WDPN31 PGTW 090300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (MARIA) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.8N 145.9E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 412 NM SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON 06W
(MARIA) AS HAVING A SLIGHTLY DEGRADED APPEARANCE OVER THE PAST 6
HOURS WITH A VERY SMALL CENTRAL DENSE OVERCAST (CDO) OVER THE
CENTER AND A DRY SLOT ALONG THE SOUTHERN PERIPHERY OF THE
CIRCULATION. A STRONG BANDING FEATURE CAN STILL BE SEEN WRAPPING
AROUND THE EASTERN SEMICIRCLE OF THE SYSTEM. ENVIRONMENTAL ANALYSIS
INDICATES THAT 06W IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR
FURTHER INTENSIFICATION CHARACTERIZED BY GOOD POLEWARD AND ROBUST
EQUATORWARD OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR, WARM
(28-29 C) SEA SURFACE TEMPERATURES, AND THE PRESENCE OF DRY AIR
THROUGHOUT THE WESTERN SEMICIRCLE. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED ON THE ANIMATED MSI AND EXTRAPOLATION
FROM A 082133Z GMI 37 GHZ MICROWAVE IMAGE WHICH REVEALS A DEFINED
MICROWAVE EYE FEATURE. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED
WITH HIGH CONFIDENCE BASED ON A 082015Z RCM-2 SAR WIND SPEED IMAGE
SHOWING A VMAX OF 64 KTS IN ADDITION TO THE SUBJECTIVE AND OBJECTIVE 
INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: WESTERN SIDE OF A DEEP-LAYER
SUBTROPICAL RIDGE TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.5 - 77 KTS
   CIMSS DPRINT: 57 KTS AT 090000Z
   CIMSS DMINT: 71 KTS AT 082133Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD
   OTHER FACTORS: EXTENSIVE DRY AIR TO THE WEST

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: 06W IS FORECAST TO CONTINUE TRACKING GENERALLY
NORTHWARD ALONG THE WESTERN SIDE OF THE STR TO THE EAST THROUGH TAU
36. AFTER TAU 36, RIDGING EXTENDING OVER NORTHERN JAPAN WILL CAUSE
THE SYSTEM TO TURN WESTWARD AND CONTINUE THAT DIRECTION FOR THE
REMAINDER OF THE FORECAST PERIOD. REGARDING INTENSITY, 06W IS NOW
FORECAST TO PEAK AT 75 KTS AROUND TAU 24 AS THE OUTFLOW REMAINS
ROBUST AND THE VERTICAL WIND SHEAR REMAINS LOW (LESS THAN 10 KTS).
HOWEVER, EXTENSIVE DRY AIR IS EXPECTED TO KEEP ANY FURTHER
INTENSIFICATION AT BAY. AFTER TAU 24, SEA SURFACE TEMPERATURES
BEGIN TO COOL AND DRY AIR STARTS TO TAKE ITS TOLL ON 06W CAUSING A
WEAKENING TREND TO START. LANDFALL IS FORECAST TO OCCUR AROUND TAU
72, ABOUT 80 NM SOUTH-SOUTHEAST OF MISAWA, WITH INTENSITY NEAR 50
KTS. AFTER THE SYSTEM HAS MADE LANDFALL IN NORTHERN HONSHU, RUGGED
TERRAIN INTERACTION WILL AID IN QUICKLY DISSIPATING THE SYSTEM
BELOW TROPCAL STORM STRENGTH AS IT TRAVERSES THROUGH THE SEA OF
JAPAN. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE CONTINUES TO IMPROVE,
WITH MODELS CONVERGING TOWARDS A WESTWARD TRACK AFTER TAU 36. THE
CROSS-TRACK TRACK SPREAD AT TAU 72 HAS DECREASED SIGNIFICANTLY TO
AROUND 280 NM. GFS CONTINUES TO MAKE UP THE MOST SOUTHERN MEMBER
WHILE UKMET MAKES UP THE NORTHERN MOST. ENSEMBLES HAVE ALSO
TIGHTENED THE SPREAD OF OUTCOMES WITH THE MAJORITY OF BOTH ECMWF
AND GFS ENSEMBLE MEMBERS MAKING LANDFALL ALONG THE COAST OF HONSHU
BETWEEN THE 37TH AND 40TH LATITUDES. THE INTENSITY GUIDANCE HAS
ALSO SIGNIFICANTLY IMPROVED, WITH NO MORE RAPID INTENSIFICATION (RI)
AIDS TRIGGERING AND MOST GUIDANCE MAINTAINING THE CURRENT 65 KNOT
INTENSITY THOUGH TAU 36 BEFORE STARTING THE STEADY WEAKENING TREND.
THE JTWC INTENSITY FORECAST IS PLACED SLIGHTLY ABOVE CONSENSUS IN
THE NEAR TERM (UP TO TAU 24) AND FOLLOWS CLOSELY AFTERWARD. 

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