WDPN31 PGTW 310300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 12W (DOLPHIN) WARNING NR
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.3N 161.9E
   INITIAL INTENSITY: 135 KTS
   GEOGRAPHIC REFERENCE: 1948 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 44 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SUPER
TYPHOON 12W (DOLPHIN) WITH A SIGNIFICANTLY WARMED EYE OVER THE PAST
6 HOURS, NOW MEASURING AT ABOUT 18 C. THE SYSTEM HAS RECOVERED AND
REBOUNDED FROM THE SECOND EYEWALL REPLACEMENT CYCLE (ERC) WHICH
COMPLETED ABOUT 12 HOURS AGO. THE CENTRAL DENSE OVERCAST (CDO)
SURROUNDING THE EYEWALL HAS REMAINED SOMEWHAT DEFORMED WITH A
SLIGHT WEAKNESS IN THE WESTERN SEMICIRCLE. THERE HAS BEEN A MARKED
LACK OF HIGH-RESOLUTION MICROWAVE IMAGERY ON THE SYSTEM OVER THE
PAST 24 HOURS, LENDING HIGH AMOUNTS OF UNCERTAINTY TO THE OVERALL
STRUCTURE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE DEFINED EYE IN ANIMATED MSI. THE INITIAL INTENSITY OF
135 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY
DVORAK AND CIMSS INTENSITY ESTIMATES LISTED BELOW. ENVIRONMENTAL
ANALYSIS INDICATES THAT 12W IS IN A FAVORABLE ENVIRONMENT
CHARACTERIZED BY STRONG RADIAL OUTFLOW ALOFT, LOW (5-10 KTS)
VERTICAL WIND SHEAR, AND VERY WARM (30-31 C) SEA SURFACE
TEMPERATURES. THERE IS AN APPEARENT RESTRICTION IN THE EASTWARD
OUTFLOW OF THE SYSTEM, INDICATED BY THE OUTFLOW BOUNDARIES IN THAT
DIRECTION BEING PRESSED BACK INWARD TOWARD THE CENTER.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK

CURRENT STEERING MECHANISM: SOUTHWESTERN EXTENT OF AN EXPANSIVE
SUBTROPICAL RIDGE (STR) COMPLEX

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T6.5 - 127 KTS
   RJTD: T7.0 - 140 KTS
   RCTP: T7.5 - 155 KTS
   KNES: T6.5 - 127 KTS
   PHFO: T6.5 - 127 KTS
   CIMSS ADT: 127 KTS AT 310000Z
   CIMSS AIDT: 123 KTS AT 310000Z
   CIMSS D-MINT: 136 KTS AT 302324Z
   CIMSS D-PRINT: 132 KTS AT 310000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: SLIGHT RESTRICTION IN EASTWARD OUTFLOW

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: STY 12W IS FORECAST TO CONTINUE TRACKING
WEST-NORTHWESTWARD, ALONG THE SOUTHWESTERN EXTENT OF AN EXPANSIVE
RIDGING COMPLEX SITUATED TO THE NORTHEAST THROUGH TAU 60. NEAR TAU
60, THE UPPER-LEVEL TROUGH THAT IS CURRENTLY JUST EAST OF KYUSHU
WILL BE POSITIONED TO THE NORTH OF 12W AND WILL BEGIN TO FILL.
AFTER THE TROUGH FILLS AND PROPAGATES FURTHER EASTWARD, RIDGING
WILL BUILD IN FROM BOTH THE NORTHEAST AND NORTHWEST OF 12W, CAUSING
THE TRACK TO TURN MORE WESTWARD. THE RIDGE THAT WILL BE POSITIONED
OVER THE KOREAN PENINSULA WILL EVENTUALLY BECOME THE PRIMARY
STEERING MECHANISM AROUND TAU 96 AS THE SYSTEM HEADS TOWARD THE
RYUKYU ISLANDS. IN TERMS OF INTENSITY, 12W IS FORECAST TO GENERALLY
MAINTAIN ITS CURRENT INTENSITY THROUGH TAU 36 WITH SOME POSSIBLE
FLUCTUATIONS IN INTENSITY DEPENDING ON FURTHER ERC EVENTS AND
INNER-CORE DYNAMICS. BY TAU 48, GRADUALLY LOWERING OCEAN HEAT CONTENT,
INCREASING NORTHEASTERLY VERTICAL WIND SHEAR, AND WEAKENING POLEWARD
OUTFLOW WILL SERVE TO STEADILY WEAKEN THE SYSTEM AS IT MOVES OFF TO
THE WEST. IN ADDITION TO THOSE MENTIONED ENVIRONMENTAL
CHARACTERISTICS, THE WIND FIELD OF 12W IS EXPECTED TO DRAMATICALLY
EXPAND STARTING AROUND TAU 96, WHICH WILL FURTHER SUPPORT A STEADY
DECLINE ON THE INTENSITY OF THE SYSTEM.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN VERY GOOD
AGREEMENT THROUGH TAU 72 WITH NO SIGNIFICANT OUTLIERS PRESENT.
AFTER TAU 72, ALONG-TRACK SPREAD INCREASES DUE TO GALWEM AND JGSM
BECOMING THE TWO FAST OUTLIERS. CROSS-TRACK SPREAD REMAINS LOW
THROUGHOUT THE FORECAST PERIOD. THE GFS IS THE MOST EQUATORWARD
TRACKER THIS MODEL RUN WITH THE EXPERIMENTAL GOOGLE DEEPMIND
ENSEMBLE MEAN BEING THE FURTHEST POLEWARD. CROSS-TRACK SPREAD AT
TAU 72 IS MEASURED TO BE ABOUT 100 NM WHICH INCREASES TO 150 NM
AT TAU 120. OVERALL, THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. INTENSITY GUIDANCE
DEPICTS A STEADY INTENSITY OR SLIGHT WEAKENING THROUGH TAU 36-48.
AFTER TAU 48, MODELS AGREE ON WEAKENING TO VARYING DEGREES. HAFS-A
CONTINUES TO BE THE QUICKEST TO WEAKEN 12W, SUGGESTING AN INTENSITY
OF AROUND 80 KTS AT TAU 120. ON THE OTHER END OF THE SPECTRUM,
COAMPS-TC HAS THE SLOWEST WEAKENING TREND, SHOWING AN INTENSITY OF
110 KTS AT TAU 120. THE JTWC INTENSITY FORECAST CLOSELY FOLLOWS THE
CONSENSUS THROUGHOUT THE FORECAST PERIOD WITH MEDIUM CONFIDENCE


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