Advisories

WDPN31 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 038//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.6N 137.2E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 509 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND ENHANCED INFRARED 
(EIR) SATELLITE IMAGERY DEPICT TYPHOON (TY) 12W WITH A CLOUD-FILLED, 
BUT WELL-DEFINED 17NM WIDE EYE EMBEDDED WITHIN A SYMMETRIC CENTRAL 
DENSE OVERCAST (CDO). EYE TEMPERATURES CONTINUE TO COOL, NOW 
ESTIMATED AT -04C AS THE EYE FILLS WITH CLOUDS, WHILE CLOUD-TOP 
TEMPERATURES HAVE STEADILY RISEN TO THE -45C RANGE, CONSISTENT WITH 
CLOUD-TOP TEMPS FROM 12 HOURS AGO. A 050436Z AMSR2 AND 050659Z SSMIS 
89GHZ IMAGE DEPICT A COMPACT INNER CORE OF CONVECTION, SURROUNDED BY 
AN EXPANSIVE OUTER RING OF MODERATE CONVECTION. THE SSMIS IMAGE 
DEPICTS A STATIONARY BANDING COMPLEX (SBC), WHICH THE CIMSS M-PERC 
FAILS TO PICK UP, DRAPED ACROSS THE SOUTHERN REGION OF THE 
CIRCULATION AND WRAPS UP ALONG THE EASTERN SIDE, ULTIMATELY MERGING 
WITH THE INNER EYEWALL IN THE NORTHEASTERN QUADRANT. BOTH MICROWAVE 
IMAGES ALSO DEPICT A RELATIVELY CLEAR MOAT SEPARATING THE SBC FROM 
THE MAIN CORE OF CONVECTION AND INNER EYEWALL. THE FACT THAT M-PERC 
IS NOT PICKING UP ON THIS SBC IS NOTABLE FOR FUTURE EYEWALL 
REPLACEMENT CYCLE PREDICTION. THE INITIAL POSITION IS ASSESSED WITH 
HIGH CONFIDENCE BASED ON THE EYE IN THE MSI. THE INITIAL INTENSITY IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF THE SUBJECTIVE 
AND OBJECTIVE INTENSITY ESTIMATES NOTED BELOW. ENVIRONMENTAL 
CONDITIONS REMAIN FAVORABLE, WITH WARM SSTS (ALTHOUGH OHC REMAINS 
LOW), STRONG RADIAL OUTFLOW (DIVERGENT CYCLONIC IN THE IMMEDIATE 
VICINITY OF THE CORE, TURNING ANTICYCLONIC AT A DISTANCE) AND LOW 
DEEP-LAYER SHEAR.

INITIAL WIND RADII BASIS: SCATTEROMETER AND SAR DATA AS WELL AS
PERSISTENCE.  

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED OVER THE SEA OF JAPAN. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 94 KTS AT 050630Z
   CIMSS ADT: 97 KTS AT 050600Z
   CIMSS AIDT: 99 KTS AT 050600Z
   CIMSS D-MINT: 102 KTS AT 050659Z
   CIMSS D-PRINT: 89 KTS AT 050630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

