WDPN31 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (BUALOI) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.4N 109.4E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 68 NM EAST-NORTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT
AND STILL ASYMMETRICAL CLOUD SHIELD, WITH DEEP CONVECTION ARRAYED
IN AN ARC EXTENDING FROM THE SOUTHEAST TO THE NORTHWEST OF THE
ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). POCKETS OF
DISORGANIZED CONVECTION ARE COALESCING INTO SPIRAL RAIN BANDS ALONG
THE COAST TO THE SOUTH OF THE LLCC AND MERGING WRAPPING INTO THE
CENTER. RADAR DATA FROM VIETNAM SHOWS A DEFINED, BUT STILL SOMEWHAT
RAGGED, RADAR EYE FEATURE, WITH WELL-DEFINED SPIRAL BANDS OF DEEP
CONVECTION ARRAYED ACROSS THE NORTHERN PERIPHERY. THE INITIAL
POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE RADAR EYE,
AND A TIGHT GROUPING OF AGENCY FIX POSITIONS. THE INITIAL INTENSITY
IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON A BLEND OF THE HIGHER
END AGENCY DVORAK CURRENT INTENSITY ESTIMATES AND THE SOMEWHAT
LOWER OBJECTIVE ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS
REMAIN FAVORABLE, WITH LOW VERTICAL WIND SHEAR (VWS), WARM SSTS AND
ROBUST EQUATORWARD OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED NEAR TAIWAN. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T5.0 - 90 KTS
   CIMSS ADT: 61 KTS AT 272030Z
   CIMSS AIDT: 65 KTS AT 272030Z
   CIMSS D-PRINT: 73 KTS AT 280000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS	
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 (TY) 26W CONTINUES TO TRACK NORTHWEST
ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP STR CENTERED NEAR
TAIWAN. NO SIGNIFICANT CHANGES ARE EXPECTED TO THE STEERING
SCENARIO AND TY 26W WILL CONTINUE TO TRACK NORTHWESTWARD THROUGH
THE ENTIRETY OF THE FORECAST PERIOD. THE SYSTEM IS EXPECTED TO MAKE
LANDFALL TO THE NORTH OF DONG HAI, VIETNAM WITHIN THE NEXT 12 TO 18
HOURS. ENVIRONMENTAL CONDITIONS ARE FORECAST TO STEADILY IMPROVE
OVER THE NEXT 12 HOURS, WITH SHEAR IN PARTICULAR FORECAST TO DROP
OFF SIGNIFICANTLY IN THE NEAR-TERM. TY 26W WILL TAKE ADVANTAGE OF
THESE IMPROVED CONDITIONS AND IS EXPECTED TO CONTINUE TO INTENSIFY
UP THROUGH LANDFALL, REACHING A PEAK INTENSITY OF 80 KNOTS JUST
PRIOR TO MOVING ASHORE. ONCE THE SYSTEM IS OVER LAND, IT WILL
CONTINUE TO TRACK NORTHWESTWARD WHILE RAPIDLY WEAKENING DUE TO TERRAIN
INDUCED FRICTIONAL EFFECTS, DISSIPATING OVER FAR NORTHERN LAOS OR
NORTHEASTERN MYANMAR NO LATER THAN TAU 48.  

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN STRONG
AGREEMENT, WITH LITTLE IN THE WAY OF CROSS- OR ALONG-TRACK SPREAD
THROUGH THE FIRST 24 HOURS OF THE FORECAST, AND INCREASING
DISPERSION THEREAFTER AS THE MODELS LOSE TRACK OF THE VORTEX. THE
JTWC FORECAST IS POSITIONED CLOSE TO THE CONSENSUS MEAN THROUGHOUT
THE FORECAST PERIOD, WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS
MUCH LESS AGGRESSIVE THAN THE PREVIOUS RUNS, AND NOW SHOWS LITTLE
IN THE WAY OF INTENSIFICATION PRIOR TO LANDFALL. THE JTWC FORECAST
IS PLACED ABOUT 5 TO 10 KNOTS HIGHER THAN THE CONSENSUS MEAN
THROUGH TAU 12, BUT THEN REJOINS THE MEAN THROUGH THE REMAINDER OF THE
FORECAST. 

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