WDPN31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (MARIA)        
WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 37.6N 143.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 210 NM SOUTHEAST OF MISAWA, JAPAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TIGHTLY-WRAPPED 
LOW-LEVEL BANDING WRAPPING INTO A WELL-DEFINED CENTER, WITH DEEP 
CONVECTIVE BANDING CONFINED TO THE CORE REGION. ANIMATED RADAR IMAGERY 
REVEALS IMPROVED CORE STRUCTURE WITH AN EYE, WHICH SUPPORTS THE 
INITIAL POSITION WITH HIGH CONFIDENCE. AN 110552Z SSMIS 91GHZ 
MICROWAVE IMAGE INDICATES A PARTIAL EYEWALL, WITH FRAGMENTED 
CONVECTIVE BANDING AND SPARSE DEEP CONVECTION OVER THE WESTERN 
SEMICIRCLE. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS BASED ON THE 
HIGH END OF THE AGENCY DVORAK ESTIMATES. THIS IS CONSISTENT WITH THE 
RECENT DPRINT ESTIMATES RANGING FROM 40-47 KNOTS. OVER THE PAST 12 
HOURS, THE INTENSITY HAS FLUCTUATED QUICKLY BETWEEN ABOUT 45-52 KNOTS 
(SAR DATA) AND APPEARS TO REINTENSIFYING OVER THE PAST TWO HOURS 
(110600-0800Z). THIS WILL BE REASSESSED AND POSSIBLY ADJUSTED AT THE 
NEXT WARNING CYCLE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) BUILDING TO THE
NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 32 KTS AT 110600Z
   CIMSS DMINT: 42 KTS AT 110551Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM (TS) HAS TURNED WEST-NORTHWESTWARD 
AS THE STR CONTINUES TO BUILD TO THE NORTH BUT IS EXPECTED TO TRACK 
GENERALLY NORTHWESTWARD THROUGH TAU 36. TS 06W SHOULD WEAKEN AS IT 
APPROACHES THE NORTHEAST COAST OF HONSHU OVER THE NEXT 12 HOURS, WITH 
LANDFALL EXPECTED NEAR TAU 18. HOWEVER, THE SYSTEM HAS REMAINED 
RESILIENT AND MAY POSSIBLY INTENSIFY SLIGHTLY IN THE NEAR-TERM. AFTER 
MAKING LANDFALL, TS 06W WILL WEAKEN RAPIDLY OVER THE JAPAN ALPS WITH 
DISSIPATION ANTICIPATED IN THE TAU 36 TO TAU 48 TIME PERIOD WHEN THE 
SYSTEM EMERGES OVER THE SEA OF JAPAN. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT
LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. AS MENTIONED,
THERE IS SOME UNCERTAINTY IN THE INTENSITY FORECAST PRIOR TO
LANDFALL, ESPECIALLY OVER THE NEXT 6 TO 12 HOURS. THE BULK OF THE
RELIABLE INTENSITY GUIDANCE INDICATES A SLIGHT WEAKENING TREND
EXCEPT AHNI, WHICH SHOWS A SLIGHT INTENSIFICATION TO 48 KNOTS AT
TAU 12.

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