WDPN31 PGTW 302100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (FIVE) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.9N 130.2E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 417 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 11 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TD 05W APPEARS TO HAVE SLOWED DOWN IN TRACK SPEED OVER THE LAST 6
HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
BUILDING MASS OF CONVECTION WITH FRAGMENTED BANDING WRAPPING INTO
AN ASSESSED LOW LEVEL CIRCULATION CENTER. LACK OF AVAILABLE
MICROWAVE IMAGERY DURING THIS WARNING CYCLE MADE IT DIFFICULT TO
PLACE, SO THE INITIAL POSITION IS LAID WITH LOW CONFIDENCE BASED
OFF EIR LOOP AND MULTI-AGENCY FIXES. THE INITIAL INTENSITY OF 30
KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON IMPROVING STRUCTURE
OF THE SYSTEM AND A COMBINATION OF AGENCY AND AUTOMATED DVORAK
ESTIMATES.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 30 KTS AT 302102Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EASTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TD 05W IS FORECAST TO TRACK NORTH-NORTHWEST
UNDER THE STEERING INFLUENCE OF STR TO THE NORTHEAST. CURRENTLY THE
SYSTEM IS UNDER A MARGINALLY FAVORABLE ENVIRONMENT DEFINED BY WARM
SEA SURFACE TEMPERATURES (SST) (29-30C) AND MODERATE OUTFLOW ALOFT
ENHANCED BY THE TUTT CELL TO THE NORTHWEST SLIGHTLY OFFSET BY
MODERATE VERTICAL WIND SHEAR (20-25 KTS). THIS ENVIRONMENT IS
FORECAST TO STEADILY INCREASE TO PEAK INTENSITY OF 50 KTS BY TAU
36, BEFORE PASSING OVER OKINAWA. BETWEEN TAU 48 AND TAU 72 AS THE
SUBTROPICAL RIDGE IS BROKEN DOWN BY A PASSING MID-LATITUDE TROUGH
THE SYSTEM WILL BEGIN TO TRACK NORTH-NORTHWESTWARD AND EVENTUALLY
NORTHWARD AS SIGNIFICANT AMOUNTS OF DRY AIR BEGIN TO ENTRAIN THE
SYSTEM. THROUGH THE REMAINING FORECAST PERIOD, AS THE SYSTEM
CONTINUES TO APPROACH THE STR AXIS SEA SURFACE TEMPERATURES DROP
(24-25C) AND SIGNIFICANT DRY AIR ENTRAINMENT IS FORECAST TO BEGIN
DISSIPATING 05W. BY TAU 120 THE SYSTEM IF FORECAST TO BE FULLY
ENTRAINED BY DRY AIR AND NEARING FULL DISSIPATION.

MODEL DISCUSSION: NUMERICAL MODELS CONTINUE TO BE IN FAIR
AGREEMENT, CONTINUING THE JTWC FORECAST TRACK BEING PLACED WITH
MEDIUM CONFIDENCE. INTENSITY GUIDANCE REMAINS CONSISTENT WITH THE
PREVIOUS FORECAST WITH ONE NOTABLE CHANGE OF TD 05W REACHING ITS
PEAK INTENSITY BY TAU 36 JUST BEFORE PASSING OVER OKINAWA DUE TO
THE IMPROVING ENVIRONMENT. MODELS ALSO AGREE WITH A DISSIPATING
TREND AS THE SYSTEM MAKES THE TURN TO THE NORTHEAST AFTER PASSING
30N. OVERALL CONFIDENCE IN THE INTENSITY FORECAST REMAINS MEDIUM.

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