WDPN33 PGTW 050300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W WARNING NR 32//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TROPICAL DEPRESSION (TD) 22W (NALGAE), LOCATED APPROXIMATELY 
180 NM SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED SOUTHWEST AT 06 
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) SHOWS A FULLY EXPOSED WEAKENING LOW LEVEL CIRCULATION 
CENTER (LLCC) AND A 042245Z SSMIS 37 GHZ IMAGE SHOWS WEAK, ERODING 
LOW LEVEL CURVATURE. THE INITIAL POSITION IS BASED ON THE MSI AND 
SSMIS IMAGE WITH POOR CONFIDENCE DUE TO THE DISORGANIZED STRUCTURE 
OF THE WEAKENING LLCC. THE INITIAL INTENSITY IS BASED ON AGENCY 
DVORAK ESTIMATES OF 25 TO 35 KNOTS. SOUNDINGS FROM THE AREA AT 
041200Z INDICATE THAT EASTERLY FLOW REMAINS TO THE NORTH OF THE 
SYSTEM, THEREFORE INDICATING THAT TD 22W CONTINUES TO BE STEERED BY 
THE SOUTHERN PERIPHERY OF A DEEP LAYER SUBTROPICAL STEERING RIDGE.
TD 22W CONTINUES TO ENCOUNTER MODERATE (20 KNOT) VERTICAL WIND SHEAR 
(VWS).     
3.  A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY.
    B. TD 22W WILL CONTINUE TO STEER ALONG THE SOUTHWESTERN 
PERIMETER OF THE SUBTROPICAL RIDGE AND CONTINUE TO WEAKEN AS IT MAKES
LANDFALL BY TAU 24. TD 22W WILL THEN DISSIPATE OVER VIETNAM BY TAU 
36. THE CONSENSUS OF MODEL GUIDANCE CONTINUES TO BE DEGRADED BY THE 
ECMWF AND GFDN TRACKERS WHICH PICK UP ON LOW LEVEL VORTICITY OVER 
THE SOUTH CHINA SEA AND THEREFORE BRING NALGAE ON A UNLIKELY 
SOUTHEASTERN TRACK BACK OVER THE OPEN WATERS OF THE SOUTH CHINA SEA. 
WBAR CONTINUES TO BE THE RIGHT MOST OUTLIER OF THE AIDS. THIS 
FORECAST IS SLIGHTLY SOUTH OF CONSENSUS AND FASTER BEFORE LANDFALL.//
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