WDPN31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (BANYAN) WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 14W (BANYAN), LOCATED APPROXIMATELY 652 NM NORTHEAST OF
MINAMI TORI SHIMA, HAS TRACKED NORTH-NORTHEASTWARD AT 15 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
DEPICTS COMPACT, TIGHTLY CURVED BANDING WRAPPING INTO A LOW LEVEL 
CIRCULATION CENTER (LLCC). A 152312Z MHS METOP-B 89 GHZ MICROWAVE 
IMAGE DEPICTS A LIMITED AREA OF DEEP CONVECTION SHEARED INTO THE 
EASTERN SEMI-CIRCLE. THE INITIAL POSITION IS PLACED WITH HIGH 
CONFIDENCE BASED ON THE MICROWAVE IMAGE AND MULTIPLE AGENCY FIXES 
USING ANIMATED MULTISPECTRAL IMAGERY. THE INITIAL INTENSITY OF 65 
KNOTS IS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T4.0 (65) 
FROM BOTH PGTW AND RJTD. ENVIRONMENTAL ANALYSIS INDICATES AN 
UNFAVORABLE ENVIRONMENT WITH LOW (5-10 KNOTS) VERTICAL WIND SHEAR 
(VWS) BEING OFFSET BY COOLER (25 CELSIUS) SEA SURFACE TEMPERATURES 
(SST). TY 14W CONTINUES TO EXPERIENCE POLEWARD OUTFLOW THAT WRAPS 
AROUND THE EASTERN SEMICIRCLE AND INTO A STRONG EQUATORWARD OUTFLOW 
CHANNEL. TY BANYAN IS TRACKING NORTHEAST ALONG THE NORTHWESTERN 
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) LOCATED TO THE 
SOUTHEAST. 
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE. 
   B. TY BANYAN IS FORECAST TO CONTINUE TO ACCELERATE AND TRACK 
NORTHEAST ALONG THE NORTHWESTERN EXTENT OF THE STR. AS THE SYSTEM 
BEGINS TO INTERACT WITH A PASSING MID-LATITUDE TROUGH, INCREASING 
VWS COMBINED WITH THE SYSTEM TRACKING THROUGH LOWER SST (<26 
CELSIUS) WILL GRADUALLY WEAKEN TY BANYAN FOR THE DURATION OF THE 
FORECAST PERIOD. AFTER TAU 12, THE SYSTEM WILL BEGIN EXTRA TROPICAL 
TRANSITION (ETT) AS IT BECOMES EMBEDDED IN THE BAROCLINIC ZONE. TY 
BANYAN WILL COMPLETE ETT BY TAU 36, BECOMING A COLD CORE LOW BUT 
RETAINING GALE-FORCE WINDS. DYNAMIC MODEL GUIDANCE REMAINS IN STRONG 
AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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