WDPN33 PGTW 302100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (HAIKUI) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.1N 134.3E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 482 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT
TROPICAL STORM (TS) 10W (HAIKUI) CONTINUES ROBUST, FLARING
CONVECTION ALOFT WITH PROMINENT NORTHEASTERLY SHEAR IN THE
UPPERMOST LAYERS OF THE ATMOSPHERE. A 301725Z ATMS MICROWAVE IMAGE
SHOWS THE STRONGEST CONVECTION OCCURRING IN THE NORTHEAST QUADRANT
OF THE CONVECTIVE PLUME, FURTHER SUPPORTING SHEAR IMPACTING THE
SYSTEM. CONVECTIVE CIRRUS DEBRIS CONTINUES TO FULLY OBSCURE THE
LOW-LEVEL CIRCULATION CENTER (LLCC), LENDING TO A LOW CONFIDENCE IN
INITIAL POSITION DUE TO LACK OF FURTHER POSITIONING AIDS AND DATA.
THE INITIAL INTENSITY OF 50 KNOTS IS ASSESSED WITH MEDIUM
CONFIDENCE, BASED ON AGENCY DVORAK INTENSITY ESTIMATES OF T3.0 TO
T3.5 AS WELL AS SUBJECTIVE ESTIMATES LISTED BELOW. THE SYSTEM
CONTINUES TO TRACK TOWARDS THE NORTHWEST ALONG THE SOUTHWESTERN
PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE
NORTHEAST. SSTS ARE VERY WARM BUT THE OUTFLOW REMAINS WEAK AND
RELATIVELY CONSTRAINED TO THE EQUATORWARD DIRECTION.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 55 KTS AT 301740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TS 10W IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD ALONG THE SOUTHWEST SIDE OF THE STRONG STR THROUGH
TAU 72. THE SYSTEM IS EXPECTED TO PASS SOUTH OF OKINAWA BETWEEN TAU
36 AND TAU 48, THEN ENTER THE EAST CHINA SEA.  BY TAU 72, ANOTHER,
MORE VIGOROUS TROUGH QUICKLY MOVES IN FROM THE WEST, WILL ERODE THE
STEERING RIDGE AND GENERATE A WEAKNESS IN THE RIDGE PATTERN WHICH
WILL INDUCE TS 10W TO TURN POLEWARD AROUND TAU 120. THE INTENSITY
FORECAST THROUGH TAU 48 BRINGS THE SYSTEMS PEAK INTENSITY TO NEAR
85KTS.  RAPID INTENSIFICATION IS POSSIBLE DURING THIS PERIOD, BUT
THE SYSTEM MUST REALIZE GREATER OUTFLOW ALOFT WITH LESS SHEAR
THROUGH THE VERTICAL STRUCTURE. DUE TO THIS AMBIGUITY, THE
INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE. POST TAU 72,
THE SYSTEM IS ANTICIPATED TO MAKE LANDFALL ALONG EASTERN CHINA AND
RAPIDLY WEAKEN.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE CONTINUES TO BETTER
ALIGN OVER THE PAST 24 HOURS.  IN GOOD AGREEMENT, THE CROSS-TRACK
SPREAD AT TAU 72 IS NOW 220NM, WHILE TAU 120 DIVERGES SLIGHTLY MORE
TO A CROSS-TRACK SPREAD OF 365NM.  ALONG-TRACK AMBIGUITY IS
NEGLIGIBLE THROUGH TAU 72 AND EXPANDS TO 240NM THEREAFTER.

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