Tropical Storm RAI Advisory jue, 16-12

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (RAI) WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 9.1N 131.0E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 333 NM EAST-NORTHEAST OF DAVAO,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
CONSOLIDATING SYSTEM CHARACTERIZED BY A DEEPER AND MORE SYMMETRICAL
CENTRAL CONVECTION WITH A DIMPLE FEATURE, INDICATIVE OF A FORMATIVE
EYE. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON
A 150417Z AMSR2 MICROWAVE EYE THAT LINED UP WELL WITH THE DIMPLE
FEATURE IN THE MSI LOOP. THE INITIAL INTENSITY OF 70KTS IS BASED ON
AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND
REFLECTS THE IMPROVED STATE OF THE SYSTEM. TY 28W IS IN A FAVORABLE
ENVIRONMENT WITH LOW VWS, VERY WARM SST IN THE PHILIPPINE SEA, AND
STRONG POLEWARD AND EQUATORWARD OUTFLOW. THE CYCLONE IS TRACKING
ALONG THE SOUTHERN PERIPHERY OF THE STR TO THE NORTH.
INITIAL WIND RADII BASIS: RECENT SCATTEROMETER DATA.
CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTH.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T4.0 - 65 KTS
   RJTD: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 80 KTS AT 150432Z
   CIMSS ADT: 82 KTS AT 150540Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 RAI WILL CONTINUE ON ITS WESTWARD
TRACK, MAKING LANDFALL OVER SURIGAO, PHILIPPINES BY TAU 24 THEN
TRACK ACROSS THE PHILIPPINE ARCHIPELAGO. AFTER TAU 48, THE SYSTEM
WILL ENTER THE SOUTH CHINA SEA (SCS) AND TURN MORE NORTHWESTWARD
THEN NORTHWARD AS IT ROUNDS THE WESTERN EDGE OF THE STR. THE
FAVORABLE ENVIRONMENT WILL FUEL STEADY INTENSIFICATION TO 90KTS JUST
BEFORE LANDFALL. AFTERWARD, INTERACTION WITH THE ISLANDS WILL REDUCE
IT TO 80KTS BY TAU 36. AFTER IT DRIFTS INTO THE OPEN WARM WATERS OF
THE SCS, AIDED BY INCREASED POLEWARD OUTFLOW, A SECONDARY
INTENSIFICATION TO A PEAK OF 95KTS BY TAU 72 WILL OCCUR. AFTER TAU
72, INCREASING VWS AND EXPOSURE TO THE DRY NORTHEAST SURGE IN THE
SCS WILL GRADUALLY WEAKEN THE SYSTEM DOWN TO 60KTS BY TAU 120 AS IT
HEADS TOWARD HAINAN.
MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT,
HOWEVER, DUE TO THE VARIABILITY OF LAND INTERACTION, THERE IS ONLY
MEDIUM CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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