Advisories

WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 054//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.1N 121.9E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 181 NM NORTH OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXPANSIVE
SYSTEM WITH OUTER RAINBANDS EXTENDING FROM TAIWAN TO SHANGHAI AND A
VERY COMPACT, CLOUD-FILLED EYE EMBEDDED WITHIN A MUCH SMALLER INNER
CORE OF DEEP CONVECTION. ANIMATED RADAR DATA SHOWS THE EYE BECOMING
MORE RAGGED AND LESS-DEFINED AS IT APPROACHES THE COAST OF ZHEJIANG
PROVINCE, CHINA BUT THE WESTERN EYEWALL IN PARTICULAR IS
WELL-DEFINED AND NOW BRUSHING THE COAST NEAR SHITANGZHEN, CHINA.
SURFACE OBSERVATIONS FROM DACHEN DAO TO THE NORTH REPORTED
EAST-NORTHEAST WINDS OF 45 KNOTS AND AN MSLP READING OF 965 MB AT
0600Z. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE RADAR DATA AND THE EYE FEATURE IN THE MSI. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE. SUBJECTIVE DVORAK
CURRENT INTENSITY ESTIMATES CONTINUE TO VASTLY OUTPERFORM THE
MAJORITY OF THE OBJECTIVE INTENSITY ESTIMATES (EXCEPT THE SATCON),
WHICH ARE STRUGGLING WITH THE COMPLEX STRUCTURE OF THE SYSTEM. THE
ENVIRONMENT REMAINS FAVORABLE, BUT THE IMMINENT LANDFALL MEANS THE
SYSTEM WILL NOT HAVE TIME TO TAKE ADVANTAGE OF THE FAVORABLE
CONDITIONS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF AN EXTENSION OF
THE SUBTROPICAL RIDGE (STR) CENTERED OVER SOUTHERN JAPAN AND
EXTENDING NORTHWEST TO THE SHANDONG PENINSULA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 80 KTS AT 090600Z
   CIMSS ADT: 51 KTS AT 090600Z
   CIMSS AIDT: 66 KTS AT 090600Z
   CIMSS D-MINT: 60 KTS AT 090427Z
   CIMSS D-PRINT: 63 KTS AT 090530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: PROXIMITY TO LAND. 

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: TYPHOON (TY) 12W WILL MAKE LANDFALL ALONG THE
SOUTHEASTERN CHINESE COAST, SOUTH OF THE CITY OF TAIZHOU WITHIN THE
NEXT FEW HOURS. THE WESTERN EYEWALL IS ALREADY BRUSHING THE
COASTLINE AND THE LATEST RADAR ANIMATIONS SUGGEST THE SYSTEM MAY
ATTEMPT ONE MORE TROCHOIDAL WOBBLE SOUTHWESTWARD BEFORE CROSSING
THE COAST. OVERALL, THE SYSTEM WILL TRACK WESTWARD ALONG THE SOUTHERN
FLANK OF THE STR BUILDING TO THE NORTH FOR THE NEXT 12 HOURS, THEN
TURN NORTHWESTWARD AS THE RIDGE RECEDES SLIGHTLY EASTWARD. NO
CHANGE IN INTENSITY IS EXPECTED IN THE SHORT TIME PRIOR TO
LANDFALL. AFTER LANDFALL, THE SYSTEM WILL RAPIDLY WEAKEN AND
DISSIPATE OVER EAST-CENTRAL CHINA WITHIN 48 HOURS. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN STRONG AGREEMENT, WITH
MINIMAL CROSS-TRACK SPREAD THROUGH THE FORECAST PERIOD, LENDING
HIGH CONFIDENCE TO THE JTWC FORECAST TRACK, WHICH IS PLACED NEAR
THE AI CONSENSUS MEAN THROUGH THE FORECAST PERIOD. INTENSITY
GUIDANCE IS ALSO IN STRONG AGREEMENT DEPICTING RAPID WEAKENING
THROUGH THE FORECAST PERIOD, LENDING HIGH CONFIDENCE TO THE JTWC
INTENSITY FORECAST. 

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