WDPN33 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 14W (FOURTEEN) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.0N 163.6E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 491 NM NORTH-NORTHWEST OF WAKE ISLAND
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY
EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION (LLCC) OF TROPICAL
DEPRESSION (TD) 14W. RELATIVELY FAVORABLE ENVIRONMENT CHARACTERIZED
BY A NARROW SLIVER OF AVAILABLE MOISTURE THROUGHOUT THE ATMOSPHERE,
COMBINED WITH GOOD EQUATORWARD OUTFLOW CHANNEL AND WARM (27-28 C)
SEA SURFACE TEMPERATURES (SST) ALLOWED THE SYSTEM TO DEVELOP A 25
KT BAND OF WINDS, PRIMARILY TO THE EAST, AS OBSERVED ON A 032219Z
METOP-C ASCAT PASS. NORTHEASTERLY VERTICAL WIND SHEAR (VWS) ALSO
REMAINS MARGINALLY FAVORABLE AT THE MOMENT, WITH 10-15 KTS
STRENGTH. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON A CLEARLY IDENTIFIABLE LLCC OBSERVED IN VISIBLE SATELLITE
IMAGERY. THE INITIAL INTENSITY OF 25 KTS IS ALSO ASSESSED WITH HIGH
CONFIDENCE BASED ON THE AFOREMENTIONED ASCAT PASS AND THE AGENCY
DVORAK FIXES LISTED BELOW.

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

CURRENT STEERING MECHANISM: WEAK STEERING SPLIT BETWEEN TWO 
SUBTROPICAL RIDGES (STR) TO THE WEST AND EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS
   CIMSS D-MINT: 25 KTS AT 031957Z
   CIMSS D-PRINT: 19 KTS AT 040000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR SURROUNDING THE SYSTEM

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TD 14W IS FORECAST TO TRACK GENERALLY
NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF A BUILDING STR TO THE
EAST. HOWEVER, CURRENT TRACK FORECAST CARRIES HIGH UNCERTAINTY DUE
TO WEAK STEERING MECHANISM ASSOCIATED WITH THE CURRENT POSITION OF
THE VORTEX BETWEEN TWO SUBTROPICAL RIDGES. NUMERICAL MODEL GUIDANCE
INDICATES THAT THE STR TO THE WEST WILL RETROGRADE WESTWARD, WHILE
THE STR TO THE EAST OF TD 14W WILL BUILD AND ASSUME STEERING WITHIN
THE NEXT 24 HOURS. AROUND THAT TIME, THE SYSTEM IS EXPECTED TO MAKE
A SHARPER POLEWARD TURN AND CONTINUE TRACKING ALONG THE WESTERN
PERIPHERY OF THE RIDGE. INTENSITY WISE TD 14W IS EXPECTED TO BE
SHORT-LIVED, DUE TO GRADUALLY WORSENING ENVIRONMENTAL CONDITIONS
ALONG ITS PATH, WITH VWS INCREASING TO OVER 30 KTS, SST COOLING TO
BELOW 26 C AFTER TAU 36, AS WELL AS INCREASED DRY AIR OVER AND
SURROUNDING THE SYSTEM. 

MODEL DISCUSSION: JTWC TRACK AND INTENSITY GUIDANCE ARE BOTH
ASSESSED WITH LOW CONFIDENCE, DUE TO HIGH UNCERTAINTY ASSOCIATED
WITH THE STEERING PATTERN ASSESSMENT BY THE AVAILABLE NUMERICAL
MODEL GUIDANCE. IN REGARD TO INTENSITY, HAFS, AS WELL AS
STATISTICAL-DYNAMICAL MODELS INDICATE POTENTIAL FOR INTENSIFICATION
REACHING A PEAK OF 35-40 KTS, HOWEVER DETERMINISTIC GFS AND
COAMPS-TC, AS WELL AS ENSEMBLE GUIDANCE INDICATE SLOW, BUT STEADY
WEAKENING UNTIL DISSIPATION. JTWC TRACK FORECAST EXTENDS OUT TO 48
HOURS, AT WHICH TIME MAJORITY OF THE MODEL GUIDANCE LOSES TRACK OF
THE VORTEX, PRIOR TO THE SYSTEM BEGINNING THE RECURVATURE MOTION
AROUND THE RIDGE AXIS.

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