WDPN31 PGTW 021500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.0N 126.2E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 400 NM SOUTH-SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A ROBUST
TYPHOON STRENGTH CIRCULATION WITH AN IMPROVED 15NM EYE. VIGOROUS 
EQUATORWARD OUTFLOW IS CREATING AN SYMMETRIC APPEARANCE TO THE 
CONVECTIVE BANDING AROUND THE SYSTEM. A 021000Z SSMIS 91GHZ MICROWAVE 
IMAGE REVEALS TIGHTLY WRAPPING CONVECTIVE BANDING FEATURES IN ALL 
QUADRANTS THOUGH THE BULK OF THE PERIPHERAL CONVECTION IS IN THE 
SOUTHWESTERN QUADRANT, DOWN SHEAR OF THE SYSTEM. A STUNNING 020937Z 
RCM-3 SAR PASS REVEALED A MUCH MORE EXPANSIVE WIND FIELD THAT 
UNSURPRISINGLY FAVORS THE SOUTHERN SEMICIRCLE AND INDICATED A VMAX OF 
105KTS IN THE SOUTHEASTERN QUADRANT. THE INITIAL POSITION IS PLACED 
WITH HIGH CONFIDENCE BASED ON EIR, SSMIS AND SAR DATA. THE INITIAL 
INTENSITY OF 110 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED PRIMARILY 
ON SAR DATA THOUGH DVORAK AND AUTOMATED INTENSITY ESTIMATES REMAIN 
SLIGHTLY AGGRESSIVE AT 115-129KTS.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T5.5 - 102 KTS
   KNES: T6.0 - 115 KTS
   CIMSS ADT: 129 KTS AT 021130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TYPHOON 14W (KOINU) IS LIKELY AT OR NEAR ITS
PEAK INTENSITY AND THE SYSTEM IS FORECAST TO CONTINUE ON A
GENERALLY NORTHWESTWARD TRACK UNDER THE STEERING INFLUENCE OF THE
DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST. AS
EVIDENCED BY THE ASYMMETRIC APPEARANCE IN MSI AND MICROWAVE
IMAGERY, 14W IS EXPERIENCING INCREASED MID-UPPER LEVEL VERTICAL
WIND SHEAR AND DRY AIR ENTRAINMENT. OVER THE NEXT 12 HOURS, THESE
NEGATIVE FACTORS ARE GENERALLY NEGATED BY FAVORABLE OUTFLOW ALOFT
AND WARM SSTS WHICH WILL LIKELY MAINTAIN OR SLIGHTLY INCREASE THE
SYSTEMS INTENSITY. BY TAU 24 HOWEVER, THE PARTY WILL BE OVER AS
FAVORABLE EQUATORWARD OUTFLOW IS LOST. WHICH WHEN COUPLED WITH 
INCREASING VWS AND DRY AIR ENTRAINMENT, THE SYSTEM WILL BEGIN TO 
GRADUALLY WEAKEN. AS THE STR TO THE EAST BUILDS WESTWARD, 14W WILL BE 
FORCED TOWARDS THE SOUTHERN TIP OF TAIWAN AS IT CONTINUES TO SLOWLY 
WEAKEN. AFTER MAKING LANDFALL PAST TAU 48, THE MOUNTAINOUS EASTERN 
COAST OF TAIWAN WILL SHARPLY WEAKEN 14W TO 75KTS BY TAU 72. IN THE 
EXTENDED TRACK, 14W IS FORECAST TO SLOWLY TRANSIT THE TAIWAN STRAIT AS
ADDITIONAL COOL DRY AIR STEAMS INTO THE SYSTEM FROM THE NORTH. THIS 
WILL RESULT IN CONTINUED WEAKENING THROUGH TAU 120 AS THE SYSTEM
APPROACHES MAINLAND CHINA.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS CLOSELY FOLLOWING THE JTWC FORECAST TRACK THROUGH TAU 36.
BY TAU 72, MEMBER GUIDANCE REMAINS IN FAIR AGREEMENT WITH AN 117NM
SPREAD IN SOLUTIONS. FOR THIS REASON THE JTWC FORECAST TRACK IS
PLACED INITIALLY WITH HIGH CONFIDENCE AND WITH MEDIUM CONFIDENCE
THEREAFTER. WITH THE EXCEPTION OF COAMPS-TC AND HAFS, RELIABLE
MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH ALL MEMBERS
INDICATING STAGNATION OR WEAKENING THROUGH TAU 12, AFTER WHICH ALL
MEMBERS WEAKEN THE SYSTEM THROUGH THE FORECAST PERIOD. COAMPS-TC
AND HAFS DO NOT INDICATE LANDFALL OVER SOUTHERN TAIWAN AND INSTEAD
EACH TRANSIT INTO THE SOUTH CHINA SEA THROUGH TAU 120. FOR THIS
REASON, THESE MEMBERS INDICATE FURTHER INTENSIFICATION BEYOND TAU
48.  DESPITE THESE FEW TROUBLE MAKERS, THE JTWC INTENSITY FORECAST
IS PLACED WITH OVERALL MEDIUM CONFIDENCE.

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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