WDPN32 PGTW 290300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 34W (THIRTYFOUR) 
WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 5.0N 105.9E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 351 NM SOUTH OF HO CHI MINH CITY, VIETNAM
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A SLOPPY AND
DISORGANIZED TROPICAL DEPRESSION, WITH CIRRUS OUTFLOW ASSOCIATED
WITH PATCHY DEEP CONVECTION OBSCURING THE LOWER-LEVEL STRUCTURE OF
THE SYSTEM. MOST OF THE CONVECTIVE ACTIVITY IS FOCUSED ON THE
NORTHWESTERN SIDE OF THE CIRCULATION, ALONG THE DOWNSHEAR VECTOR
BASED ON THE MOST RECENT CIMSS SHEAR ESTIMATE. A 282238Z SSMIS
37GHZ MICROWAVE IMAGE SHOWS A FISHHOOK TYPE FEATURE, WITH SHALLOW
CURVED BANDING ALONG THE EASTERN HALF OF THE SYSTEM AND MORE
DEFINED BANDING FEATURES ALONG THE NORTHWESTERN SIDE, WRAPPING INTO
A WEAKLY DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL
POSITION IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PGTW
POSITION AND MICROWAVE FIXES AND ANALYSIS OF THE MICROWAVE IMAGE
NOTED ABOVE. THE INITIAL INTENSITY REMAINS SET AT 30 KNOTS WITH
HIGH CONFIDENCE BASED ON A BLEND OF THE SUBJECTIVE AND OBJECTIVE
INTENSITY ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS ARE
MARGINAL, WITH LOW TO MODERATE EASTERLY SHEAR, MODERATE POLEWARD
OUTFLOW AND WARM SSTS. THE INNER CORE OF TD 34W IS QUITE SMALL AND
SMALL CHANGES IN THE ENVIRONMENT MAY RESULT IN SIGNIFICANT IMPACTS
ON THE SYSTEM.

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

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF THE LOW- TO
MID-LEVELS OF A DEEP-LAYER NEAR EQUATORIAL RIDGE (NER) DEVELOPING
OVER BORNEO. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 33 KTS AT 290020Z
   CIMSS AIDT: 30 KTS AT 290020Z
   CIMSS D-MINT: 31 KTS AT 282238Z
   CIMSS D-PRINT: 31 KTS AT 290020Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   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: OVER THE NEXT 12 HOURS, THE RIDGE CURRENTLY
OVER NORTHEASTERN BORNEO IS FORECAST TO MOVE SOUTHWESTWARD AND
STRENGTHEN SIGNIFICANTLY, ENHANCING THE LOW-LEVEL STEERING GRADIENT
ON THE EASTERN FLANK OF TS 34W, ENTICING IT TO ACCELERATE TOWARDS
THE NORTHEAST. THE SYSTEM SLOWS SLIGHTLY BY THE END OF THE FORECAST
PERIOD AS THE NER SLIDES SOUTHWESTWARD AND THE GRADIENT FLOW
SLACKENS. BEING VERY COMPACT, TD 34W WILL BE SUBJECT TO RAPID
INTENSITY CHANGES GOING FORWARD. IN THE SHORT-TERM, THE SYSTEM IS
LIKELY TO INTENSIFY SLIGHTLY AS POLEWARD OUTFLOW IS EXPECTED TO
INCREASE A NOTCH OVER THE NEXT 12 HOURS OR SO. BUT THE WINDOW OF
OPPORTUNITY IS SMALL AND A RAPID UPTICK IN EASTERLY SHEAR AND AN
INFLUX OF DRY AIR ARE EXPECTED TO IMPACT THE SYSTEM BEGINNING AT
TAU 24, WHICH WILL RAPIDLY WEAKEN IT TO DISSIPATION BY TAU 36. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN STRONG
AGREEMENT ON THE NORTHEASTWARD TRACK THROUGH THE FORECAST PERIOD,
WITH A MINIMAL CROSS-TRACK SPREAD OF JUST 60NM. THE JTWC FORECAST
IS PLACED NEAR THE GFS DETERMINISTIC TRACKER WITH HIGH CONFIDENCE.
INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT, WITH ALL MODELS
EXCEPT FOR THE SHIPS-GFS INDICATING A SHORT WINDOW OF
INTENSIFICATION FOLLOWED BY STEADY TO RAPID WEAKENING TO
DISSIPATION BY TAU 36 OR EVEN AS EARLY AS TAU 24. THE JTWC FORECAST
IS POSITIONED NEAR THE GFS DETERMINISTIC GUIDANCE THROUGH THE
FORECAST PERIOD WITH HIGH CONFIDENCE. 

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