Tropical Storm MUIFA Advisory Mi, 14.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (MUIFA) WARNING NR 031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 28.0N 123.3E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 214 NM SOUTH-SOUTHEAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 34 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND RADAR IMAGERY
DEPICT A 40 NM WIDE EYE THAT HAS BEGUN CONTRACTING DURING THE PAST
THREE HOURS. DEEP CONVECTION OF AROUND -70C CLOUD TOP TEMPERATURE
HAS NOW ENCIRCLED THE EYE, A MARKED IMPROVEMENT RELATIVE TO SIX
HOURS AGO WHEN THE NORTHWESTERN SEMICIRCLE HAD MUCH WARMER CLOUD
TOPS. RADAR IMAGERY CONFIRMS THAT THE NORTHWESTERN EYEWALL HAS
STRENGTHENED CONSIDERABLY, THOUGH A NEARLY OPEN WALL IS NOW
OBSERVED ON THE SOUTHEAST SIDE. UPPER-LEVEL OUTFLOW IS SEEN
EXPANDING IN ALL QUADRANTS, THOUGH PARTICULARLY SO TOWARD THE NORTH
AS AN OUTFLOW CHANNEL DEVELOPS ALONG THE EASTERN FLANK OF AN
UPPER-LEVEL TROUGH SITUATED WEST OF THE STORM OVER EASTERN CHINA.
SURFACE OBSERVATIONS INDICATE THAT THE GALE-FORCE WIND FIELD IS NOW
APPROACHING THE COASTLINE OF CHINA NEAR TAIZHOU, AND WILL PROGRESS
NORTHWARD TOWARD SHANGHAI DURING THE NEXT SEVERAL HOURS. MAXIMUM
WINDS ARE ESTIMATED AT 85 KTS, A BLEND OF SUBJECTIVE DVORAK
ESTIMATES OF 77 KTS FROM PGTW AND RJTD AND HIGHER ADT ESTIMATES OF
90 KTS.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE EAST
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T4.5 - 77 KTS
   CIMSS ADT: 97 KTS AT 132040Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE RADIAL
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THE FORECAST TRACK HAS ACCELERATED
SIGNIFICANTLY BEYOND 36 HOURS, AND NOW REACHES THE VICINITY OF
DALIAN, CHINA BY 72 HOURS DUE TO A FASTER FORWARD MOTION
FORECAST DISCUSSION: TYPHOON 14W (MUIFA) CONTINUES TO MOVE
NORTH-NORTHWESTWARD TOWARD THE CHINESE COASTLINE, AND IS EXPECTED
TO MAKE LANDFALL JUST EAST OF NINGBO, CHINA IN ABOUT 12 HOURS, WITH
A SECONDARY LANDFALL NEAR SHANGHAI, CHINA IN ABOUT 18 HOURS AFTER
CROSSING HANGZHOU BAY. THE CYCLONE HAS DISPLAYED HEALTHY TRENDS IN
SATELLITE AND RADAR IMAGERY DURING THE PAST SIX HOURS, WITH A MORE
SYMMETRIC INNER CORE DEVELOPING AS THE CYCLONE MOVES AWAY FROM COOL
WATERS CHURNED UP TO ITS SOUTH THAT IT HAD BEEN PASSING OVER DURING
THE LAST 36 HOURS. THE CURRENTLY WARMER SEA SURFACE TEMPERATURES OF
27-28 DEGREES CELSIUS WILL BE SHORT-LIVED, HOWEVER, AS THE SHELF
WATER OFF OF NINGBO IS COOLER AT 26-27 DEGREES CELSIUS, AND ALSO
SHALLOWER, THUS HOLDING LESS TOTAL HEAT CONTENT. THIS, COMBINED
WITH LAND INTERACTION SHOULD RESULT IN SLIGHT WEAKENING ON APPROACH
TO LANDFALL TO AN INTENSITY OF 75 KTS ON THE JTWC FORECAST. STEADY
WEAKENING WILL CONTINUE AS MUIFA TRACKS JUST INLAND OF THE CHINESE
COASTLINE ON A NORTHWESTWARD TRAJECTORY DICTATED BY AN UPPER-LEVEL
TROUGH OVER EASTERN CHINA AND A SUBTROPICAL RIDGE OVER MAINLAND
JAPAN. MAXIMUM WINDS MAY BE SLOW TO FALL BELOW WARNING CRITERIA,
HOWEVER, DUE TO THE LOW, FLAT TERRAIN IN THIS PART OF CHINA AND THE
FACT THAT THE EASTERN SEMICIRCLE WILL REMAIN MOSTLY OVER WATER.
GRADUAL DISSIPATION IS FORECAST BY 72 HOURS AS MUIFA IS STEERED
NORTHEASTWARD TOWARD THE VICINITY OF DALIAN, CHINA BY THE SOUTHERN
EDGE OF THE MID-LATITUDE JET STREAM. THE CURRENT JTWC TRACK
FORECAST IS SIGNIFICANTLY FASTER DURING THE 36-72 HOUR PERIOD DUE
TO A MARKED MULTI-RUN TREND IN GFS, ECMWF, AND ENSEMBLE GUIDANCE
TOWARD A FASTER FORWARD MOTION AROUND THE PERIPHERY OF THE
SUBTROPICAL RIDGE.
MODEL DISCUSSION: THE JTWC TRACK FORECAST FOLLOWS A BLEND OF THE
ECMWF AND GFS GLOBAL MODELS, AS WELL AS THE GEFS AND EPS ENSEMBLES.
THE INTENSITY FORECAST FOLLOWS CLOSE TO THE MULTI-MODEL CONSENSUS.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM//
NNNN
NNNN