Tropical Storm HINNAMNOR Advisory Fr, 02.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (HINNAMNOR) WARNING NR
020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 21.5N 125.4E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 328 NM SOUTH-SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 01 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN ERODING
SYSTEM WITH DEEP CONVECTION OVER THE SOUTHERN SEMICIRCLE AND
EVIDENCE OF UPPER LEVEL CONVERGE CREATING PRESSURE OVER THE
NORTHERN SEMI-CIRCLE. THE CENTRAL CONVECTION CONTINUES TO SHOW
SIGNS OF DECAY DUE TO THE UPWELLING CREATED BY THE QUASI-STATIONARY
POSTURE OF TY 12W OVER THE PAST 12 HOURS. IN ADDITION, THE SYSTEM
HAS AN EYE THAT HAS BECOME FULLY EMBEDDED UNDER THE CONVECTIVE
PLUME OVER THE CENTER OF THE LOW LEVEL CIRCULATION CENTER (LLCC). A
012244Z SSMIS COMPOSITE 37 PASS SHOWS THE CONVECTIVE BANDS ARE IN
UNIFORM SHAPE AS THEY CIRCLE THE LLCC WITH THE HEAVIEST CONVECTIVE
ACTIVITY IN THE SOUTHEASTERN SEMICIRCLE DUE THE STRONG EQUATORWARD
OUTFLOW ALOFT AND THE PRESENCE OF THE WARMEST SEA SURFACE
TEMPERATURES NEAR THE SYSTEM.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: QUASI-STATIONARY DUE TO BEING NESTED
BETWEEN THE AFOREMENTIONED RIDGE TO THE NORTHWEST, THE SUBTROPICAL
RIDGE TO THE EAST-NORTHEAST, AND THE NEAR EQUATORIAL RIDGE TO THE
SOUTH.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T5.5 - 102 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 78 KTS AT 012245Z
   CIMSS ADT: 97 KTS AT 012040Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: UPWELLING COOLER WATER
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: TY HINNAMNOR WILL REMAIN SOMEWHAT
QUASI-STATIONARY OVER THE NEXT 24 HOURS. AS A RESULT, THE SEA
SURFACE TEMPERATURE WILL CONTINUE TO COOL DUE TO IMMENSE
UPWELLING AND DECREASE THE OVERALL INTENSITY OF THE SYSTEM TO 90
KTS BY TAU 12 AND WILL REMAIN THIS INTENSITY THROUGH TAU 36. AS TAU
36 APPROACHES, TY 12W WILL BE PICKING UP TRACK SPEED AND TRANSITING
NORTHWARD DUE TO THE WEAKENING OF THE SUBTROPICAL RIDGE. AT THE
SAME TIME, TY 12W WILL SLOWLY INCREASE IN INTENSITY TO 95 KTS DUE
TO THE ENVIRONMENT BECOMING FAVORABLE CHARACTERIZED BY GOOD OUTFLOW
ALOFT AND VERY WARM (29-30C) SSTS. BY TAU 72, TY 12W WILL ROUND THE
RIDGE AXIS AND MAKE THE A NORTHEASTWARD TURN REACHING ITS MAX
INTENSITY OF 115 KTS. SOME ENSEMBLE TRACKERS HAVE TY 12W ON A MORE
WESTERLY TRACK WHICH COULD BE A LIMITING FACTOR OF THIS MAX
INTENSITY DUE TO COOLER WATERS OFF THE EAST COAST OF CHINA. BY TAU
96, TY 12W WILL BEGIN ITS EXTRA-TROPICAL TRANSITION, AS WELL AS
SHOW SIGNS DETERIORATION DUE TO LAND INTERACTION AND COOLER SSTS AS
IT APPROACHES THE SOUTHERN COAST OF KOREA, DECREASING IN INTENSITY
TO 95 KTS. BY TAU 120, TY 12W WILL BECOME FULLY EXTRA-TROPICAL OVER
THE SEA OF JAPAN WITH AN OVERALL INTENSITY OF 65 KTS.
MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT IN THE FIRST 72 HOURS, HOWEVER, THE ENVELOPE WILL WIDEN
AFTER TAU 72 WITH A 150NM SPREAD AT TAU 96. THIS SPREAD GRADUALLY
INCREASES TO 270NM BY TAU 120 WHICH IS MUCH WIDER THAN THE PREVIOUS
MODEL RUN. IN ADDITION, UNCERTAINTY REMAINS AMONG THE MODEL MEMBERS
WITH TRACK SPEED AFTER TAU 72. THIS, IN ADDITION TO THE WIDER
SPREAD, LENDS LOW CONFIDENCE AFTER TAU 72. THERE IS MEDIUM
CONFIDENCE IN THE JTWC INTENSITY FORECAST THROUGH TAU 72 AS THE
LARGE SPREAD IN INTENSITY GUIDANCE REMAINS AS IT DID ON THE
PREVIOUS MODEL RUN. AFTER TAU 72, THE CONFIDENCE REMAINS LOW DUE TO
THE TIMING OF EXTRA-TROPICAL TRANSITION, THE INFLUENCE OF THE
COOLER SSTS AND LAND INTERACTION AS IT PASSES SOUTHEAST OF THE
KOREAN PENINSULA.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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