Advisories

WDPN31 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 032//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.1N 144.2E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 889 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 47 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS THE INNER
EYEWALL OF TYPHOON 12W (DOLPHIN) STRENGTHENING OVER THE LAST 6
HOURS AS THE PREVIOUSLY OBSERVED EYEWALL REPLACEMENT CYCLE (ERC)
FAILED TO COMPLETE, ALLOWING THE ORIGINAL INNER EYEWALL TO REBUILD.
THE EYE TEMPERATURE HAS WARMED TO 16 C AND CLEARED OUT TO ITS
CURRENT OBLONG APPEARANCE. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE
CONDITIONS WITH WARM (29-30 C) SEA SURFACE TEMPERATURES (SSTS), LOW
(5-10 KTS) VERTICAL WIND SHEAR (VWS), AND GOOD OUTFLOW ALOFT,
ALTHOUGH IT HAS BEEN SUPPRESSED ON THE NORTHWEST QUADRANT OF TY 12W
DUE TO INCREASED PRESSURE. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE IMPROVED DEFINITION OF THE EYE. THE INITIAL
INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE IMPROVED
AGREEMENT BETWEEN THE CIMSS OBJECTIVE ESTIMATES AND AGENCY DVORAK
FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTWARD EXTENSION OF THE
DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 96 KTS AT 031800Z
   CIMSS ADT: 99 KTS AT 031800Z
   CIMSS AIDT: 95 KTS AT 031800Z
   CIMSS D-MINT: 93 KTS AT 031450Z
   CIMSS D-PRINT: 83 KTS AT 031800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: SYSTEM HAS MAINTAINED FAVORABLE EQUATORWARD AND
EASTWARD OUTFLOW INTO THE TUTT POSITIONED TO THE EAST, HOWEVER,
INCREASING NORTHWESTERLY PRESSURE HAS SUPPRESSED OUTFLOW ON THE
NORTHWEST QUADRANT.

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: TY 12W IS FORECAST TO CONTINUE ITS WESTWARD TRACK 
TOWARDS THE RYUKYU ISLANDS OF JAPAN UNDERNEATH THE STEERING INFLUENCE 
OF THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) CENTERED 
TO THE NORTHEAST. IN THE NEXT 12 HOURS, TY DOLPHIN IS EXPECTED TO 
SHIFT TO THE INFLUENCE OF THE STR CENTERED TO THE NORTHWEST OVER THE 
KOREAN PENINSULA. HOWEVER, THE RESULTANT MOTION OF TY 12W IS FORECAST 
TO REMAIN THE SAME OVERALL WESTWARD TRACK FOR THE REMAINDER OF THE 
FORECAST PERIOD REGARDLESS OF WHICH STR IS THE PRIMARY STEERING 
FACTOR. IN TERMS OF TRACK SPEED, THE BULK OF PHYSICS-BASED AND AI 
MODELS DEPICT TRANSLATIONAL SPEED SLOWING TO 5-8 KTS BETWEEN TAUS 72 
AND 96, DUE TO THE WEAKENING OF THE WESTERN STR ASSOCIATED WITH THE 
PASSAGE OF A MID-LATITUDE TROUGH. TROCHOIDAL MOTION OF TY 12W IS 
OBSERVABLE IN ANIMATED SATELLITE IMAGERY AND EXPECTED TO CONTINUE, 
WHICH COULD CAUSE SLIGHT CHANGES IN THE DISTANCE AND TIMING OF THE CPA 
OF TY 12W TO OKINAWA AS IT CONTINUES TO WOBBLE. REGARDING INTENSITY, 
TY DOLPHIN HAS TEMPORARILY INCREASED AS ITS INNER EYEWALL STRENGTHENS 
AND IS EXPECTED TO MAINTAIN OVER THE NEXT 6-12 HOURS, FOLLOWED BY A 
DECLINE IN ONLY 5-10 KTS OVER THE REMAINDER OF THE FORECAST PERIOD. 
THE EYE SIZE OF TY 12W IS EXPECTED TO EXPAND AS IT APPROACHES OKINAWA 
WHICH WOULD CONTRIBUTE TO THE SLIGHT DROP IN INTENSITY, HOWEVER THE 
WIND FIELD SIZE OF TY 12W IS EXPECTED TO REMAIN LARGE ENOUGH TO BRING 
GALE FORCE WINDS TO THE ENTIRETY OF THE RYUKYU ISLAND CHAIN.

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT FOR THE
FORECAST PERIOD, WITH  A CROSS TRACK SPREAD OF 75 NM AS IT PASSES
OKINAWA. ALONG TRACK SPREAD HAS IMPROVED, WITH GFS CONTINUING TO BE 
THE SLOWEST SOLUTION. THE FORECAST TRACK IS LAID WITH HIGH CONFIDENCE, 
SLIGHTLY NORTH OF BOTH THE JTWC MULTI-MODEL CONSENSUS AND THE 
EXPERIMENTAL AI MODELS. INTENSITY MODEL GUIDANCE REMAINS A BIT SPREAD 
WITH BOTH COAMPS-TC MODELS DEPICTING CONTINUED IINTENSIFICATION OUT TO 
TAU 60, WHILE THE REMAINDER OF THE AIDS DEPICT A SLIGHT WEAKENING 
TREND THROUGHOUT THE ENTIRE FORECAST PERIOD. THE OFFICIAL JTWC 
FORECAST INTENSITY IS ASSESSED WITH LOW CONFIDENCE, BELOW THE JTWC 
MULTI-MODEL CONSENSUS AND EXPERIMENTAL GOOGLE DEEP-MIND AI MODEL. THE 
BULK OF THE GOOGLE DEEP MIND ENSEMBLE MEMBERS DEPICT BETWEEN 70 AND 90 
KTS INTENSITY AS TY 12W CPAS OKINAWA.

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