WDPN31 PGTW 230900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MA-ON)       
WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.7N 121.7E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 190 NM NORTH-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 10W MADE LANDFALL ALONG THE NORTHEAST COAST OF
LUZON AT APPROXIMATELY 230200Z WITH AN INCIPIENT EYE. SINCE MAKING
LANDFALL, ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS
GRADUAL WEAKENING OF THE CONVECTIVE STRUCTURE WITH WARMING CLOUD
TOPS. A 230542Z AMSR2 89GHZ COLOR COMPOSITE MICROWAVE IMAGE
REFLECTS THIS WEAKENING TREND BUT INDICATES THE SYSTEM HAS RETAINED
A COMPACT, ORGANIZED CORE WITH A SMALL MICROWAVE EYE FEATURE ON THE
NORTHERN EDGE OF THE CORE CONVECTION. THE AMSR2 IMAGE AS WELL
SURFACE OBSERVATIONS FROM APARRI (18.4N 121.6E), SHOWING
NORTHEASTERLY WINDS AS HIGH AS 27 KNOTS, AND TUGUEGARAO (17.6N
121.7E), SHOWING SOUTHWESTERLY WINDS AT 23 KNOTS, SUPPORT THE
INITIAL POSITION WITH HIGH CONFIDENCE. SURFACE WINDS AT TUGUEGARAO
HAVE NOW SHIFTED SOUTHERLY AS THE SYSTEM CENTER TRACKED TO THE
NORTHWEST PAST THE SITE. UPPER-LEVEL CONDITIONS REMAIN FAVORABLE
WITH STRONG EQUATORWARD OUTFLOW AND WEAK POLEWARD OUTFLOW OFFSET BY
MODERATE EASTERLY VERTICAL WIND SHEAR. OBVIOUSLY, INTERACTION WITH
THE MOUNTAINOUS TERRAIN OF LUZON WILL HINDER DEVELOPMENT IN THE
NEAR-TERM. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE RJTD DVORAK ESTIMATE, WHICH IS CONSISTENT
WITH THE MICROWAVE EYE FEATURE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   RJTD: T3.5 - 55 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: INTERACTION WITH LAND

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 10W IS FORECAST TO TRACK WEST-NORTHWESTWARD
THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE STR, WHICH IS
EXPECTED TO REMAIN ENTRENCHED OVER CENTRAL CHINA. AFTER TAU 72, THE
SYSTEM WILL TURN WESTWARD AS IT TRACKS FURTHER INLAND. AFTER 
TRAVERSING LUZON OVER THE NEXT SIX TO TWELVE HOURS AND WEAKENING, TS 
10W SHOULD RAPIDLY RE-CONSOLIDATE DUE TO FAVORABLE UPPER-LEVEL 
CONDITIONS, WARM (29-30C) SST VALUES AND HIGH OCEAN HEAT CONTENT. A 
PEAK INTENSITY OF 75 KNOTS IS EXPECTED BY TAU 36 WITH RAPID WEAKENING 
AFTER TAU 48 WITH LANDFALL EXPECTED WEST OF HONG KONG. TS 10W WILL 
DISSIPATE OVERLAND BY TAU 96.     

MODEL DISCUSSION: THERE HAVE BEEN NO SIGNIFICANT CHANGES TO THE
JTWC TRACK AND INTENSITY FORECASTS, AND THE LATEST JTWC TRACK
FORECAST REMAINS HIGHLY CONSISTENT WITH THE PREVIOUS JTWC TRACK
FORECAST. NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT WITH A
80-100 NM SPREAD IN THE MULTI-MODEL SOLUTIONS FROM TAU 36 TO TAU 48. 
THERE IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST WITH HWRF 
AND COAMPS-TC INDICATING A PEAK INTENSITY RANGING FROM 70-75 KNOTS. 
THE 230000Z COAMPS INTENSITY ENSEMBLE INDICATES A 20 PERCENT 
PROBABILITY OF RAPID INTENSIFICATION, THEREFORE, A HIGHER PEAK 
INTENSITY IS POSSIBLE. HOWEVER, VWS IS EXPECTED TO GRADUALLY INCREASE 
WHICH SHOULD SLOW DEVELOPMENT.       

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: HIGH//
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