WDPN31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (AERE) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.5N 130.3E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 181 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTION FLARING ALONG THE NORTHERN PERIPHERY OF A
PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER. ANIMATED WATER
VAPOR IMAGERY AND UPPER-LEVEL ATMOSPHERIC MOTION VECTORS INDICATE
THAT A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) IS FIRMLY
ENTRENCHED ABOVE THE LOW-LEVEL CIRCULATION, INDUCING UNFAVORABLE
VERTICAL WIND SHEAR AND UPPER-LEVEL SUBSIDENCE OVER THE CENTER.
BECAUSE OF THESE UNFAVORABLE INFLUENCES, THE DEEPEST CONVECTION AND
STRONGEST WIND SPEEDS ASSOCIATED WITH TS 05W REMAIN DISPLACED TO
THE NORTH AND EAST OF THE CIRCULATION CENTER, WHERE UPPER-LEVEL
FLOW IS DIVERGENT. THE INITIAL POSITION IS PLACED ON THE
PARTIALLY-EXPOSED LOW LEVEL CIRCULATION CENTER WITH MEDIUM
CONFIDENCE BASED ON RECENT SATELLITE FIXES FROM PGTW AND RJTD AND
RADAR FIXES FROM JAPAN. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON A 011730Z PGTW DVORAK ANALYSIS OF
T3.0 AND PERSISTENCE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 34 KTS AT 012340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: TUTT OVER THE LOW-LEVEL CIRCULATION CENTER

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 05W WILL TRACK GENERALLY WEST-NORTHWESTWARD
FOR THE NEXT 36 HOURS UNDER THE CONTINUED INFLUENCE OF THE DEEP
LAYER SUBTROPICAL STEERING RIDGE TO THE EAST. THE SYSTEM WILL SLOW
AS IT ROUNDS THE RIDGE AXIS, BETWEEN TAU 36 AND TAU 48, AND
ACCELERATE AS IT MOVES ALONG THE NORTHERN PERIPHERY OF THE STEERING 
RIDGE IN THE EXTENDED PERIOD. NEAR TERM INTENSITY CHANGE WILL BE
LIMITED BY THE TUTT ALOFT, AND THE STRONGEST WINDS AND CONVECTION 
WILL REMAIN CONFINED TO THE EASTERN AND NORTHERN PORTIONS OF THE
CIRCULATION. STEADY WEAKENING IS ANTICIPATED IN THE EXTENDED PERIOD 
DUE TO PASSAGE OVER COOLER WATER, LAND INTERACTION AND AN 
UNFAVORABLE 
UPPER-LEVEL FLOW PATTERN. THE SYSTEM MAY ENCOUNTER MID-LATITUDE 
BAROCLINIC FLOW DURING THE EXTENDED PERIOD, BUT IT IS TOO SOON TO 
TELL WHETHER THE SYSTEM WILL DISSIPATE, AS SOME MODEL SOLUTIONS 
SUGGEST, OR TRANSITION INTO A SUBTROPICAL OR EXTRATROPICAL SYSTEM.

MODEL DISCUSSION: TRACK AND INTENSITY MODEL FORECAST GUIDANCE
REMAINS IN GENERALLY GOOD AGREEMENT THROUGH TAU 36. THEREAFTER,
DETERMINISITC AND ENSEMBLE MODEL GUIDANCE DIVERGES WITH THE NAVGEM,
JGSM AND UKMET GLOBAL ENSEMBLE MEAN SOLUTIONS INDICATING A TRACK
CURVING TO THE SOUTH OF HONSU AND THE OTHER CONSENSUS MODELS
CARRYING THE SYSTEM FARTHER TO THE WEST. A FEW ENSEMBLE MODEL
MEMBERS STILL INDICATE THAT MORE POLEWARD TRACKS INTO THE YELLOW
SEA OR SEA OF JAPAN ARE POSSIBLE, BUT NO CONSENSUS MODEL SUPPORTS
THAT OUTCOME. SOLUTIONS HAVE SETTLED TOWARD NORTHEASTWARD CURVATURE
OVER OR NEAR HONSHU ON THE LATEST RUN, ALBEIT WITH VARYING
ORIENTATIONS AND TRACK SPEEDS THAT LOWER CONFIDENCE IN THE EXTENDED
FORECAST TRACK. INTENSITY GUIDANCE, ON THE OTHER HAND, IS IN GOOD
AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH COMPETING INFLUENCES
HOLDING INTENSITY NEARLY STEADY IN THE NEAR-TERM AND INCREASINGLY
UNFAVORABLE CONDITIONS DRIVING WEAKENING BY TAU 72.

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