WDPN31 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (MARIA) WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.0N 145.7E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 439 NM SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
06W (MARIA) AS A VERY COMPACT SYSTEM WITH A SYMMETRICAL CENTRAL
DENSE OVERCAST (CDO) OBSCURING THE LOW-LEVEL CIRCULATION CENTER
(LLCC) AND BANDING FEATURES RUNNING ALONG THE EASTERN PERIPHERY.
ENVIRONMENTAL ANALYSIS INDICATES THAT 06W IS IN A FAVORABLE
ENVIRONMENT FOR FURTHER INTENSIFICATION CHARACTERIZED BY STRONG
POLEWARD AND ROBUST EQUATORWARD OUTFLOW ALOFT, LOW (5-10 KTS)
VERTICAL WIND SHEAR, AND WARM (29-30C) SEA SURFACE TEMPERATURES.
THESE FACTORS ARE SLIGHTLY OFFSET BY THE PRESENCE OF DRY AIR IN THE
WESTERN SEMICIRCLE, HINDERING THE CONVECTIVE DEVELOPMENT IN THAT
REGION. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED
ON THE ANIMATED EIR AND A 081636Z AMSR2 89 GHZ MICROWAVE IMAGE
SHOWING THE CLOUD LINES TIGHTLY WRAPPING INTO THE LLCC. THE INITIAL
INTENSITY OF 70 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
PERSISTENCE OF THE 080827Z SAR WIND SPEED IMAGE SHOWING A CLUSTER
OF 70 KNOT WINDS ALONG THE EASTERN SECTOR OF THE CIRCULATION
CENTER. OBJECTIVE INTENSITY ESTIMATES ARE DEPICTING A SLIGHTLY
WEAKER SYSTEM, HOWEVER THE SUBJECTIVE ESTIMATES HELP SUPPORT THE
CURRENT INTENSITY.

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: T3.0 - 45 KTS
   KNES: T4.5 - 77 KTS
   CIMSS DMINT: 69 KTS AT 1605Z
   CIMSS SATCON: 59 KTS AT 1800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 TRACK GENERALLY NORTHWARD
THROUGH TAU 48 ALONG THE WESTERN PERIPHERY OF THE STR TO THE EAST.
AFTER TAU 48, RIDGING EXTENDING OVER NORTHERN JAPAN WILL TURN THE
SYSTEM WESTWARD. 06W WILL THEN CONTINUE ON THE WESTWARD TRACK
THROUGH THE REMAINDER OF THE FORECAST PERIOD AS IT MAKES ITS WAY
INTO THE SEA OF JAPAN. 06W IS FORECAST TO CONTINUE STEADILY
INTENSIFYING OVER THE NEXT 24 HOURS, TO A PEAK INTENSITY OF 85 KTS
AT TAU 24. AFTER TAU 24, COOLING SEA SURFACE TEMPERATURES, DRY AIR
ENTRAINMENT, AND REDUCED OUTFLOW WILL INITIATE A WEAKENING TREND.
BETWEEN TAU 72 AND 96, 06W IS ANTICIPATED TO MAKE LANDFALL
SOUTHEAST OF MISAWA WITH AN INTENSITY OF 45-50 KTS. AFTER MAKING
LANDFALL, TERRAIN INTERACTION WILL AID IN WEAKENING THE SYSTEM. BY
TAU 120, 06W IS FORECAST TO BE BORDERLINE TROPICAL DEPRESSION
STRENGTH AS IT TRAVERSES THE SEA OF JAPAN. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN BETTER AGREEMENT,
BUT STILL HIGH VARIANCE BETWEEN MODELS. GFS AND ECMWF
(DETERMINISTIC AND ENSEMBLE MEAN) ARE CONVERGING TO A WESTWARD
TRACK WITH MEMBERS MAKING LANDFALL BETWEEN THE 37TH AND 40TH
LATITUDES OF THE COAST OF HONSHU. GFS ENSEMBLE IS STILL SHOWING A
GROUP OF MEMBERS TAKING THE SHARP WESTWARD TURN AND INTENSIFYING
TOWARDS YOKOSUKA, BUT THE ENSEMBLE MEAN IS STAYING TO THE NORTH AND
WITHIN THE 50-60 KNOT RANGE. UKMET AND GALWEM ARE BOTH DEPICTING
THE NORTHWARD AND THEN NORTHEASTWARD TRACK PAST HOKKAIDO. THE JTWC
FORECAST TRACK IS PLACED WITHIN THE NORTHERN RANGE OF THE WESTWARD
TURNING MODELS. OVERALL, THE JTWC TRACK FORECAST IS PLACED WITH
MEDIUM CONFIDENCE THROUGH TAU 72 AND LOW THEREAFTER. INTENSITY
GUIDANCE IS IN DISAGREEMENT WITH RAPID INTENSIFICATION (RI) AIDS
STILL TRIGGERING AND SHOWING A POSSIBLE PEAK INTENSITY OF 95-110
KTS WHILE THE NON-RI AIDS ARE MAINTAINING CURRENT INTENSITY WITH A
STEADY WEAKENING TREND AFTER TAU 48. THE JTWC INTENSITY FORECAST IS
PLACED ABOVE THE NON-RI AIDS BUT BELOW THE RI AIDS FOR A CONTINUED
STEADY INTENSIFICATION TREND OVER THE NEXT 24-36 HOURS BEFORE
WEAKENING. AS A RESULT, THE JTWC INTENSITY FORECAST IS PLACED WITH
LOW CONFIDENCE.

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