WDPN31 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (MARIA) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.9N 145.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 340 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERY
COMPACT CENTRAL CORE THAT REMAINS FAIRLY WELL-ORGANIZED, THOUGH A
RECENT INFLUX OF DRY AIR HAS COMPLETELY ERODED THE PREVIOUSLY
VIGOROUS CDO FEATURE. THE LOW LEVEL CIRCULATION CENTER (LLCC)
REMAINS OBSCURED BY CIRRUS DEBRIS LEFT OVER FROM THE NOW ERODED
CDO. A 091135Z NOAA-19 AMSU-9 89GHZ IMAGE SHOWED LOW-LEVEL BANDING
FEATURES ACROSS THE SOUTHERN HEMISPHERE OF THE LLCC, WITH MODERATE
CONVECTIVE BANDS ACROSS THE NORTHERN SIDE. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON THE GROUPING OF AGENCY FIX
POSITIONS AND THE MICROWAVE IMAGE NOTED ABOVE. THE INITIAL
INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED
CONSISTENT AGENCY SUBJECTIVE DVORAK ESTIMATES OF 3.5 FOR PGTW,
RJTD, KNES AND RTCP. OBJECTIVE INTENSITY AIDS ARE ALSO
CORRESPONDING TO 55 KTS ASSESSMENT, WITH RECENT ADT, AIDT AND
DPRINT RANGING FROM 45 TO 54 KTS. TS MARIA IS CURRENTLY LIMITED TO
A MODERATE TO STRONG OUTFLOW BUT ONLY IN POLEWARD DIRECTION, WITH
NEARLY NO EQUATORWARD OUTFLOW VISIBLE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE EAST OF THE
SYSTEM

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 61 KTS AT 091300Z
   CIMSS ADT: 45 KTS AT 091300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY MID-LEVEL AIR PENETRATING INTO THE CORE OF
THE SYSTEM. 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE CURRENT FORECAST NO LONGER CALLS
FOR AN INCREASE IN INTENSITY PRIOR TO LANDFALL. 

FORECAST DISCUSSION: TS 06W IS EXPECTED TO START MAKING A MORE
NORTHWESTWARD TURN WITHIN THE NEXT 12 TO 24 HOURS AS A DEEP-LAYER
RIDGE TO THE NORTH OF THE SYSTEM DEVELOPS. AS THE RIDGE CONTINUES
TO BUILD IN ACROSS THE NORTHERN PORTION OF JAPAN, TS MARIA WILL
CONTINUE TO TURN ONTO A PROGRESSIVELY MORE NORTHWESTWARD TRACK
TOWARDS SENDAI BAY. TS MARIA IS EXPECTED TO MAKE LANDFALL SOON
AFTER TAU 48 AND EMERGE ON THE WESTERN SIDE OF HONSHU ISLAND AROUND
TAU 72 AND CONTINUE TRACKING NORTHWESTWARD INTO THE CENTRAL SEA OF
JAPAN BY THE END OF THE FORECAST PERIOD. AS A SIGNIFICANT DRY AIR
INTRUSION IS INHIBITING THE SYSTEMS ABILITY TO FURTHER DEVELOP,
WHILE ENVIRONMENTAL CONDITIONS REMAIN MARGINAL, TS MARIA IS
EXPECTED TO MAINTAIN CURRENT INTENSITY THROUGH TAU 36, FOLLOWED BY
STEADY WEAKENING. POST LANDFALL, THE SYSTEM IS EXPECTED TO
RE-EMERGE AS A 35 KTS TROPICAL STORM, BEGINNING ITS DISSIPATION
SOON AFTER.

MODEL DISCUSSION: NUMERICAL WEATHER PREDICTION MODEL GUIDANCE
IMPROVED SLIGHTLY IN REGARDS TO CROSS-TRACK SPREAD, WHICH IS NOW
190 NM AT TAU 72, WHILE THE ALONG-TRACK SPREAD INCREASED TO 90 NM.
OVERALL TRACK GUIDANCE REMAINS GOOD, WITH THE GFS ON THE SOUTHERN
SIDE OF THE ENVELOPE AND THE NAVGEM ON THE RIGHT. THE REMAINDER OF
THE CONSENSUS MEMBERS ARE CLOSELY PACKED AROUND THE CONSENSUS MEAN,
AND THE JTWC GUIDANCE IS POSITIONED CLOSELY TO THE MEAN, AS WELL AS
THE ECMWF. INTENSITY GUIDANCE CHANGED SINCE THE LAST FORECAST,
LEANING TOWARDS SLOW, BUT STEADY WEAKENING OF THE SYSTEM AS
SUGGESTED BY THE MAJORITY OF THE MODELS. HOWEVER, THE HFAI AND AHNI
INDICATE POTENTIAL FOR 5-10 KTS RE-INTENSIFICATION PRIOR TO
LANDFALL. JTWC GUIDANCE STIPULATE THE SYSTEM MAINTAINING ITS CURRENT
INTENSITY OF 55 KTS THROUGH TAU 24, FOLLOWED BY STEADY DOWNWARD
INTENSITY TREND AFTER TAU 48, WITH A POTENTIAL FOR MAINTAINING
CURRENT INTENSITY OVER 12 HOUR PERIODS, DRIVEN BY POTENTIAL OF
MARGINALLY FAVORABLE CONDITIONS OVERCOMING THE DOMINANT DRY AIR
INTRUSION.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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