Tropical Storm TAPAH Advisory mar, 29.04.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (TAPAH) WARNING NR 07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 06W (TAPAH), LOCATED APPROXIMATELY 97 NM EAST-
NORTHEAST OF SAIPAN, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS CONVECTIVE
BANDS HAVE WRAPPED TIGHTER INTO THE LOW LEVEL CIRCULATION CENTER AS
THE CENTRAL CONVECTION HAS CONTINUED TO DEEPEN, PUNCTUATED BY THE
APPEARANCE OF A DIMPLE FEATURE - PRELUDE TO THE FORMATION OF AN EYE.
THE INITIAL POSITION IS BASED ON THE ABOVE ANIMATION AND
EXTRAPOLATED FROM A MICROWAVE EYE ON A 282214Z SSMI-S PASS WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY IS BASED ON THE 282230Z DVORAK
ESTIMATE FROM PGTW. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH LOW (05 TO 10 KNOT) VERTICAL WIND SHEAR (VWS) AND
GOOD POLEWARD OUTFLOW. TY 06W IS TRACKING NORTHWARD ALONG THE
WESTERN EDGE OF A MID-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
   B. TY 06W IS FORECAST TO TRACK NORTHWARD THROUGH TAU 12 THEN
NORTHWESTWARD AS THE STR BUILDS. AFTER TAU 48, THE CYCLONE WILL
CREST THE RIDGE AXIS AND TURN MORE NORTHWARD. THERE IS A 12-18 HOUR
WINDOW OF CONTINUED FAVORABLE CONDITIONS FOR THE SYSTEM TO FURTHER
INTENSIFY, PEAKING AT 70 KNOTS BEFORE INCREASING VWS, DIMINISHING
OUTFLOW, AND COOLING SEA SURFACE TEMPERATURES (SSTS) BEGIN TO ERODE
THE CYCLONE.
   C. IN THE EXTENDED TAUS, TY TAPAH IS FORECAST TO RE-CURVE
NORTHEASTWARD AHEAD OF AN APPROACHING SHORTWAVE TROUGH. INCREASING
VWS, DECREASING SSTS, AND INTERACTION WITH THE COLD BAROCLINIC ZONE
WILL RAPIDLY WEAKEN THE SYSTEM, DISSIPATING IT BY TAU 96. THE
DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT. THE TRACK FORECAST
IS LAID EAST OF THE MULTI-MODEL CONSENSUS TO OFFSET LESS LIKELY
WESTWARD OUTLIERS. DUE TO THE TIGHT GROUPING OF MODEL GUIDANCE,
THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.  //
NNNN
NNNN