WDPN32 PGTW 210900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (LINGLING) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 31.7N 129.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 85 NM SOUTH OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERY
COMPACT TROPICAL STORM (TS) POSITIONED JUST OFFSHORE OF
SOUTHWESTERN KYUSHU. A COMPACT AREA OF DEEP CONVECTION, FORMING A
SMALL CENTRAL DENSE OVERCAST (CDO) IS LOCATED ON THE EASTERN SIDE
OF THE LOW LEVEL CIRCULATION CENTER (LLCC), AND PRIMARILY OVER
LAND, WHILE THE WESTERN SIDE OF THE CIRCULATION IS OBSCURED BY
CIRRUS. ANIMATED JMA RADAR DATA SHOWS A WELL-DEFINED RADAR EYE
FEATURE LOCATED JUST SOUTHEAST OF NAKA-KOSHIKI ISLAND. SUBSEQUENT
MSI-EIR COMPOSITES SHOW STRONG POCKETS OF CONVECTION FORMING ALONG
THE COASTLINE SOUTH OF ICHIKIKUSHIMA AND A POSSIBLE WARM SPOT IN
THE EIR JUST WEST OF THE HOT TOWERS. RADAR DATA SHOWS THE RADAR EYE
ALIGNING WELL WITH THIS WARM SPOT AND MAKING LANDFALL ALONG THE
COASTLINE DUE WEST OF KAGOSHIMA AS OF 210730Z. SURFACE OBSERVATIONS
FROM KAGOSHIMA ARE UP TO 32 KNOTS AND PRESSURES ARE FALLING RAPIDLY
AS THE CENTER OF TS 18W APPROACHES. THE INITIAL POSITION IS
ASSESSED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE RADAR
DATA. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON AN AVERAGE OF THE SUBJECTIVE AND OBJECTIVE INTENSITY
ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS ARE MARGINAL, WITH
LOW TO MODERATE NORTHEASTERLY SHEAR, WARM SSTS AND MODERATE
POLEWARD OUTFLOW. HOWEVER, THE PROXIMITY OF THE SYSTEM TO LAND WILL
HINDER ANY FURTHER DEVELOPMENT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) POSITIONED TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 48 KTS AT 210600Z
   CIMSS ADT: 45 KTS AT 210540Z
   CIMSS AIDT: 46 KTS AT 210540Z
   CIMSS D-PRINT: 48 KTS AT 210600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: PROXIMITY TO LAND

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: TS 18W IS FORECAST TO TRACK SOUTHEASTWARD OVER
THE NEXT FEW HOURS, PASSING VERY CLOSE TO OR DIRECTLY OVER
KAGOSHIMA BEFORE TURNING EAST AND PASSING THE FAR NORTHERN PORTION
OF KAGOSHIMA BAY. TS 18W WILL QUICKLY WEAKEN AFTER LANDFALL AS IT
PASSES OVER KYUSHU. THE SYSTEM THEN TURNS NORTHEASTWARD, EMERGING
BACK OVER WATER NEAR MIYAZAKI WITHIN THE NEXT 12 TO 18 HOURS. TS
18W IS THEN FORECAST TO CONTINUE TRACKING NORTHEASTWARD ALONG THE
COAST OF SHIKOKU, ALONG THE NORTHERN SIDE OF THE RIDGE TO THE
SOUTH. THE SYSTEM IS EXPECTED TO EMERGE BACK OVER WATER AS A VERY
WEAK TROPICAL STORM AND STRONG TROPICAL DEPRESSION. HOWEVER, AROUND
THE SAME TIME AS THE SYSTEM MOVES OVER WATER, IT WILL RUN INTO VERY
STRONG NORTHEASTERLY FLOW ALOFT, WITH SHEAR EXPECTED TO RAPIDLY
INCREASE TO NEAR 45 KNOTS BY TAU 24. THE EXTREMELY HIGH SHEAR
VALUES, ALONG WITH AN INFLUX OF DRY AIR WILL EFFECTIVELY SHRED TS
18W IN SHORT ORDER. THE REMNANT VORTEX WILL SLOWLY SPIN DOWN AND
DISSIPATE BELOW WARNING CRITERIA NO LATER THAN TAU 48. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT
THROUGH THE FORECAST PERIOD, WITH MINIMAL CROSS-TRACK UNCERTAINTY
UNTIL TAU 36 WHEN THE MODELS BEGIN TO DIVERGE A BIT AS THEY START
TO LOSE TRACK OF THE VORTEX. THE JTWC FORECAST IS POSITIONED CLOSE
TO THE MULTI-MODEL CONSENSUS MEAN WITH HIGH CONFIDENCE. INTENSITY
GUIDANCE IS ALSO IN GOOD AGREEMENT ON THE OVERALL SCENARIO, THOUGH
THE HAFS-A AND HWRF WEAKEN THE SYSTEM AT A MUCH SLOWER RATE,
KEEPING IT ABOVE WARNING CRITERIA THROUGH AT LEAST FOUR DAYS. THE
COAMPS-TC (BOTH GFS AND NAVGEM VERSIONS) AND THE GFS DETERMINISTIC
TRACKER SHOW A MORE REALISTIC INTENSITY TREND AND THE JTWC FORECAST
IS PLACED NEAR THESE MODELS THROUGH THE FORECAST PERIOD WITH HIGH
CONFIDENCE. 

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