Tropical Storm NANGKA Advisory mar, 14.07.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NANGKA) WARNING NR 43//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 11W (NANGKA), LOCATED APPROXIMATELY 290 NM WEST-
SOUTHWEST OF IWO TO, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST
SIX HOURS. RECENT MSI DEPICTS SPIRAL BANDS TIGHTLY WRAPPING INTO A
CLOUD-FILLED EYE.  ADDITIONALLY, THE MSI CONTINUES TO SHOW THINNING
CONVECTION ON THE NORTHERN SEMI-CIRCLE. THE CURRENT POSITION IS
BASED ON THE MSI AND CORRESPONDING SATELLITE FIXES FROM PGTW AND
RJTD WITH HIGH CONFIDENCE. THE CURRENT INTENSITY REMAINS 95 KNOTS
BASED ON AN OVERALL ASSESSMENT OF DVORAK CURRENT INTENSITY ESTIMATES
FROM ALL REPORTING AGENCIES. UPPER-LEVEL ANALYSIS INDICATES THE
SYSTEM IS LOCATED IN AN AREA OF LOW TO MODERATE (10 TO 15 KNOT) VWS
WITH RADIAL OUTFLOW AS EVIDENT ON THE WATER VAPOR IMAGERY. THE
CYCLONE IS TRACKING ALONG THE SOUTHWESTERN SIDE OF THE STEERING STR.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 11W WILL CONTINUE TO TRACK POLEWARD AS THE STEERING STR
BACKS TO THE EAST. BY TAU 48, THE STEERING STR IS EXPECTED TO
REBUILD, FORCING TY NANGKA WEST-NORTHWESTWARD. FAVORABLE CONDITIONS
WILL PERSIST; HOWEVER, THE NORTHERN SEMI-CIRCLE WILL BE IMPACTED BY
THE HIGH PRESSURE TO THE NORTH. THEREFORE, TY NANGKA IS EXPECTED TO
STEADILY INTENSIFY OVER THE NEXT 48 HOURS. AFTERWARD INCREASING VWS
AND DECREASING ENVIRONMENTAL CONDITIONS WILL BEGIN TO WEAKEN THE
SYSTEM AS IT APPROACHES THE SOUTHERN COAST OF JAPAN.
   C. BY TAU 72, TY NANGKA IS EXPECTED TO TRACK OVER THE SOUTHERN
ISLANDS OF JAPAN. TY 11W WILL ROUND THE RIDGE AXIS AND TRACK
NORTHEASTWARD ALONG THE NORTHWESTERN EDGE OF THE STEERING STR. MODEL
GUIDANCE CONTINUES TO SHOW A SIGNIFICANT SPREAD AT TAU 72. DUE TO
THE UNCERTAINTY IN THE EXTENT OF THE STR AND DIFFERENCES IN THE
TRACK SPEEDS, THE OVERALL JTWC FORECAST REMAINS LOW.//
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