WDPN31 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (TRAMI) WARNING 
NR 033//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.0N 108.6E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 17 NM EAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 8 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY-
EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH NO ASSOCIATED DEEP 
CONVECTION. THE INITIAL POSITION OVER WATER IS PLACED WITH HIGH 
CONFIDENCE BASED ON THE EIR IMAGERY. SURFACE OBSERVATIONS FROM DA
NANG (VVDN) INDICATE VARIABLE WINDS WITH SLP NEAR 1004MB. THE
OBSERVED SLP CORRESPONDS TO A WEAK TROPICAL DEPRESSION OR TROPICAL
DISTURBANCE STRENGTH SYSTEM (20-25 KNOTS) ON THE KNAFF-ZEHR WIND
PRESSURE RELATIONSHIP (WPR) CHART. THE INITIAL INTENSITY OF 25 KTS
IS ASSESSED CONSERVATIVELY WITH MEDIUM CONFIDENCE BASED ON THE
MINIMUM SEA LEVEL PRESSURE AT DA NANG, CONSISTENT WITH THE
RELATIVELY WEAK LOW-LEVEL STRUCTURE.

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

CURRENT STEERING MECHANISM: LOW-LEVEL SOUTHWESTERLY FLOW ALONG THE
NORTHWESTERN PERIPHERY OF THE NEAR-EQUATORIAL RIDGE (NER).

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TROPICAL DEPRESSION (TD) 22W IS SITUATED WITHIN 
AN UNFAVORABLE ENVIRONMENT, UNDER UPPER-LEVEL CYCLONIC FLOW, WITH 
MODERATE TO HIGH VERTICAL WIND SHEAR AND WEAK POLEWARD OUTFLOW. 
CONSEQUENTLY, TD 22W IS NOT EXPECTED TO INTENSIFY SIGNIFICANTLY 
THROUGH THE FORECAST PERIOD. THE SYSTEM SHOULD STEER GENERALLY 
EASTWARD TO SOUTHEASTWARD ALONG THE NORTHERN PERIPHERY OF THE NER AND 
WILL LIKELY DISSIPATE BY TAU 36 UNDER THE UNFAVORABLE CONDITIONS.    

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC MODEL GUIDANCE
SUPPORTS THE JTWC TRACK FORECAST WITH MEDIUM CONFIDENCE. RELIABLE
INTENSITY GUIDANCE SUPPORTS THE GRADUAL WEAKENING AND DISSIPATION
OF THE SYSTEM BETWEEN TAU 36 TO TAU 48.

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