WDPN33 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (TORAJI) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.7N 130.3E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 540 NM EAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 26W IS UNDERGOING RAPID INTENSIFICATION (RI)
OVER THE PAST 18 HOURS INCREASING FROM ABOUT 20 KNOTS AT 081800Z TO
THE INITIAL INTENSITY OF 55 KNOTS AT 091200Z. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY DEPICTS A SMALL SYSTEM WITH AN
OBLONG, COMPACT CENTRAL DENSE OVERCAST FEATURE, APPROXIMATELY
70-80NM DIAMETER. A 090933Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS A
COMPLETE EYEWALL SURROUNDING A SMALL MICROWAVE EYE FEATURE AND A
PRIMARY DEEP CONVECTIVE BAND OVER THE SOUTHERN QUADRANT. THE
OVERALL CONVECTIVE STRUCTURE IS IMPRESSIVE WITH ROBUST RADIAL
OUTFLOW EVIDENT IN ANIMATED WATER VAPOR IMAGERY. IN GENERAL, THE
INITIAL PRESENCE OF A MICROWAVE EYE FEATURE TYPICALLY INDICATES A
50-55 KNOT SYSTEM. DUE TO THE RI, AGENCY DVORAK ESTIMATES LAGGED A
BIT DUE TO CONSTRAINTS BUT ARE NOW CATCHING UP, WITH BOTH RCTP AND
KNES NOW AT T3.5 (55 KNOTS). CIMSS ADT AND AIDT OBJECTIVE INTENSITY
ESTIMATES ARE ALSO TOO LOW HOWEVER, THE ADT ADJUSTED-T ESTIMATE HAS
INCREASED TO 3.0 (45 KNOTS) AT 091400Z WITH A RAW-T ESTIMATE OF 3.5
(55 KNOTS). THE LATEST CIMSS D-MINT AND D-PRINT ESTIMATES JUMPED
QUICKLY TO 67 KNOTS AND 63 KNOTS, RESPECTIVELY. CONSEQUENTLY, THERE
IS SIGNIFICANT UNCERTAINTY IN THE INITIAL INTENSITY WITH A WIDE
RANGE OF SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 32 KTS AT 091140Z
   CIMSS AIDT: 31 KTS AT 091140Z
   CIMSS D-MINT: 67 KTS AT 090940Z
   CIMSS D-PRINT: 63 KTS AT 091230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE PEAK INTENSITY HAS BEEN INCREASED
FROM 60 KNOTS TO 90 KNOTS BASED ON THE CURRENT RI EVENT AND IMPROVED
ORGANIZATION EVIDENT IN MICROWAVE IMAGERY.

FORECAST DISCUSSION: TS 26W IS FORECAST TO TRACK WESTWARD TO WEST-
NORTHWESTWARD THROUGH TAU 48, WITH LANDFALL ANTICIPATED NEAR TAU 42. 
DUE TO THE HIGHLY FAVORABLE ENVIRONMENT AND RAPIDLY IMPROVING 
CONVECTIVE ORGANIZATION, THE SYSTEM WILL LIKELY REACH TYPHOON 
STRENGTH QUICKLY AND CONTINUE TO INTENSIFY AT A FASTER-THAN-
CLIMATOLOGICAL RATE, REACHING A PEAK OF 90 KNOTS BY TAU 36. THE 
LATEST HAFS-A RUN INDICATES RAPID CONSOLIDATION WITH A PEAK INTENSITY 
OF 75-80 KNOTS AT TAU 36. UNFORTUNATELY, RI GUIDANCE IS VERY LIMITED 
AT THIS TIME. AFTER CROSSING LUZON AND WEAKENING, THE SYSTEM SHOULD 
TRACK WEST-NORTHWESTWARD TO NORTHWESTWARD ALONG THE SOUTHWEST 
PERIPHERY OF THE STR, WITH STEADY WEAKENING DUE TO INCREASING VWS AND 
DRY AIR ENTRAINMENT. 

MODEL DISCUSSION: THE 090600Z ECMWF ENSEMBLE (EPS) INDICATES A FAIRLY 
TIGHT CLUSTER OF SOLUTIONS THROUGH TAU 72, WITH LANDFALL LIKELY OVER 
THE CENTRAL TO NORTHEAST COAST OF LUZON. AFTER TAU 72, THE ECMWF 
ENSEMBLE DIVERGES WITH INCREASING UNCERTAINTY AFTER TAU 72. THE 
090600Z GFS ENSEMBLE (GEFS) SHOWS A SIMILAR PLUME OF SOLUTIONS. THE 
PRIMARY SOURCE OF THE LARGE SPREAD AND INCREASING UNCERTAINTY AFTER 
TAU 72 IS DUE TO UNCERTAINTY IN THE SYSTEM'S INTENSITY AND 
UNCERTAINTY IN THE DEGREE OF WEAKENING OF THE STR OVER SOUTHEAST 
CHINA. IF THE SYSTEM IS STRONGER THAN EXPECTED, IT MAY TRACK MORE 
NORTHWESTWARD TOWARD THE HONG KONG REGION AND IF IT WEAKENS 
SIGNIFICANTLY, IT MAY STALL AND TURN EQUATORWARD UNDER THE LOW-LEVEL 
STEERING FLOW.     

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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