WDPN31 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (BUALOI) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.0N 108.1E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 61 NM NORTH OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDS
OF DEEP CONVECTION TIGHTLY WRAPPING INTO A FULLY OBSCURED LOW-LEVEL
CIRCULATION CENTER (LLCC) OF TYPHOON (TY) 26W (BUALOI). THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE, WITH THE ASSISTANCE OF
RADAR DATA, AGENCY FIXES AND COASTAL SURFACE PRESSURE OBSERVATIONS
ALONG THE VIETNAMESE COAST. THE INITIAL INTENSITY OF 70 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON CONSISTENT AGENCY DVORAK
FIXES LISTED BELOW. OBJECTIVE INTENSITY AIDS PRESENT AN ASSESSMENT
RANGING FROM 59 TO 80 KTS, SLIGHTLY INCREASING EVALUATION 
UNCERTAINTY. ENVIRONMENTAL ANALYSIS REVEALS RELATIVELY FAVORABLE 
CONDITIONS, WITH LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS), WARM (28-
29 C) SEA SURFACE TEMPERATURES (SST) AND GOOD EQUATORWARD OUTFLOW. AS 
THE SYSTEM IS CURRENTLY ASSESSED TO BE CENTERED WITHIN APPROXIMATELY 
35 NM FROM THE COASTLINE, THE LAND INTERACTION IS BEGINNING TO SLOW 
DOWN INTENSIFICATION.

INITIAL WIND RADII BASIS: A 280247Z METOP-C ASCAT PASS

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST, EXTENDING TO THE SOUTH, OVER THE PHILIPPINES

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.0 - 65 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 80 KTS AT 280610Z
   CIMSS ADT: 59 KTS AT 280530Z
   CIMSS AIDT: 66 KTS AT 280530Z
   CIMSS D-MINT: 79 KTS AT 280610Z
   CIMSS D-PRINT: 74 KTS AT 280600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: BEGINNING OF LAND INTERACTION

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: TY 26W IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER STR.
LANDFALL IS EXPECTED TO OCCUR BEFORE TAU 12 LIKELY NEAR THE GIANH
RIVER DELTA. UNTIL THEN, TY BUALOI CAN UTILIZE THE FAVORABLE
ENVIRONMENT TO BRIEFLY INTENSIFY. CURRENT FORECAST TIMELINE DOES
NOT FULLY CAPTURE THE POSSIBILITY OF THE SYSTEM REACHING A PEAK OF
75-80 KTS, JUST PRIOR TO LANDFALL. AT TAU 12, TY 26W IS FORECAST TO
WEAKEN TO 60 KTS DUE TO FRICTIONAL EFFECTS OF LAND INTERACTION,
WHICH WILL ONLY AMPLIFY AS THE LLCC TRACKS ACROSS THE MOUNTAINOUS
TERRAIN FURTHER INLAND. FULL DISSIPATION IS EXPECTED TO OCCUR NO
LATER THAN TAU 36.

MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS IN GOOD
AGREEMENT THROUGHOUT THE FORECAST PERIOD AND THE OFFICIAL JTWC
PREDICTION IS ASSESSED WITH HIGH CONFIDENCE. INTENSITY ON THE OTHER
HAND IS PLACED WITH MEDIUM CONFIDENCE DUE TO A POTENTIAL FOR A
SHORT-LIVED INTENSIFICATION JUST PRIOR TO LANDFALL. OTHERWISE, ALL
AVAILABLE GUIDANCE SUGGESTS AN IMMEDIATE WEAKENING TREND, WITH
MAJORITY OF THE MODELS PREDICTING FULL DISSIPATION AT OR AROUND TAU
36.

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