WDPN31 PGTW 260900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (BUALOI) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.7N 120.6E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 116 NM SOUTH-SOUTHWEST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 23 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM 26W (BUALOI) EMERGING WITHIN THE SOUTH CHINA SEA WITH DEEP
CONVECTIVE BURSTS OBSCURING THE LOW-LEVEL CIRCULATION CENTER
(LLCC). SURFACE OBSERVATIONS FROM SAN JOSE REPORTED 35 KTS
SUSTAINED FROM THE WEST AT 0500Z WITH A PRESSURE OF 998 MB AS THE
CIRCULATION PASSED BY TO THE NORTH. ENVIRONMENTAL ANALYSIS
INDICATES THAT 26W IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY
MODERATE RADIAL OUTFLOW ALOFT, LOW TO MODERATE (15-20 KTS)
NORTHEASTERLY VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE
TEMPERATURES. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE
BASED ON THE ANIMATED MSI. THE INITIAL INTENSITY OF 60 KTS IS ALSO
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK FIXES
AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: 260149Z METOP-C ASCAT SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF THE SUBTROPICAL
RIDGED POSITIONED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   RJTD: T3.5 - 55 KTS
   RCTP: T4.5 - 77 KTS
   CIMSS SATCON: 56 KTS AT 260505Z
   CIMSS ADT: 63 KTS AT 260530Z
   CIMSS AIDT: 53 KTS AT 260530Z
   CIMSS D-MINT: 61 KTS AT 260505Z
   CIMSS D-PRINT: 47 KTS AT 260600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: 26W IS FORECAST TO TRACK WEST-NORTHWESTWARD
ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE THROUGH TAU
36. AFTER TAU 36, THE TRAJECTORY WILL TURN SLIGHTLY MORE
NORTHWESTWARD AS THE SYSTEM TRACKS ALONG THE SOUTHWESTERN EXTENT OF
THE RIDGE. THE LANDFALL LOCATION IN VIETNAM HAS BEEN SHIFTING
SOUTHWARD OVER THE PAST FEW MODEL RUNS. LANDFALL IS NOW FORECAST TO
OCCUR NEAR TAU 48, JUST NORTH OF HUE. THE ENVIRONMENT IS EXPECTED
TO BE CONDUCIVE FOR FURTHER DEVELOPMENT THROUGHOUT THE SOUTH CHINA
SEA WITH LOW VERTICAL WIND SHEAR AND WARM SEA SURFACE TEMPERATURES.
AS A RESULT, 26W IS FORECAST TO STEADILY INTENSIFY TO AROUND 80 KTS
BEFORE MAKING LANDFALL. RAPID DETERIORATION WILL THEN OCCUR AS THE
REMNANT VORTEX TRACKS INTO LAOS, WITH DISSIPATION NO LATER THAN TAU
96. 

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL
TRACK GUIDANCE IS IN VERY GOOD AGREEMENT WITH A 75 NM CROSS TRACK
SPREAD AT TAU 48, NEAR THE TIME OF LANDFALL. THE JTWC TRACK
FORECAST IS PLACED IN LINE WITH THE BULK OF GUIDANCE WITH HIGH
CONFIDENCE THROUGH TAU 72 AND MEDIUM CONFIDENCE THEREAFTER.
INTENSITY GUIDANCE AGREES ON INTENSIFICATION THROUGH TAU 48 WITH
PEAK INTENSITIES ALL AROUND 70-80 KTS. ALL MODELS THEN DEPICT RAPID
WEAKENING AFTER TAU 48. THE JTWC INTENSITY FORECAST IS PLACED CLOSE
TO THE MULTI-MODEL CONSENSUS WITH OVERALL MEDIUM CONFIDENCE. 

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