WDPN31 PGTW 212100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (DUJUAN) WARNING
NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 01W (DUJUAN), LOCATED APPROXIMATELY 390 NM 
SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 
12 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS SITUATED 
DOWNSTREAM FROM A WEAKENING LOW-LEVEL CIRCULATION CENTER EVIDENT IN  
211641Z AMSR2 36 GHZ IMAGERY. THE INTENSITY IS SET AT 25 KNOTS BASED 
ON 211216Z METOP-B AND 211313Z METOP-C PARTIAL ASCAT PASSES SHOWING 
A LIMITED AREA OF 20-25 KNOT WINDS EMBEDDED WITHIN THE NORTHEASTERN 
PORTION OF THE LOW LEVEL CIRCULATION. PATCHY DEEP CONVECTION IS 
DEVELOPING OVER THE PHILIPPINE ISLANDS, AHEAD OF THE SYSTEM, BUT IS 
NO LONGER PERSISTING OVER THE CIRCULATION CENTER. VERTICAL WIND 
SHEAR IS MINIMAL (5-10 KNOTS), SEA SURFACE TEMPERATURE IS WARM (28-
29C) AND WESTWARD AND POLEWARD DIFFLUENCE ARE UPPER-LEVEL ARE 
EVIDENT IN THE UPPER-LEVEL FLOW. TD 01W IS TRACKING WEST-
NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF EXPANSIVE SUBTROPICAL 
RIDGING TO THE NORTH. 
3. FORECAST REASONING.
   A. THE CURRENT ANALYSIS (211800Z) POSITION LIES NEAR THE 
PREVIOUSLY-ANALYZED (211200Z) POSITION, AND WELL TO THE EAST-
SOUTHEAST OF THE 211800Z LOCATION PREDICTED ON THE PREVIOUS 
FORECAST, DUE TO A RELOCATION OF LOW LEVEL CENTER ANALYSES BASED ON 
NEWLY AVAILABLE SATELLITE DATA AND SURFACE OBSERVATIONS. OTHERWISE, 
THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST AND NO CHANGE IN THE 
OVERALL FORECAST PHILOSOPHY FROM THE PREVIOUS WARNING.
   B. TD 01W WILL TRACK WEST-NORTHWESTWARD TO WESTWARD OVER THE 
CENTRAL PHILIPPINE ISLAND AND CONTINUE TO STEADILY DISSIPATE OVER 
THE NEXT 24 TO 36 HOURS AS VERTICAL WIND SHEAR INCREASES, ALONG-
TRACK SEA SURFACE TEMPERATURE DECREASES AND THE CIRCULATION 
INTERACTS OCCASIONALLY WITH LAND. NUMERICAL MODEL FORECAST GUIDANCE 
IS IN GOOD OVERALL AGREEMENT REGARDING THE SPEED AND DIRECTION OF TD 
01W ALONG THE SOUTHERN PERIPHERY OF CONTINUOUS SUBTROPICAL RIDGING 
TO THE NORTH. THERE IS HIGH CONFIDENCE IN THE CURRENT JTWC TRACK 
FORECAST.//
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