WDPN31 PGTW 030300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.5N 125.1E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 340 NM SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SPIRAL
BANDING WRAPPING INTO A FORMATIVE, RAGGED EYE, WHICH SUPPORTS THE
INITIAL POSITION WITH MEDIUM CONFIDENCE. OVERALL, THE SYSTEM HAS
WEAKENED SLIGHTLY DUE TO PERSISTENT EASTERLY VERTICAL WIND SHEAR
(VWS) AND DRY AIR ENTRAINMENT. THIS IS CLEARLY EVIDENT IN A 022232Z 
SSMIS 91 GHZ MICROWAVE IMAGE WHICH DEPICTS A PARTIAL EYEWALL OVER
THE WESTERN SEMICIRCLE AND A DRY SLOT OVER THE EASTERN SEMICIRCLE, 
WITH DEEP CONVECTIVE BANDING WRAPPING TIGHTLY AROUND THE ELONGATED
LOW-LEVEL CIRCULATION CENTER. THE INITIAL INTENSITY IS ASSESSED AT
105 KNOTS BASED ON THE AGENCY FINAL-T (102 KTS) ESTIMATES AND CURRENT
INTENSITY ESTIMATES OF 6.0 (115 KTS) AS WELL AS A 022233Z DMINT
ESTIMATE OF 101 KTS. THE 030130Z AIDT ESTIMATE OF 111 KTS IS ALSO
IN BETTER ALIGNMENT WITH THE INITIAL INTENSITY ASSESSMENT. A
022130Z RCM-3 SAR IMAGE REVEALS MAXIMUM WINDS OF ONLY 88 KNOTS WITH
EXPANSIVE GALE-FORCE AND STORM-FORCE WINDS ESPECIALLY OVER THE
SOUTHEAST QUADRANT. THE SAR IMAGE WAS USED TO ADJUST THE INITIAL
WIND RADII WITH HIGH CONFIDENCE HOWEVER THE MAXIMUM WIND ESTIMATE IS 
TOO LOW.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST AND NORTHEAST WITH A BREAK TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: 6.0 - 115 KTS
   RJTD: 6.0 - 115 KTS
   KNES: 6.0 - 115 KTS
   CIMSS ADT: 124 KTS AT 022330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 (TY) 14W IS FORECAST TO TRACK
NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE STR THROUGH
TAU 12 TOWARD A BREAK IN THE STR ASSOCIATED WITH A MIDLATITUDE
SHORTWAVE TROUGH. AFTER TAU 12, THE TROUGH WILL PROPAGATE EASTWARD
ALLOWING THE STR TO REBUILD TO THE NORTH, WHICH WILL TURN THE
SYSTEM ON A WEST-NORTHWESTWARD TO WESTWARD TRAJECTORY THROUGH TAU
120. TY 14W SHOULD WEAKEN STEADILY DUE TO THE PERSISTENT VWS AS IT
APPROACHES AND TRACKS OVER SOUTHERN TAIWAN WITH FURTHER WEAKENING
AS IT TRACKS OVER THE SOUTH CHINA SEA, TAIWAN STRAIT REGION. A
WEAK NORTHEAST SURGE IS EXPECTED TO BUILD INTO THE TAIWAN STRAIT WITH
EXPANSIVE GALE-FORCE WINDS AND INFUSION OF COOLER, DRIER, MORE STABLE 
AIR. 

MODEL DISCUSSION: THROUGH TAU 72, NUMERICAL MODEL GUIDANCE IS IN
TIGHT AGREEMENT WITH A 67 NM CROSS-TRACK SPREAD IN SOLUTIONS
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST THROUGH TAU 72.
AFTER TAU 72, THERE IS INCREASING SPREAD AND UNCERTAINTY DUE TO
THE NORTHEAST SURGE THROUGH THE TAIWAN STRAIT AND ITS INFLUENCE ON A
WEAKENING, SHALLOWER SYSTEM. MUCH OF THE DETERMINISTIC GUIDANCE IS
TURNING THE SYSTEM WEST-SOUTHWESTWARD TO SOUTHWESTWARD NEAR TAU
120. BOTH THE GEFS AND EPS ENSEMBLES INDICATE RAPID WEAKENING NEAR THE 
SOUTHEAST COAST OF CHINA WITH INCREASING POTENTIAL FOR A SLOW,
ERRATIC TRACK AND A SHARP SOUTHWESTWARD TURN NEAR OR JUST
SOUTHEAST OF HONG KONG. AS A RESULT OF THIS COMPLEX SCENARIO, THERE IS 
LOW CONFIDENCE IN THE JTWC FORECAST TRACK AFTER TAU 72. OVERALL, THERE 
IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST. 

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