WDPN32 PGTW 290900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 34W (THIRTYFOUR) 
WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 4.8N 106.8E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 360 NM SOUTH OF HO CHI MINH CITY, VIETNAM
   MOVEMENT PAST 6 HOURS: EASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
DEPRESSION 34W WITH DISORGANIZED FLARING CONVECTION OVER A
PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). A 290615Z
AMSR2 89 GHZ MICROWAVE IMAGE REVEALED DEFINED LOW-LEVEL CLOUD LINES
WRAPPING INTO THE ASSESSED CENTER. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE AMSR2 MICROWAVE IMAGE. THE
INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AGENCY DVORAK FIXES AND CIMSS OBJECTIVE INTENSITY
ESTIMATES LISTED BELOW. ENVIRONMENTAL ANALYSIS INDICATES THAT 34W
IS IN A MARGINAL ENVIRONMENT CHARACTERIZED BY WEAK OUTFLOW ALOFT,
MODERATE (15-20 KTS) EASTERLY VERTICAL WIND SHEAR, AND WARM (28-29C) 
SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE (NER) CENTERED OVER BORNEO. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   DEMS: T2.5 - 35 KTS
   CIMSS ADT: 39 KTS AT 290600Z
   CIMSS AIDT: 31 KTS AT 290600Z
   CIMSS D-MINT: 25 KTS AT 290615Z
   CIMSS D-PRINT: 25 KTS AT 290600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: 34W IS FORECAST TO TRACK NORTHEASTWARD, ALONG
THE NORTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE POSITIONED OVER
BORNEO THROUGHOUT THE FORECAST PERIOD. 34W IS FORECAST TO MAINTAIN
INTENSITY OVER THE NEXT 12 HOURS AS THE SYSTEM FIGHTS OFF DRY AIR
FROM THE WEST. AFTER TAU 12, DRY AIR IS EXPECTED TO ENTRAIN INTO
THE CORE OF THE VORTEX, CAUSING 34W TO SHALLOW AND WEAKEN.
DISSIPATION IS FORECAST TO OCCUR NO LATER THAN TAU 36. THE COMPACT
NATURE OF 34W MAKES IT MORE SUSCEPTIBLE TO CHANGES IN THE
ENVIRONMENT, POTENTIALLY ALLOWING FOR AN EVEN EARLIER DISSIPATION. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN MODERATE
AGREEMENT WITH ALL MODELS DEPICTING A NORTHEASTWARD TRACK. HOWEVER,
THERE IS A 120 NM CROSS-TRACK SPREAD AT TAU 36, PRIMARILY CAUSED BY
GALWEM, WHICH TURNS THE VORTEX NORTHWARD AFTER TAU 24. THE JTWC
TRACK FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH
MEDIUM CONFIDENCE. INTENSITY GUIDANCE AGREES ON WEAKENING AFTER TAU
12, BUT WITH SOME MODELS DISSIPATING THE SYSTEM CLOSER TO TAU 24
VICE 36. THE JTWC INTENSITY FORECAST IS ALSO PLACED CLOSE TO THE
CONSENSUS WITH MEDIUM CONFIDENCE. 

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