WDPN32 PGTW 242100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (HIGOS) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.0N 138.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 824 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 08W (HIGOS) WITH FLARING BUT INCREASINGLY PERSISTENT
CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE
ENVIRONMENT HAS BEEN ANALYZED AS MARGINALLY FAVORABLE, WITH WARM
SEA SURFACE TEMPERATURES RANGING BETWEEN 29-30 C, LOW VERTICAL WIND
SHEAR (VWS) OF 5-10 KTS, AND WEAK EQUATORWARD OUTFLOW ALOFT. DRY
AIR HAS REMAINED PREVALENT OVER THE LAST FEW HOURS AROUND THE
WESTERN SEMICIRCLE OF TS 08W, EVIDENT ON ANIMATED EIR. THE INITIAL
POSITION HAS BEEN PLACED WITH MEDIUM CONFIDENCE, BASED ON OBSERVED
FRAGMENTED CLOUD LINES WRAPPING TIGHTLY BENEATH THE PRIMARY
CONVECTIVE STRUCTURE FLARING OVER THE ASSESSED LLCC. THE INITIAL
INTENSITY HAS BEEN ASSESSED WITH MEDIUM CONFIDENCE BASED ON
SUBJECTIVE AGENCY DVORAK ESTIMATES RANGING BETWEEN T2.0-2.5.

INITIAL WIND RADII BASIS: EARLIER AMSR-2 WIND SPEED DATA

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) POSITIONED TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 43 KTS AT 241830Z
   CIMSS ADT: 49 KTS AT 241900Z
   CIMSS AIDT: 42 KTS AT 241900Z
   CIMSS D-MINT: 40 KTS AT 241711Z
   CIMSS D-PRINT: 33 KTS AT 241830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 08W IS FORECASTED TO TRACK NORTHWESTWARD
THROUGH TAU 24, ALONG THE SOUTHWESTERN AND WESTERN PERIPHERY OF THE
STR POSITIONED TO THE NORTHEAST. FOLLOWING TAU 24, TS HIGOS WILL
BEGIN TRACKING NORTHWARD, ALONG THE STR AXIS UNTIL JUST AFTER TAU
36. AFTER TAU 36, THE TROPICAL STORM IS FORECASTED TO BEGIN ITS
TERMINAL NORTH-NORTHEASTWARD TRACK, ALONG THE NORTHWEST EXTENT OF
THE AFOREMENTIONED STR UNTIL THE END OF THE FORECAST PERIOD. AFTER
TAU 36, TS 08W WILL ALSO BEGIN INTERACTING WITH THE UPPER-LEVEL
MID-LATITUDE JET, INCREASING THE SPEED OF APPROACH UNTIL
DISSIPATION BY TAU 60. REFERENCING THE PREVIOUS FORECAST, BINARY
INTERACTION BETWEEN THE LARGER TS 07W (MEKKHALA) AND TS 08W IS
BECOMING LESS LIKELY, WITH TS MEKKHALA FORECASTED TO FILL INTO A
SURFACE WAVE DURING THE EXPECTED COMPLETE DISSIPATION PHASE BY TAU
60 DUE TO BECOMING EMBEDDED WITHIN THE MID-LATITUDE WESTERLIES. THE
FORECASTED POSITION BETWEEN THE AFOREMENTIONED VORTICITY LOBES
ASSOCIATED WITH TS 08W AND TS 07W HAS INCREASED SINCE THE PREVIOUS
WARNING, LIMITING AN OPPORTUNITY FOR BINARY INTERACTION AS THE
EQUATORWARD EXTENDING MID-LEVEL TROUGH BECOMES THE PRIMARY
INFLUENCING FACTOR. REGARDING INTENSITY, TS 08W IS FORECASTED TO
INCREASE TO 50 KTS BY TAU 36 WITH ENHANCED OUTFLOW ALOFT, SUSTAINED
WARM SEA SURFACE TEMPERATURES, AND LOW VWS. FOLLOWING TAU 36,
INCREASED VWS TO ABOVE 20 KTS WILL BEGIN THE SYSTEMS TERMINAL
WEAKENING PHASE. FURTHER INTERACTION WITH THE MID-LATITUDE
WESTERLIES WILL WEAKEN SURFACE INTENSITIES TO NEAR 20 KTS BY TAU
60, DISSIPATING THE SYSTEM OVER WATER. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN
MODERATE AGREEMENT THROUGH TAU 36, WITH ALL MODELS AGREEING ON A
NORTHWESTWARD TRACK. AFTER TAU 36 AND AS THE SYSTEM ROUNDS THE STR
AXIS, NUMERICAL MODEL AND AI GUIDANCE BEGINS TO DIVERGE
SIGNIFICANTLY THROUGH CROSS-TRACK AND ALONG-TRACK SPREAD. A FEW OF
THE AI SOLUTIONS CHARACTERIZE A LOSS IN THE SYSTEMS VORTEX
FOLLOWING TAU 36, WHILE NUMERICAL MODELS ILLUSTRATE A NORTHEASTWARD
TURN EAST OF MINAMI DAITO JIMA. THE JTWC TRACK FORECAST HAS BEEN
PLACED IN CLOSE PROXIMITY TO THE JTWC MULTI-MODEL CONSENSUS THROUGH
TAU 36, THEN ALIGNED CLOSER TO THE GFS DETERMINISTIC SOLUTION
THEREAFTER WITH CONTINUED LOW CONFIDENCE. REGARDING INTENSITY
GUIDANCE, MESOSCALE SOLUTIONS INDICATE A SLIGHT INTENSIFICATION
PHASE INTO TAU 36, AND A WEAKENING PHASE THEREAFTER, WHEREAS GFS
AND COAMPS-TC LIMIT THE SYSTEMS INTENSITY BELOW TROPICAL STORM
STRENGTH UNTIL THE EXPECTED DISSIPATION PHASE. THE JTWC INTENSITY
FORECAST HAS BEEN PLACED CLOSE TO THE MULTI-MODEL INTENSITY
CONSENSUS THROUGH TAU 36 AND ALIGNED NEAR MESOSCALE SOLUTIONS UNTIL
THE END OF THE FORECAST PERIOD WITH LOW CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: LOW
   INTENSITY 00-72 HR: LOW//
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