WDPN31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (KOINU) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.4N 129.5E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 518 NM EAST-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT TROPICAL
STORM (TS) 14W (KOINU) CONTINUES TO BECOME BETTER CONSOLIDATED WITH
DEEP CONVECTIVE BANDING ON THE SOUTHERN SEMICIRCLE WRAPPING INTO A
DEVELOPING CLOUD DENSE OVERCAST, WHICH IS OBSCURING THE LOW-LEVEL
CIRCULATION CENTER (LLCC). MSI ALSO SHOWS WELL DEFINED LOW-LEVEL
CLOUD LINES ON THE NORTHERN SIDE OF THE SYSTEM WRAPPING INTO THE
LLCC. A 302135Z SSMIS 89GHZ MICROWAVE IMAGE DEPICTS FORMATIVE
BANDING IN ALL QUADRANTS AND SEVERAL ADDITIONAL BANDS TO THE NORTH
AND WEST OF THE LLCC. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED
HIGH CONFIDENCE BASED ON AGENCY DVORAK INTENSITY ESTIMATES IN LINE
WITH THE OBJECTIVE ESTIMATES FROM ADT AND SATCON RANGING FROM 53
AND 54 KNOTS, RESPECTIVELY. RECENT DPRINT AND DMINT ESTIMATES RANGE
FROM 57 TO 55 KNOTS. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT
WITH MODERATE EQUATORWARD OUTFLOW, WARM SSTS, AND FAVORABLE (10-15
KNOTS) VERTICAL WIND SHEAR. ADDITIONALLY, THE LATEST CIMSS TOTAL
PRECIPITABLE WATER (TPW) DATA SUGGESTS THE SYSTEM IS WITHIN A VERY
MOIST ENVIRONMENT.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 54 KTS AT 301940Z
   CIMSS ADT: 53 KTS AT 302330Z

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: OVER THE NEXT 48 HOURS OF THE FORECAST, TS 14W
IS EXPECTED TO TRACK GENERALLY TOWARDS THE NORTHWEST ALONG THE
WESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTHEAST. ADDITIONALLY, THE STR IS EXPECTED TO
REALIGN TO THE NORTHEAST, WHILE A WEAK MID-LATITUDE SHORTWAVE
TROUGH WILL WEAKEN THE STR ENOUGH TO ALLOW 14W TO GAIN LATITUDE. BY
TAU 48, THE STEERING PATTERN WILL BEGIN TO SHIFT, AS THE STR IS
EXPECTED TO BUILD AND REORIENT THE TRACK WEST-NORTHWESTWARD. BY TAU
72, THE STR BECOMES THE PRIMARY STEERING INFLUENCE, AND TS 14W WILL
CONTINUE TO TRACK WEST-NORTHWEST TOWARDS SOUTHERN TAIWAN THROUGH
THE REMAINDER OF THE FORECAST. TS 14W WILL STEADILY INTENSIFY
THROUGH TAU 36 AS ENVIRONMENTAL CONDITIONS WILL REMAIN FAVORABLE
WITH LOW VERTICAL WIND SHEAR, AND WARM SSTS. MESOSCALE MODELS AND 
RAPID INTENSIFICATION (RI) AIDS AGREE THAT RAPID INTENSIFICATION 
CHANCES INCREASE AS THE SYSTEM COULD TAP INTO DUAL CHANNEL OUTFLOW 
ALONG WITH WARM (30-31C) SSTS AND HIGH OCEAN HEAT CONTENT. THIS 
CONGRUENCE OF FAVORABLE ENVIRONMENTAL PARAMETERS COULD ALLOW FOR A 
BURST OF RAPID INTENSIFICATION THROUGH TAU 48. BETWEEN TAU 72 AND TAU 
96, THE SYSTEM IS EXPECTED TO REACH A PEAK NEAR 110 KTS WHILE THE 
SYSTEM PASSES NEAR THE SOUTHERN TIP OF TAIWAN.

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN FAIR
AGREEMENT, ASIDE FROM NAVGEM AND GALWEM WHICH ARE RIGHT OF TRACK,
WHILE THE REST OF THE CONSENSUS MEMBERS ARE CONSTRAINED TO A 140NM
ENVELOPE BY TAU 72. AFTER TAU 72 AND FOR THE REMAINING TRACK,
DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE FROM BOTH GFS AND ECMWF
INCREASE IN BOTH CROSS TRACK AND ALONG TRACK SPREAD. THEREFORE,
THERE IS MEDIUM CONFIDENCE THROUGH TAU 72 AND LOW CONFIDENCE
THEREAFTER AS THE SPREAD INCREASES. IN TERMS OF INTENSITY, RI AIDS ARE 
REFLECTING A CONDUCIVE RI ENVIRONMENT CHARACTERIZED BY ROBUST DUAL 
CHANNEL OUTFLOW, LOW VERTICAL WIND SHEAR, AND WARM SST VALUES THROUGH 
TAU 48. AFTER TAU 72, INTENSITY MODEL GUIDANCE INCREASES IN SPREAD 
WITH COAMPS-TC INDICATING A PEAK NEAR 135 KTS, WHILE DECAY SHIPS AND 
GFS CONTINUES TO REPRESENT THE LOW END OF THE GUIDANCE ENVELOPE. IN 
LIGHT OF THE HIGH UNCERTAINTY IN THE GUIDANCE, CONFIDENCE IN THE 
INTENSITY FORECAST IS MEDIUM TO TAU 72, AND LOW THEREAFTER. 

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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