WDPN31 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (AERE) WARNING 
NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.2N 126.8E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 277 NM SOUTH-SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION WITH DEEP CONVECTION
BEGINNING TO REDEVELOP OVER THE SOUTHEASTERN PERIPHERY. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON RECENT
SATELLITE POSITION FIXES FROM RJTD AND PGTW PLACED WITHIN THE
EXPOSED LOW-LEVEL CENTER. THE INITIAL INTENSITY OF 30 KTS IS
ASSESSED WITH HIGH CONFIDENCE BASED ON A CONSENSUS OF SUBJECTIVE
DVORAK CURRENT INTENSITY AND AUTOMATED SATELLITE INTENSITY
ESTIMATES. ANIMATED WATER VAPOR IMAGERY AND ATMOSPHERIC MOTION
VECTOR DATA INDICATES THAT AN TROPICAL UPPER-LEVEL TROUGH THAT HAS
BEEN PRESENT OVER THE CIRCULATION FOR THE PAST TWO DAYS IS FILLING
AND BECOMING LESS DEFINED. CONSEQUENT CHANGES IN THE UPPER-LEVEL
FLOW PATTERN, INCLUDING ENHANCED OUTFLOW ALOFT, ARE ENABLING
CONVECTION TO REDEVELOP OVER THE CIRCULATION.

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

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE TO THE
EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.0 - 30 KTS
   CIMSS SATCON: 32 KTS AT 031342Z
   CIMSS ADT: 25 KTS AT 031740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 25-30 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: TROPICAL UPPER TROPOSPHERIC TROUGH OVER THE
LOW-LEVEL CIRCULATION

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 WILL TURN NORTHEASTWARD TO EASTWARD
OVER THE NEXT 48 HOURS AS IT TRACKS AROUND THE NORTHWESTERN AND
NORTHERN PERIPHERIES OF THE CURRENT SUBTROPICAL STEERING RIDGE. THE
SYSTEM WILL CONTINUE TO FOLLOW THE FLOW ASSOCIATED WITH THE
SUBTROPICAL RIDGE EASTWARD UNTIL TAU 96, BY WHICH TIME IT IS
EXPECTED TO MERGE WITH A DEVELOPING MIDLATITUDE SHORTWAVE TROUGH AND
SLOW SIGNIFICANTLY OFF THE EAST COAST OF HONSHU. IN THE NEAR-TERM,
TD 05W IS UNLIKELY TO INTENSIFY PRIOR TO LANDFALL AS PERSISTENT
VERTICAL WIND SHEAR OFFSETS THE FAVORABLE INFLUENCES OF IMPROVING
UPPER-LEVEL DIFFLUENCE AND CONVECTIVE DEVELOPMENT NEAR AND OVER THE
CIRCULATION. SLIGHT WEAKENING IS ANTICIPATED AFTER TAU 24 AS THE
SYSTEM PASSES OVER LAND. BY TAU 72, TD 05W SHOULD REEMERGE OVER
WATER TO THE EAST OF HONSHU. FAVORABLE BAROCLINIC INTERACTION WITH
THE AFOREMENTIONED SHORTWAVE TROUGH, WHICH IS EXPECTED TO REMAIN
CUTOFF FROM THE PRIMARY WESTERLY FLOW PATTERN, WILL ALLOW TD 05W TO
INTENSIFY AS IT UNDERGOES SUBTROPICAL TRANSITION.

MODEL DISCUSSION: ASIDE FROM THE JGSM MODEL, WHICH INDICATES A
TRACK FARTHER TO THE SOUTH OF HONSHU, THE NUMERICAL MODELS ARE IN
GOOD AGREEMENT WITH THE CURRENT FORECAST SCENARIO THROUGH TAU 120.
HOWEVER, THERE IS STILL SOME SPREAD IN THE ORIENTATION OF THE TRACK
AND FORWARD TRACK SPEEDS AS THE SYSTEM ROUNDS THE RIDGE AXIS AND IN
THE DIRECTION OF MOTION FOLLOWING SUBTROPICAL TRANSITION LATE IN
THE FORECAST PERIOD, SO OVERALL CONFIDENCE IN THE TRACK FORECAST IS
MEDIUM. WITH INTENSITY CHANGE CONSTRAINED TO A NARROW RANGE BY
OFFSETTING INFLUENCES THROUGH TAU 72, INTENSITY FORECAST CONFIDENCE
IS HIGH IN THE NEAR-TERM. INTENSITY DURING AND AFTER SUBTROPICAL
TRANSITION WILL DEPEND ON THE EXACT NATURE OF THE INTERACTION
BETWEEN TD 05W AND THE DEVELOPING SHORTWAVE TROUGH, AND SPREAD IN
THE INTENSITY GUIDANCE INCREASES DURING THAT PERIOD, SO INTENSITY
FORECAST CONFIDENCE FOR THE EXTENDED PERIOD IS MEDIUM.

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