WDPN32 PGTW 250300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (HIGOS) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.8N 137.6E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 754 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM 08W WITH BURSTING BUT SHORT-LIVED CONVECTION OBSCURING THE
LOW-LEVEL CIRCULATION CENTER (LLCC). AROUND THE PERIPHERY OF THE 
SYSTEM, DRY AIR HAS REMAINED THROUGHOUT THE WESTERN SEMICIRCLE, WHILE
FRAGMENTED LOW-LEVEL CLOUD LINES HAVE BEEN OBSERVED TUCKING BENEATH
THE PRIMARY CONVECTIVE STRUCTURES EASTERN QUADRANT. THE ENVIRONMENT
HAS BEEN ANALYZED AS MARGINALLY FAVORABLE, WITH WARM SEA SURFACE
TEMPERATURES (29-30 C), LOW VERTICAL WIND SHEAR (VWS) (5-10 KTS),
AND WEAK EQUATORWARD OUTFLOW ALOFT. THE INITIAL POSITION HAS BEEN
PLACED WITH MEDIUM CONFIDENCE BASED ON ANIMATED MSI IMAGERY. THE
INITIAL INTENSITY HAS BEEN ASSESSED WITH MEDIUM CONFIDENCE BASED ON
SUBJECTIVE AGENCY DVORAK ESTIMATES STEADY AT T2.5.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE POSITIONED DIRECTLY TO THE NORTH AND NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 57 KTS AT 250100Z
   CIMSS AIDT: 49 KTS AT 250100Z
   CIMSS D-MINT: 35 KTS AT 242039Z
   CIMSS D-PRINT: 35 KTS AT 250100Z

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: THE FORECAST HAS BEEN LIMITED TO 48
HOURS AS TS 08W UNDERGOES A QUICK TRANSITION TO A SHALLOW,
COLD-CORE LOW INTO DISSIPATION.

FORECAST DISCUSSION: TS 08W IS FORECASTED TO CONTINUE TRACKING TO
THE NORTHWEST ALONG THE SOUTHWESTERN PERIPHERY OF THE STR
POSITIONED DIRECTLY TO THE NORTH AND NORTHEAST UNTIL TAU 12.
FOLLOWING TAU 12, THE SYSTEM IS EXPECTED TO TURN NORTHWARD ALONG
THE STR AXIS FOR A SHORT PERIOD, BEFORE BEGINNING TO TRACK
NORTH-NORTHEASTWARD UNTIL TAU 36. AFTER TAU 36, TS 08W WILL BEGIN
ITS TERMINAL NORTHEASTWARD TRACK ALONG THE WESTERN PERIPHERY OF THE
STR WHILE STARTING TO UNDERGO A SHORT PERIOD OF EXTRATROPICAL
TRANSITION, BEING PARTIALLY POSITIONED BELOW THE MID-LATITUDE JET
ALOFT. BETWEEN TAU 36 AND TAU 48, THE INCREASINGLY HOSTILE
ENVIRONMENT WITH VWS NEARING 30 KTS WILL INITIATE A SHARP
EXTRATROPICAL TRANSITION AS THE SYSTEM BECOMES FULLY ENVELOPED BY
THE MID-LATITUDE WESTERLIES ALOFT. INCREASED UPPER-LEVEL SUPPORT
WILL ASSIST IN SUSTAINING SURFACE INTENSITIES TOWARD 45 KTS BY TAU
48 AS TS 08W BECOMES A SHALLOW, SYMMETRIC COLD-CORE LOW. THE
POSSIBILITY FOR THE SURFACE CIRCULATION TO FILL INTO AN OPEN TROUGH
PERSISTS, HOWEVER, ELEVATED SURFACE INTENSITIES ARE FORECASTED TO
REMAIN UNTIL THE END OF THE FORECAST PERIOD. AS OF NOW, BINARY
INTERACTION BETWEEN TS 07W (MEKKHALA) AND TS 08W (HIGOS) CONTINUES
TO LOOK LESS LIKELY AS TS 08W APPROACHES THE MID-LATITUDE
WESTERLIES JUST TO THE NORTHEAST OF TS MEKKHALA. WHEN THIS OCCURS,
THE VORTICITY LOBE ASSOCIATED WITH TS 08W BEGINS TO ELONGATE AND
EJECT NORTHEASTWARD, AHEAD OF TS 07W. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN FAIR
AGREEMENT THROUGH TAU 24, WITH THE MAJORITY OF MODELS AGREEING ON A
NORTHWESTWARD TRACK TOWARD THE STR AXIS. FOLLOWING TAU 24,
NUMERICAL MODEL AND ARTIFICIAL INTELLIGENCE (AI) GUIDANCE STARTS TO
DIVERGE SIGNIFICANTLY, THROUGH CROSS-TRACK AND ALONG-TRACK SPREAD.
A FEW SOLUTIONS CHARACTERIZE A SHALLOWING AND LOSS OF THE VORTEX
PRIOR TO TAU 48, WHILE OTHERS ILLUSTRATE EXTRATROPICAL TRANSITION
AND EVENTUAL FILLING INTO AN OPEN TROUGH BETWEEN TAU 36 AND TAU 48.
THE JTWC TRACK FORECAST HAS BEEN PLACED WITH LOW CONFIDENCE DUE TO
UNCERTAINTIES WITH THE EXPECTED QUICK EXTRATROPICAL TRANSITION OR
COMPLETE DISSIPATION INTO AN OPEN TROUGH. REGARDING INTENSITY 
GUIDANCE, NUMERICAL GUIDANCE HAS CONTINUED TO ILLUSTRATE A FEW 
DIFFERENT POSSIBILITIES, WITH GFS AND HAFS-A INITIALLY SHOWING A 
SLIGHT WEAKENING TREND INTO TAU 12, WHILE COAMPS-TC INTENSIFIES TS 
08W INTO TAU 48. ADDITIONALLY, COAMPS-TC EPS INTENSITY TOOLS HAVE 
BEGUN TO ILLUSTRATE MODERATE INTENSIFICATION OVER THE NEXT 42 HOURS. 
THE OFFICIAL JTWC INTENSITY FORECAST HAS BEEN ANALYZED WITH LOW 
CONFIDENCE DUE TO UNCERTAINTIES DURING THE QUICK EXTRATROPICAL 
CYCLONE TRANSITION INTO DISSIPATION BETWEEN TAU 24 AND TAU 48.

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