE, CLOUD-FREE EYE EMBEDDED WITHIN A 
SYMMETRIC, ALBEIT LESS SMOOTH, CENTRAL DENSE OVERCAST (CDO) WITH 
EXCELLENT RADIAL OUTFLOW. AN EYEWALL REPLACEMENT CYCLE (ERC) IS 
UNDERWAY, AS CLEARLY EVIDENCED BY THE DOUBLE EYEWALL FEATURE SEPARATED 
BY A MOAT IN THE 140349Z AMSR2 89 GHZ AND IN THE PGUA RADAR IMAGERY. 
OVERSHOOTING TOPS ALONG WITH AN EXPANDING RING OF BLACK-WHITE GREY
SHADES IN THE BD ENHANCEMENT CURVE, OUTLINE THE 50 NM WIDE OUTER 
EYEWALL, INDICATING THAT THE OUTER EYEWALL IS CONSOLIDATING WHILE THE 
INNER ONE IS WEAKENING. HIGH OCEAN HEAT CONTENT (OHC) OF 150 KJ CM2,
ABUNDANT DEEP-LAYER MOISTURE, AND LOW VERTICAL WIND SHEAR (VWS)
INDICATE A HIGHLY FAVORABLE ENVIRONMENT. AT 40 NM FROM THE CENTER
OF THE EYE AND CLOSING, SAIPAN INTERNATIONAL AIRPORT REPORTED A
SUSTAINED WIND OF 63 KTS, A GUST OF 99 KTS SO FAR, AND A MEAN SEA
LEVEL PRESSURE OF 956.2 MB. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE WELL-DEFINED EYE IN THE MSI AND RADAR.
THE INITIAL INTENSITY IS SET AT 130 KTS WITH MEDIUM CONFIDENCE
BASED ON A BLEND OF THE T6.5 FROM PGTW AND KNES, SUPPORTED BY THE
OBJECTIVE ESTIMATES FROM CIMSS. THE EFFECT OF THE ONGOING ERC ON
THE VISIBLE AND IR PRESENTATION OF THE STORM REDUCES CONFIDENCE IN
THE INTENSITY.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.0 - 140 KTS 
   KNES: T6.5 - 127 KTS
   CIMSS SATCON: 138 KTS AT 140530Z
   CIMSS ADT: 129 KTS AT 140530Z
   CIMSS AIDT: 126 KTS AT 140530Z
   CIMSS D-MINT: 138 KTS AT 140349Z
   CIMSS D-PRINT: 131 KTS AT 140630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: STY 04W IS BEING STEERED TO THE NORTHWEST BY A
BUILDING NER TO THE EAST, APPROACHING A WEAKNESS IN THE SUBTROPICAL
RIDGE (STR) TO THE NORTH. A LANDFALL NEAR AGUIJAN OR TINIAN IS
IMMINENT. AS THE SYSTEM GAINS LATITUDE AND ROUNDS THE STR AXIS
BETWEEN TAU 36 AND TAU 48, THE MID-LATITUDE WESTERLIES WILL INDUCE
A FASTER MOTION TO THE NORTHEAST. THE SYSTEM WILL BECOME EMBEDDED
WITHIN THE DEEP-LAYER WESTERLIES AND UNDERGO EXTRATROPICAL
TRANSITION (ETT) BY TAU 120. WHILE THE SURROUNDING ENVIRONMENT IS
FAVORABLE FOR INTENSIFICATION, THE ONGOING ERC IS LEADING TO SOME
WEAKENING. SLOW WEAKENING IS FORECAST THROUGH TAU 24 AS THE PROCESS
CONTINUES. AFTER TAU 24, THE ENVIRONMENT WILL BECOME MORE HOSTILE,
CHARACTERIZED BY A DRIER ATMOSPHERIC COLUMN AND INCREASING VWS.
THESE FACTORS WILL ENTRAIN DRY AIR INTO THE VORTEX, LEADING TO MORE
RAPID WEAKENING. HOWEVER, SINLAKU SHOULD STILL BE A POTENT,
STORM-FORCE SYSTEM AS IT ACQUIRES EXTRATROPICAL CHARACTERISTICS.

MODEL DISCUSSION: THE FORECAST TRACK THROUGH TAU 24 IS HEDGED
SLOWER THAN THE MAJORITY OF THE MODEL GUIDANCE AND ON THE SOUTHWEST
SIDE OF THE ENVELOPE TO ACCOUNT FOR CURRENT STORM MOTION. FROM TAU
24 TO TAU 48, THE FORECAST TRACK SPEEDS UP AND CLOSELY FOLLOWS THE
HAFS-A AND HWRF MESOSCALE MODELS WITH MEDIUM CONFIDENCE. TOWARDS
THE END OF THE FORECAST PERIOD, THE TRACK IS HEDGED CLOSER TO THE
ECMWF AND EXPERIMENTAL AI MODELS WITH LOW CONFIDENCE BECAUSE THE
MODEL SPREAD INCREASES TO 430 NM. THE INTENSITY FORECAST SHARES A
SIMILAR STORY, ALIGNING WITH THE SLOW WEAKENING THROUGH TAU 24 AND
MORE RAPID WEAKENING FROM TAU 48 TO TAU 96 DEPICTED BY HAFS-A AND
HWRF. THE INTENSITY FORECAST HEDGES CLOSER TO THE GFS GLOBAL MODEL.

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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