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 UNDER THE STEERING INFLUENCE OF THE 
STRONG STR CENTERED OVER THE SEA OF JAPAN. TRACK SPEEDS ARE FORECAST 
TO REMAIN CONSISTENT FOR THE NEXT 36-48 HOURS AS THE RIDGE REMAINS 
FIRMLY ENTRENCHED TO THE NORTH. SOME TROCHOIDAL WOBBLES ARE 
ANTICIPATED, ESPECIALLY IF AND WHEN THE SYSTEM BEGINS ANOTHER ERC,
THOUGH THERE ARE NO SIGNIFICANT CHANGES IN TRACK EXPECTED BEFORE THE 
SYSTEM REACHES THE RYUKYUS. BY TAU 48, AN UPPER-LEVEL TROUGH WILL 
MOVE ACROSS FAR NORTHEASTERN CHINA, ERODING THE WESTERN EXTENT OF THE 
STR, INDUCING A BREAK OR WEAKNESS IN THE STEERING RIDGE OVER THE 
KOREAN PENINSULA. THE TROUGH IS NOT FORECAST TO BE STRONG ENOUGH TO 
PULL TY 12W NORTHWARD, THOUGH ITS PRESENCE INTRODUCES SOME MARGINAL 
UNCERTAINTY INTO THE FORECAST TRACK. ALL OF THE MAJOR GLOBAL MODELS 
DEPICT THE SAME SCENARIO, WITH A WEAKNESS DEVELOPING IN THE RIDGE 
OVER THE KOREAN PENINSULA, BUT DIFFERENCES EMERGE IN HOW THE MODELS 
PREDICT TY 12W TO RESPOND. THE NAVGEM, WITH ITS KNOWN POLEWARD TRACK 
BIASES SHOW AN AGGRESSIVE RESPONSE AND A DRAMATIC TURN NORTHWARD, 
THOUGH NOW DELAYED SIGNIFICANTLY LATER THAN IN PREVIOUS RUNS. THE GFS 
STILL INSISTS ON TURNING THE SYSTEM POLEWARD BUT A SHALLOWER ANGLE 
AND NOT UNTIL AFTER PASSING OKINAWA. ENSEMBLES WILL BE DISCUSSED IN 
MORE DETAIL BELOW BUT IN GENERAL SUPPORT A WESTWARD TRAJECTORY 
THROUGH TAU 120, WITH A LOW PROBABILITY SCENARIO OF A TURN NORTHWARD 
AFTER TAU 96. THE SYSTEM IS EXPECTED TO SLOW DOWN AFTER TAU 48, BUT 
MAINTAIN A GENERALLY WESTWARD TRACK THROUGH TAU 120. THE FIRST 
LANDFALL IS FORECAST TO OCCUR AT OKINAWA AROUND TAU 48, WITH A SECOND 
LANDFALL SOUTH OF SHANGHAI BETWEEN TAU 96 AND TAU 120. REGARDING 
INTENSITY, WHILE THE SOLE ERC PREDICTION AID IS CURRENTLY NOT PICKING 
UP ON A STRONG SBC SIGNATURE, THE PRESENCE OF CYCLONIC OUTFLOW ALOFT 
AND THE PRESENCE OF THE SBC STRONGLY SUGGEST SECONDARY EYEWALL 
FORMATION IS LIKELY. IF THE SYSTEM ATTEMPTS ANOTHER ERC, DUE TO THE 
EXTREMELY BROAD NATURE OF THE OUTER CONVECTIVE RING, AND OCEANIC 
UPWELLING, IT IS UNLIKELY TO BE ABLE TO COMPLETE IT. THE FORECAST 
CALLS FOR A STEADY INTENSITY, WITH THE POSSIBILITY OF SWINGS OF PLUS 
OR MINUS 5-10 KNOTS, OVER THE NEXT 48 HOURS AS THE SYSTEM HURTLES 
TOWARDS OKINAWA. AFTER MOVING INTO THE ECS, THE SYSTEM WILL RAPIDLY 
WEAKEN AS IT CONTINUES TO EXPAND, UPWELLS SIGNIFICANTLY COOLER WATERS 
AND ENCOUNTERS SOME CONVERGENCE ALOFT. AFTER LANDFALL IN CHINA, THE
SYSTEM WILL RAPIDLY WEAKEN DUE TO LAND EFFECTS. 

MODEL DISCUSSION: TRACK GUIDANCE IS BY AND LARGE CONTINUING TO
TREND TOWARDS STRONGER AGREEMENT. GFS AND GEFS ARE NOW THE SOLE
OUTLIERS, TRANSITIONING THE SYSTEM NORTHWESTWARD AFTER TAU 72, WITH 
THE JGSM NOW HAVING GIVEN UP ON THE POLEWARD TURN AND NOW ALIGNING 
WITH THE BULK OF THE OTHER MODELS. THE NAVGEM DIVES THE SYSTEM
SOUTHWESTWARD, PASSING OVER THE SOUTHERN TIP OF OKINAWA, THEN MAKES A 
LITERAL RIGHT TURN AT TAU 96. THE REMAINDER OF THE GUIDANCE PACKAGE 
IS CONFINED TO A ENVELOPE WHICH GRADUALLY EXPANDS TO 230NM AT TAU 
120, WITH EC-AIFS, JGSM AND THE UKMET ENSEMBLE ON THE NORTHERN EDGE 
AND THE GALWEM ON THE SOUTHERN. ENSEMBLE GUIDANCE IS ALSO COMING INTO 
BETTER AGREEMENT. OF THE AVAILABLE, RELIABLE ENSEMBLE MODELS (GEFS, 
EPS, ICON, AIFS, GDM), ONLY THE GEFS SHOWS A SIGNIFICANT NUMBER OF 
MEMBERS TURNING POLEWARD, WITH APPROXIMATELY 50 PERCENT DOING SO 
AFTER TAU 84 AND ALL BUT TWO REMAIN WEST OF 128E. EVERY OTHER 
ENSEMBLE NOTED ABOVE DEPICTS A WEST-NORTHWESTWARD TRACK THROUGH 
LANDFALL IN CHINA, WITH MEMBERS CONFINED TO AN ENVELOPE BETWEEN 
SHANGHAI AND NORTHERN TAIWAN. THE JTWC FORECAST IS PLACED NEAR THE AI 
CONSENSUS MEAN WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS IN 
RELATIVELY GOOD AGREEMENT, THE BULK OF MODELS DEPICTING A TIGHTLY 
CONFINED ENVELOPE PLUS OR MINUS 10 KNOTS OF 95 KNOTS THROUGH TAU 48, 
THEN QUICKLY WEAKENING THEREAFTER.  

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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