WDPN31 PGTW 252100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (BUALOI) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.1N 125.5E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 302 NM EAST-SOUTHEAST OF MANILA,
   PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE
CENTRAL DENSE OVERCAST (CDO) OBSCURING THE LOW-LEVEL CIRCULATION
CENTER (LLCC). A 251930Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS WEAK
CONVECTIVE BANDING WRAPPING INTO THE LLCC, WHICH APPEARS TO BE NEAR
OR OVER SAMAR ISLAND. SURFACE OBSERVATIONS FROM CATARMAN (98546),
WHICH SHOWS NORTHEASTERLY WINDS AT 16 KNOTS, AND BORONGAN (98553),
WHICH SHOWS SOUTHWESTERLY WINDS AT 12 KNOTS, SUPPORT THE INITIAL
POSITION OVER NORTHEAST SAMAR ISLAND. MINIMUM SLP REPORTED IS NEAR 
995MB AT CATARMAN ON THE NORTHERN SIDE OF THE ISLAND. THE INITIAL 
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE AFOREMENTIONED 
DATA. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE LOWER RANGE OF AGENCY DVORAK ESTIMATES, WHICH 
IS MORE CONSISTENT WITH THE CONVECTIVE STRUCTURE AND SURFACE 
OBSERVATIONS. CIMSS OBJECTIVE ESTIMATES RANGE FROM 57 TO 69 KNOTS.

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: T4.0 - 65 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T3.5 - 55 KTS
   CIMSS SATCON: 58 KTS AT 251706Z
   CIMSS ADT: 63 KTS AT 251740Z
   CIMSS AIDT: 57 KTS AT 251740Z
   CIMSS D-PRINT: 69 KTS AT 251830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE 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: TROPICAL STORM (TS) 26W WILL TRACK WEST-
NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR THROUGH TAU 72. 
TS 26W WILL WEAKEN SLIGHTLY AS IT TRACKS ACROSS THE CENTRAL 
PHILIPPINE ISLANDS. AFTER EMERGING BACK OVER WATER NEAR TAU 18, TS
26W IS FORECAST TO GRADUALLY INTENSIFY TO TYPHOON STRENGTH BY TAU 48 
TO TAU 60. AFTER TAU 48, THE SYSTEM WILL TURN MORE NORTHWESTWARD AS 
IT TRACKS ALONG THE SOUTHWESTERN PERIPHERY OF THE STR, WITH LANDFALL 
OVER NORTHERN VIETNAM EXPECTED BY ABOUT TAU 72. TS 26W WILL DISSIPATE 
QUICKLY AS IT TRACKS INLAND OVER NORTHERN VIETNAM. 

MODEL DISCUSSION: WITH THE EXCEPTION OF JGSM, WHICH CONTINUES TO
STRUGGLE, THE DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT SUPPORTING 
THE JTWC FORECAST TRACK WITH MEDIUM CONFIDENCE. RELIABLE INTENSITY 
GUIDANCE SUPPORTS THE REINTENSIFICATION PHASE OVER THE SOUTH CHINA 
SEA, WITH A LARGE SPREAD IN PEAK INTENSITY VALUES. HAFS-A INDICATES A 
MODEST PEAK INTENSITY OF 62 KNOTS AT TAU 60. COAMPS-TC (GFS) 
INDICATES A PEAK INTENSITY OF 87 KNOTS.  

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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