WDPN31 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (KROSA) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.7N 144.5E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 572 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL CLOUD
BANDS WRAPPING INTO A FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER
(LLCC). A 280545Z F-18 DMSP SSMIS 91GHZ IMAGE REVEALS THE FULLY
SHALLOW SYSTEM LACKING DEEP CONVECTION WITHIN THE CORE AND WEAK
BANDS OF DEEP CONVECTION WRAPPING AROUND THE SOUTHERN PERIPHERY.
THE 37GHZ VERSION OF THE IMAGE HIGHLIGHTS THE DISTINCT LLCC WITH A
MICROWAVE EYE FEATURE CENTERED WITHIN THE CURVED BANDS. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
ANIMATED MSI AND MICROWAVE IMAGE. THE INITIAL INTENSITY OF 70 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY AND
OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT BETWEEN
A SUBTROPICAL RIDGE TO THE NORTH AND NEAR EQUATORIAL RIDGE TO THE
SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 77 KTS AT 280353Z
   CIMSS ADT: 69 KTS AT 280530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE 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: TYPHOON (TY) 12W WILL CONTINUE TO SLOW WHILE
TRACKING IN A NORTHWESTWARD DIRECTION FOR THE NEXT 12 HOURS. AFTER
TAU 12, QUASI-STATIONARY MOVEMENT WHILE IN AN INCREASINGLY
COMPETITIVE STEERING ENVIRONMENT BETWEEN A SUBTROPICAL RIDGE TO THE
NORTHWEST AND A NEAR EQUATORIAL RIDGE TO THE SOUTHEAST. THE RIDGE
TO THE NORTHWEST WILL DEGRADE, AND THE RIDGE TO THE SOUTHEAST WILL
REORIENT ON A SOUTHWEST-NORTHEAST AXIS, ALLOWING FOR TY 12W TO
TRACK NORTHEASTWARD FOR THE REMAINDER OF THE FORECAST. THE DRY AIR
THAT IS ACTIVELY DEGRADING THE CORE OF TY 12W WILL CONTINUE FOR THE
NEXT 12-24 HOURS. AS THE TRACK SLOWS, STRONG UPWELLING WILL
INCREASE THE RATE OF WEAKENING TO 55KTS BY TAU 48. AS TY 12W MOVES
NORTHEASTWARD AFTER TAU 48, THE OCEAN ENVIRONMENT WILL BE MORE
SUPPORTIVE AND SLIGHT INTENSIFICATION WILL CONTINUE TO A PEAK OF
65KTS BY THE END OF THE FORECAST PERIOD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
IN THE NEAR-TERM FORECAST, BUT SPREADS IRREGULARLY AFTER TAU 24 AS
THE SYSTEM ENTERS A QUASI-STATIONARY PHASE. THE JTWC MULTI-MODEL
CONSENSUS MEMBERS ARE SPREAD AFTER TAU 48 AS THE SYSTEM TRACKS
NORTHEASTWARD DEPENDING ON THE STRENGTH OF THE REORIENTED NEAR
EQUATORIAL RIDGE TO THE SOUTHEAST. THE DETERMINISTIC GUIDANCE IS IN
GOOD AGREEMENT IN THE NEAR-TERM FORECAST, BUT SPREADS AFTER TAU 48
DUE TO VARIATIONS IN THE TRACK GUIDANCE.

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