WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (MARIA) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.1N 145.9E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 364 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM 06W (MARIA) PLACED WITH MEDIUM CONFIDENCE TO THE WEST OF A
SUBTROPICAL RIDGE (STR). TS MARIA IS WELL-ORGANIZED, WITH STRONG
POLEWARD AND EQUATORWARD OUTFLOW, CURRENTLY ON A NORTHERLY TRACK.
THE LOW LEVEL CIRCULATION CENTER (LLCC) IS CURRENTLY FULLY OBSCURED
BY A CENTRAL DENSE OVERCAST (CDO). A 090723Z GMI 89GHZ MICROWAVE
IMAGE SHOWED AN ASYMMETRIC CONVECTIVE FIELD, WITH THE BULK OF THE
DEEP CONVECTION DISPLACED TO THE NORTH OF THE DEFINED LLCC. THE
ACCOMPANYING 37GHZ IMAGE SHOWED DEFINED LOW-LEVEL BANDING FEATURES
WRAPPING INTO ASSESSED CENTER, WHICH IS PLACED WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON SUBJECTIVE AIDS BETWEEN 3.5 AND 4.0 DVORAK
T-NUMBERS, AS WELL AS OBJECTIVE AIDS BETWEEN 47 AND 53 KTS WINDS,
AS WELL AS AN INTERMEDIATE 033422 AMSR2 MICROWAVE IMAGE PRESENTING
MAXIMUM WINDS OF 47 KTS. ECMWF RELATIVE HUMIDITY CHARTS ARE SHOWING
A LARGE PATCH OF DRIER AIR EXTENDING FROM THE WEST TO NORTH SIDE OF
THE SYSTEM DEGRADING THE POTENTIAL FOR INTENSIFICATION.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 53 KTS AT 090400Z
   CIMSS ADT: 49 KTS AT 090700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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: TS 06W (MARIA) IS CURRENTLY HEADING NORTH,
FORECASTED TO BEGIN TURNING TO THE NORTHWEST BY TAU 12. TRACK
SPEEDS ARE EXPECTED TO SLOW AS A PASSING TROUGH WEAKENS THE
STEERING GRADIENT BETWEEN TAU 24 AND 48. THE DEVELOPMENT OF A
DEEP-LAYER RIDGE TO THE NORTH OF THE SYSTEM, STRETCHING FROM THE
SEA OF JAPAN, IS EXPECTED TO TURN TS MARIA ONTO A MORE
WEST-NORTHWESTWARD TRACK, GENERALLY TOWARDS SENDAI BAY SOON AFTER
TAU 48. LANDFALL IS ANTICIPATED AROUND TAU 60. AFTER LANDFALL, THE
SYSTEM WILL CONTINUE TO TRACK WEST-NORTHWESTWARD ACROSS HONSHU AND
REEMERGE INTO THE SEA OF JAPAN SHORTLY AFTER TAU 72. FORECASTED
PEAK INTENSITY IS CURRENTLY 70 KTS EXPECTED BY TAU 36, AS THE
TROPICAL CYCLONE DEVELOPMENT CONDITIONS WILL REMAIN MARGINALLY
FAVORABLE FOR THE NEXT 24 HOURS. WIND SHEAR, OCEAN HEAT CONTENT AND
SEA SURFACE TEMPERATURES WILL REMAIN MARGINALLY FAVORABLE UNTIL
LANDFALL, BUT A DECREASE IN MID-LEVEL MOISTURE AND DECREASE IN THE
UPPER LEVEL DIVERGENCE, WHICH STARTS TO KICK IN AROUND TAU 24, WILL
OVERCOME THE MORE POSITIVE ENVIRONMENTAL FACTORS AND LEAD TO A SLOW
BUT STEADY WEAKENING TREND AFTER TAU 36. THE SYSTEM IS EXPECTED TO
START DISSIPATING SHORTLY AFTER MAKING ITS WAY INTO THE SEA OF
JAPAN. 

MODEL DISCUSSION: NUMERICAL WEATHER PREDICTION MODEL GUIDANCE
AGREEMENT KEEPS ON IMPROVING IN REGARDS TO BOTH TRACK AND INTENSITY
FORECAST, WITH THE CURRENT CROSS-TRACK SPREAD AT TAU 72 OF 265 NM
AND ALONG-TRACK OF 45 NM. BOTH GFS AND ECMW TRACKERS AGREE ON A
GENERAL NORTH-WESTERLY TRACK. THE JTWC FORECAST CLOSELY TRACKS THE
CONSENSUS MEAN AND THE LATEST ECMWF TRACKER. INTENSITY GUIDANCE
REMAINS GOOD AS WELL, WITH ONLY THE HAFS MODEL INDICATING MAXIMUM
INTENSITY ABOVE 70 KTS, AND MAJORITY OF THE MODELS OSCILLATING
AROUND 60-70 KTS. THERE ARE NO RAPID INTENSIFICATION TRIGGERS
PRESENT AT THE MOMENT. THE JTWC INTENSITY ESTIMATE IS PLACED ON THE
HIGHER END OF THE MODEL GUIDANCE, DRIVEN BY THE COMPACT STRUCTURE
OF THE SYSTEM, AS WELL AS CONTINUOUSLY MARGINALLY FAVORABLE
DEVELOPMENT CONDITIONS. THE JTWC FORECAST, AS WELL AS ALL OTHER
MODELS INDICATE A STEADY DOWNWARD INTENSITY TREND AFTER TAU 24,
REACHING BELOW 35 KNOTS AROUND TAU 96.

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