WDPN31 PGTW 031500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (NANMADOL) 
WARNING NR 07//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 05W (NANMADOL), LOCATED APPROXIMATELY 284 NM
SOUTHWEST OF SASEBO, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 20
KNOTS OVER THE PAST SIX HOURS. TS 05W BRIEFLY DEVELOPED A SMALL EYE 
EVIDENT IN ENHANCED INFRARED IMAGERY AT 03/0830Z WITH DVORAK 
ESTIMATES OF T4.0 FROM KNES AND, UNOFFICIALLY, PGTW. SINCE THIS 
TIME, ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES A 
SLIGHT WEAKENING TREND WITH TIGHTLY-CURVED BANDING WRAPPING INTO A 
RAGGED CENTER. THE CURRENT POSITION IS BASED ON A 03/1226Z GPM 37GHZ 
MICROWAVE IMAGE, WHICH SHOWS A SMALL MICROWAVE EYE FEATURE. THE 
CURRENT INTENSITY IS ASSESSED AT 60 KNOTS BASED ON AN AVERAGE OF 
DVORAK ESTIMATES RANGING FROM T3.5 (55 KNOTS) TO T4.0 (65 KNOTS). 
UPPER-LEVEL ANALYSIS INDICATES ROBUST POLEWARD OUTFLOW ENHANCED BY 
THE MIDLATITUDE WESTERLIES TO THE NORTH. TS 05W IS TRACKING QUICKLY 
POLEWARD ALONG THE NORTHWESTERN EDGE OF THE DEEP SUBTROPICAL RIDGE 
(STR).
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY 
SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. 
   B. TS 05W IS FORECAST TO TRACK NORTHEASTWARD THROUGH TAU 12 AS IT 
ROUNDS THE NORTHWEST PERIPHERY OF THE STR AND BEGINS TO INTERACT 
WITH MIDLATITUDE WESTERLY FLOW. TS NANMADOL IS EXPECTED TO WEAKEN 
AFTER TAU 06 AS IT TRACKS OVER COOLER SST (26 TO 25C) AND APPROACHES 
THE WESTERN COAST OF KYUSHU. AFTER TAU 12, TS 05W SHOULD WEAKEN 
FURTHER AS IT BEGINS TO INTERACT WITH THE ROUGH TERRAIN OF 
KYUSHU. AFTER TAU 18, RAPID WEAKENING IS FORECAST AS THE SYSTEM 
TRACKS EAST-NORTHEASTWARD ACROSS KYUSHU, SHIKOKU AND HONSHU WHILE 
UNDERGOING EXTRA-TROPICAL TRANSITION (ETT). STRONG VERTICAL WIND 
SHEAR AND LAND INTERACTION WILL SERVE TO SIGNIFICANTLY WEAKEN THE 
SYSTEM BEFORE IT COMPLETES ETT BY TAU 36. THE DYNAMIC AIDS ARE IN 
UNUSUALLY TIGHT AGREEMENT FOR A RE-CURVE SCENARIO LENDING HIGH 
CONFIDENCE TO THE FORECAST TRACK.//
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